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Reports of symptomatic rebound and/or test re-positivity among COVID-19 patients following the standard five-day treatment course of nirmatrelvir/ritonavir have sparked debates regarding optimal treatment timing and dosage. It is unclear whether initiating nirmatrelvir/ritonavir immediately after symptom onset would improve clinical outcomes and/or lead to post-treatment viral burden rebound due to inadequate viral clearance during treatment. Here we show that, by emulating a randomized target trial using real-world electronic medical record data from all 87,070 adult users of nirmatrelvir/ritonavir in Hong Kong between 16th March 2022 and 15th January 2023, early initiation of nirmatrelvir/ritonavir treatment (0 to 1 days after symptom onset or diagnosis) significantly reduced the incidence of 28-day all-cause mortality and hospitalization compared to delayed initiation (2 or more days) (absolute risk reduction [ARR]: 1.50% (95% confidence interval 1.17-1.80%); relative risk [RR]: 0.77 (0.73, 0.82)), but may be associated with a significant elevated risk of viral burden rebound (ARR: −1.08% (−1.55%, −0.46%)), although the latter estimates were associated with high uncertainty due to limited sample sizes. As such, patients should continue to initiate nirmatrelvir/ritonavir early after symptom onset or diagnosis to better protect against the more serious outcomes of hospitalization and mortality. Nirmatrelvir/ritonavir can reduce COVID-19 severity when initiated within five days of symptom onset but the optimal timing within this window is unknown. Here, the authors emulate a randomised trial using electronic health records from Hong Kong and find evidence for a benefit of early treatment initiation. [ABSTRACT FROM AUTHOR]

Background: Elevations in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were reported as adverse events of nirmatrelvir/ritonavir users in the EPIC‐HR trial. Aim: To quantify the risk and severity of acute liver injury (ALI) associated with nirmatrelvir/ritonavir use. Methods: This self‐controlled case‐series study was conducted using electronic medical records of patients with confirmed diagnosis of SARS‐CoV‐2 infection between 26th February 2022 and 12th February 2023 in Hong Kong. Results: Among 2 409 848 patients with SARS‐CoV‐2 infection during the study period, 153 853 were prescribed with nirmatrelvir/ritonavir, of whom 834 (.5%) had incident ALI (moderate: 30.5%; moderate to severe: 18.9%; severe or fatal: 5.8%). Compared with the non‐exposure period, risk of ALI increased significantly during the pre‐exposure period (IRR = 38.13, 95% CI = 29.29–49.62) and remained elevated during the five‐day nirmatrelvir/ritonavir treatment (IRR = 20.75, 95% CI = 17.06–25.25) and during wash‐out period (IRR = 16.27, 95% CI = 13.23–20.01). Compared to the pre‐exposure period, risk of ALI was not increased during the five‐day nirmatrelvir/ritonavir treatment period (IRR =.54, 95% CI =.43–.70). Compared to 5469 non‐nirmatrelvir/ritonavir users with incident ALI, nirmatrelvir/ritonavir users had less severe ALI by the severity index (p <.001) and peak INR (1.7 vs. 2.3; p <.001). ALI cases with nirmatrelvir/ritonavir use had lower risk of all‐cause death (29.1% vs. 39.1%; OR =.64; p <.001) and no increase in risk of liver decompensation (1.0% vs. 1.3%; OR =.62; p =.230) compared to non‐users. Conclusion: The risk of ALI associated with nirmatrelvir/ritonavir treatment for COVID‐19 was elevated in the pre‐exposure period, but not following nirmatrelvir/ritonavir initiation. ALI following nirmatrelvir/ritonavir treatment were mostly mild and less severe than ALI events in non‐nirmatrelvir/ritonavir users. [ABSTRACT FROM AUTHOR]

Background: With increasing hypercholesterolemia prevalence in East Asian adolescents, pharmacologic interventions (e.g., HMGCR inhibitors (statins) and PCSK9 inhibitors) may have to be considered although their longer-term safety in the general adolescent population is unclear. This study aims to investigate the longer-term safety of HMGCR inhibitors and PCSK9 inhibitors among East Asian adolescents using genetics. Methods: A drug-target Mendelian randomization study leveraging the Global Lipid Genetics Consortium (East Asian, n = 146,492) and individual-level data from Chinese participants in the Biobank clinical follow-up of Hong Kong's "Children of 1997" birth cohort (n = 3443, aged ~ 17.6 years). Safety outcomes (n = 100) included anthropometric and hematological traits, renal, liver, lung function, and other nuclear magnetic resonance metabolomics. Positive control outcomes were cholesterol markers from the "Children of 1997" birth cohort and coronary artery disease from Biobank Japan. Results: Genetic inhibition of HMGCR and PCSK9 were associated with reduction in cholesterol-related NMR metabolomics, e.g., apolipoprotein B (HMGCR: beta [95% CI], − 1.06 [− 1.52 to − 0.60]; PCSK9: − 0.93 [− 1.56 to − 0.31]) and had the expected effect on the positive control outcomes. After correcting for multiple comparisons (p-value < 0.006), genetic inhibition of HMGCR was associated with lower linoleic acid − 0.79 [− 1.25 to − 0.35]. Genetic inhibition of PCSK9 was not associated with the safety outcomes assessed. Conclusions: Statins and PCSK9 inhibitors in East Asian adolescents appeared to be safe based on the outcomes concerned. Larger studies were warranted to verify these findings. This study serves as a proof of principle study to inform the medication safety among adolescents via genetics. [ABSTRACT FROM AUTHOR]

We described the frequency of residential case clusters and the efficiency of compulsory testing in identifying cases using buildings targeted in compulsory testing and locally infected coronavirus disease 2019 (COVID-19) cases matched by residence in Hong Kong. Most of the buildings (4246 of 7688, 55.2%) with COVID-19 cases identified had only 1 reported case, and 13% of the daily reported cases were detected through compulsory testing. Compulsory testing notices could be essential in attempting to eliminate infections ("zero COVID") and have an impact early in an epidemic, but they appear to be relatively inefficient in response to sustained community transmission. [ABSTRACT FROM AUTHOR]

There has long been controversy over the potential for asymptomatic cases of the influenza virus to have the capacity for onward transmission, but recognition of asymptomatic transmission of COVID-19 stimulates further research into this topic. Here, we develop a Bayesian methodology to analyze detailed data from a large cohort of 727 households and 2515 individuals in the 2009 pandemic influenza A(H1N1) outbreak in Hong Kong to characterize household transmission dynamics and to estimate the relative infectiousness of asymptomatic versus symptomatic influenza cases. The posterior probability that asymptomatic cases [36% of cases; 95% credible interval (CrI): 32%, 40%] are less infectious than symptomatic cases is 0.82, with estimated relative infectiousness 0.57 (95% CrI: 0.11, 1.54). More data are required to strengthen our understanding of the contribution of asymptomatic cases to the spread of influenza. [ABSTRACT FROM AUTHOR]

Breastfeeding is widely promoted. Experimental evidence concerning long-term benefits is limited. Observational studies are open to bias from confounding by socio-economic position. We assessed the association of breastfeeding with late adolescent lipid sub-fractions, particularly apolipoprotein B (ApoB) and non-high-density lipoprotein cholesterol (non-HDL-c), overall and by sex. We took advantage of a setting where breastfeeding has little association with higher socio-economic position and where several results from randomized controlled trials of breastfeeding promotion have been replicated. We used the population-representative "Children of 1997" birth cohort comprising 88% of births in Hong Kong in April and May 1997. Associations of breastfeeding in the first 3 months of life (never, mixed, exclusive) with lipid sub-fractions were obtained using linear regression adjusted for potential confounders including parental socio-economic position, maternal place of birth, type of delivery, gestational age, and birth weight. Differences by sex were assessed. Multiple imputation and inverse probability weighting were used to recover the original sample. Of the 3462 participants included, mean age was 17.6 years and 48.8% were girls. Mean ApoB was 0.74 g/L (standard deviation 0.15). Exclusive versus never breastfeeding was associated with lower ApoB (−0.027 g/L, 95% confidence interval (CI)−0.046 to−0.007, p = 0.007) and lower non-HDL-c (−0.143 mmol/L, 95% CI−0.237 to−0.048) with similar estimates by sex. Conclusion: Breastfeeding may provide some population-level lifelong protection against cardiovascular disease. This study supports policies promoting breastfeeding as a modifiable exposure that contributes to a healthy start in life as an investment for lifelong cardiovascular disease prevention. What is Known: • Apolipoprotein B (ApoB) is a recognized risk factor for cardiovascular disease, but whether breastfeeding affects ApoB in later life overall and by sex is unknown. What is New: • Exclusive breastfeeding in the first 3 months of life was associated with lower ApoB in late adolescence, with similar estimates for both sexes. • The inverse association of breastfeeding with ApoB suggests that breastfeeding could reduce cardiovascular disease and overall mortality over the lifespan. [ABSTRACT FROM AUTHOR]

