Padmavathi Ramaswamy

Exposure assessment for respirable particulates associated with household fuel use in rural districts of Andhra Pradesh, India

Indoor air pollution associated with combustion of solid fuels seems to be a major contributor to the national burden of disease in India, but relatively few quantitative exposure assessment studies are available. This study quantified the daily average concentrations of respirable particulates (50% cut-off at 4 μm) in 412 rural homes selected through stratified random sampling from three districts of Andhra Pradesh, India and recorded time activity data from 1400 individuals to reconstruct 24-h average exposures. The mean 24-h average concentrations ranged from 73 to 732 μg/m3 in gas- versus solid fuel-using households, respectively. Concentrations were significantly correlated with fuel type, kitchen type, and fuel quantity. The mean 24-h average exposures ranged from 80 to 573 μg/m3. Among solid fuel users, the mean 24-h average exposures were the highest for women cooks and were significantly different from men and children. Among women, exposures were the highest in the age group of 15–40 years (most likely to be involved in cooking or helping in cooking), while among men, exposures were highest in the age group of 65–80 years (most likely to be indoors). The data are being used to develop a model to predict quantitative categories of population exposure based on survey information on housing and fuel characteristics. This would facilitate the development of a regional exposure database and enable better estimation of health risks.

Causal inference methods to study nonrandomized, preexisting development interventions

Empirical measurement of interventions to address significant global health and development problems is necessary to ensure that resources are applied appropriately. Such intervention programs are often deployed at the group or community level. The gold standard design to measure the effectiveness of community-level interventions is the community-randomized trial, but the conditions of these trials often make it difficult to assess their external validity and sustainability. The sheer number of community interventions, relative to randomized studies, speaks to a need for rigorous observational methods to measure their impact. In this article, we use the potential outcomes model for causal inference to motivate a matched cohort design to study the impact and sustainability of nonrandomized, preexisting interventions. We illustrate the method using a sanitation mobilization, water supply, and hygiene intervention in rural India. In a matched sample of 25 villages, we enrolled 1,284 children <5 y old and measured outcomes over 12 mo. Although we found a 33 percentage point difference in new toilet construction [95% confidence interval (CI) = 28%, 39%], we found no impacts on height-for-age Z scores (adjusted difference = 0.01, 95% CI = −0.15, 0.19) or diarrhea (adjusted longitudinal prevalence difference = 0.003, 95% CI = −0.001, 0.008) among children <5 y old. This study demonstrates that matched cohort designs can estimate impacts from nonrandomized, preexisting interventions that are used widely in development efforts. Interpreting the impacts as causal, however, requires stronger assumptions than prospective, randomized studies.

Air pollution from household solid fuel combustion in India: an overview of exposure and health related information to inform health research priorities

Environmental and occupational risk factors contribute to nearly 40% of the national burden of disease in India, with air pollution in the indoor and outdoor environment ranking amongst leading risk factors. It is now recognized that the health burden from air pollution exposures that primarily occur in the rural indoors, from pollutants released during the incomplete combustion of solid fuels in households, may rival or even exceed the burden attributable to urban outdoor exposures. Few environmental epidemiological efforts have been devoted to this setting, however. We provide an overview of important available information on exposures and health effects related to household solid fuel use in India, with a view to inform health research priorities for household air pollution and facilitate being able to address air pollution within an integrated rural–urban framework in the future.

Prevalence of chronic obstructive pulmonary disease in rural women of Tamilnadu: implications for refining disease burden assessments attributable to household biomass combustion

Background Chronic obstructive1 1This paper was orally presented in the Annual conference International Society of Environmental Epidemiology held in Pasadena in 2008. pulmonary disease (COPD) is the 13th leading cause of burden of disease worldwide and is expected to become 5th by 2020. Biomass fuel combustion significantly contributes to COPD, although smoking is recognized as the most important risk factor. Rural women in developing countries bear the largest share of this burden resulting from chronic exposures to biomass fuel smoke. Although there is considerable strength of evidence for the association between COPD and biomass smoke exposure, limited information is available on the background prevalence of COPD in these populations. Objective This study was conducted to estimate the prevalence of COPD and its associated factors among non-smoking rural women in Tiruvallur district of Tamilnadu in Southern India. Design This cross-sectional study was conducted among 900 non-smoking women aged above 30 years, from 45 rural villages of Tiruvallur district of Tamilnadu in Southern India in the period between January and May 2007. COPD assessments were done using a combination of clinical examination and spirometry. Logistic regression analysis was performed to examine the association between COPD and use of biomass for cooking. R software was used for statistical analysis. Results The overall prevalence of COPD in this study was found to be 2.44% (95% CI: 1.43–3.45). COPD prevalence was higher in biomass fuel users than the clean fuel users 2.5 vs. 2%, (OR: 1.24; 95% CI: 0.36–6.64) and it was two times higher (3%) in women who spend >2 hours/day in the kitchen involved in cooking. Use of solid fuel was associated with higher risk for COPD, although no statistically significant results were obtained in this study. Conclusion The estimates generated in this study will contribute significantly to the growing database of available information on COPD prevalence in rural women. Moreover, with concomitant indoor air pollution measurements, it may be possible to increase the resolution of the association between biomass use and COPD prevalence and refine available attributable burden of disease estimates.

