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Background: The effectiveness of preventive measures in combating travel-related illnesses is well recognized. However, there is a lack of information on the economic value of any travel-associated preventive measures in the literature.Objectives: The purpose of this article is to report the values of willingness to pay (WTP) to prevent travel health problems in Hong Kong's travelers.Methods: A cross-sectional telephone survey for a sample of Hong Kong population was conducted in 1998 using a random digit dialing technique. The sample WTP values were elicited using an open-ended question. Logistic regression was performed to identify predictors of WTP. Mean WTP was estimated using Heckman's sample selection model on log-WTP.Results: Of the subjects interviewed, 77% (285/369) offered positive values of WTP to prevent travel health problems. The observable WTP (zero excluded) had a higher mean (447 Hong Kong dollars) than did the zero-inclusive data (351 Hong Kong dollars). The median values were 200 Hong Kong dollars in both cases because there were a large number of protest responses. Age, travel frequency, ability to assess travel health risk, precautionary behavior, and previous exposure to health protection materials explained one's willingness to pay a positive amount for preventing travel health problems. Age, education level, and precautionary behavior were predictors of the WTP levels.Conclusion: The findings of this study suggest that Chinese travelers are willing to pay for the prevention of travel-related illnesses. The predictors of WTP identified could be used to suggest policy changes. However, future studies are needed to explore further the relationship between the experience of travel illnesses, the magnitude of travel health risks, and WTP. [ABSTRACT FROM AUTHOR]

Objective: To describe the characteristics of the Chinese subjects who utilised the first telephone smoking cessation service in Hong Kong, and to evaluate its effectiveness.Methods: The Quitline provided Hong Kong residents with free telephone smoking cessation services which was publicised through a press conference, media reports, pamphlets, and posters at public and private hospitals and clinics. Callers who completed an initial interview from 13 December 2000 to 31 May 2002 were included. Smokers were interviewed using a structured record sheet and provided with stage matched counselling. A follow up interview was carried out after six months. Analysis was conducted by intention-to-treat.Results: Of the 1120 callers who completed initial assessments, 1047 were current smokers and 872 consented to follow ups. Compared to the general smoking population, the Quitline attracted more of those who were female, younger, single, unemployed, higher educated, smoking more than 20 cigarettes per day, and those with quitting experience. At six months, 12% (95% confidence interval 10% to 15%) of the participants reported that they had not smoked a cigarette for the past seven days. A stepwise logistic regression model showed that the use of nicotine replacement therapy at the present attempt to quit, having made one or more serious attempts to quit in the past, perceiving less difficulties in quitting, and smoking the first cigarette at age 15 years or above were significant predictors of quitting.Conclusion: This first Quitline in Asia appears to be acceptable to Chinese smokers, with quit rate comparable to those of better funded Quitlines in the West. A low cost Quitline is a promising model for smoking cessation services in the East. [ABSTRACT FROM AUTHOR]

Background: Accurate, objective models of triage for patients with suspected severe acute respiratory syndrome (SARS) could assess risks and improve decisions about isolation and inpatient treatment.Objective: To develop and validate a clinical prediction rule for identifying patients with SARS in an emergency department setting.Design: Retrospective analysis using a 2-step coefficient-based multivariable logistic regression scoring method with internal validation by bootstrapping.Setting: 2 hospitals in Hong Kong.Participants: 1274 consecutive patients from 1 hospital and 1375 consecutive patients from another hospital.Measurements: Points were assigned on the basis of history, physical examination, and simple investigations obtained at presentation. The outcome measure was a final diagnosis of SARS, as confirmed by World Health Organization laboratory criteria.Results: Predictors for SARS on the basis of history (step 1) included previous contact with a patient with SARS and the presence of fever, myalgia, and malaise. Age 65 years and older and younger than 18 years and the presence of sputum, abdominal pain, sore throat, and rhinorrhea were inversely related to having SARS. In step 2, haziness or pneumonic consolidation on chest radiographs and low lymphocyte and platelet counts, in addition to a positive contact history and fever were associated with a higher probability of SARS. A high neutrophil count, the extremes of age, and sputum production were associated with a lower probability of SARS. In the derivation sample, the observed incidence of SARS was 4.4% for those assigned to the low-risk group (in steps 1 or 2); in the high-risk group, incidence of SARS was 21.0% for quartile 1, 39.5% for quartile 2, 61.2% for quartile 3, and 79.7% for quartile 4. This prediction rule achieved an optimism-corrected sensitivity of 0.90, a specificity of 0.62, and an area under the receiver-operating characteristic curve of 0.85.Limitations: The prediction rule may not apply to isolated cases occurring during an interepidemic period. Generalizability of the findings should be confirmed in other SARS-affected countries and should be prospectively validated if SARS returns.Conclusions: Our findings suggest that a simple model that uses clinical data at the time of presentation to an emergency department during an acute outbreak predicted the incidence of SARS and provided good diagnostic utility. [ABSTRACT FROM AUTHOR]