Hong Kong experienced a surge of Omicron BA.2 infections in early 2022, resulting in one of the highest per-capita death rates of COVID-19. The outbreak occurred in a dense population with low immunity towards natural SARS-CoV-2 infection, high vaccine hesitancy in vulnerable populations, comprehensive disease surveillance and the capacity for stringent public health and social measures (PHSMs). By analyzing genome sequences and epidemiological data, we reconstructed the epidemic trajectory of BA.2 wave and found that the initial BA.2 community transmission emerged from cross-infection within hotel quarantine. The rapid implementation of PHSMs suppressed early epidemic growth but the effective reproduction number (Re) increased again during the Spring festival in early February and remained around 1 until early April. Independent estimates of point prevalence and incidence using phylodynamics also showed extensive superspreading at this time, which likely contributed to the rapid expansion of the epidemic. Discordant inferences based on genomic and epidemiological data underscore the need for research to improve near real-time epidemic growth estimates by combining multiple disparate data sources to better inform outbreak response policy. Hong Kong experienced a large wave of COVID-19 in early 2022 driven by Omicron BA.2. Here, the authors describe the epidemiological dynamics of this wave and show discordant inferences based on genomic and epidemiological data that underscore the need to improve near real-time epidemic growth estimates. [ABSTRACT FROM AUTHOR]

Background Rapid growth is related to adverse respiratory outcomes although possibly confounded or limited by growth modelling methods. We investigated the association of infant and pubertal growth with lung function, wheezing and asthma in a non-Western setting. Methods In Hong Kong's 'Children of 1997' Chinese birth cohort (n  = 8327), weight during infancy and weight, height and body mass index (BMI) during puberty were modelled using a super-imposition by translation and rotation model to identify (larger or smaller) size, (earlier or later) tempo and (slower or faster) velocity. Sex-specific associations with forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC (Global Lung function Initiative z-score) and self-reported wheezing and asthma at ∼17.5 years were assessed. Results For each fraction higher than average weight growth velocity during infancy, FVC was higher in boys (0.90 SD, 95% CI 0.35; 1.44) and girls (0.77 SD, 95% CI 0.24; 1.30), FEV1/FVC was lower (–0.74 SD, 95% CI –1.38; –0.10) and wheezing was higher (odds ratio 6.92, 95% CI 1.60; 29.99) in boys and an inverse association with FVC was observed for tempo but not for size. Associations for weight growth velocity in puberty were similar but weaker. Greater size and higher velocity of BMI growth was associated with higher FVC, lower FEV1/FVC and higher asthma and wheezing risk. Conclusion Accelerated infant and pubertal weight growth were associated with disproportionate lung size and airway growth, and higher risk of asthma; optimizing early-life growth patterns could be important. [ABSTRACT FROM AUTHOR]

Influenza vaccination is an important intervention to prevent influenza virus infection. Our previous analysis suggested that indirect protection is limited in an influenza B epidemic in Hong Kong. We further analyzed six influenza A epidemics to determine such potential. We applied a statistical model to estimate household transmission dynamics in the 3 influenza A(H3N2) and 3 pandemic influenza A(H1N1) epidemics. Then, we estimated the reduction in infection risk among unvaccinated household members when all children in households are vaccinated, with different assumptions on vaccine efficacy (VE). In the optimal scenario that VE was 70%, the reduction to the total probability of infection was only marginal, with relative probabilities ranged from 0.91–0.94 when all children in households were vaccinated because community was by far the main source of infection during the six epidemics in our study. The proportion of cases attributed to household transmission was 10% (95% CrI: 7%, 13%). Individual influenza vaccination is important even when other household members are vaccinated, given the degree of indirect protection is small. [ABSTRACT FROM AUTHOR]

Background and Aims: Hong Kong reduced beer and wine tax in 2007, eliminated taxes on beer and wine and strengthened drink‐driving legislation in 2008, and increased police traffic enforcement after the 2014 social unrest. This study aimed to measure the effects of implementing road safety policies on road traffic harm in the context of deregulated alcohol control policy in Hong Kong. Design: Population‐based interrupted time series analysis using seasonal autoregressive integrated moving average (sARIMA) models. Multiple sensitivity analyses were conducted. Setting: Hong Kong, China and Singapore from January 2004 to December 2019. Cases A total of 313 728 road traffic injuries in Hong Kong and 163 773 road traffic injuries in Singapore as controls. Measurements Monthly rates of road traffic injuries, non‐fatal injuries and serious/fatal injuries from Hong Kong and Singapore Police Force. Findings The elimination of alcohol taxes and the enactment of road safety legislation in 2008 were associated with immediate reductions in total road traffic injuries of 6.71% (95% CI, 1.99%–11.20%), serious/fatal injuries of 13.80% (95% CI, 1.85%–24.30%) and sustained declines in drink‐driving and collisions involving drink‐driving. The effects of the 2007 tax reduction were inconclusive. Progressively increasing traffic enforcement was associated with continuous reductions in road traffic injuries by 0.21% per month (95% CI, 0.13%–0.30%), and serious/fatal injuries by 1.10% per month (95% CI, 0.85%–1.35%). Effects at the corresponding timepoints in Singapore did not reach statistical significance; the results were inconclusive regarding confounding effects on both regions. Conclusions: Despite weakened alcohol control and increased alcohol sales over the same period, road safety policies in Hong Kong are associated with net reductions in road traffic injuries, particularly serious/fatal injuries. [ABSTRACT FROM AUTHOR]

Background Testing of an entire community has been used as an approach to control coronavirus disease 2019 (COVID-19). In Hong Kong, a universal community testing program (UCTP) was implemented at the fadeout phase of a community epidemic in July to September 2020. We described the utility of the UCTP in finding unrecognized infections and analyzed data from the UCTP and other sources to characterize transmission dynamics. Methods We described the characteristics of people participating in the UCTP and compared the clinical and epidemiological characteristics of COVID-19 cases detected by the UCTP versus those detected by clinical diagnosis and public health surveillance (CDPHS). We developed a Bayesian model to estimate the age-specific incidence of infection and the proportion of cases detected by CDPHS. Results In total, 1.77 million people, 24% of the Hong Kong population, participated in the UCTP from 1 to 14 September 2020. The UCTP identified 32 new infections (1.8 per 100000 samples tested), consisting of 29% of all local cases reported during the two-week UCTP period. Compared with the CDPHS, the UCTP detected a higher proportion of sporadic cases (62% vs 27%, P <.01) and identified 6 (out of 18) additional clusters during that period. We estimated that 27% (95% credible interval: 22%, 34%) of all infections were detected by the CDPHS in the third wave. Conclusions We reported empirical evidence of the utility of population-wide COVID-19 testing in detecting unrecognized infections and clusters. Around three quarters of infections have not been identified through existing surveillance approaches including contact tracing. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sewage surveillance, by detecting SARS-CoV-2 virus circulation at the community level, has the potential to supplement individual surveillance for COVID-19. However, to date, there have been no reports about the large-scale implementation and validation of sewage surveillance for public health action. OBJECTIVE: Here, we developed a standardized approach for SARS-CoV-2 detection in sewage and applied it prospectively to supplement public health interventions. METHODS: We analyzed 1,169 sewage samples collected at 492 sites from December 2020 to March 2021. Forty-seven of 492 sites tested positive, 44 (94%) of them had traceable sources of viral signals in the corresponding sewershed, either from previously unsuspected but subsequently confirmed patients or recently convalescent patients or from both patient groups. RESULTS: Sewage surveillance had a sensitivity of 54%, a specificity of 95%, a positive predictive value of 53%, and a negative predictive value of 95% for identifying a previously unsuspected patient within a sewershed. Sewage surveillance in Hong Kong provided a basis for the statutory public health action to detect silent COVID-19 transmission. DISCUSSION: Considering the epidemiological data together with the sewage testing results, compulsory testing was conducted for individual residents at 27 positive sewage sites and uncovered total of 62 previously unsuspected patients, demonstrating the value of sewage surveillance in uncovering previously unsuspected patients in the community. Our study suggests that sewage surveillance could be a powerful management tool for the control of COVID-19. [ABSTRACT FROM AUTHOR]

