International Journal of Hygiene and Environmental Health

BackgroundChildhood lead exposure is prevalent worldwide including low- and middle-income countries (LMICs). Structured screening and prevention programs to address pediatric lead exposure are largely absent in these settings. Adapted interventions are needed to close this implementation gap in an urban African context. This paper describes the protocol for the Lead Exposure Intervention Program (LEIP), which aims to adapt, pilot, and evaluate a pediatric lead exposure screening and risk-reduction protocol in Nairobi, Kenya. MethodsLEIP is a multi-phase, hybrid type 3 implementation-effectiveness study. Phase 1 is a formative one-arm study leveraging an existing mother-child cohort and stakeholder-led tools adaptation to pilot a program comprising blood lead level (BLL) screening with a lead risk survey and tailored caregiver risk reduction messaging. Phase 2 is a randomized trial in public sector clinics. In this phase, approximately 1,500 children will be screened to identify 100 with elevated BLL ([≥]5 {micro}g/dL) for enrollment, who will then be randomized 1:1 to receive either clinic-only risk-reduction messaging or the same clinic-based messaging plus a home visit for environmental assessment and additional tailored messaging. Follow-up at 3 and 9 months will assess caregiver recall of key messages and adoption of recommended exposure-reduction behaviors, as well as changes in child BLL. Phase 3 involves qualitative interviews with caregivers and key stakeholders to identify multi-level barriers and facilitators to intervention uptake. Quantitative and qualitative findings will be integrated to inform refinements for scale-up. DiscussionThis study represents a critical opportunity to develop and evaluate an adaptive, screening-based lead exposure intervention tailored to the urban LMIC context. By incorporating implementation science principles and stakeholder-driven design, LEIP is well-positioned to inform scalable national and regional approaches. The inclusion of both quantitative and qualitative components enhances the protocols ability to capture multilevel dynamics of uptake, fidelity, and sustainability, and generate actionable insights for future large-scale implementations. Trial RegistrationRegistered on ClinicalTrials.gov (NCT07401251)

The emergence of the novel monkeypox virus (MPXV) clade Ib in the Democratic Republic of the Congo (DRC) and neighboring countries in late 2023 highlighted the need for rapid, scalable surveillance approaches to support outbreak detection and response. As part of the ODIN-Mpox project, wastewater surveillance (WWS) systems were established as an emergency public health measure in three Sub-Saharan African countries (DRC, Tanzania, and Burkina Faso) to evaluate the feasibility of wastewater-based monitoring for mpox and strengthen local surveillance capacity. Between January 2025 and April 2026, 117 wastewater samples were collected from selected sites and analyzed for MPXV DNA using targeted qPCR assays. Clinical mpox data were obtained from national surveillance systems and WHO reports to assess epidemiological linkages between wastewater detections and reported infections. Six wastewater samples tested positive for MPXV DNA. During the study period, DRC experienced the highest disease burden, with weekly reported cases peaking at about 3,000 in January 2025, while Tanzania reported a peak of 20 weekly cases in March 2025. No confirmed clinical cases were reported in Burkina Faso. No clear relationship was observed between reported case numbers and qPCR Ct values in positive wastewater samples. Despite the low detection frequency, the project demonstrated the operational feasibility of implementing MPXV wastewater surveillance in resource-limited settings and established laboratory capacity for environmental monitoring of emerging infectious diseases. Given the early stage of WWS implementation in the region, the study identified opportunities for further system strengthening, including optimization of sample processing and reporting workflows, improved access to laboratory supplies, and enhanced integration of environmental and clinical surveillance data streams. These findings highlight the value of WWS as a complementary component of integrated public health surveillance systems and emphasize the need for continued investment in laboratory capacity, harmonized methodologies, governance frameworks, and knowledge exchange to enhance outbreak preparedness and response in low-resource settings.

Enteric pathogen infections are a major global health challenge, influenced by a variety of host and environmental factors, and their clinical presentation and treatment can be complicated by the presence of co-infections. The prevalence of enteric infections and co-infections tend to vary between rural and urban contexts, likely driven by underlying environmental, geographic, and demographic characteristics. To improve understanding of urbanicity and age on enteric pathogen prevalence and on co-infection risk, we measured 22 enteric pathogens in fecal samples collected from children aged 6, 12, and 18 months across a rural-urban gradient within the ECoMiD birth cohort study (n=473). Enteric pathogen burden was high and increased with age, with at least one pathogen detected in 91% of children at 6 months, 97% at 12 months, and 98% at 18 months. However, prevalence of some pathogens-- notably Salmonella enterica, enterovirus, and rotavirus-- decreased with age. Co-infections were also common (88%), and children were infected with as many as 11 pathogens simultaneously. The most frequently observed co-infection profiles included enteroaggregative E. coli and atypical enteropathogenic E. coli, followed by combinations with diffusely adherent E. coli, enterovirus, enterotoxigenic E. coli, and/or adenovirus. Enteric pathogen detection generally was higher in more rural settings, though patterns varied by pathogen. These results provide useful information for future examination of pathogen dynamics of co-occurrence. Given the ubiquity of enteric infections in high transmission settings, strategies that aim to reduce overall microbial exposure may be needed to supplement interventions targeting control of individual pathogens.