Background: Several countries have adopted nationally organized cervical screening programs, but many continue with opportunistic screening. Comparison of the effectiveness and efficiency of the 2 systems is important for informing policy.Objectives: The objectives of this study were to assess the effectiveness and efficiency of an opportunistic cervical screening system, and to compare this with what could be achieved through an organized program.Research Design: We propose a model for estimating the effectiveness and efficiency of opportunistic screening systems and demonstrate it using data from a cross-sectional study of 1826 women in Hong Kong. We estimated the coverage and frequency of screening and used this to estimate effectiveness (number of cases of invasive cervical cancer potentially prevented) and efficiency (tests per case prevented) of the current system. Similar estimates were made for various organized programs with different screening intervals and coverage.Results: Ever screening coverage in this opportunistic system was 44%, resulting in 26% to 31% reduction in potential new cases (n = 144-183). Compared with this, a 3-yearly or 5-yearly screening policy aiming for 80% coverage would prevent an additional 46% (equivalent to 254 new cases out of a population of 2.3 million women per year) and 41% (222 per year), respectively. This could be achieved with more efficient use of resources, reducing the number of tests per case prevented from 2018 to 1545 and 1007, respectively.Conclusions: At best, the effectiveness of this opportunistic system is equivalent to an organized program with 10-yearly screening and 50% coverage but at much greater cost. Poor coverage and over screening of a minority of women contributes to its inefficiency. [ABSTRACT FROM AUTHOR]

Background: In July, 1990, a restriction was introduced over one weekend that required all power plants and road vehicles in Hong Kong to use fuel oil with a sulphur content of not more than 0.5% by weight. This intervention led to an immediate fall in ambient sulphur dioxide (SO2). We assessed the effect of this intervention on mortality over the next 5 years.Methods: Changes in trends in deaths were estimated by a Poisson regression model of deaths each month between 1985 and 1995. Changes in seasonal deaths immediately after the intervention were measured by the increase in deaths from warm to cool season. We also estimated the annual proportional change in number of deaths before and after the intervention. We used age-specific death rates to estimate person-years of life gained.Findings: In the first 12 months after introduction of the restriction, a substantial reduction in seasonal deaths was noted, followed by a peak in the cool-season death rate between 13 and 24 months, returning to the expected pattern during years 3-5. Compared with predictions, the intervention led to a significant decline in the average annual trend in deaths from all causes (2.1%; p=0.001), respiratory (3.9%; p=0.0014) and cardiovascular (2.0%; p=0.0214) diseases, but not from other causes. The average gain in life expectancy per year of exposure to the lower pollutant concentration was 20 days (females) to 41 days (males).Interpretation: Pollution resulting from sulphur-rich fuels has an effect on death rates, especially respiratory and cardiovascular deaths. The outcome of the Hong Kong intervention provides direct evidence that control of this pollution has immediate and long-term health benefits. [ABSTRACT FROM AUTHOR]

Background: Two-thirds of complaints received by the Hong Kong Environmental Protection Department in 1988 were related to poor air quality. In July 1990 legislation was implemented to reduce fuel sulphur levels. The intervention led to a reduction in respiratory symptoms and bronchial hyperresponsiveness of primary school children. The objectives of this study were to investigate the differences in respiratory health between non-smoking women living in the more polluted district (Kwai Tsing) and those living in the less polluted district (Southern); to assess the impact of the government air quality intervention; and to study the effect of environmental tobacco smoke on respiratory health in non-smoking women in both districts.Method: A total of 3405 non-smoking women, aged 36.5 years (standard deviation = 3.0), from two districts with good and poor air quality respectively before the intervention were followed yearly from 1989 to 1991. Binary latent variable modelling was used to summarize the six respiratory symptoms and to estimate the effects of risk factors.Results: In 1989, living in the polluted district was associated with poor respiratory health (odds ratio [OR] = 1.55, 95% confidence interval [CI]: 1.11-2.17, P < 0.01). After the intervention, in the polluted district only, sulphur dioxide levels fell by up to 80% and sulphate concentrations in respirable particulates by 38%. Between 1989 and 1990-1991, there was no significantly greater decline (P > 0.241) in the more polluted compared with the less polluted district for poor respiratory health. In 1989, the effects on poor respiratory health for exposure to two or more categories of smokers relative to none in the home (OR = 1.80, 95% CI: 1.15-2.83, P < 0.01) were higher but not significantly than those for living in polluted relative to less polluted district (95% CI of the two effects overlapping each other).Conclusions: Environmental tobacco smoke (ETS) and outdoor air pollution had independent adverse effects on respiratory health of non-smoking women and improvement in air quality had produced some but non-significant benefits. [ABSTRACT FROM AUTHOR]