On January 6, 2022, a cluster of COVID-19 cases* caused by the Omicron variant of SARS-CoV-2, the virus that causes COVID-19, was detected in Hong Kong Special Administrative Region, China (Hong Kong), resulting in the territory's fifth wave of COVID-19 cases (1). This wave peaked on March 4, 2022, with 8,764 COVID-19 cases per million population (2), resulting in a total of 1,049,959 cases and 5,906 COVID-19-associated deaths reported to the Hong Kong Department of Health during January 6-March 21, 2022.† Throughout this period, the COVID-19 mortality rate in Hong Kong (37.7 per million population) was among the highest reported worldwide since the COVID-19 pandemic began (3). Publicly available data on age-specific vaccination coverage in Hong Kong with a 2-dose primary vaccination series (with either Sinovac-CoronaVac [Sinovac], an inactivated COVID-19 viral vaccine, recommended for persons aged ≥3 years or BNT162b2 [Pfizer-BioNTech], an mRNA vaccine, for persons aged ≥5 years), as of December 23, 2021,§,¶ and COVID-19 mortality during January 6-March 21, 2022, were analyzed. By December 23, 2021, 67% of vaccine-eligible persons in Hong Kong had received ≥1 dose of a COVID-19 vaccine, 64% had received ≥2 doses, and 5% had received a booster dose. Among persons aged ≥60 years, these proportions were 52%, 49%, and 7%, respectively. Among those aged ≥60 years, vaccination coverage declined with age: 48% of persons aged 70-79 years had received ≥1 dose, 45% received ≥2 doses, and 7% had received a booster, and among those aged ≥80 years, 20%, 18%, and 2% had received ≥1 dose, ≥2 doses, and a booster dose, respectively. Among 5,906 COVID-19 deaths reported, 5,655 (96%) occurred in persons aged ≥60 years**; among these decedents, 3,970 (70%) were unvaccinated, 18% (1,023) had received 1 vaccine dose, and 12% (662) had received ≥2 doses. The overall rates of COVID-19-associated mortality among persons aged ≥60 years who were unvaccinated, who had received 1 COVID-19 vaccine dose, and who had received ≥2 vaccine doses were 10,076, 1,099, and 473 per million population, respectively; the risk for COVID-19-associated death among unvaccinated persons was 21.3 times that among recipients of 2-3 doses in this age group. The high overall mortality rate during the ongoing 2022 Hong Kong Omicron COVID-19 outbreak is being driven by deaths among unvaccinated persons aged ≥60 years. Efforts to identify and address gaps in age-specific vaccination coverage can help prevent high mortality from COVID-19, especially among persons aged ≥60 years. [ABSTRACT FROM AUTHOR]

For >70 years, a 4-fold or greater rise in antibody titer has been used to confirm influenza virus infections in paired sera, despite recognition that this heuristic can lack sensitivity. Here we analyze with a novel Bayesian model a large cohort of 2353 individuals followed for up to 5 years in Hong Kong to characterize influenza antibody dynamics and develop an algorithm to improve the identification of influenza virus infections. After infection, we estimate that hemagglutination-inhibiting (HAI) titers were boosted by 16-fold on average and subsequently decrease by 14% per year. In six epidemics, the infection risks for adults were 3%–19% while the infection risks for children were 1.6–4.4 times higher than that of younger adults. Every two-fold increase in pre-epidemic HAI titer was associated with 19%–58% protection against infection. Our inferential framework clarifies the contributions of age and pre-epidemic HAI titers to characterize individual infection risk. Serological classification of influenza infection has classically been based on a four-fold or higher increase in antibody levels, but this approach may not be optimal. Here, the authors develop a Bayesian model to improve identification of infections in serological samples by accounting for individual antibody dynamics. [ABSTRACT FROM AUTHOR]

Many locations around the world have used real-time estimates of the time-varying effective reproductive number ( R t ) of COVID-19 to provide evidence of transmission intensity to inform control strategies. Estimates of R t are typically based on statistical models applied to case counts and typically suffer lags of more than a week because of the latent period and reporting delays. Noting that viral loads tend to decline over time since illness onset, analysis of the distribution of viral loads among confirmed cases can provide insights into epidemic trajectory. Here, we analyzed viral load data on confirmed cases during two local epidemics in Hong Kong, identifying a strong correlation between temporal changes in the distribution of viral loads (measured by RT-qPCR cycle threshold values) and estimates of R t based on case counts. We demonstrate that cycle threshold values could be used to improve real-time R t estimation, enabling more timely tracking of epidemic dynamics. The time-varying effective reproductive number (Rt) is useful for monitoring transmission of infections such as COVID-19, but reporting delays impact case count-based estimation methods. Here, the authors demonstrate and validate a method for estimation of Rt based on viral load data from Hong Kong that does not require accurate daily counts. [ABSTRACT FROM AUTHOR]

Hong Kong employed a strategy of intermittent public health and social measures alongside increasingly stringent travel regulations to eliminate domestic SARS-CoV-2 transmission. By analyzing 1899 genome sequences (>18% of confirmed cases) from 23-January-2020 to 26-January-2021, we reveal the effects of fluctuating control measures on the evolution and epidemiology of SARS-CoV-2 lineages in Hong Kong. Despite numerous importations, only three introductions were responsible for 90% of locally-acquired cases. Community outbreaks were caused by novel introductions rather than a resurgence of circulating strains. Thus, local outbreak prevention requires strong border control and community surveillance, especially during periods of less stringent social restriction. Non-adherence to prolonged preventative measures may explain sustained local transmission observed during wave four in late 2020 and early 2021. We also found that, due to a tight transmission bottleneck, transmission of low-frequency single nucleotide variants between hosts is rare. Hong Kong has used an elimination strategy to control SARS-CoV-2 with stringent measures including traveller quarantine. Here, the authors show that the majority of community-acquired cases until January 2021 resulted from three importations, and that increased transmission followed prolonged periods of restrictions, likely due to adherence fatigue. [ABSTRACT FROM AUTHOR]

Background Disparities were marked in previous pandemics, usually with higher attack rates reported for those in lower socioeconomic positions and for ethnic minorities. Methods We examined characteristics of laboratory-confirmed coronavirus disease 2019 (COVID-19) cases in Hong Kong, assessed associations between incidence and population-level characteristics at the level of small geographic areas, and evaluated relations between socioeconomics and work-from-home (WFH) arrangements. Results The largest source of COVID-19 importations switched from students studying overseas in the second wave to foreign domestic helpers in the third. The local cases were mostly individuals not in formal employment (retirees and homemakers) and production workers who were unable to WFH. For every 10% increase in the proportion of population employed as executives or professionals in a given geographic region, there was an 84% (95% confidence interval [CI], 1–97%) reduction in the incidence of COVID-19 during the third wave. In contrast, in the first 2 waves, the same was associated with 3.69 times (95% CI, 1.02–13.33) higher incidence. Executives and professionals were more likely to implement WFH and experienced frequent changes in WFH practice compared with production workers. Conclusions Consistent findings on the reversed socioeconomic patterning of COVID-19 burden between infection waves in Hong Kong in both individual- and population-level analyses indicated that risks of infections may be related to occupations involving high exposure frequency and WFH flexibility. Contextual determinants should be taken into account in policy planning aiming at mitigating such disparities. [ABSTRACT FROM AUTHOR]

