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

Abstract

IntroductionIn 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 analysesThe 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 disseminationThe 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.

Stringent Emission Control Policies Can Provide Large Improvements in Air Quality and Public Health in India

“…The disease burden associated with long‐term ambient PM 2.5 exposure was estimated using the nonlinear integrated exposure‐response (IER) functions from the GBD2016 (GBD 2016 Risk Factors Collaborators, ) for five causes: ischemic heart disease (IHD), cerebrovascular disease (CEV), chronic obstructive pulmonary disease (COPD), acute lower respiratory infections (ALRI), and lung cancer (LC) (Figure S1). The IER functions from the GBD are used here as epidemiological studies of long‐term exposure to ambient PM 2.5 concentrations in India are underway but not yet completed (Balakrishnan et al, ). The IER functions use age‐specific modifiers for each disease to estimate relative risk (RR) of mortality associated with ambient PM 2.5 concentrations (equation ), where z is the ambient PM 2.5 concentrations and z cf is the theoretical minimum risk exposure level where no additional risk is assumed for ambient PM 2.5 concentrations below 2.5 μg/m 3 (Cohen et al, ).…”

Effect of exposure to PM10on child health: evidence based on a large-scale survey from 184 cities in India

“…A review of studies examining the effects of air pollution on human health in India highlighted that barring a few studies, 17 20 the rest examine the issue in silos, failing to consider other important predictors such as household socioeconomic status or hygiene practices of families. 21 This paper hypothesises that air pollution will continue to have a significant effect on child health outcomes as found by earlier studies regardless of hygienic condition. Another aspect of existing literature is the focus of analysis being limited only to select cities in India.…”

A review on effect of air pollutants on fetal development and pregnancy outcomes

“…Peripheral and cord blood samples were also collected to investigate gene-environment interactions [6] 3 24 h household PM 2.5 exposure during pregnancy PM 2.5 PM 2.5 exposure in pregnancy was associated with 4 g decrease in birth weight while 2% increase in its prevalence. [7] 4 Association between prenatal exposure to PM 2.5 and its constituents and preterm delivery PM 2.5 and PM 10 , ammonium, chlorine, sodium, nitrate, vanadium and bromine Increased risk of preterm delivery with full gestational exposure to PM 2.5 and its constituents; preterm delivery were observed for blacks, Asians and older mothers [8] Exposure to all air pollutants was associated with SGA; proximity to highways was related with 26% increase in SGA and 11% increase in LBW.…”