Pivotal relationship between heavy metal, PM2.5 exposures and tuberculosis in Bangladeshi children: protocol paper of a case-control study.

INTRODUCTION: Air pollution is a global issue that poses a significant threat to public health. Children, due to their developing physiology, are particularly susceptible to the inhalation of environmental pollutants. Exposure can trigger immune modulation and organ damage, increasing susceptibility to respiratory diseases. Therefore, we aim to examine the association between heavy metal and particulate matter exposure with tuberculosis in children. METHODS AND ANALYSIS: As a case-control study, we will include children diagnosed with pulmonary tuberculosis (n=60) and matched healthy controls (n=80) recruited from the same communities in Dhaka, Bangladesh. Exposure data for both cases and controls will be collected by a trained field team conducting home visits. They will administer an exposure questionnaire, measure child anthropometry, collect blood and household dust samples and instal 48-hour air quality monitors. The blood samples will be analysed by inductively coupled plasma mass spectrometry for serum heavy metal concentrations (lead, cadmium, arsenic, mercury and chromium), as a representative marker of exposure, and the presence of inflammatory biomarkers. Descriptive and inferential statistics, including independent samples t-tests, analysis of variance and conditional regression analysis, will be used to quantify heavy metal and particulate matter exposure status in tuberculosis cases compared with healthy controls, while accounting for potential confounders. Dust samples and air quality results will be analysed to understand household sources of heavy metal and particulate matter exposure. To test the study hypothesis, there is a positive association between exposure and tuberculosis diseases, we will also measure the accumulated effect of simultaneous exposures using Bayesian statistical modelling. ETHICS AND DISSEMINATION: This study has been approved by International Centre for Diarrhoeal Disease Research, Bangladesh's Institutional Review Board (PR-22030). The study findings will be disseminated at conferences and published in peer-reviewed journals.

Development and validation of the Self-Efficacy in Addressing Menstrual Needs Scale (SAMNS-26) in Bangladeshi schools: A measure of girls' menstrual care confidence.

OBJECTIVE: Qualitative studies have described girls' varying levels of confidence in managing their menstruation, with greater confidence hypothesized to positively impact health, education, and social participation outcomes. Yet, measurement of this and other psychosocial components of adolescent girls' menstrual experiences has been weak in global health research, in part due to a dearth of appropriate psychometric tools. We describe the development and validation of the Self-Efficacy in Addressing Menstrual Needs Scale (SAMNS-26). METHODS: We conducted nine focus group discussions with girls in schools in rural and urban Bangladesh to identify tasks involved in menstrual self-care. This informed our creation of an initial pool of 50 items, which were reviewed by menstrual health experts and refined through 21 cognitive interviews with schoolgirls. Using a self-administered survey, we administered 34 refined items plus additional validation measures to a random sample of 381 post-menarcheal girls (ages 9-17) and retested a subsample of 42 girls two weeks later. We examined the measure's dimensionality using exploratory factor analysis and assessed internal consistency, temporal stability, and construct validity. RESULTS: Exploratory factor analysis suggested a 26-item scale comprising three correlated sub-scales: the 17-item Menstrual Hygiene Preparation and Maintenance (α = 0.86), the 5-item Menstrual Pain Management (α = 0.87), and the 4-item Executing Stigmatized Tasks (α = 0.77). Sub-scales exhibited good temporal stability. SAMNS-26 scores correlated negatively with measures of anxiety, and girls who preferred to stay at home during their periods had lower SAMNS-26 scores than those who did not. CONCLUSION: The SAMNS-26 provides a reliable measure of a schoolgirl's confidence in her capabilities to address her menstrual needs. There is initial evidence to support the measure's construct validity in the Bangladesh context as indicated by its relationships with other factors in its theorized nomological network. The tool enables incorporation of self-efficacy into multivariate models for exploring the relationships among antecedents to menstrual experiences and hypothesized impacts on health, wellbeing, and education attainment. Further testing of the tool is recommended to strengthen evidence of its validity in additional contexts.

Chlorine taste can increase simulated exposure to both fecal contamination and disinfection byproducts in water supplies.

Expanding drinking water chlorination could substantially reduce the burden of disease in low- and middle-income countries, but the taste of chlorinated water often impedes adoption. We developed a Monte Carlo simulation to estimate the effect of people's choice to accept or reject drinking water based on chlorine taste and their subsequent exposure to E. coli and trihalomethanes, a class of disinfection byproduct (DBP). The simulation used empirical data from Dhaka, Bangladesh, a megacity with endemic waterborne disease. We drew on published taste acceptability thresholds from Dhaka residents, measured residual chlorine and thermotolerant E. coli inactivation following the addition of six chlorine doses (0.25-3.0 mg/L as Cl2) to untreated piped water samples from 100 locations, and analyzed trihalomethane formation in 54 samples. A dose of 0.5 mg/L, 75% lower than the 2 mg/L dose typically recommended for household chlorination of low-turbidity waters, minimized overall exposure to E. coli. Doses of 1-2 mg/L maximized overall exposure to trihalomethanes. Accounting for chlorine taste aversion indicates that microbiological exposure increases and DBP exposure decreases above certain doses as a higher proportion of people reject chlorinated water in favor of untreated water. Taken together with findings from other modeling analyses, empirical studies, and field trials, our results suggest that taste acceptability should be a critical consideration in establishing chlorination dosing guidelines. Particularly when chlorination is first implemented in water supplies with low chlorine demand, lower doses than those generally recommended for household water treatment can help avoid taste-related objections while still meaningfully reducing contaminant exposure.