Background: Hypertension is a leading preventable risk factor of chronic disease and all-cause mortality. Housing is a fundamental social determinant of health. Yet, little is known about the impacts of liveable residential space and density on hypertension. Methods and findings: This retrospective observational study (median follow-up of 2.2 years) leveraged the FAMILY Cohort, a large territory-wide cohort in Hong Kong, Special Administrative Region, People's Republic of China to quantify associations of objectively measured liveable space and residential density with blood pressure outcomes among adults aged ≥16 years. Blood pressure outcomes comprised diastolic blood pressure (DBP), systolic blood pressure (SBP), mean arterial pressure (MAP), and hypertension. Liveable space was measured as residential floor area, and density was assessed using the number of residential units per building block and neighborhood residential unit density within predefined catchments. Multivariable regression models examined associations of liveable floor area and residential density with prevalent and incident hypertension. We investigated effect modifications by age, sex, income, employment status, and housing type. Propensity score matching was further employed to match a subset of participants who moved to smaller residences at follow-up with equivalent controls who did not move, and generalized linear models examined the impact of moving to smaller residences upon blood pressure outcomes. Our fully adjusted models of prevalent hypertension outcomes comprised 30,439 participants at baseline, while 13,895 participants were available for incident models at follow-up. We found that each interquartile range (IQR) increment in liveable floor area was associated with lower DBP (beta [β] = −0.269 mm Hg, 95% confidence interval [CI]: −0.419 to −0.118, p < 0.001), SBP (β = −0.317 mm Hg, −0.551 to −0.084, p = 0.008), MAP (β = −0.285 mm Hg, −0.451 to −0.119 with p < 0.001), and prevalent hypertension (odds ratio [OR] = 0.955, 0.918 to 0.993, p = 0.022) at baseline. Each IQR increment in residential units per building block was associated with higher DBP (β = 0.477 mm Hg, 0.212 to 0.742, p = <0.001), SBP (β = 0.750 mm Hg, 0.322 to 1.177, p = <0.001), MAP (β = 0.568 mm Hg, 0.269 to 0.866, p < 0.001), and prevalent hypertension (OR = 1.091, 1.024 to 1.162, p = 0.007). Each IQR increase in neighborhood residential density within 0.5-mi street catchment was associated with lower DBP (β = −0.289 mm Hg, −0.441 to −0.137, p = <0.001), SBP (β = −0.411 mm Hg, −0.655 to −0.168, p < 0.001), MAP (β = −0.330 mm Hg, −0.501 to −0.159, p = <0.001), and lower prevalent hypertension (OR = 0.933, 0.899 to 0.969, p < 0.001). In the longitudinal analyses, each IQR increment in liveable floor area was associated with lower DBP (β = −0.237 mm Hg, −0.431 to −0.043, p = 0.016), MAP (β = −0.244 mm Hg, −0.444 to −0.043, p = 0.017), and incident hypertension (adjusted OR = 0.909, 0.836 to 0.988, p = 0.025). The inverse associations between larger liveable area and blood pressure outcomes were more pronounced among women and those residing in public housing. In the propensity-matched analysis, participants moving to residences of lower liveable floor area were associated with higher odds of incident hypertension in reference to those who did not move (OR = 1.623, 1.173 to 2.199, p = 0.002). The major limitations of the study are unmeasured residual confounding and loss to follow-up. Conclusions: We disentangled the association of micro-, meso-, and macrolevel residential densities with hypertension and found that higher liveable floor area and neighborhood scale residential density were associated with lower odds of hypertension. These findings suggest adequate housing in the form of provisioning of sufficient liveable space and optimizing residential density at the building block, and neighborhood levels should be investigated as a potential population-wide preventive strategy for lowering hypertension and associated chronic diseases. In a cohort study, Dr. Chinmoy Sarkar and colleagues investigate the association between liveable residential space, residential density and hypertension in Hong Kong. Author summary: Why was this study done?: Hypertension is the leading preventable risk factor of cardiovascular disease (CVD) and all-cause mortality. The fundamental role of housing in shaping population health has been acknowledged by the World Health Organization (WHO) and the American Heart Association. However, scientific evidence with regard to the relationship of housing overcrowding and residential density with hypertension has been insufficient. What did the researchers do and find?: We examined associations of objectively measured liveable space and multiscalar residential density with hypertension among adults employing 2 consecutive waves of a large territory-wide cohort in Hong Kong, Special Administrative Region, People's Republic of China. At baseline, each interquartile range (IQR) increment in liveable floor area was associated with lower blood pressure and prevalent hypertension. At the block level, each IQR increase in residential units per building block was associated with higher blood pressure and prevalent hypertension. At a neighborhood level, higher residential density was associated with lower blood pressure and hypertension. Our longitudinal analysis found that each IQR increment in liveable floor area was associated with 9.1% lower odds of incident hypertension. Propensity-matched analysis found that in reference to participants who did not move, those relocating to residences of lower liveable floor area was associated with higher odds of hypertension. What do these findings mean?: Provisioning adequate liveable space and optimizing density of residential units at building block and neighborhood levels may act as population-wide preventive strategies for lowering the burden of hypertension. The evidence can inform housing policy toward health-centric housing space allocation and densification while planning, designing, and retrofitting high-density cities of similar contexts. [ABSTRACT FROM AUTHOR]

Digital proxies of human mobility and physical mixing have been used to monitor viral transmissibility and effectiveness of social distancing interventions in the ongoing COVID-19 pandemic. We develop a new framework that parameterizes disease transmission models with age-specific digital mobility data. By fitting the model to case data in Hong Kong, we are able to accurately track the local effective reproduction number of COVID-19 in near real time (i.e., no longer constrained by the delay of around 9 days between infection and reporting of cases) which is essential for quick assessment of the effectiveness of interventions on reducing transmissibility. Our findings show that accurate nowcast and forecast of COVID-19 epidemics can be obtained by integrating valid digital proxies of physical mixing into conventional epidemic models. Digital proxies of human mobility can be used to monitor social distancing, and therefore have potential to infer COVID-19 dynamics. Here, the authors integrate travel card data from Hong Kong into a transmission model and show that it can be used to track transmissibility in near real-time. [ABSTRACT FROM AUTHOR]

Controlling transmission in restaurants is an important component of public health and social measures for coronavirus disease. We examined the effects of restaurant measures in Hong Kong. Our findings indicate that shortening operating hours did not have an effect on time-varying effective reproduction number when capacity was already reduced. [ABSTRACT FROM AUTHOR]

To investigate the prevalence, associations, and causes of visual impairment and blindness in the adult population of Hong Kong. This cross-sectional population-based study included 2018 (870, 43% male) randomly selected adults with a mean age 52 ± 16 years (range 18–90 years) in Hong Kong. Each participant underwent comprehensive ophthalmic examinations. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) of each eye was recorded. Prevalence of visual impairment and blindness was calculated using both World Health Organization (WHO) and United States (US) definitions, based on BCVA and PVA. Visual acuity measurements were available for 1952 (96.8%) participants. The prevalence of visual impairment, based on BCVA value, using WHO and US definition, was 1.0 ± 0.1% and 2.7 ± 0.4%, respectively. The prevalence of visual impairment, based on PVA value, was 5.1 ± 0.5% and 14.0 ± 0.8%, using WHO and US definition, respectively. Multivariate analysis demonstrated the presence of visual impairment (PVA, WHO definition) increased significantly with older age (odds ratio 1.039, P <.001) and thinner central cornea thickness (odds ratio 0.994, P =.014), but not significantly associated with other socioeconomic, systemic or ocular parameters after adjusting for age and central corneal thickness. Under-correction of refractive error was the most common reason for presenting visual impairment. Causes of impaired BCVA were cataract (37%), age-related macular degeneration (26%), diabetic macular edema (11%), glaucoma (11%), epiretinal membrane (5%), and unknown (11%). The prevalence of visual impairment in Hong Kong increased significantly with older age and thinner central corneal thickness. The major causes for impairment were under-correction of refractive error, cataract, and age-related macular degeneration. [ABSTRACT FROM AUTHOR]

Background: Although the World Health Organization (WHO) has defined health as a state of physical, mental and social well-being, public health strategies have primarily focused on one domain of well-being. We sought to systematically and simultaneously identify and validate associations of behavioural patterns, psychosocial factors, mental and physical health conditions, access to and utilization of health care and anthropometrics with physical, mental and social well-being.Methods: We conducted a longitudinal environment-wide association study (EWAS) with a training and testing set approach, accounting for multiple testing using a false discovery rate control. We used multivariate multilevel regression to examine the association of each exposure at wave 1 with the three outcomes at wave 2 in the Hong Kong FAMILY Cohort (n = 10 484).Results: Out of 194 exposures, we identified and validated 14, 5 and 5 exposures that were individually associated with physical, mental and social well-being, respectively. We discovered three factors, namely depressive symptoms, life satisfaction and happiness, that were simultaneously associated with the three domains that define health.Conclusions: These associations, if verified to be causal, could become intervention targets to holistically improve population health. Our findings provide empirical support for placing mental health at the forefront of the public health agenda, and also support recent calls to use life satisfaction and happiness to guide public policy. [ABSTRACT FROM AUTHOR]