Smoking habits, knowledge about the health consequences of smoking and the perception of developing risks of smoking were investigated among a group of Asian female airline cabin crew trainees working in Hong Kong (N = 409) who were compared with an earlier cohort of experienced Asian female airline cabin crew (N = 585). The instrument was a self-administered questionnaire worded in simple English. Results indicate that in general, smokers and non-smokers did not significantly differ in their level of awareness about the hazards of smoking. Perceived risks for non-smoking-related hazards did not differ between smokers and nonsmokers. However, smokers perceived a lesser risk of developing smoking-related disease and rated higher the likelihood of obtaining benefits from smoking than did non-smokers. This may contribute to, or be a consequence of, smoking behaviour. If the latter, this questions the value of continuing education among smokers about the long-term health risks of smoking particularly for better-known risks. New directions for future smoking prevention education measures are suggested. [ABSTRACT FROM AUTHOR]

Background: Evidence on respiratory symptoms due to smoking and passive smoking in children is mainly derived from studies in Western countries. Evidence from the East was required to support stronger tobacco control policy in Asia. This study aimed to analyse the relationship between respiratory symptoms and smoking status in junior secondary students and between respiratory symptoms and family smoking in never-smoking students.Methods: In a cross-sectional survey in 1994, anonymous questionnaires were administered to a two-stage cluster probability sample of 6304 students, aged mostly 12-15 years, from 172 classes of 61 schools in Hong Kong.Results: Significant linear trends were found between smoking and the prevalence of throat and nose problems, cough and phlegm, and wheezing. The odds ratio (OR), after adjustment for age, gender, area of residence, type of housing and correlation within schools and classes (cluster effects), for smoking at least weekly ranged from 1.35 to 4.84. In never-smoking children, significant trends were found between the number of smokers living with the children and throat and nose problems, cough and phlegm, and recent wheezing. The adjusted OR and 95% confidence interval (CI) for any cough or phlegm symptoms was 1.19 (95% CI: 1.01-1.47) for one smoking household member, 1.38 (95% CI: 1.07-1.79) for two and 1.85 (95% CI: 1.19-2.85) for three (P for trend <0.001). Increased OR were found for father and mother smoking.Conclusions: This study provides strong evidence that both active and passive smoking can cause respiratory ill health in Chinese children in Hong Kong. Urgent measures are needed to protect children from the health hazards of active and passive smoking in Asia. [ABSTRACT FROM AUTHOR]

Background: Levels of sexual experience among Chinese university students are considerably lower than in western countries. Measuring sexual risk-taking behavior of Chinese students is important in designing any effective preventive health programs. This study assessed the prevalence and factors associated with high-risk sexual behavior among students in a Hong Kong university.Methods: A cross-sectional survey conducted among year 1 and year 3 Chinese undergraduate students in 1997, using a structured, self-administered questionnaire.Results: Of the 1197 students surveyed, only 11% were sexually active (ever had sexual intercourse). Reported sexual activity was higher among year 3 (17%) than year 1 (6.6%) students and higher among males (14.4%) than females (8.3%). Consistent (always) use of condoms was reported by only 43% of the sexually active respondents. Males were more likely to think that premarital sex was acceptable than were females. About 1 in 20 students (55 of 1197) were categorized as belonging to a "greater risk behavior" group, defined by inconsistent or nonuse of condoms during sexual intercourse and having had three or more sexual partners in the past 3 months, or having has sex with prostitutes or ever having a sexually transmitted disease, or using alcohol or other stimulating drugs during sexual intercourse. Males with favorable attitudes toward premarital sex were more likely to belong to the greater risk behavior group.Conclusions: This study demonstrated the potential risk for contracting sexually transmitted diseases among a substantial proportion of university students, suggesting the need for promotion of preventive education programs. [ABSTRACT FROM AUTHOR]

