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Abstract Background In epidemiological studies, subjects are often followed for a period during which study outcomes are measured at selected time points, such as by diagnostic testing performed on biological samples collected at each visit. Although test results may indicate the presence or absence of a disease or condition, they cannot provide information on when exactly it occurred. Such study designs generate arbitrarily censored time-to-event data, which can include left, interval and right censoring. Adding to this complexity, the data may be clustered such that observations within the same cluster are not independent, such as time to recovery of an infectious disease of family or community members. This data structure is observed when evaluating circumcision's effect on clearance of penile high risk human papillomavirus (HR-HPV) infections using data collected from the male circumcision(MC) trial conducted in Rakai, Uganda, where the multiple infections within individual and HPV testings performed at trial follow-up visits gave rise to the clustered data with arbitrary censoring. Methods We describe the use of parametric proportional hazards frailty models and accelerated failure time frailty models to examine the relationship between explanatory variables and the survival outcomes that are subject to arbitrary censoring, while accounting for the correlation within clusters. Standard software such as SAS can be used for parameter estimation. Results Circumcision's effect on HPV infection was a secondary end point in the Rakai MC trial, and HPV genotyping was conducted for penile samples of a subset of trial participants collected at enrollment, 6, 12 and 24-month follow up visits. At enrollment, 36.7% intervention arm men (immediate circumcision) and 36.6% control arm men (delayed circumcision at 2 years) were infected with HR-HPV, with the number of infections per man being 1-5. The proposed models were used to examine whether MC facilitated clearance of the prevalent infections. Results show that clearance of multiple infections within each man is highly correlated, and clearance was 60% faster if a man was circumcised. Conclusions Parametric frailty models provide viable ways to study the relationship between exposure variables and clustered survival outcome that is subject to arbitrary censoring, as is often observed in HPV epidemiology studies.

Rationale: Approximately 40% of people worldwide are exposed to household air pollution (HAP) from the burning of biomass fuels. Previous efforts to document health benefits of HAP mitigation have been stymied by an inability to lower emissions to target levels. Objectives: We sought to determine if a household air pollution intervention with liquefied petroleum gas (LPG) improved cardiopulmonary health outcomes in adult women living in a resource-poor setting in Peru. Methods: We conducted a randomized controlled field trial in 180 women aged 25-64 years living in rural Puno, Peru. Intervention women received an LPG stove, continuous fuel delivery for 1 year, education, and behavioral messaging, whereas control women were asked to continue their usual cooking practices. We assessed for stove use adherence using temperature loggers installed in both LPG and biomass stoves of intervention households. Measurements and Main Results: We measured blood pressure, peak expiratory flow (PEF), and respiratory symptoms using the St. George's Respiratory Questionnaire at baseline and at 3-4 visits after randomization. Intervention women used their LPG stove exclusively for 98% of days. We did not find differences in average postrandomization systolic blood pressure (intervention - control 0.7 mm Hg; 95% confidence interval, -2.1 to 3.4), diastolic blood pressure (0.3 mm Hg; -1.5 to 2.0), prebronchodilator peak expiratory flow/height2 (0.14 L/s/m2; -0.02 to 0.29), postbronchodilator peak expiratory flow/height2 (0.11 L/s/m2; -0.05 to 0.27), or St. George's Respiratory Questionnaire total score (-1.4; -3.9 to 1.2) over 1 year in intention-to-treat analysis. There were no reported harms related to the intervention. Conclusions: We did not find evidence of a difference in blood pressure, lung function, or respiratory symptoms during the year-long intervention with LPG. Clinical trial registered with www.clinicaltrials.gov (NCT02994680). [ABSTRACT FROM AUTHOR]

Background: Schistosoma haematobium is a parasitic helminth that causes urogenital pathology. The impact of urogenital schistosomiasis during pregnancy on birth outcomes and child growth is poorly understood.Methods: Risk factors for urogenital schistosomiasis were characterized among 4437 pregnant women enrolled in a cluster-randomized community-based trial in rural Zimbabwe. Infection was defined via urine microscopy (≥1 S. haematobium egg) and urinalysis (hematuria). Associations between infection and pregnancy outcomes were assessed in case-control analyses using conditional logistic regression. The association of maternal infection with birthweight and length-for-age Z scores (LAZ) at 1 and 18 months of age were assessed using generalized estimating equations.Results: Urogenital schistosomiasis (egg positive and/or hematuria positive) was detected in 26.8% of pregnant women. Risk factors significantly associated with infection were maternal age, education, marital status, and religion; household drinking water source and latrine; study region; and season. Urogenital schistosomiasis was not significantly associated with adverse pregnancy outcomes (miscarriage, stillbirth, preterm, and small-for-gestational age), birthweight, neonatal death, or LAZ.Conclusions: Including pregnant women in antihelminthic treatment programs would benefit a large number of women in rural Zimbabwe. However, clearance of the low-intensity infections that predominate in this context is unlikely to have additive benefits for pregnancy outcomes or child growth.Clinical Trials Registration: NCT01824940. [ABSTRACT FROM AUTHOR]