Background: Although the association of moderate alcohol consumption with specific disorders, such as cardiovascular disease and cancers, has been well documented, the evidence of the broader impact of alcohol consumption on health-related quality of life is less clear. Our objective was to examine the association of drinking patterns with changes in physical and mental well-being across populations.Methods: We conducted a multilevel analysis with multivariate responses in the population-representative FAMILY Cohort in the Hong Kong Special Administrative Region, China, to examine the association between alcohol drinking patterns across 2 waves (2009-2013) (i.e., quitters, initiators, persistent drinkers, persistent former drinkers and lifetime abstainers) and changes in physical and mental well-being (Physical and Mental Component Summary of the 12-Item Short Form Health Survey [SF-12]). Analyses were stratified by sex. We validated findings using a nationally representative cohort in the United States, the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC, 2001-2005).Results: In the FAMILY Cohort (n = 10 386; median follow-up 2.3 yr), the change in mental well-being was more favourable in female quitters than in lifetime abstainers (β = 1.44, 95% confidence interval [CI] 0.43 to 2.45; mean score change of +2.0 for quitters and +0.02 for lifetime abstainers). This association was validated in the NESARC (n = 31 079; median follow-up 3.1 yr) (β = 0.83, 95% CI 0.08 to 1.58; mean score change of -1.1 for quitters and -1.6 for lifetime abstainers).Interpretation: The change in mental well-being was more favourable in female quitters, approaching the level of mental well-being of lifetime abstainers within 4 years of quitting in both Chinese and American populations. [ABSTRACT FROM AUTHOR]

Background: From an evolutionary biology perspective, where growth and reproduction trade‐off against longevity, we assessed the associations of growth from birth to puberty by phase with later glycemic indicators and any differences by sex. Methods: In the population‐representative Hong Kong Chinese "Children of 1997" birth cohort (n = 8327), the relation of initial size (weight‐for‐age z score (WAZ) at birth, length/height‐for‐age z score (LAZ) at 3 months or body‐mass‐index‐for‐age z score (BAZ) at 3 months based on the World Health Organization growth standards/references) and growth at different phases (WAZ gains from 0 to 2 and 2 to 8 years, LAZ or BAZ gains from 3 months to 3 years, 3 to 8 years and 8 to 14 years) with fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) at ~17.5 years, was assessed using adjusted partial least squares regression. Additional analyses further considered growth in late and early infancy. Results: This study included 3276 of the cohort participants. Higher WAZ gain from 2 to 8 years, LAZ and BAZ gains from 3 to 8 years were consistently associated with higher FPG, adjusted for maternal and infant characteristics, family history of diabetes and household income. Also, higher BAZ gain from 3 to 8 years was associated with higher HbA1c. These associations did not differ by sex. Conclusions: Our findings suggest different mechanisms could underlie the pathogenesis of glucose intolerance. Factors that drive specific growth at different phases need to be evaluated to better inform child growth management for long‐term health outcomes. [ABSTRACT FROM AUTHOR]

Objective: This study used two complementary designs, an observational and a Mendelian randomization (MR) study, to assess whether sleep duration causes adiposity in children and adults.Methods: In Hong Kong's "Children of 1997" birth cohort, the adjusted cross-sectional associations of sleep duration with BMI z score and obesity and overweight were assessed at ~11 years of age. Generalized estimating equations were also used to examine longitudinal associations of sleep duration at ~11 years with annual BMI z score and obesity and overweight at about 11 to 16 years of age. Using MR, this study assessed the association of genetically predicted sleep duration, based on 54 single-nucleotide polymorphisms, applied to genetic studies of adiposity in children (n = 35,668), men (n = 152,893), and women (n = 171,977).Results: Longer sleep was cross-sectionally associated with lower BMI z score at ~11 years of age (-0.13 per category, 95% CI: -0.22 to -0.04) and at about 11 to 16 years of age longitudinally in girls (-0.39, 95% CI: -0.66 to -0.13). Using MR, sleep duration was inversely associated with BMI in children (-0.29 SD per hour, 95% CI: -0.54 to -0.04), but was not clearly associated with BMI in adults, particularly for women.Conclusions: A small beneficial effect of sleep on BMI in children cannot be ruled out. [ABSTRACT FROM AUTHOR]

Prior studies on the association between traffic noise and mental health have been mostly conducted in settings with lower population densities. However, evidence is lacking in high population-density settings where traffic noise is more pervasive and varies by topography and the vertical elevation of the residential unit. This study aimed to assess the mental health impact of residential traffic noise in one of the world's most urbanised populations. Data were analysed from 13,401 participants aged ≥15 years in a prospective cohort in Hong Kong from 2009 to 2014. Residential traffic noise level was estimated using 3D-geocoding and validated models that accounted for sound propagation in a highly vertical landscape. The 24-h day-night exposure to traffic noise, denoted as L dn , was estimated with a 10-dB(A) penalty for night hours. Probable depression and mental wellbeing were assessed using the Patient Health Questionnaire-9 and the Short Form Health Questionnaire SF-12v2, respectively. Mixed effect regressions with random intercepts were used to examine the association between traffic noise and mental health outcomes. Residential road traffic noise (for each increment of 10 A-weighted decibels [dB(A)] 24-h average exposure) was associated with probable depression (odds ratio (OR) = 1.17, 95% CI: 1.05, 1.31), and poorer mental wellbeing (mean difference = −0.19, 95% CI: 0.31, −0.06), adjusting for sociodemographics, smoking, body mass index, self-reported health, proximity to green space, and neighbourhood characteristics (average household income, population density, and Gini coefficient). The results were robust to further adjustment for air pollution. In stratified analyses, residential traffic noise was associated with probable depression and poorer mental wellbeing among students and individuals aged 15–34 years. Residential traffic noise was associated with probable depression and poorer mental wellbeing in a highly urbanised setting. As traffic noise is increasing in urban settings, the public health impact of noise pollution could be substantial. [Display omitted] • Traffic noise was associated with poorer mental health in a highly urbanised setting. • Night-time traffic noise >40 dB(A) was associated with probable depression. • Students and those aged 15–34 were at risk to mental health impact of traffic noise. • Reducing traffic noise could be associated with better population mental health. [ABSTRACT FROM AUTHOR]

Breastfeeding has many benefits for mother and infant. Whether breastfeeding also protects against type 2 diabetes is unclear. To clarify the role of breastfeeding in type 2 diabetes, we assessed the association of breastfeeding with insulin resistance in late adolescence in a birth cohort from a non-Western setting where breastfeeding was not associated with higher socio-economic position. We used multivariable linear regression, with multiple imputation and inverse probability weighting, to examine the adjusted associations of contemporaneously reported feeding in the first 3 months of life (exclusively breastfed, mixed feeding, or always formula-fed) with fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) at 17 years in a subset ( n = 710, 8.6% of entire cohort) of the Hong Kong Chinese birth cohort 'Children of 1997.' We found a graded association of breastfeeding exclusivity in the first 3 months of life with lower fasting insulin and HOMA-IR ( p-for-trend < .05), but not fasting glucose, at 17 years. Exclusively breastfed adolescents (7%) had nonsignificantly lowest fasting insulin and HOMA-IR, adjusted for sex, birth weight, parity, length of gestation, pregnancy characteristics, parents' education, and mother's place of birth. Exclusively breastfeeding for 3 months may be causally associated with lower insulin resistance in late adolescence. Further follow-up studies into adulthood are required to clarify the long-term protection of breastfeeding from type 2 diabetes. [ABSTRACT FROM AUTHOR]

Background Previous studies from Western settings have found inconsistent associations of air pollutants with birth outcomes, which are open to residual confounding by socioeconomic position (SEP). We assessed this association in the economically developed non-Western setting of Hong Kong, with high levels of air pollution but little social patterning of these outcomes. Methods We obtained PM10, SO2, NO and NO2 from monitoring stations, and assessed their associations with birthweight and gestational age in a large population-representative birth cohort 'Children of 1997', using partial least-square regression to account for the colinearity between pollutants. Results PM10 (per 5.7 µg/m³ higher) and NO2 (per 10.9 µg/m³ higher) were associated with birthweight lower by 47.0 g (95% confidence interval (CI) 36.2-56.3) and 16.9 g (95% CI 10.8-22.6), respectively; and were associated with gestational age shorter by 2.1 days (95% CI 1.7-2.4) and 0.7 days (95% CI 0.5-0.8), respectively. Conclusions Given minimal confounding by SEP in our setting, these findings provide unequivocal evidence of adverse effects of PM10 and NO2 exposure during pregnancy on birthweight and gestational age. Physiological mechanisms need to be better understood to support effective public health action globally. [ABSTRACT FROM AUTHOR]