Women's disproportionate responsibility for unpaid domestic and care work, including water collection, remains a barrier to gender equality globally and may constrain women's ability to engage in income-generating activities. We compared women's and men's time use in rural Kenya and Honduras and assessed whether women's time spent on water collection and income-generating activities differed between communities that had or had not received an improved water source from World Vision. We also examined the measurement of time-use agency among women and men. In-person surveys were conducted in July-August 2024 with 95 participants (48 women, 47 men) in six Kenyan communities and 102 participants (53 women, 49 men) in six Honduran communities. Surveys included a 24-hour time-use recall module and items on time-use agency. Analyses compared time use by gender and by community intervention status (improved vs. not yet improved water supply), and confirmatory factor analysis assessed the validity of the time-use agency measure. Women in both study sites spent substantially more time than men on unpaid domestic and care work activities, including cooking, cleaning, laundry, and caregiving. In Kenya, women also spent significantly more time collecting water. Men spent more time sleeping (Kenya), on paid work (Honduras), unpaid agricultural work (both settings), and traveling (both settings). Across both countries, there were no significant differences between intervention and comparison communities in women's time spent on water collection or income-generating activities. In Kenya, most respondents reported high influence over their time, and six items showed strong validity for measuring instrumental time-use agency. Women's time burdens remained high even in communities that had received improved water sources, including at the household level. Our results suggest that more transformative water infrastructure, combined with interventions that address gendered social norms, may be needed to meaningfully reduce women's domestic work burden and support their economic empowerment.

Abstract Background: The sanitation crisis poses a significant public health risk, leading to diseases like diarrhea, cholera, and typhoid, which impede children's health and development in developing countries like Uganda. Improving sanitation infrastructure is crucial for safeguarding child health and future generations. However, the link between sanitation and children's health is complex, influenced by various factors. This investigation in Gulu scrutinizes the correlation between sanitation practices and child well-being, considering moderating factors such as age, climate, and consistent water accessibility. Methods: The study used a convergent parallel design with equal priority. The Social Ecological Model, Social Learning Theory, and Diffusion of Innovations Model guided it. Researchers collected data from 10 health facilities and 317 households, using purposive and simple random sampling. They used sampling proportions proportional to village size within strata. The researcher analyzed quantitative data using SPSS with factor analysis, structural equation modeling, and multivariate analysis. To analyze qualitative data, they used DQA Minor Lite software, which facilitated thematic analysis. Results: The finding shows 56.8% of households had low socio-economic status. Sanitation was poor; 24.9% household had improved latrines, 20.5% had handwashing facilities with soap, and 68.1% used basic anal cleansing. For nutrition, 38.5% of children were malnourished by MUAC; by Z-scores, 28.7% were stunted, 16.4% underweight, 13.6% wasted. Diarrhea affected 62% of children. Climate worsened sanitation: 48.3% had latrines collapse from floods, and 63.4% of waterborne diseases occurred in both dry and wet seasons. Moderation analysis on childhood diarrhea shows that sociocultural factors ({beta} = -0.20, p < 0.001), sanitation ({beta} = -0.15, p < 0.001), and health system response ({beta} = -0.18, p < 0.001) reduced diarrhea. Climate change increased risk ({beta} = 0.15, p < 0.001) and moderated sanitation effects ({beta} = 0.01, p < 0.05). Models explained 10-14% variance. Age and water access had no moderating effect. While childhood malnutrition shows that sociocultural factors ({beta} = -0.43, p < 0.001) and health system response ({beta} = -0.13, p < 0.001) reduced malnutrition. Sanitation had no effect ({beta} = 0.01, p > 0.05). Age increased malnutrition risk ({beta} = 0.28, p < 0.01) and moderated sociocultural effects ({beta} = 0.16, p < 0.001), but not sanitation. The model explained 21% variance, R{superscript 2} = 0.21, p < 0.001. Conclusion: Sociocultural improvements and health system responses lower both diarrhea and malnutrition. Climate worsens diarrhea and alters sanitation's impact. Age worsens malnutrition and changes sociocultural effects. These findings are valuable for policymakers, healthcare professionals, and researchers