Background: Health authorities worldwide, especially in the Asia Pacific region, are seeking effective public-health interventions in the continuing epidemic of severe acute respiratory syndrome (SARS). We assessed the epidemiology of SARS in Hong Kong.Methods: We included 1425 cases reported up to April 28, 2003. An integrated database was constructed from several sources containing information on epidemiological, demographic, and clinical variables. We estimated the key epidemiological distributions: infection to onset, onset to admission, admission to death, and admission to discharge. We measured associations between the estimated case fatality rate and patients' age and the time from onset to admission.Findings: After the initial phase of exponential growth, the rate of confirmed cases fell to less than 20 per day by April 28. Public-health interventions included encouragement to report to hospital rapidly after the onset of clinical symptoms, contact tracing for confirmed and suspected cases, and quarantining, monitoring, and restricting the travel of contacts. The mean incubation period of the disease is estimated to be 6.4 days (95% CI 5.2-7.7). The mean time from onset of clinical symptoms to admission to hospital varied between 3 and 5 days, with longer times earlier in the epidemic. The estimated case fatality rate was 13.2% (9.8-16.8) for patients younger than 60 years and 43.3% (35.2-52.4) for patients aged 60 years or older assuming a parametric gamma distribution. A non-parametric method yielded estimates of 6.8% (4.0-9.6) and 55.0% (45.3-64.7), respectively. Case clusters have played an important part in the course of the epidemic.Interpretation: Patients' age was strongly associated with outcome. The time between onset of symptoms and admission to hospital did not alter outcome, but shorter intervals will be important to the wider population by restricting the infectious period before patients are placed in quarantine. [ABSTRACT FROM AUTHOR]

Purpose: To examine whether smoking, alcohol drinking and other risk factors were associated with non-fatal coronary heart disease (CHD) in Hong Kong Chinese.Methods: A case control study was carried out with 598 CHD hospital cases (431 men, 167 women) and 1100 community controls (663 men, 437 women). Standardized questionnaires were used and blood lipids were measured using standard methods.Results: Stepwise logistic regression models showed adjusted odds ratios (AOR) of 3.36 [95% confidence interval (CI): 2.35 to 4.81] for smoking and 0.32 (95% CI: 0.22 to 0.45) for alcohol drinking in men, and 6.50 (95% CI: 2.61 to 16.19) and 0.15 (95% CI: 0.08 to 0.30), respectively, in women. The OR increased with decreasing levels of high-density lipoprotein cholesterol (HDL) and increasing levels of triglycerides. No patterns were observed for body mass index (BMI), total and low-density lipoprotein cholesterol (LDL). The protective effect of drinking was observed for different types of drinks and frequency of drinking, although few drank alcohol more than 3 days per week.Conclusions: Smoking was a strong risk factor and moderate alcohol drinking was a protective factor for CHD, and low HDL and high triglyceride levels were important risk factors in Hong Kong Chinese. [ABSTRACT FROM AUTHOR]

Purpose: To compare the mortality risk of smoking and overall occupational exposure in Guangzhou, China.Methods: Baseline data on smoking and occupational exposure of 82159 workers aged 30+ were retrieved from medical records established in 1988-92. Vital status and causes of death were followed through 1998.Results: During follow-up 1584 workers had died. Adjusted relative risks (RR) with 95% confidence intervals (95%CI) for ever-smoking in men was 1.23 (1.07-1.41) for total deaths, 1.43 (1.17-1.74) for all cancer, 3.77 (2.31-6.14) for lung cancer and 2.54 (1.09-5.92) for stomach cancer (all showing significant linear trends with amount and duration of smoking). The RR in women of 1.10 (0.59-2.06) for total deaths and 1.60 (0.65-3.92) for all cancer were positive but not significant. No significant excess mortality risk was observed for occupational exposure in each gender. In both genders combined, the RR for total deaths was 1.23 (1.08-1.40) for smoking and 1.07 (0.96-1.19) for occupational exposure. If the relationships were causal, 12% of all deaths could be attributed to smoking but only 3% to occupational exposure.Conclusion: Smoking was more predictive of premature deaths than overall occupational exposures in middle aged workers. Smoking cessation should be a top priority in occupational health practice. [ABSTRACT FROM AUTHOR]