Many pollutants are endocrine disruptors with impacts on reproduction and health in animals, but evidence in humans, of which sex-specific effects on pubertal development may be an indicator, is less clear. We examined the association of air pollution in utero and during early life with pubertal development in Hong Kong, China, an area with a high level of air pollution compared with other similarly developed cities. We assessed sex-specific associations of particulate matter less than or equal to 10 µm in diameter (PM10), nitric oxide, sulfur dioxide, and nitrogen dioxide in different growth phases with clinically assessed pubertal stage at approximately age 11 years (as indicated by Tanner stage) in a large population-representative birth cohort, the "Children of 1997." We used partial least squares regression to account for colinearity between air pollutants. Among 1,938 girls, PM10 exposure in utero and during infancy was negatively associated with pubertal stage and breast development, whereas among 2,136 boys, sulfur dioxide and nitrogen dioxide exposure in utero, during infancy, and in childhood were negatively associated with pubertal stage. These sex-specific associations with pubertal development are consistent with endocrine-disrupting effects. Given the health impact of altered pubertal timing, further investigation across the life course may help quantify the full effects and the corresponding need for preventive measures. [ABSTRACT FROM AUTHOR]

The FAMILY Cohort is a longitudinal study of health, happiness and family harmony (the '3Hs') at individual, household and neighbourhood levels in Hong Kong. Using a family living in the same household as the sampling unit, the study (n = 20 279 households and 46 001 participants) consists of a composite sample from several sources, including: a population-representative random core sample (n = 8115 households and 19 533 participants); the first-degree relatives of this sample (n = 4658 households and 11 063 participants); and oversampling in three new towns (n = 2891 households and 7645 participants) and in three population subgroups with anticipated changes in family dynamics (n = 909 households and 2160 participants). Two household visits and five telephone- or web-based follow-ups were conducted over 2009-14. Data collected include socio-demographics, anthropometrics, lifestyle and behavioural factors, measures of social capital, and standardized instruments assessing the 3Hs. We also intend to collect biomaterials in future. The analytical plan includes multilevel inter-relations of the 3Hs for individuals, households, extended families and neighbourhoods. With Hong Kong's recent history of socioeconomic development, the FAMILY Cohort is therefore relevant to global urban populations currently experiencing similarly rapid economic growth. The FAMILY Cohort is currently set up as a supported access resource. [ABSTRACT FROM AUTHOR]

Despite the extensive history of social movements around the world, the evolution of population mental health before, during, and after a social movement remains sparsely documented. We sought to assess over time the prevalence of depressive symptoms during and after the Occupy Central movement in Hong Kong and to examine the associations of direct and indirect exposures to Occupy Central with depressive symptoms. We longitudinally administered interviews to 909 adults who were randomly sampled from the population-representative FAMILY Cohort at 6 time points from March 2009 to March 2015: twice each before, during, and after the Occupy Central protests. The Patient Health Questionnaire-9 was used to assess depressive symptoms and probable major depression (defined as Patient Health Questionnaire-9 score ≥10). The absolute prevalence of probable major depression increased by 7% after Occupy Central, regardless of personal involvement in the protests. Higher levels of depressive symptoms were associated with online and social media exposure to protest-related news (incidence rate ratio (IRR) = 1.28, 95% confidence interval (CI): 1.06, 1.55) and more frequent Facebook use (IRR = 1.38, 95% CI: 1.12, 1.71). Higher levels of intrafamilial sociopolitical conflict was associated with more depressive symptoms (IRR = 1.05, 95% CI: 1.01, 1.09). The Occupy Central protests resulted in substantial and sustained psychological distress in the community. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to examine the role of stress across the life course in the development of depression among older adults in a non-Western developing setting.Methods: Multivariable linear and multinomial logistic regression were used in cross-sectional analyses of 9729 Chinese participants (mean age 60.2 years) from phase 3 of the Guangzhou Biobank Cohort Study (2006-2008) to investigate the association of childhood adversities and adulthood stressors with depression.Results: Childhood adversities were associated with mild depression (odds ratio (OR) 1.78, 95% confidence interval (CI) 1.58, 2.02) and moderate-to-severe depression (OR 2.30, 95% CI 1.68, 3.15), adjusted for age, sex, education and childhood socio-economic status. Past-year adulthood stressors were also associated with mild depression (OR 1.96, 95% CI 1.54, 2.02) and moderate-to-severe depression (OR 3.55, 95% CI 2.21, 5.68), adjusting additionally for occupation and income. Adulthood stressors were more strongly associated with depressive symptoms among individuals with a history of childhood adversities.Conclusions: Childhood adversities and adulthood stressors were independently associated with an increased risk of depression among older ambulatory adults, although adulthood stressors were more strongly associated with depression following exposure to childhood adversities. This is consistent with evidence from Western settings in which the social context of risk and protective factors for depression may differ and implies that the role of stress in the aetiology of depression is not context specific. [ABSTRACT FROM AUTHOR]

Background: Birth order has been proposed as a cardiovascular risk factor, because the lower birth weight and greater infant weight gain typical of firstborns could programme metabolism detrimentally. Methods: We examined the associations of birth order (firstborn or laterborn) with birth weight-for-gestational age, length/height and body mass index (BMI) z-scores during infancy, childhood, and puberty using generalized estimating equations, with age at pubertal onset using interval-censored regression and with age-, sex- and height-standardized blood pressure, height and BMI z-scores at 13 years using linear regression in a population-representative Chinese birth cohort: “Children of 1997” (n = 8,327). Results: Compared with laterborns, firstborns had lower birth weight-for-gestational age (mean difference = -0.18 z-score, 95% confidence interval (CI) -0.23, -0.14), lower infant BMI (-0.09 z-score, 95% CI -0.14, -0.04), greater childhood height (0.10 z-score, 95% CI 0.05, 0.14) and BMI (0.08 z-score, 95% CI 0.03, 0.14), but not greater pubertal BMI (0.05 z-score, 95% CI -0.02, 0.11), adjusted for sex, parental age, birthplace, education and income. Firstborns had earlier onset of pubic hair (time ratio = 0.988, 95% CI 0.980, 0.996), but not breast or genitalia, development. Firstborns had greater BMI (0.07 z-score, 95% CI 0.002, 0.15), but not height (0.05 z-score, 95% CI -0.01, 0.11), at 13 years, but similar blood pressure. Conclusions: Differences by birth order continue into early adolescence with firstborns being heavier with earlier pubic hair development, which could indicate long-term cardiovascular risk. [ABSTRACT FROM AUTHOR]

Background: Preterm birth, early term birth, and low birthweight are associated with childhood wheezing disorders in developed Western settings, but observed associations could be confounded by socio-economic position. This study aims to clarify such associations in a developed non-Western setting with a different confounding structure.Methods: Using Cox regression, we examined the adjusted associations of gestational age and birthweight for gestational age with time to first public hospital admission for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490, and 493) from 9 days to 12 years in a population-representative birth cohort of 8327 Chinese children in Hong Kong, a developed setting with less clear social patterning of prematurity or birthweight. Analyses were adjusted for infant and parental characteristics and socio-economic position.Results: Children born late preterm (34 to <37 weeks) had higher risk of hospitalisation for asthma and other wheezing disorders [hazard ratio (HR) 1.99, 95% confidence interval (CI) 1.48, 2.67] than children born full term (39 to <41 weeks). Early term births (37 to <39 weeks) had HR 1.01 (95% CI 0.84, 1.22), late term births (41 to <42 weeks) had HR 0.77 (95% 0.59, 1.01), and post-term births (≥42 weeks) had HR 0.56 (95% CI 0.32, 0.98). Large for gestational age was associated with lower risk of hospitalisation (HR 0.76, 95% CI 0.57, 0.99).Conclusion: The association of preterm birth with childhood wheezing could be biologically mediated. We cannot rule out an association for early term births. [ABSTRACT FROM AUTHOR]