Between birth and 2 years, children's well‐being depends on the quality of care they receive from caregivers, primarily their mothers. We developed a quantitative survey instrument to assess seven psychosocial characteristics of women that determine their caregiving ability ('maternal capabilities': physical health, mental health, decision‐making autonomy, social support, mothering self‐efficacy, workload and time stress, and gender norm attitudes). We measured maternal capabilities in 4,025 mothers and growth in their 4,073 children participating in the Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial in rural Zimbabwe. We used generalized estimating equation models with exchangeable correlation structure to test the association between each maternal capability during pregnancy, and infant length‐for‐age Z (LAZ) at 18 months, accounting only for within‐cluster correlation and intervention arms in unadjusted analyses and for potential confounders in adjusted analyses to examine the association between each capability, assessed during pregnancy, with child LAZ at 18 months of age. In adjusted models, each unit increase in gender norm attitudes score (reflecting more equitable gender norm attitudes) was associated with +0.09 LAZ (95% CI: 0.02, 0.16) and a decreased odds of stunting (adjusted odds ratio [AOR]: 0.86; 95% CI: 0.74, 1.01); each unit increase in social support score was associated with +0.11 LAZ (95% CI: 0.05, 0.17, p < 0.010) and decreased odds of stunting (AOR: 0.83; 95% CI: 0.73, 0.96). Each unit increase in decision‐making autonomy was associated with a 6% reduced odds of stunting (AOR: 0.94; 95% CI: 0.89, 0.996, p = 0.04). Interventions and social programming that strengthen these maternal capabilities may improve child nutritional status. [ABSTRACT FROM AUTHOR]

Background Clinical outcomes of children who are human immunodeficiency virus (HIV)–exposed in sub-Saharan Africa remain uncertain. Methods The Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial evaluated improved infant and young child feeding (IYCF) and/or improved water, sanitation, and hygiene in 2 rural Zimbabwean districts with 15% antenatal HIV prevalence and > 80% prevention of mother-to-child transmission (PMTCT) coverage. Children born between February 2013 and December 2015 had longitudinal HIV testing and anthropometry. We compared mortality and growth between children who were HIV-exposed and HIV-unexposed through 18 months. Children receiving IYCF were excluded from growth analyses. Results Fifty-one of 738 (7%) children who were HIV-exposed and 198 of 3989 (5%) children who were HIV-unexposed (CHU) died (hazard ratio, 1.41 [95% confidence interval {CI}, 1.02–1.93]). Twenty-five (3%) children who were HIV-exposed tested HIV positive, 596 (81%) were HIV-exposed uninfected (CHEU), and 117 (16%) had unknown HIV status by 18 months; overall transmission estimates were 4.3%–7.7%. Mean length-for-age z score at 18 months was 0.38 (95% CI,.24–.51) standard deviations lower among CHEU compared to CHU. Among 367 children exposed to HIV in non-IYCF arms, 147 (40%) were alive, HIV-free, and nonstunted at 18 months, compared to 1169 of 1956 (60%) CHU (absolute difference, 20% [95% CI, 15%–26%]). Conclusions In rural Zimbabwe, mortality remains 40% higher among children exposed to HIV, vertical transmission exceeds elimination targets, and half of CHEU are stunted. We propose the composite outcome of "alive, HIV free, and thriving" as the long-term goal of PMTCT programs. Clinical Trials Registration NCT01824940. [ABSTRACT FROM AUTHOR]