Objectives: To examine trends in deaths for conditions associated with secondhand smoke exposure over the years prior to and following the implementation of a smoke-free policy in Hong Kong., Design: Time-series study., Setting: Death registration data from Hong Kong Special Administrative Region (SAR) Government Census and Statistics Department., Participants: All deaths registered from 1 January 2001 to 31 December 2011., Main Outcome Measures: Deaths for conditions associated with passive smoking include cardiovascular disease (CVD), respiratory disease and other causes., Results: There was a decline in the annual proportional change for ischaemic heart disease (IHD), acute myocardial infarction (AMI) and CVD mortality in the year after the intervention for all ages and those aged 65 years or older. There were also clear declines in the cool season peaks for these three conditions in the first postintervention year. There was a further drop in the cool season peak for AMI among all ages in the year after the exemptions ceased. No declines in annual proportional change or changes in seasonal peaks of mortality were found for any of the control conditions., Conclusions: The findings in this study add to the evidence base, as summarised in the Surgeon General's report, extending the impact of effective smoke-free legislation to those aged 65 years or older and to cerebrovascular events in younger age groups. They also reinforced the need for comprehensive, enforced and effective smoke-free laws if the full extent of the health gains are to be achieved., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Background: A limited number of studies on long-term effects of particulate matter with aerodynamic diameter < 2.5 μm (PM2.5) on health suggest it can be an important cause of morbidity and mortality. In Asia where air quality is poor and deteriorating, local data on long-term effects of PM2.5 to support policy on air quality management are scarce., Objectives: We assessed long-term effects of PM2.5 on the mortality in a single Asian city., Methods: For 10-13 years, we followed up a cohort of 66,820 participants ≥ 65 years of age who were enrolled and interviewed in all 18 Elderly Health Centres of the Department of Health, Hong Kong, in 1998-2001. Their residential addresses were geocoded into x- and y-coordinates, and their proxy exposures to PM2.5 at their addresses in 1 × 1 km grids were estimated from the U.S. National Aeronautics and Space Administration (NASA) satellite data. We used Cox regression models to calculate hazard ratios (HRs) of mortality associated with PM2.5., Results: Mortality HRs per 10-μg/m3 increase in PM2.5 were 1.14 (95% CI: 1.07, 1.22) for all natural causes, 1.22 (95% CI: 1.08, 1.39) for cardiovascular causes, 1.42 (95% CI: 1.16, 1.73) for ischemic heart disease, 1.24 (95% CI: 1.00, 1.53) for cerebrovascular disease, and 1.05 (95% CI: 0.90, 1.22) for respiratory causes., Conclusions: Our methods in using NASA satellite data provide a readily accessible and affordable approach to estimation of a sufficient range of individual PM2.5 exposures in a single city. This approach can expand the capacity to conduct environmental accountability studies in areas with few measurements of fine particles., Citation: Wong CM, Lai HK, Tsang H, Thach TQ, Thomas GN, Lam KB, Chan KP, Yang L, Lau AK, Ayres JG, Lee SY, Chan WM, Hedley AJ, Lam TH. 2015. Satellite-based estimates of long-term exposure to fine particles and association with mortality in elderly Hong Kong residents. Environ Health Perspect 123:1167-1172; http://dx.doi.org/10.1289/ehp.1408264.

Objective: Estimates of illicit cigarette consumption are limited and the data obtained from studies funded by the tobacco industry have a tendency to inflate them. This study aimed to validate an industry-funded estimate of 35.9% for Hong Kong using a framework taken from an industry-funded report, but with more transparent data sources., Methods: Illicit cigarette consumption was estimated as the difference between total cigarette consumption and the sum of legal domestic sales and legal personal imports (duty-free consumption). Reliable data from government reports and scientifically valid routine sources were used to estimate the total cigarette consumption by Hong Kong smokers and legal domestic sales in Hong Kong. Consumption by visitors and legal duty-free consumption by Hong Kong passengers were estimated under three scenarios for the assumptions to examine the uncertainty around the estimate. A two-way sensitivity analysis was conducted using different levels of possible undeclared smoking and under-reporting of self-reported daily consumption., Results: Illicit cigarette consumption was estimated to be about 8.2-15.4% of the total cigarette consumption in Hong Kong in 2012 with a midpoint estimate of 11.9%, as compared with the industry-funded estimate of 35.9% of cigarette consumption. The industry-funded estimate was inflated by 133-337% of the probable true value. Only with significant levels of under-reporting of daily cigarette consumption and undeclared smoking could we approximate the value reported in the industry-funded study., Conclusions: The industry-funded estimate inflates the likely levels of illicit cigarette consumption., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background: The purpose of this study was to determine the reliability of detecting age-related macular degeneration (AMD) during screening for diabetic retinopathy (DR)., Methods: This prospective study included 2,003 subjects with diabetes mellitus who underwent photographic screening for DR. The reliability of detecting AMD lesions was tested by interobserver and intraobserver agreement, and the sensitivity and specificity of diagnosing AMD at different grades of severity were tested using the consensus grading of a group as the reference standard., Results: DR affected 24.7% of the subjects. The age-standardized prevalence of early AMD was 17.9%, and late AMD was 0.1%. The interobserver and intraobserver agreement for grading AMD was substantial (k = 0.72 and 0.71 respectively, p < 0.001). It was equally good in those with different severities of DR. There was also no difference in sensitivity and specificity of detecting AMD in those with different levels of DR (sensitivity 62-68% and specificity 97-98%)., Conclusion: Intermediate- and high-risk AMD that warrant treatment with zinc and anti-oxidant supplements could be reliably detected during screening for diabetic retinopathy.