A Pilot Study of Blood Lead Levels and Neurobehavioral Function in Children Living in Chennai, India

Abstract The relationship between blood lead level and neurodevelopment was assessed in a pilot cross-sectional study of 74 4-14-year-old children in Chennai, India. Mean blood lead level was 11.1 μg/dL (2.5,–38.3). The Binet-Kamath IQ test and the Wide Range Assessment of Visual Motor Activity (WRAVMA) were administered to 58 children. Teachers completed the Connors Behavioral Rating Scale. Excluding two outliers, IQ and WRAVMA composite scores were inversely related to blood lead level, with an effect size of approximately 6 points decline for a 10-μg/dL. increase in blood lead. Children in the highest and lowest blood lead quartiles had mean IQs of 95.6±13.3. and 102.0±22.5, respectively. Behavior ratings were not associated with blood lead level. Lead exposure is a significant problem among Indian children, with many having blood lead leveIs associated with increased neurodevelopmental risk.

H2S as an Indicator of Water Supply Vulnerability and Health Risk in Low-Resource Settings: A Prospective Cohort Study

In this large-scale longitudinal study conducted in rural Southern India, we compared a presence/absence hydrogen sulfide (H2S) test with quantitative assays for total coliforms and Escherichia coli as measures of water quality, health risk, and water supply vulnerability to microbial contamination. None of the three indicators showed a significant association with child diarrhea. The presence of H2S in a water sample was associated with higher levels of total coliform species that may have included E. coli but that were not restricted to E. coli. In addition, we observed a strong relationship between the percent positive H2S test results and total coliform levels among water source samples (R(2) = 0.87). The consistent relationships between H2S and total coliform levels indicate that presence/absence of H2S tests provide a cost-effective option for assessing both the vulnerability of water supplies to microbial contamination and the results of water quality management and risk mitigation efforts.

Reactivity in Rapidly Collected Hygiene and Toilet Spot Check Measurements: A Cautionary Note for Longitudinal Studies

Discreet collection of spot check observations to measure household hygiene conditions is a common measurement technique in epidemiologic studies of hygiene in low-income countries. The objective of this study was to determine whether the collection of spot check observations in longitudinal studies could itself induce reactivity (i.e., change participant behavior). We analyzed data from a 12-month prospective cohort study in rural Tamil Nadu, India that was conducted in the absence of any hygiene or toilet promotion activities. Our data included hygiene and toilet spot checks from 10,427 household visits. We found substantial evidence of participant reactivity to spot check observations of hygiene practices that were easy to modify on short notice. For example, soap observed at the households primary handwashing location increased from 49% at enrollment to 81% by the fourth visit and remained at or above 77% for the remainder of the study.

Establishing integrated rural–urban cohorts to assess air pollution-related health effects in pregnant women, children and adults in Southern India: an overview of objectives, design and methods in the Tamil Nadu Air Pollution and Health Effects (TAPHE) study