Mass gatherings pose significant public health risks by facilitating the spread of infectious diseases. While wastewater-based surveillance (WBS) has been widely used to monitor pathogens in high-income settings, its use as a practical, multi-pathogen surveillance tool during mass gatherings in low- and middle-income countries remains limited. This study aimed to assess the operational feasibility, epidemiological significance, and public health utility of multi-pathogen WBS during the African Nations Championship (CHAN) football tournament in Uganda. Wastewater surveillance was conducted at Mandela National Stadium during eight match days in August 2025. Moore swabs were deployed at 38 manholes receiving wastewater from different toilet facilities across the stadium to capture representative wastewater samples. Samples were processed using Nanotrap(R) microbiome virus particles to concentrate pathogens, followed by nucleic acid extraction. Samples were analyzed for multiple enteric and respiratory pathogens, including Mpox, using quantitative PCR (qPCR). Descriptive analyses were performed to characterize pathogen detection patterns, positivity rates, and temporal distribution across surveillance sites. A total of 304 wastewater samples were collected and analyzed, of which 259 (85.2%) tested positive for at least one pathogen. Multiple pathogens were consistently detected across sampling days, with enteric pathogens predominating, particularly Shigella spp. (53.6%), Rotavirus A (35.9%) and Enterovirus (32.2%). The mpox virus was also detected in a notable proportion of samples (28.6%) across several sampling days. Respiratory pathogens, including SARS-CoV-2 (11.8%) and Influenza B (8.2%), were identified intermittently at lower frequencies. Pathogen diversity varied over time, with up to eight pathogens detected on a single day, and co-detection of multiple pathogens observed in the majority of positive samples. Cq value distributions further demonstrated variability in detected signal patterns across pathogens. Surveillance findings informed real-time public health interventions, including sanitation reinforcement, intensified hygiene promotion, environmental disinfection, and targeted risk communication, strengthened syndromic surveillance with on-site triage, and targeted environmental health assessments of food handling and wastewater infrastructure. These findings demonstrate the operational feasibility and public health utility of integrating multi-pathogen wastewater-based surveillance into mass-gathering preparedness and response frameworks in low-resource settings. By capturing diverse pathogen signals and informing targeted interventions during the CHAN football tournament, WBS can provide actionable population-level insights that can support outbreak preparedness and response. Scaling WBS within national preparedness systems could strengthen epidemic intelligence, enhance early warning capacity, and support data-driven public health decision-making during future mass gatherings and emerging infectious disease threats.

Background. Current exposure-health models rely on averaged, residential-based environmental exposures, failing to account for human movement. This aggregation can lead to exposure misclassification and biased exposure-response estimates, potentially distorting our understanding of the true health effects of environmental conditions. We developed exposure disaggregation regression models that explicitly account for human movement when linking environmental exposures to health outcomes. Methods. By weighting pixel-level exposures according to distance from home as a simple proxy for human movement, our model linked disaggregated environmental exposures to individual-level health outcomes. Weights were either fixed a priori or derived from a latent distance-decay power parameter learned from the data. We additionally evaluated model performance under a nonlinear exposure-response relationship. Model performance was assessed across multiple sample sizes (N = 1,114; 50,000; and 100,000). A simulation study examined parameter recovery using bias, empirical standard error (EmpSE), and credible interval coverage. As a case study, Demographic and Health Surveys (DHS) data from Albania were used to link acute respiratory infection (ARI) outcomes among children under five to pixel-level NDVI within a 3 km buffer around DHS cluster centroids, and the proposed models were applied to these data. Results. Across all models (fixed-weight, learned-weight, and restricted cubic spline models), parameter recovery improved with increasing sample size. At N = 1,114, estimates were biased and imprecise, with incorrect effect direction for exposure-response parameters (e.g., learned-weight {beta}1 bias = - 0.79; EmpSE = 2.61; coverage = 0.88). In contrast, the models accurately recovered parameters at larger sample sizes, including the latent distance-decay parameter (bias = - 0.02; EmpSE = 0.15; coverage = 0.95 at N = 100,000), demonstrating their ability to reliably learn movement-based exposure weights when sufficient data were available. Conclusion. Instead of relying on arbitrarily-sized buffers, this statistical framework provides a novel method for studying environmental exposure-health relationships whilst accounting for human movement. With sufficiently large sample sizes, it can accurately estimate the influence of disaggregated environmental exposures on individual-level health and help address exposure misclassification arising from residential-only metrics. This methodological framework remains scalable, interpretable, and adaptable to other exposures and outcomes, offering a foundation for future work that integrates richer mobility-informed exposure-health research.