Background The study investigated public risk perception regarding influenza A(H7N9) and attitudes towards closure of live poultry markets (LPMs) before and after LPMs closed in Hong Kong. Methods Two population-based surveys were conducted before and after LPMs closed in January-February 2014, respectively. Adults were recruited using random digital dialing. Results In total, 670 and 1011 respondents completed the survey before and after closure of LPMs, respectively. Perceived susceptibility to H7N9 infection was low across surveys. Among respondents who completed the survey after LPMs closed, only 14.6% agreed that temporary closure of LPMs caused inconvenience to the daily life; 38.7% valued the Chinese tradition of live poultry consumption more than controlling the risk of avian influenza; 54.6% recognized greater risk of influenza epidemic associated with LPMs. Support for permanent closure of LPMs which was comparably low across surveys was strongly associated with perceived risk of avian influenza related to LPMs, the effectiveness of LPM closure in control of avian influenza and the inconvenience caused by closure. Conclusions Risk communication that promotes people's perceived risk of avian influenza associated with LPMs and the effectiveness of LPM closure in control of avian influenza outbreaks may improve support for permanent closure of LPMs. [ABSTRACT FROM AUTHOR]

Background: In influenza epidemiology, analysis of paired sera collected from people before and after influenza seasons has been used for decades to study the cumulative incidence of influenza virus infections in populations. However, interpretation becomes challenging when sera are collected after the start or before the end of an epidemic, and do not neatly bracket the epidemic.Methods: Serum samples were collected longitudinally in a community-based study. Most participants provided their first serum after the start of circulation of influenza A(H1N1)pdm09 virus in 2009. We developed a Bayesian hierarchical model to correct for nonbracketing sera and estimate the cumulative incidence of infection from the serological data and surveillance data in Hong Kong.Results: We analyzed 4,843 sera from 2,097 unvaccinated participants in the study, collected from April 2009 to December 2010. After accounting for nonbracketing, we estimated that the cumulative incidence of H1N1pdm09 virus infection was 45% (95% credible interval [CI] = 40%, 49%), 17% (95% CI = 13%, 20%), and 11% (95% CI = 6%, 18%) for children ages 0-18 years, adults 19-50 years, and older adults >50 years, respectively. Including all available data substantially increased precision compared with a simpler analysis based only on sera collected at 6-month intervals in a subset of participants.Conclusions: We developed a framework for the analysis of antibody titers that accounted for the timing of sera collection with respect to influenza activity and permitted robust estimation of the cumulative incidence of infection during an epidemic. [ABSTRACT FROM AUTHOR]

Purpose: To examine whether the two-item version (CD-RISC2) of the Connor-Davidson Resilience Scale (CD-RISC) has adequate internal consistency and construct validity, as well as significant correlation with the full scale, and to provide normative data for the CD-RISC and the CD-RISC2 in a Chinese general population in Hong Kong.Methods: In total, 10,997 randomly selected participants aged ≥20 years completed the Chinese version of the CD-RISC (including the 2 items of the CD-RISC2), the Patient Health Questionnaire, Family Harmony Scale, Family APGAR, and CAGE Questionnaire. Internal consistency and convergent and discriminant validity of the CD-RISC and CD-RISC2 were assessed.Results: Cronbach's α for CD-RISC and CD-RISC2 was 0.97 and 0.79, respectively. CD-RISC2 was associated with the 25-item version of the CD-RISC (r = 0.88), depressive symptoms (r s = -0.18), family harmony (r = 0.20), family functioning (r = 0.27) and was not associated with alcohol consumption (r = 0.05). The mean score for the CD-RISC and CD-RISC2 was 59.99 (SD = 13.92) and 5.03 (SD = 1.37), respectively. Men, younger individuals, and those with higher education or higher household income reported higher resilience levels.Conclusions: The Chinese version of the CD-RISC2 was demonstrated to be a reliable and valid measure in assessing resilience among the general population in Hong Kong. [ABSTRACT FROM AUTHOR]

In winter 2018, schools in Hong Kong were closed 1 week before the scheduled Chinese New Year holiday to mitigate an influenza B virus epidemic. The intervention occurred after the epidemic peak and reduced overall incidence by ≈4.2%. School-based vaccination programs should be implemented to more effectively reduce influenza illnesses. [ABSTRACT FROM AUTHOR]

Background and Aims Second-hand smoke (SHS) exposure is associated negatively with childhood behavioural problems in western settings. In a developed non-western setting, we estimated the associations of early SHS exposure during the prenatal and postnatal periods with several aspects of adolescent mental health. Design Multivariable linear regression was used to estimate the adjusted associations of pre- and postnatal SHS exposure with adolescent mental health. Setting Hong Kong. Participants Population-representative 'Children of 1997' birth cohort. Behavioural problems at ~11 years were available for 5598, self-esteem at ~11 years for 6937 and depressive symptoms at ~13 years for 5797. Measurements SHS was categorized as no SHS exposure, occasional prenatal SHS exposure from non-parental sources, daily prenatal SHS exposure from non-parental sources, postnatal SHS exposure from non-parental sources, prenatal and postnatal SHS exposure from non-parental sources, occasional paternal smoking, daily paternal smoking and any maternal smoking. Behavioural problems were assessed from parent-reported Rutter score, self-esteem from self-reported Culture-Free Self-Esteem Inventory score and depressive symptoms from self-reported Patient Health Questionnaire-9 score. Findings Prenatal SHS exposure from non-parental sources was associated with behavioural problems at ~11 years (1.24, 95% confidence interval 0.20-2.28) adjusted for sex, age of assessment, survey mode (for depressive symptoms only), socio-economic position (SEP), mother's birthplace, gestational age and parity; paternal smoking and maternal smoking were associated with more mental health problems but also with lower SEP. Conclusions In Hong Kong, prenatal second-hand tobacco smoke exposure appears to be a risk factor for behavioural problems at age 11 years independent of socio-economic position. [ABSTRACT FROM AUTHOR]

Influenza B viruses split into 2 distinct lineages in the early 1980s, commonly named the Victoria and Yamagata lineages. There are few data on the comparative epidemiology of Victoria- and Yamagata-lineage viruses. In 2007-2011,we enrolled 75 and 34 households containing index patients with acute respiratory illness who tested positive for Yamagata- and Victoria-lineage viruses, respectively, from outpatient clinics in Hong Kong, China. These index patients and their household contacts were followed up for 7-10 days. We examined overall risk of polymerase chain reaction--confirmed infection among household contacts and the risk of secondary infection within households using an individual-based hazard model that accounted for tertiary transmission and infections occurring outside the household. We found that for Victoria-lineage viruses, the risk of within-household infection among household contacts aged ≤15 years was significantly higher (risk ratio = 12.9, 95% credibility interval: 4.2, 43.6) than that for older household contacts, while for Yamagata-lineage viruses, the risk of within-household infection for household contacts did not differ by age. Influenza B Yamagata- and Victoria-lineage viruses have similar characteristics in terms of viral shedding and clinical illness. The mechanisms underlying these epidemiologic differences deserve further investigation. [ABSTRACT FROM AUTHOR]

Background Preterm, and more recently early term, birth has been identified as a risk factor for poor health. Whether the sequelae of late preterm or early term birth extends to poor mental health and well-being in adolescence is unclear and has not been systematically assessed. Method Linear regression was used to assess the adjusted associations of gestational age (very/moderate preterm (<34 weeks, n=85), late preterm (34-36 weeks, n=305), early term (37-38 weeks, n=2228), full term (39-40 weeks, n=4018), late term (41 weeks, n=809), post-term (=42 weeks, n=213)) with self-reported selfesteem at ~11 years (n=6935), parent-reported Rutter score assessing the common emotional and behavioural problems at ~7 years (n=6292) and ~11 years (n=5596) and self-reported depressive symptoms at ~13 years (n=5795) in a population-representative Hong Kong Chinese birth cohort 'Children of 1997' where gestational age has little social patterning. Results: Very/moderate preterm birth was associated with higher Rutter subscore for hyperactivity (ß coefficients 0.5, 95% CI 0.01 to 1.00) at ~7 years but not at ~11 years, adjusted for sex, age, socioeconomic position, parents' age at birth, birth order and secondhand smoke exposure. Similarly adjusted, late preterm, early term, late term and post-term birth were not associated with self-esteem or depressive symptoms. Conclusions: In a population-representative birth cohort from a non-Western-developed setting, gestational age had few associations with mental health and well-being in adolescence, whereas very preterm birth was specifically associated with hyperactivity in childhood. Inconsistencies with studies from Western settings suggest setting specific unmeasured confounding may underlie any observed associations. [ABSTRACT FROM AUTHOR]