The World Health Organization (WHO) Air Quality Guidelines (AQG) were launched in 2006, but gaps remain in evidence on health impacts and relationships between short-term and annual AQG needed for health protection. We tested whether relationships between WHO short-term and annual AQG for particulates (PM10 and PM2.5) and nitrogen dioxide (NO2) are concordant worldwide and derived the annual limits for sulfur dioxide (SO2) and ozone (O3) based on the short-term AQG. We obtained air pollutant data over seven years (2004-2010) in seven cities from Asia-Pacific, North America and Europe. Based on probability distribution concept using maximum as the short-term limit and arithmetic mean as the annual limit, we developed a new method to derive limit value one from another in each paired limits for each pollutant with capability to account for allowable exceedances. We averaged the limit derived each year for each city, then used meta-analysis to pool the limit values in all cities. Pooled mean short-term limit for NO2 (140.5μg/m(3) [130.6-150.4]) was significantly lower than the WHO AQG of 200μg/m(3) while for PM10 (46.4μg/m(3) [95CI:42.1-50.7]) and PM2.5 (28.6μg/m(3) [24.5-32.6]) were not significantly different from the WHO AQG of 50 and 25μg/m(3) respectively. Pooled mean annual limits for SO2 and O3 were 4.6μg/m(3) [3.7-5.5] and 27.0μg/m(3) [21.7-32.2] respectively. Results were robust in various sensitivity analyses. The distribution relationships between the current WHO short-term and annual AQG are supported by empirical data from seven cities for PM10 and PM2.5, but not for NO2. The short-term AQG for NO2 should be lowered for concordance with the selected annual AQG for health protection., (Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.)

We assessed the effects of apparent temperature (AT) on mortality and the effect modifications attributable to individual characteristics in Hong Kong with subtropical climate conditions. Two datasets are used for analyses: one from mortality data of the general elderly population in 1998-2009; the other from an elderly cohort with 66,820 subjects recruited in 1998-2001 with mortality outcomes followed up until 2009. We found that AT below 20.8 °C was associated with an increase in mortality risk of 1.99% (95% confidence interval: 0.64%, 2.64%) for all causes, 2.48% (0.57%, 4.36%) for cardiovascular disease, and 3.19% (0.59%, 5.73%) for respiratory disease for every 1 °C decrease in AT over the following 3 days. The associations were modified by sex and body mass index, in particular stronger associations were observed for females and for obese subjects., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objective: To examine whether the inverse care law operates in a screening program for diabetic retinopathy (DR) based on fee for service in Hong Kong., Design: Randomized controlled trial., Participants: All those with type 1 or 2 diabetes from 2 clinics were recruited., Intervention: Diabetic retinopathy screening with a small copayment versus free access in a publicly funded family medicine service., Main Outcome Measures: Uptake of screening and severity of DR detected. Association between these outcome variables and independent variables were determined using multivariate logistic regression models and reported as odds ratios (ORs)., Results: After randomization, 1387 subjects in the free group and 1379 subjects in the pay group were eligible for screening, and 94.9% (1316/1387) and 92.6% (1277/1379), respectively, agreed to participate in the study. The offer of screening was accepted by 94.8% (1247/1316) in the free group and 91.2% (1164/1277) in the pay group, and the final uptake ratios were 88.5% (1165/1316) and 82.4% (1052/1277), respectively (Pearson chi = 19.74, P<0.001). Being in the pay group was associated with a lower uptake of screening than being in the free group (OR, 0.59; confidence interval [CI], 0.47-0.74) and a lower detection rate of DR (OR, 0.73; CI, 0.60-0.90) after adjustment for potential confounding factors. Subjects with higher socioeconomic status were more likely to attend screening and had a lower prevalence of DR detected., Conclusions: The inverse care law seems to operate in a preventive intervention when a relatively small copayment is applied. There is a case for making effective preventive services free of charge., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Global marine vessels emissions are adversely affecting human health particularly in southeast Asia. But health burdens from both ocean- and river-going vessels in Pearl River Delta (PRD) regions are not quantified. We estimated the potential health impacts using pooled relative risks of mortality and hospital admissions in China, and the model derived concentrations of sulfur dioxide (SO₂), particulate matter (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃) due to vessels emissions. SO₂ concentrations due to marine emissions in Hong Kong were 13.6 μg m⁻³ compared with 0.7 μg m⁻³ in PRD regions that were far from the marine vessels. In PRD regions, the estimated annual numbers (per million people) of excess deaths from all natural causes and hospital admissions from cardiorespiratory causes attributable to SO₂, NO₂, O₃ and PM₁₀ combined from marine emissions were 45 and 265 respectively. Marine emission control measures could contribute a large reduction in mortality and hospital admissions in PRD regions especially in Hong Kong., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