Abstract Background: Open defecation remains a major public health challenge in Ghana and across sub-Saharan Africa, with persistent rural-urban inequalities undermining progress toward Sustainable Development Goal 6.2 (SDG 6.2). Despite two decades of national sanitation programming, structural and equity barriers continue to constrain progress. A repeated cross sectional analyses and longitudinal analysis combining WHO-standardised inequality measures, temporal trend modelling, and projections remain absent from the literature for Ghana. Methods: National, rural, and urban open defecation prevalence (2000-2024) was analysed using WHO Health Equity Assessment Toolkit (HEAT) data. Four inequality measures: Difference, Ratio, Population Attributable Risk (PAR), and Population Attributable Fraction (PAF), quantified rural-urban disparities. Joinpoint regression identified statistically significant trend inflection points across MDG and SDG eras. ARIMA models projected prevalence to 2030 under status quo, accelerated, and decelerated scenarios; hold-out validation confirmed high forecast accuracy across all series (MAPE <1%). Results: National prevalence declined from 20.31% to 17.79% (AAPC: -0.55%, p<0.001), with a joinpoint at 2016 (95% CI: 2015-2017) after which decline slowed during the SDG era. Rural prevalence rose marginally (AAPC: +0.07%) with no significant joinpoints across the 25-year period; urban prevalence also increased (AAPC: +0.76%). Rural prevalence exceeded urban more than threefold by 2024 (R=3.38); PAF improved from -62.62% to -48.85%, indicating a substantial national burden attributable to rural disadvantage. Under the status quo scenario, national and rural prevalence are projected at 17.24% and 30.88% by 2030, far exceeding the SDG 6.2 threshold. Conclusion: Despite modest national progress, substantial rural-urban inequalities remain entrenched, and Ghana is unlikely to achieve SDG 6.2 under current trajectories. Accelerated, equity-focused interventions targeting structurally disadvantaged rural populations are urgently required to reduce sanitation inequalities and improve health outcomes.

ABTRACT Background Children from low- and middle-income countries are particularly vulnerable to air pollution, a major environmental health risk, due to the immaturity of their lungs and their proximity to sources of household pollution. This study aimed to investigated the effect of exposure to biomass combustion through domestic and maternal occupational activities on respiratory health of children living in disadvantaged urban areas of Abidjan, Cote dIvoire. Methods Between February and December 2023, we conducted a cross-sectional observational study among children <16 years from households of women using biomass fuel for cooking (Group (G) 1), engaged in occupational fish smoking activities (G2), or primarily using gas for domestic cooking (G3). We assessed reported respiratory symptoms through standardized questionnaires and the presence of lung function impairments (LFI) though pulmonary function tests (spirometry and Rint). We assessed the association between study groups and key covariates with respiratory symptoms and LFI using mixed-effects regression models. Results Of 210 children enrolled - 119 (56.8%) female, median age 9 (6-12) years, 82 (39.0%) in G1, 47 (22.4%) in G2, and 81 (38.6%) in G3 - 15 (7.1%) reported wheezing in the last 12 months, 82 (39.0%) reported dry cough at night, 9 (4.9%) presented with dyspnea and 5 (2.7%) had chest pain on clinical examination, for an overall proportion of children with reported respiratory symptoms of 43.8% (92/210). Of 176 children who underwent pulmonary function testing, 59 (33.5%) had LFI detected, including 34 (45.9%) in G1, 8 (22.2%) in G2, and 17 (25.8%) in G3 (p = 0.011). Study group was associated with respiratory symptoms (G1 vs G3; aOR 3.82, 95% CI 1.68-8.68; p < 0.001), as well as with LFI (p = 0.042). Girls were at greater risk of LFI than boys (aOR 2.69, 95% CI 1.24-5.80; p = 0.012). Children whose mothers used charcoal or wood as cooking fuel had higher odds of respiratory symptoms (OR 2.61, 95% CI 1.22-5.58; p = 0.013) but no association was found with LFI (p = 0.459) compared with unexposed children. Conclusion Respiratory symptoms and lung function impairments were highly prevalent among children living disadvantaged, especially when mothers cook with wood or charcoal. Targeted maternal awareness and broader interventions to reduce household air pollution in disadvantaged urban areas are urgently needed to protect long-term respiratory health.