Vitamin D plays an important role in skeletal health throughout life. Some studies have hypothesised that vitamin D may reduce the risk of other diseases. Our study aimed to estimate age-specific and sex-specific serum 25-hydroxyvitamin D (25(OH)D) status and to identify the determinants of serum 25(OH)D status in Hong Kong, a subtropical city in southern China. In 2009-2010, households in Hong Kong were followed up to identify acute respiratory illnesses, and sera from 2694 subjects were collected in three to four different study phases to permit measurement of 25(OH)D levels at different times of the year. A questionnaire survey on diet and lifestyle was conducted among children, with simultaneous serum collection in April and May 2010. The mean of serum 25(OH)D levels in age groups ranged from 39 to 63 nmol/l throughout the year with the mean values in all age groups in spring below 50 nmol/l. Children aged 6-17 years, and girls and women had significantly lower serum 25(OH)D levels than adults, and boys and men, respectively (all P<0·001). We estimated that serum 25(OH)D levels in Hong Kong followed a lagged pattern relative to climatic season by 5 weeks with lowest observed levels in early spring (March). For children aged 6-17 years, reporting a suntan, having at least 1 servings of fish/week and having at least 1 serving of eggs/week were independently associated with higher serum 25(OH)D levels. Adequate sunlight exposure and increased intake of dietary vitamin D could improve vitamin D status, especially for children and females in the winter and spring. [ABSTRACT FROM AUTHOR]

Background: Informal child care (child care by untrained family members, relatives or employees in the home) in Western populations is often associated with poorer psychological well-being, which may be confounded by socioeconomic position. We examined the association of informal child care, common in non-Western settings, with adolescent psychological well-being, using Hong Kong’s Chinese “Children of 1997” birth cohort. Methods: Multivariable linear regression was used to examine the adjusted associations of informal child care (at 0.5, 3, 5 and 11 years) with parent-reported Rutter score for child behavior at 11 years, self-reported Culture-Free Self-Esteem Inventories score at 11 years and self-reported Patient Health Questionnaire-9 depressive symptom score at 13 years. Model comparisons were used to identify the best representation of child care, in terms of a critical period of exposure to informal child care (independent variable) at a specific age, combination of exposures to informal child care at several ages or an accumulation of exposures to informal child care. Results: Child care was not associated with behavioral problems. A model considering child care at 3 years best represented the association of child care with self-esteem while a model considering child care at 5 years best represented the association of child care with depressive symptoms. Informal child care at 3 years was associated with lower self-esteem (-0.70, 95% confidence interval (CI) -1.26 to -0.14). Informal child care at 5 years was associated with more depressive symptoms (0.45, 95% CI 0.17 to 0.73). Conclusion: In a developed non-Western setting, informal child care was associated with lower self-esteem and more depressive symptoms. [ABSTRACT FROM AUTHOR]

Background: In Western settings, migration is associated with psychological well-being, but studies inevitably focus on culturally distinct ethnic minorities, making it difficult to distinguish migration from cultural assimilation. Many children in Hong Kong, a developed non-Western setting, have migrant parents with the same Chinese ethnicity. This study examined the association of migration with the child’s psychological well-being in Hong Kong. Methods: Multivariable linear regression was used in Hong Kong’s ‘Children of 1997’ Chinese birth cohort to examine the adjusted associations of migration (both parents Hong Kong born n=4285, both parents migrant n=1921, mother-only migrant n=462, father-only migrant n=1110) with a parent-reported Rutter score for child behaviour at ∼7 (n=6294, 80% follow-up) and ∼11 years (n=5598, 71% follow-up), self-reported Culture-Free Self-Esteem Inventory score at ∼11 years (n=6937, 88% follow-up) and self-reported Patient Health Questionnaire-9 (PHQ-9) depressive symptom score at ∼13 years (n=5797, 73% follow-up), adjusted for sex, highest parental education and occupation, household income, maternal and paternal age at birth, age of assessment and survey mode (PHQ-9 only). Results: Migration was unrelated to the overall self-esteem or depressive symptoms, but both parents migrant was associated with better behaviour (lower Rutter scores) at ∼7 years (β-coefficient (β) −1.07, 95% CI –1.48 to −0.66) and ∼11 years (−0.89, 95% CI −1.33 to −0.45). Conclusions: In a non-Western context, migration appeared to be protective for childhood behaviour. [ABSTRACT FROM AUTHOR]

Through follow-up of 796 children for up to 3 years, we found that infection with influenza A(H1N1)pdm09 in 2009–2010 and influenza A(H3N2) in 2010 was associated with protection against infection with subsequent epidemics of the same subtype.Background. School-aged children suffer high rates of influenza virus infections and associated illnesses each year, and are a major source of transmission in the community. However, information on the cumulative incidence of infection in specific epidemics is scarce, and there are limited studies with sufficient follow-up to identify the strength and duration of protection against reinfection.Methods. We randomly allocated children 5–17 years of age to receive trivalent inactivated influenza vaccine (TIV) or placebo from September 2009 through January 2010, and then conducted follow-up for 3 years including regular collection of sera, symptom diaries, and collection of nose and throat swabs during illness episodes in participants or their household members.Results. Of 796 children initially randomized, 484 continued to participate for all 3 years. In unvaccinated children, cumulative incidence of infection was estimated to be 59% in the first wave of H1N1pdm09 in 2009–2010, and 7%, 14%, 20%, and 31% in subsequent epidemics of H3N2 (2010), H1N1pdm09 (2011), B (2012), and H3N2 (2012), respectively. Infection with H1N1pdm09 in 2009–2010 and H3N2 in 2010 was associated with protection against infection with subsequent epidemics of the same subtype in 2011 and 2012, respectively, but we found no evidence of heterotypic or heterosubtypic protection against infection.Conclusions. We identified substantial incidence of influenza virus infections in children in Hong Kong in 5 major epidemics over a 3-year period, and evidence of homosubtypic but not heterosubtypic protection following infection.Clinical Trials Registration. NCT00792051. [ABSTRACT FROM PUBLISHER]

Background: Smokefree legislation may protect children from secondhand smoke (SHS) in the home from smoking parent(s). We examined the effect of the 2007 smokefree legislation on children’s exposure to SHS in the home and maternal action to protect children from SHS exposure in Hong Kong. Methods: Families with a smoking father and a non-smoking mother were recruited from public clinics before (2005–2006, n = 333) and after the legislation (2007–2008, n = 742) which led to a major extension of smokefree places in Hong Kong. Main outcomes included children’s SHS exposure in the home, nicotine level in mothers’ and children’s hair and home environment, mothers’ action to protect children from SHS, and their support to the fathers to quit. Results: Fewer mothers post-legislation reported children’s SHS exposure in the home (87.2% versus 29.3%, p<0.01), which was consistent with their hair nicotine levels (0.36ng/mg versus 0.04ng/mg, p<0.01). More mothers post-legislation in the last month took their children away from cigarette smoke (6.3% versus 92.2%; p<0.01) and advised fathers to quit over 3 times (8.3% versus 33.8%; p<0.01). No significant change was found in the content of smoking cessation advice and the proportion of mothers who took specific action to support the fathers to quit. Conclusions: SHS exposure in the home decreased and maternal action to protect children from SHS increased after the 2007 smokefree legislation. Maternal support to fathers to quit showed moderate improvement. Cessation services for smokers and specific interventions for smoking families should be expanded together with smokefree legislation. [ABSTRACT FROM AUTHOR]

Hong Kong experienced two large epidemics of pandemic influenza A( H1 N1pdm09). We used regression methods to estimate the excess mortality associated with each epidemic. The first epidemic of H1 N1pdm09 peaked in September 2009 and was associated with 2·13 [95% confidence interval ( CI): −8·08, 11·82] excess all-cause deaths per 100 000 population. The second epidemic of H1 N1pdm09 in early 2011 was associated with 4·72 [95% CI: −0·70, 10·50] excess deaths per 100 000 population. More than half of the estimated excess all-cause deaths were attributable to respiratory causes in each epidemic. The reasons for substantial impact in the second wave remain to be clarified. [ABSTRACT FROM AUTHOR]

Highlights: [•] We did a representative assessment of HPV vaccine acceptability in Hong Kong. [•] We found that while acceptability was moderate, the actual uptake was markedly lower. [•] Female adolescent HPV vaccine acceptability increased from 2008 to 2012. [•] The willingness to pay of HPV vaccination was largely lower than the market price. [•] Cost of vaccination was a barrier against HPV vaccine acceptability. [ABSTRACT FROM AUTHOR]