This study examined if 2-week free nicotine replacement therapy (NRT) would be more effective than 1-week free NRT to help smokers quit smoking at 6 and 12 months. In a single-blinded randomized controlled trial design, 562 Chinese smokers who attended a smoking cessation clinic in Hong Kong, China, were randomly allocated into two groups (A1 and A2): A1 (n = 284) received behavioural counselling with free NRT for 1 week; A2 (n = 278) received similar counselling with free NRT for 2 weeks. All subjects received printed self-help materials to support their quitting efforts. A structured questionnaire was used for data collection, including pattern of NRT use and self-reported 7-day point prevalence quit rate at 6 months and 12 months. Among the participants, the mean number of cigarettes smoked per day was 18.8 (SD = 10.9). By intention-to-treat analysis, 7-day point prevalence quit rates were not significantly different between A1 and A2 groups at 6-month (27.5% versus 27.3%; P = 0.97) and 12-month (21.1% versus 21.2%; P = 0.98) followup. The findings suggest that two-week free NRT was not more effective than 1-week free NRT to increase smoking cessation rate among Chinese smokers.

Introduction: After the implementation of a regulation restricting sulfur to 0.5% by weight in fuel on July 1, 1990, in Hong Kong, sulfur dioxide (SO2*) levels fell by 45% on average and as much as 80% in the most polluted districts (Hedley et al. 2002). In addition, a reduction of respiratory symptoms and an improvement in bronchial hyperresponsiveness in children were observed (Peters et al. 1996; Wong et al. 1998). A recent time-series study (Hedley et al. 2002) found an immediate reduction in mortality during the cool season at six months after the intervention, followed by an increase in cool-season mortality in the second and third years, suggesting that the reduction in pollution was associated with a delay in mortality. Proportional changes in mortality trends between the 5-year periods before and after the intervention were measured as relative risks and used to assess gains in life expectancy using the life table method (Hedley et al. 2002). To further explore the relation between changes in pollution-related mortality before and after the intervention, our study had three objectives: (1) to evaluate the short-term effects on mortality of changes in the pollutant mix after the Hong Kong sulfur intervention, particularly with changes in the particulate matter (PM) chemical species; (2) to improve the methodology for assessment of the health impact in terms of changes in life expectancy using linear regression models; and (3) to develop an approach for analyzing changes in life expectancy from Poisson regression models. A fourth overarching objective was to determine the relation between short- and long-term benefits due to an improvement in air quality., Methods: For an assessment of the short-term effects on mortality due to changes in the pollutant mix, we developed Poisson regression Core Models with natural spline smoothers to control for long-term and seasonal confounding variations in the mortality counts and with covariates to adjust for temperature (T) and relative humidity (RH). We assessed the adequacy of the Core Models by evaluating the results against the Akaike Information Criterion, which stipulates that, at a minimum, partial autocorrelation plots should be between -0.1 and 0.1, and by examining the residual plots to make sure they were free from patterns. We assessed the effects for gaseous pollutants (NO2, SO2, and O3), PM with an aerodynamic diameter < or = 10 microm (PM10), and its chemical species (aluminum [Al], iron [Fe], manganese [Mn], nickel [Ni], vanadium [V], lead [Pb], and zinc [Zn]) using the Core Models, which were developed for the periods 5 years (or 2 years in the case of the sensitivity analysis) before and 5 years after the intervention, as well as in the10-year (or 7-year in the case of the sensitivity analysis) period pre- and post-intervention. We also included an indicator to separate the pre- and post-intervention periods, as well as the product of the indicator with an air pollution concentration variable. The health outcomes were mortality for all natural causes and for cardiovascular and respiratory causes, at all ages and in the 65 years or older age group. To assess the short- and long-term effects, we developed two methods: one using linear regression models reflecting the age-standardized mortality rate D(j) at day j, divided by a reference D(ref); and the other using Poisson regression models with daily mortality counts as the outcome variables. We also used both models to evaluate the relation between outcome variables and daily air pollution concentrations in the current day up to all previous days in the past 3 