Background: Wastewater and environmental surveillance (WES) expanded rapidly during the COVID-19 pandemic and is increasingly proposed for routine public health use across a broader range of pathogens. Yet empirical evidence on how decision-makers judge when WES is actionable, how it integrates with existing surveillance, and how its role varies across resource and epidemiological contexts remains limited. Methods: We conducted three structured tabletop exercises (TTXs) at regional Global Wastewater Surveillance Consortium (GLOWACON) meetings in Singapore, Ethiopia, and Panama between March 2024 and May 2025, engaging more than 1,100 participants from over 60 countries spanning public health, government, research, industry, and international organisations. Standardised scenarios and decision prompts, covering respiratory, contact-transmitted, and vector-borne pathogens across multiple outbreak phases, elicited how participants prioritised, implemented, and responded to WES. Data from structured observation notes, participant worksheets, and post-exercise surveys were systematically analysed using a thematic qualitative approach to identify cross-cutting decision patterns and context-specific considerations across regions. This working paper has not been peer reviewed. Findings: Four cross-cutting decision patterns emerged. First, WES was most actionable when it addressed defined surveillance gaps, particularly during early outbreak phases when clinical testing was limited or delayed. Second, decisions to initiate, scale, or de-escalate WES depended on disease severity, the availability of actionable interventions, and the completeness of existing surveillance, not on pathogen type. Third, participants consistently treated WES as complementary to, not a substitute for, clinical and epidemiological surveillance, with its role evolving over the course of an outbreak. Fourth, implementation considerations, including sewer infrastructure, resource constraints, tourism, and mass gatherings varied substantially by setting, while governance, data-sharing, and trust concerns recurred across all three regions. Interpretation: The value of WES is determined less by pathogen-specific characteristics than by how it is embedded within decision-making frameworks in public health systems. These findings provide empirical evidence on how WES is operationalised across diverse global contexts and underscore an urgent need for clearer governance, integration, and prioritisation frameworks without which WES risks remaining an underutilised or inconsistently applied tool despite its demonstrated potential to strengthen pandemic preparedness and response. Funding: This working paper was independently initiated and conducted within the Center on AI, Security, and Technology using income from operations and gifts and grants from philanthropic supporters. A complete list of donors and funders is available at www.rand.org/CAST. RAND clients, donors, and grantors have no influence over research findings or recommendations.

Background Foodborne diseases cause substantial global morbidity and mortality, yet remain largely unattended. To support countries to address this public health concern, the World Health Assembly Resolution 73.5 called for strengthening global food safety efforts and led to the development of the WHO Global Strategy for Food Safety 2022-2030, adopted at the 75th WHA (2022). To this end, the World Health Organization (WHO) reconvened the Foodborne Disease Burden Epidemiology Reference Group (FERG) to advise and support the work to generate updated global, regional, and national estimates of the foodborne disease burden for the reference period 2000-2021. Methods We developed an incidence-based framework expanding coverage to 42 foodborne hazards. Standardized systematic reviews, Global Health Estimates and Global Burden of Disease envelopes, and United Nations population data informed the evidence base. Missing epidemiological data were imputed using Bayesian hierarchical meta-regression models. Disease models mapped acute and chronic health outcomes, applying updated disability weights, life tables, and probabilistic Monte Carlo calculations to estimate incidence, mortality, Years Lived with Disability, Years of Life Lost and Disability-Adjusted Life Years for all 194 WHO Member States. Transparency and analysis reproducibility were ensured through availed open-source R packages and standardized workflows. Results The computational framework provides annual, country-level estimates with improved internal consistency and an expanded hazard scope compared with the WHO 2015 edition. Advances include refined modelling, enhanced uncertainty propagation, and broader inclusion of microbial, parasitic, and chemical hazards. Persistent data gaps---especially in high-burden regions---were filled through extensive imputation. Conclusions The computational framework for the WHO 2026 edition delivers the most comprehensive and transparent assessment of the global burden of foodborne diseases to date. Despite remaining limitations, it enables routine monitoring, supports evaluation of global food safety efforts, and highlights priorities for strengthening national data systems.

Food contamination contributes to 40% of childhood diarrhoea cases globally. It occurs when pathogens are transmitted from faecal matter to food through the faecal oral route. Food hygiene can prevent food contamination and improve the microbial quality of weaning foods in domestic settings. However, context specific evidence is needed to identify risk factors associated with food contamination, especially in complex low-income communities. Our study used a modified Hazard Analysis Critical Control Point approach to assess the quality of weaning foods and identify associated risk factors in a low income setting of Lusaka, Zambia. We enrolled 60 caregivers of children aged <1 year who had begun complementary feeding and collected data on household characteristics and food hygiene behaviours using surveys and structured observations. We collected samples of complimentary foods prepared for the child and tested them for Escherichia coli (E. coli) using the IDEXX Colilert-18 method. Multivariable logistic regression was performed to determine risk factors associated with food contamination. Of 59 food samples, 17 (29%) were contaminated with E. coli. Porridge (AOR = 0.04; 95% CI: 0.01, 0.28; p = 0.001) and non-animal source foods (AOR = 0.11; 95% CI: 0.02, 0.69; p = 0.019) were associated with lower odds of contamination compared with animal source foods. Heating of food was also associated with lower odds of contamination but was not significant. Food hygiene behaviours including utensil and surface cleaning were low (17% and 15%, respectively), and handwashing with soap before food preparation was not practiced. Our study identifies the microbiological risk associated with animal source foods and the potential health risk posed to weaning children. Nutrition guidelines should take into consideration this risk as programs promote an increased uptake of animal source foods in child diets.