Background Norovirus is a leading cause of acute gastroenteritis worldwide, yet there is limited information on homotypic or heterotypic protection following natural infection to guide vaccine development. Methods A total of 6020 stools collected from 299 Peruvian children between 2010 and 2014 were tested by norovirus real-time reverse-transcription polymerase chain reaction followed by sequence-based genotyping. Cox proportional hazards models were used to derive adjusted hazard ratios (HRs) of infection among children with vs without prior exposure. Results Norovirus was detected in 1288 (21.3%) samples. GII.4 (26%), GII.6 (19%), and GI.3 (9%) viruses accounted for 54% of infections. Homotypic protection for GI.3 (HR, 0.35; P  = .015), GI.7 (HR, 0.19; P  = .022), GII.4 (HR, 0.39; P  < .001), and GII.6 (HR, 0.52; P  = .006) infections was observed. Hazard analysis showed that children with prior GII.4 infection exhibited heterotypic protection with a 48% reduction of subsequent GI.3 infection (HR, 0.52; P  = .005). Prior exposure to GI.3, GII.2, and GII.17 infections enhanced susceptibility to subsequent infections with several other norovirus genotypes. Conclusions Children up to 2 years of age infected with GII.4 noroviruses demonstrated both homotypic and heterotypic protection to reinfection with other genotypes. These data support the need for ongoing vaccine development efforts with GII.4 as the main component and caution the inclusion of genotypes that may enhance susceptibility to infections. [ABSTRACT FROM AUTHOR]

Background: The prediction of future obesity patterns is crucial for effective strategic planning. However, disproportionally changing body mass index (BMI) distributions pose particular challenges. Flexible modelling of the shape of BMI distributions may improve prediction performance.Methods: We used data from repeated national health surveys conducted in Mexico, Colombia and Peru at four or five time points between 1988 and 2014. Data from all surveys except the last survey were used to construct prediction models for three obesity indicators (median BMI, overweight/obesity prevalence and obesity prevalence) for the time of the last survey. We assessed their performance using predicted curves, absolute prediction errors and comparison of actual and predicted distributions. With one method, we modelled the shape of BMI distributions assuming BMI follows a Box-Cox Power Exponential (BCPE) distribution, whose parameters were modelled as a function of interval or nominal 5-year age groups, time and their interaction terms. In a second method, we modelled each of the obesity indicators directly as a function of the same covariates using quantile and logistic regression.Results: The BCPE model with interval age groups yielded the best prediction performance in predicting obesity prevalence. Average absolute prediction errors across all age groups were 4.3 percentage points (95% percentile interval: 1.9, 7.5), 2.5 (1.2, 6.1) and 1.7 (1.0, 9.3), with data from Mexico, Colombia and Peru, respectively. This superiority was weak or none for overweight/obesity prevalence and median BMI.Conclusion: The BCPE model performed better for prediction of the extremes of BMI distribution, possibly by incorporating its shape more precisely. [ABSTRACT FROM AUTHOR]

Background: We assessed the impact of water, sanitation, and hygiene (WASH) and infant and young child feeding (IYCF) interventions on enteric infections in the Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial in rural Zimbabwe.Methods: We tested stool samples collected at 1, 3, 6, and 12 months of age and during diarrhea using quantitative molecular diagnostics for 29 pathogens. We estimated the effects of the WASH, IYCF, and combined WASH + IYCF interventions on individual enteropathogen prevalence and quantity, total numbers of pathogens detected, and incidence of pathogen-attributable diarrhea.Results: WASH interventions decreased the number of parasites detected (difference in number compared to non-WASH arms, -0.07 [95% confidence interval, -.14 to -.02]), but had no statistically significant effects on bacteria, viruses, or the prevalence and quantity of individual enteropathogens after accounting for multiple comparisons. IYCF interventions had no significant effects on individual or total enteropathogens. Neither intervention had significant effects on pathogen-attributable diarrhea.Conclusions: The WASH interventions implemented in SHINE (improved pit latrine, hand-washing stations, liquid soap, point-of-use water chlorination, and clean play space) did not prevent enteric infections. Transformative WASH interventions are needed that are more efficacious in interrupting fecal-oral microbial transmission in children living in highly contaminated environments. [ABSTRACT FROM AUTHOR]

The Iraq war in 2003 is regarded as an instance of highly asymmetrical conflict, although Iraq's armed forces were in different league from the Taliban ragtag troops. Accordingly, a study about civilian victims in Afghanistan that emerged as a sideline to a landmine contamination assessment is conducted.