to 4 years. In the linear regression approach, we adjusted the data for temperature and relative humidity. We then removed season as a potential confounder, or deseasonalized them, by calculating a standard seasonal mortality rate profile, normalized to an annual average of unity, and dividing the mortality rates by this profile. Finally, to correct for long-term trends, we calculated a reference mortality rate D(ref)(j) as a moving average of the corrected and deseasonalized D(j) over the observation window. Then we regressed the outcome variable D(j)/D(ref) on an entire exposure sequence {c(i)} with lags up to 4 years in order to obtain impact coefficient f(i) from the regression model shown below: deltaD(j)/D (ref) = i(max)sigma f(i) c(j - i)(i = 0). The change in life expectancy (LE) for a change of units (deltac) in the concentration of pollutants on T(day)--representing the short interval (i.e., a day)--was calculated from the following equation (deltaL(pop) = average loss in life expectancy of an entire population): deltaL(pop) = -deltac T(day) infinity sigma (j = 0) infinity sigma f(i) (i = 0). In the Poisson regression approach, we fitted a distributed-lag model for exposure to previous days of up to 4 years in order to obtain the cumulative lag effect sigma beta(i). We fit the linear regression model of log(LE*/LE) = gamma(SMR - 1) + alpha to estimate the parameter gamma by gamma, where LE* and LE are life expectancy for an exposed and an unexposed population, respectively, and SMR represents the standardized mortality ratio. The life expectancy change per Ac increase in concentration is LE {exp[gamma delta c(sigma beta(i))]-1}., Results: In our assessment of the changes in pollutant levels, the mean levels of SO2, Ni, and V showed a statistically significant decline, particularly in industrial areas. Ni and V showed the greatest impact on mortality, especially for respiratory diseases in the 5-year pre-intervention period for both the all-ages and 65+ groups among all chemical species. There were decreases in excess risks associated with Ni and V after the intervention, but they were nonsignificant. Using the linear regression approach, with a window of 1095 days (3 years), the losses in life expectancy with a 10-microg/m3 increase in concentrations, using two methods of estimation (one with adjustment for temperature and RH before the regression against pollutants, the other with adjustment for temperature and RH within the regression against pollutants), were 19.2 days (95% CI, 12.5 to 25.9) and 31.4 days (95% CI, 25.6 to 37.2) for PM10; and 19.7 days (95% CI, 15.2 to 24.2) and 12.8 days (95% CI, 8.9 to 16.8) for SO2. The losses in life expectancy in the current study were smaller than the ones implied by Elliott and colleagues (2007) and Pope and colleagues (2002) as expected since the observation window in our study was only 3 years whereas these other studies had windows of 16 years. In particular, the coefficients used by Elliott and colleagues (2007) for windows of 12 and 16 years were non-zero, which suggests that our window of at most 3 years cannot capture the full life expectancy loss and the effects were most likely underestimated. Using the Poisson regression approach, with a window of 1461 days (4 years), we found that a 10-microg/m3 increase in concentration of PM10 was associated with a change in life expectancy of -69 days (95% CI, -140 to 1) and a change of -133 days (95% CI, -172 to -94) for the same increase in SO2. The effect estimates varied as expected according to most variations in the sensitivity analysis model, specifically in terms of the Core Model definition, exposure windows, constraint of the lag effect pattern, and adjustment for smoking prevalence or socioeconomic status., Conclusions: Our results on the excess risks of mortality showed exposure to chemical species to be a health hazard. However, the statistical power was not sufficient to detect the differences between the pre- and post-intervention periods in Hong Kong due to the data limitations (specifically, the chemical species data were available only once every 6 days, and data were not available from some monitoring stations). Further work is needed to develop methods for maximizing the information from the data in order to assess any changes in effects due to the intervention. With complete daily air pollution and mortality data over a long period, time-series analysis methods can be applied to assess the short- and long-term effects of air pollution, in terms of changes in life expectancy. Further work is warranted to assess the duration and pattern of the health effects from an air pollution pulse (i.e., an episode of a rapid rise in air pollution) so as to determine an appropriate length and constraint on the distributed-lag assessment model.