Background: Men with prostate cancer (PCa) may be especially vulnerable to per- and polyfluoroalkyl substances (PFAS) exposure due to their endocrine-disrupting and cardiometabolic impacts and cardiotoxicity and immune suppression of treatments. Objective: A pilot study was launched to measure serum and tap water PFAS concentrations in PCa survivors. Methods: Men with PCa were recruited from Rutgers Cancer Institute between February 2025 and March 2026, with ongoing enrollment and follow-up. Eligible men were aged [&ge;]40 years and either on active surveillance or within 3-12 months of initial definitive treatment. Participants provided blood and residential tap water samples, which were analyzed using mass spectrometry (serum) and modified EPA method 537 (water). Geometric means were used to summarize PFAS concentrations by race and assess serum-tap water correlations. Results: Of 235 eligible patients, 124 (60%) enrolled. Median age was 64 years; 63% were non-Hispanic White, 43% had a Gleason score [&le;]6. Roughly half of participants provided serum and/or tap water samples. In serum, six PFAS analytes had >80% detection; of these analytes, median concentrations ranged from 0.13 ng/mL (IQR: 0.07-0.20) for PFHpS to 2.55 ng/mL (IQR:1.54-3.82) for nPFOS. Among 74 tap water samples, 9 PFAS analytes had >60% detection; of these, median concentrations of PFNA (0.56 ng/L; IQR: 0.33-0.75), PFOA (3.75 ng/L; IQR: 1.21-5.27), and PFOS (2.29 ng/L; IQR: 0.46-2.89), were below New Jersey Maximum Contaminant Levels. Non-White participants had significantly higher levels of multiple PFAS analytes in both serum and tap water. Serum-tap water correlations were modest (r=0.22-0.41). Significance: The pilot study has demonstrated both the feasibility and importance of studying PFAS exposure pathways as well as potential impacts of PFAS exposure in diverse populations. Keywords: Prostatic Neoplasms, Per- and Polyfluoroalkyl Substances (PFAS), Biomonitoring, Environmental Exposure, Cohort Studies, Pilot study Impact Statement: This study provides some of the first estimates of PFAS exposure among prostate cancer patients in serum and tap water, showing moderate correlations between tap water and serum concentrations of specific PFAS analytes. These findings can support larger studies to identify environmental exposure sources and evaluate the role of PFAS in prostate cancer progression and outcomes.

Background Childhood overweight and obesity represent major public health challenges, shaped by socio-economic and environmental factors. This study investigates the mediating and moderating role of urban environmental exposures in socio-economic disparities in childhood excess weight. Methods Data was drawn from a population-based sample of children (2-9 years) and adolescents (10-17 years) living in Geneva, Switzerland. Parents reported household financial situation and children's height and weight, from which excess weight (i.e. overweight or obesity) was derived. Residential exposures to air pollution (PM2.5, NO2), noise (daytime, nighttime), and neighborhood greenness (green areas, canopy coverage) were estimated based on geocoded residential addresses. The association between household financial situation and excess weight was evaluated, as well as the mediating and moderating roles of urban environmental exposures. Results The analysis included 1006 children and 1154 adolescents. Among children, an average-to-poor household financial situation was associated with higher odds of excess weight in children (adjusted odds ratio [aOR]: 1.79, 95% confidence interval [CI]: 1.13; 2.84). Higher noise exposure was associated with excess weight (daytime: aOR: 1.40, 95% CI: 1.10; 1.77, nighttime: aOR: 1.37, 95% CI: 1.08; 1.74), while the association with PM2.5 appeared stronger among socio-economically disadvantaged children, though the interaction did not reach statistical significance (financial situation x PM2.5 interaction: aOR: 1.59, 95% CI: 0.98; 2.59). No significant associations were observed among adolescents. Conclusion These findings highlight the joint influence of social and environmental inequalities on childhood excess weight and stress the need to address these interconnected determinants to design equitable, targeted public health interventions.

Introduction: Waste pickers face chemical exposures. We evaluated whether chemical exposure is associated with psychological distress and depression. Methods: A 2017 cross-sectional survey included 1,141 waste pickers working in the Estrutural open dump in Brasilia, Brazil. Participants self-reported occupational exposure to 11 chemical categories, 17 psychological distress symptoms, and depression diagnoses. Associations of chemical exposure with mean psychological distress scores and depression prevalence were assessed, adjusted for age, sex, marital status, and income. Results: Mean psychological distress score was higher among those exposed to any chemical (mean of 8.1 vs 6.1; adjusted mean difference [aMD]: 1.8 [0.9, 2.7]) and higher among those exposed to each of 11 chemical categories, for example, smoke (aMD: 1.2 [0.6, 1.7]), batteries (aMD: 1.5 [1.0, 1.9], and oils (aMD: 1.3 [0.9, 1.8]). Depression was more prevalent among those exposed to oils (16.6% vs 10.6%; adjusted prevalence difference [aPD]: 6.3% [95% CI: 2.3, 10.2]), cleaning products (aPD: 5.4% [1.2, 9.5]), medications (aPD: 4.7% [0.6, 8.8]), and aerosols (aPD: 5.3% [1.3, 9.3]) but, not smoke, batteries, greases, insecticides, solvents, paints, chemical containers, or any chemical. Conclusion: These associations highlight the need to consider policy level protections for waste pickers to reduce chemical exposure and guard against psychological distress. Further research is necessary to explore which specific chemicals, within broad chemical categories, are associated with psychological distress and depression.