Introduction In rapidly developing countries such as India, the ubiquity of air pollution sources in urban and rural communities often results in ambient and household exposures significantly in excess of health-based air quality guidelines. Few efforts, however, have been directed at establishing quantitative exposure–response relationships in such settings. We describe study protocols for The Tamil Nadu Air Pollution and Health Effects (TAPHE) study, which aims to examine the association between fine particulate matter (PM2.5) exposures and select maternal, child and adult health outcomes in integrated rural–urban cohorts. Methods and analyses The TAPHE study is organised into five component studies with participants drawn from a pregnant mother–child cohort and an adult cohort (n=1200 participants in each cohort). Exposures are assessed through serial measurements of 24–48 h PM2.5 area concentrations in household microenvironments together with ambient measurements and time-activity recalls, allowing exposure reconstructions. Generalised additive models will be developed to examine the association between PM2.5 exposures, maternal (birth weight), child (acute respiratory infections) and adult (chronic respiratory symptoms and lung function) health outcomes while adjusting for multiple covariates. In addition, exposure models are being developed to predict PM2.5 exposures in relation to household and community level variables as well as to explore inter-relationships between household concentrations of PM2.5 and air toxics. Finally, a bio-repository of peripheral and cord blood samples is being created to explore the role of gene–environment interactions in follow-up studies. Ethics and dissemination The study protocols have been approved by the Institutional Ethics Committee of Sri Ramachandra University, the host institution for the investigators in this study. Study results will be widely disseminated through peer-reviewed publications and scientific presentations. In addition, policy-relevant recommendations are also being planned to inform ongoing national air quality action plans concerning ambient and household air pollution.

The Effect of Ageing on Nasal Mucociliary Clearance in Women: A Pilot Study

Introduction. Pneumonia is the leading infectious cause of death in the elderly. Impaired respiratory defences are one of the causes for increased susceptibility of the elderly to such infections. Nasal mucociliary clearance, the mirror image of bronchial clearance, is crucial in respiratory defence and is affected by various factors. Little is known about the effect of ageing on nasal respiratory epithelium. Aim. To evaluate the effect of ageing on nasal mucociliary clearance (NMC) in women. Materials and Methods. NMC was measured in 91 apparently healthy women of ages ranging from 20 to 80 years. The time taken to experience sweet taste at nasopharynx following the placement of saccharin pellet in the nostril was recorded as NMC time. Results and Discussion. NMC time was 10 min 36 secs in elderly women and it was significantly prolonged when compared to younger women (8 min 39 secs). The prolonged clearance may be due to altered cilia, slowed ciliary beating, or changes in the properties of mucus. Conclusion. NMC time clearly shows an increase with age signifying decreasing respiratory epithelium function. This study highlights an important cause of impaired respiratory health in older individuals and emphasises the need for preventive measures to be put in place.

Exposures to fine particulate matter (PM 2.5 ) and birthweight in a rural-urban, mother-child cohort in Tamil Nadu, India

Background: Exposure to PM2.5 (fine particulate matter <less than 2.5 &mgr;m in aerodynamic diameter) related to ambient and household air pollution has been associated with low birthweight. Few of these studies, however, have been conducted in high exposure settings that are commonly encountered in low and middle income countries (LMICs). Objectives: We examined whether PM2.5 exposures during pregnancy were associated with birthweight in an integrated rural‐urban, mother‐child cohort in the state of Tamil Nadu, India. Methods: We recruited 1285 pregnant women in the first trimester of pregnancy from primary health care centers and urban health posts and followed them until birth to collect antenatal care data and birthweight. We estimated pregnancy period PM 2.5 exposures through direct serial measurements of 24‐h household PM2.5 concentrations, performed across each trimester. Mothers also completed detailed questionnaires to provide data on covariates related to household, socio‐economic, demographic and maternal health characteristics. The association between PM2.5 exposures and birth weight was assessed using linear and logistic regression models that controlled for potential confounders. Results: A 10‐&mgr;g/m3 increase in pregnancy period PM2.5 exposures was associated with a 4 g (95% CI: 1.08 g, 6.76 g) decrease in birthweight and 2% increase in prevalence of low birthweight [odds ratio(OR) = 1.02; 95%CI:1.005,1.041] after adjusting for gestational age, infant sex, maternal BMI, maternal age, history of a previous low birth weight child, birth order and season of conception. Conclusions: The study provides some of the first quantitative effects estimates for linking rural‐urban PM2.5 exposures and birthweight in India, adding important evidence for this association from high exposure settings in LMICs, that also experience dual health burdens from ambient and household air pollution. Study results also point to the need for considering maternal PM2.5 exposures alongside other risk factors for low birthweight in India HIGHLIGHTSProvides E‐R relationships between PM2.5 and birth‐weight in high exposure settings.Examines the association in a rural‐urban, mother‐child cohort in India.Estimates a 4g decrease in birth‐weight per 10‐&mgr;g/m3 increase in PM2.5 exposures.Estimates a 2% increase in low birth‐weight per 10‐&mgr;g/m3 increase in PM2.5 exposures.Maternal PM2.5 exposures may be an important risk factor for low birth‐weight in India.