Background: Environmental enteric dysfunction (EED) may be an important modifiable cause of child stunting. We described the evolution of EED biomarkers from birth to 18 months in rural Zimbabwe and tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF), on EED. Methodology and findings: The Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial was a 2x2 factorial cluster-randomised trial of improved IYCF and improved WASH on child stunting and anaemia at 18 months of age. 1169 infants born to HIV-negative mothers provided plasma and faecal specimens at 1, 3, 6, 12, and 18 months of age. We measured EED biomarkers that reflect all domains of the hypothesized pathological pathway. Markers of intestinal permeability and intestinal inflammation declined over time, while markers of microbial translocation and systemic inflammation increased between 1–18 months. Markers of intestinal damage (I-FABP) and repair (REG-1β) mirrored each other, and citrulline (a marker of intestinal epithelial mass) increased from 6 months of age, suggesting dynamic epithelial turnover and regeneration in response to enteric insults. We observed few effects of IYCF and WASH on EED after adjustment for multiple comparisons. The WASH intervention decreased plasma IGF-1 at 3 months (β:0.89, 95%CI:0.81,0.98) and plasma kynurenine at 12 months (β: 0.92, 95%CI:0.87,0.97), and increased plasma IGF-1 at 18 months (β:1.15, 95%CI:1.05,1.25), but these small WASH effects did not translate into improved growth. Conclusions: Overall, we observed dynamic trends in EED but few effects of IYCF or WASH on biomarkers during the first 18 months after birth, suggesting that these interventions did not impact EED. Transformative WASH interventions are required to prevent or ameliorate EED in low-income settings. Author summary: Child stunting remains a global health challenge rooted in an intergenerational cycle of poor health, reduced neurodevelopment and poverty. Environmental enteric dysfunction (EED) is an acquired condition of the small intestine likely resulting from frequent faecal-oral microbial exposure, which is hypothesized to underlie stunting. We found dynamic changes in EED biomarkers between 1 and 18 months of age in a cohort of rural Zimbabwean infants, suggesting a complex developmental period of intestinal maturation, adaptation and response to environmental insults. Randomized improved infant and young child feeding, and improved water, sanitation and hygiene (WASH) interventions had no meaningful impact on EED. Greater investment in transformative WASH is needed to prevent EED in low-income countries. [ABSTRACT FROM AUTHOR]

Background: Demographic and Health Survey (DHS) data are an important source of maternal, newborn, and child health as well as nutrition information for low- and middle-income countries. However, DHSs are often unavailable at the administrative unit that is most interesting or useful for program planning. In addition, the location of DHS survey clusters are geomasked within 10 km, and prior to 2009, may have crossed district boundaries. We aim to use DHS surveyed information with these geomasked coordinates to estimate district assignments for use in health program planning and evaluation. Methods: We developed three methods to assign a district to a geomasked survey cluster in two DHS surveys from Malawi: 2000 and 2004. Method A assigns districts of origin in proportion to the likelihood that results from repeated simulated geomasking, allowing more than one possible district of origin. Method B assigns a single district of origin which contains the greatest proportion of simulated geomasked survey clusters. Method C maps the geomasked survey cluster's location to a district polygon. We used these method assignments to estimate a selection of commonly used coverage indicators for each district. We compared the district coverage estimates, confidence intervals, and concordance correlation coefficients, by each of the methods, to those which used validated district assignments in 2004, and we looked at coverage change from 2000 to 2004. Results: The methods we tested each approximated the validated estimates in 2004 by confidence interval comparison and concordance correlation coefficient. Estimated agreement for method A was between.14 and.98, for method B the estimated agreement was between.97 and.99, and for method C the agreement ranged from.93 to.99 when compared with the validated district assignments. Therefore, we recommend the protocol which is the simplest to implement—method C—overlaying geomasked survey cluster within district polygon. Conclusions: Using geomasked survey clusters from DHSs to assign districts provided district level coverage rates similar to those using the validated surveyed locations. This method may be applied to data sources where survey cluster centroids are available and where district level estimates are needed for program implementation and evaluation in low- and middle-income settings. This method is of special interest to those using DHSs to study spatiotemporal trends as it allows for the utilization of historic DHS data where geomasking hinders the generation of reliable subnational estimates of health in areas smaller than the first-order administrative unit (ADM1). [ABSTRACT FROM AUTHOR]