Background Bacteriological contamination of drinking water remains a major public health burden in sub-Saharan Africa, yet the full contamination chain from source to household has rarely been quantified at national scale. This study analyses water quality at both levels using the 2021 Cote d'Ivoire Demographic and Health Survey (DHS-CI 2021). Methods Cross-sectional secondary analysis of DHS-CI 2021 data. Households with paired bacteriological tests at the source (SH3227) and at the household (SH3225) were included (n = 2,541 for determinants; n = 2,528 for chain analysis). Contamination was defined as >0 CFU/100 ml. Determinants of source contamination were assessed by weighted logistic regression accounting for complex survey design. The contamination chain was described across four categories: safe throughout, recontaminated during transport/storage, decontaminated at home, and contaminated throughout. Results Weighted prevalence of source contamination was 63.6% [95% CI: 60.7-66.5%] and 77.0% [74.1-79.9%] at the household. Only 15.0% of households had safe water throughout the chain; 21.2% showed domestic recontamination and 60.8% consumed water contaminated at both levels. Key determinants of source contamination were use of an unimproved source (aOR = 8.15; 95% CI: 4.54-14.66), administrative region, travel time [&le;]30 minutes (aOR = 1.92; 95% CI: 1.41-2.62), and higher wealth quintiles (protective; aOR = 0.25 for richest). Model discrimination was good (AUC = 0.809). Conclusions The vast majority of Ivorian households consume bacteriologically unsafe water, with domestic recontamination representing a distinct and significant degradation pathway even among users of improved sources. Dual interventions targeting source protection and safe household water storage are urgently needed to advance progress toward SDG 6 in Cote d'Ivoire.

Short-term environmental exposures have been linked to cognitive and behavioral outcomes, although many reported associations may reflect broader geographic and contextual differences. Using longitudinal data from the All of Us Research Program (2018--2024), we linked daily weather and air-pollution exposures to repeated attention-related and subjective cognitive outcomes. Associations were evaluated using pooled, fixed-effects, lagged, and event-study analyses. Additional machine-learning analyses were conducted to explore potential heterogeneity and latent psychosocial structure. Replication analyses were performed using the 2024 Behavioral Risk Factor Surveillance System (BRFSS). Several environmental exposure measures showed small associations with cognitive outcomes in pooled analyses, but most attenuated substantially after accounting for within-location temporal variation. Mediation, sensitivity, and machine-learning analyses yielded similar conclusions. In contrast, mental-health burden, loneliness, and social functioning were consistently associated with subjective cognitive difficulty and exhibited substantially larger effect sizes than environmental exposures. Similar patterns were observed in BRFSS. Exploratory AI-assisted analyses yielded findings broadly consistent with the primary longitudinal analyses. These findings suggest that short-term environmental perturbations may have limited associations with cognitive outcomes after accounting for within-location variation, whereas psychosocial factors appear to be more consistently associated with subjective cognitive burden.

Background: Urban environmental and lifestyle factors during early life may influence pubertal timing, but the combined effects of multiple environmental exposures within an exposome analytical framework remain poorly understood. Objective: To examine the association between early-life urban environmental exposures and pubertal timing, and to explore whether these exposures interact with early-life nutritional factors, namely breastfeeding duration and childhood diet quality. Methods: Data from two European population-based birth cohorts were analysed: Generation XXI (G21, Portugal; n=5263; 51.5% girls) and INfancia y Medio Ambiente (INMA, Spain; n=1019; 50.1% girls). Urban environmental exposures including indicators of air pollution, traffic, built environment, and natural spaces were estimated at 4 early-life stages at both cohorts: pregnancy (INMA only), birth, 1 year, and 4-5 years of age. Pubertal development timing was assessed using Tanner staging and/or the Pubertal Development Scale (PDS), and age at menarche was self-reported. Exposome-Wide Association Study (ExWAS) models and unsupervised clustering followed by ordinal logistic regression models were used to examine single- and multi-exposure associations, respectively. Regression models were fitted adjusting for relevant child characteristics, maternal factors, and household socioeconomic conditions, and corrected for multiple testing. Results: Individuals living in more unfavourable urban environments characterised by higher building density, air pollution, and lower access to natural spaces showed earlier pubertal timing according to multiple outcomes, across multiple early-life exposure periods, and in both cohorts. In the G21 cohort, these environmental profiles were associated with earlier age at menarche, particularly for exposures at 1-1.5 and 4-5 years (e.g., 1-1.5y: {beta}=-0.172, FDR-adjusted p-value=0.041), while in the INMA cohort, boys exposed to more unfavourable environmental profiles showed more advanced pubertal development, also particularly for exposures at 1-1.5 and 4-5 years of age (e.g., 1-1.5y; {beta}=0.572, FDR-adjusted p-value=0.008). Among environmental domains, air pollution and traffic were the factors most consistently associated with pubertal timing. Regarding early-life nutritional factors, longer duration of exclusive breastfeeding was associated with a lower Tanner stage among girls in G21. No significant interactions between breastfeeding duration and environmental exposure clusters were observed. Conclusion: Early-life urban environmental exposures, particularly air pollution and traffic, may influence pubertal timing. Exclusive breastfeeding may have a protective role against earlier pubertal development. These findings highlight the importance of improving urban environmental conditions and promoting breastfeeding to support healthy developmental trajectories.