Background Oral vaccines have lower efficacy in developing compared to developed countries. Poor water, sanitation, and hygiene (WASH) may contribute to reduced oral vaccine immunogenicity. Methods We conducted a cluster-randomized 2 × 2 factorial trial in rural Zimbabwe. Pregnant women and their infants were eligible if they lived in clusters randomized to (1) standard of care (52 clusters); (2) improved infant feeding (53 clusters); (3) WASH: ventilated improved pit latrine, 2 hand-washing stations, liquid soap, chlorine, infant play space, and hygiene counseling (53 clusters); or (4) feeding plus WASH (53 clusters). This substudy compared oral rotavirus vaccine (RVV) seroconversion (primary outcome), and seropositivity and geometric mean titer (GMT) (secondary outcomes), in WASH vs non-WASH infants by intention-to-treat analysis. Results We included 801 infants with documented RVV receipt and postvaccine titer measurements (329 from 84 WASH clusters; 472 from 102 non-WASH clusters); 328 infants with prevaccination titers were included in the primary outcome. Thirty-three of 109 (30.3%) infants in the WASH group seroconverted following rotavirus vaccination, compared to 43 of 219 (19.6%) in the non-WASH group (absolute difference, 10.6% [95% confidence interval {CI},.54%–20.7%]; P =.031). In the WASH vs non-WASH groups, 90 of 329 (27.4%) vs 107 of 472 (22.7%) were seropositive postvaccination (absolute difference, 4.7% [95% CI, –1.4% to 10.8%]; P =.130), and antirotavirus GMT was 18.4 (95% CI, 15.6–21.7) U/mL vs 14.9 (95% CI, 13.2–16.8) U/mL (P =.072). Conclusions Improvements in household WASH led to modest but significant increases in seroconversion to RVV in rural Zimbabwean infants. Clinical Trials Registration NCT01824940. [ABSTRACT FROM AUTHOR]

Background: Household surveys are an essential tool for vaccine coverage monitoring in developing countries, and the World Health Organization (WHO) Expanded Program on Immunization (EPI) cluster survey design has been a default choice for decades. In response to methodological limitations of the traditional EPI sampling, alternative methods have been proposed, based on modern statistical and geographical techniques. This study compared the coverage estimates and the time efficiency of the EPI sampling design and two alternative methods: the compact segment sampling and innovative grid-based geographical information system (GIS) sampling.Methods: We conducted a series of equal-sized concurrent prospective vaccine coverage surveys in Karachi, Pakistan, from January to December 2016, using traditional EPI, compact segment and grid-based GIS sampling methods.Results: No differences in vaccine coverage estimates were identified across sampling methods in the peri-urban setting; however, due to stronger clustering effects and correct incorporation of sampling weights, the compact segment [design effect (DEFF) = 2.03] and the grid-based GIS surveys (DEFF = 1.72) had higher design effects and, therefore, appeared to have lower statistical precision than the traditional EPI surveys (DEFF = 1.57). To achieve the same level of apparent precision, data collection activities in the compact segment surveys would require more than twice the implementation time needed compared with the traditional EPI surveys.Conclusions: The precision of the EPI surveys appeared higher than that of the alternative methods because, under a questionable self-weighting assumption, the estimated design effect did not account for variable sampling weights. The compact segment and grid-based GIS methods were designed to improve randomness and representativeness of sampling households. Although these alternative methods did not result in coverage estimates that differed from the EPI survey results in the peri-urban setting, they have a lower risk of selection bias and therefore may be preferred. [ABSTRACT FROM AUTHOR]

Background Tuberculosis (TB) remains the leading cause of death among human immunodeficiency virus (HIV)–infected individuals globally. Screening for TB at the point of HIV diagnosis with a high-sensitivity assay presents an opportunity to reduce mortality. Methods We performed a cluster randomized trial of TB screening among adults newly diagnosed with HIV in 12 primary health clinics in rural Thyolo, Malawi. Clinics were allocated in a 1:1 ratio to perform either point-of-care Xpert MTB/RIF assay (Xpert) or point-of-care light-emitting diode fluorescence microscopy (LED-FM) for individuals screening positive for TB symptoms. Asymptomatic participants were offered isoniazid preventive therapy in both arms. Investigators, but not clinic staff or participants, were masked to allocation. Our primary outcome was the incidence rate ratio (RR) of all-cause mortality within 12 months of HIV diagnosis. Results Prevalent TB was diagnosed in 24 of 1001 (2.4%) individuals enrolled in clinics randomized to Xpert, compared with 10 of 841 (1.2%) in clinics randomized to LED-FM. All-cause mortality was 22% lower in the Xpert arm than in the LED-FM arm (6.7 vs 8.6 per 100 person-years; RR, 0.78 [95% confidence interval {CI},.58–1.06]). A planned subgroup analysis suggested that participants with more advanced HIV (World Health Organization clinical stage 3 or 4) disease had lower mortality in clinics randomized to Xpert than to LED-FM (RR, 0.43 [95% CI,.22–.87]). Conclusions In rural Malawi, using point-of-care Xpert MTB/RIF to test symptomatic patients for TB at the time of HIV diagnosis reduced all-cause 12-month mortality among individuals with advanced HIV. Clinical Trials Registration NCT01450085. [ABSTRACT FROM AUTHOR]