Residential greenness has been associated with reduced heat-related illness, yet the specific role of greenspace morphology at the neighborhood scale remains insufficiently understood. This study quantified the relationship between heat-related illness and multiple dimensions of greenspace morphology using an eight year (2016-2023) unbalanced panel dataset comprising 19,021 block group year observations across 2,427 census block groups in Arizona, USA. One meter high resolution National Agricultural Imagery Program aerial imagery was classified to calculate greenspace percentage, number of greenspaces, average size, shape complexity, connectedness, and distantness, at the block group level. We applied conditional spatial autoregressive models with a negative binomial distribution to estimate associations between each morphology metric and yearly heat-related illness counts, adjusting for sociodemographic and geographic covariates. We found higher greenspace percentage, aggregation, shape complexity, connectedness, and density were consistently associated with lower heat-related illness risk. A one standard deviation increases in shape complexity corresponded to a 12.4% decrease in expected heat-related illness counts (IRR=0.876, 95% CI: 0.834-0.921). Similarly, increases in greenspace percentage (14.6% decrease; IRR=0.855, 95% CI: 0.827-0.885), number of greenspace patches (3.7% decrease; IRR=0.963, 95% CI: 0.937-0.990), average size (4.5% decrease; IRR=0.955, 95% CI: 0.923-0.989), and connectedness (5.5% decrease; IRR=0.945, 95% CI: 0.918-0.972) were all protective. In contrast, larger inter greenspace distances were associated with increased heat-related illness risk (6.1% increase; IRR=1.061, 95% CI: 1.033-1.091). Our findings highlight the critical importance of multiple dimensions of greenspace morphology in mitigating heat-related health risks. These results suggest that heat reduction planning with greening initiatives should consider not only the amount of greenspace but also its spatial configuration to maximize cooling and result in health benefits.

Wastewater surveillance is increasingly used for antimicrobial resistance (AMR) monitoring in urban environments, but low-resource settings often lack a piped sewerage system. Instead, coprophagous flies--flies that ingest feces--may serve as composite samplers for monitoring fecal wastes present in terrestrial environments. We evaluated whether the class 1 integron-integrase gene intI1 was associated with genetic markers of AMR and fecal source tracking markers (FST) in coprophagous flies collected from latrine entrances and food preparation areas in low-income urban Maputo, Mozambique. We quantified intI1, an enteric 16S rRNA target (for normalization), three FST markers, and 30 ARG targets using qPCR. We normalized concentrations of intI1 and each target to enteric 16S rRNA. We fit linear mixed models with a random intercept for housing compound to estimate within-fly associations between log10 relative abundance of intI1 and log10 relative abundance of each target with and without adjustment for fly taxonomic group, capture location, and standardized fly mass. We also modeled per-fly unique ARG count (i.e., number of ARG targets detected) using Poisson regression. Of 188 flies assayed, 176 passed internal controls; intI1 and enteric 16S rRNA were detected in 95% and 96% of flies, respectively. Higher relative abundance of intI1 was positively associated with ARG and FST targets, with the strongest associations observed for sulfonamide-(sul1: {beta} = 0.87; 95% CI: 0.81, 0.94; sul2: {beta} = 0.81; 95% CI: 0.73, 0.89), tetracycline- (tetA: {beta} = 0.78; 95% CI: 0.70, 0.85; tetB: {beta} = 0.69; 95% CI: 0.60, 0.79), and trimethoprim-related (dfrA17: {beta} = 0.78; 95% CI: 0.70, 0.86) genes. Associations with FST markers were weaker (i.e., human mtDNA: {beta} = 0.46; 95% CI: 0.37, 0.55; human-associated Bacteroides: {beta} = 0.34; 95% CI: 0.25, 0.43). Higher relative abundance of intI1 was also associated with a greater number of ARGs detected: each 10-fold increase in intI1 was associated with an 8% higher expected unique ARG count (aRR=1.08, 95% CI: 1.04-1.12). These findings support the need for further research across different settings exploring intI1 carried by coprophagous flies as a potential standardized screening target for AMR surveillance in unsewered terrestrial environments.