PRENATAL FINE PARTICULATE MATTER (PM2.5) AND POLYCYCLIC AROMATIC HYDROCARBON (PAH) EXPOSURES AND THEIR ASSOCIATION WITH BIRTHWEIGHT IN SOUTHERN INDIA - PROJECT SUMMARY / ABSTRACT
Air pollution is a leading risk factor for the national disease burden in India, resulting in an estimated 1.17
million adult and 116,000 neonatal deaths in 2019. Ambient air pollution is increasing steadily across Indian
megacities and nearly 100% of the population experience exposures to unsafe levels of fine particulate matter
(PM2.5). Further, exposures to air toxics such as polycyclic aromatic hydrocarbons (PAHs) are likely to be
widespread in urban India on account of ubiquity of sources and high volume of emissions, but exposures to
air toxics remain poorly characterized. Impacts of air pollution on pregnant women and the developing fetus
have tremendous implications for India where, the prevalence of low birth weight (LBW <2.5 kg birthweight) is
already high (15 to 30% across states). Despite the ubiquity of health damaging PM2.5 and PAHs exposure and
high prevalence of LBW, evidence linking these exposures to adverse pregnancy outcomes has been limited in
India. To address this evidence gap, the study proposes to establish an urban cohort of 300 pregnant women
in Chennai (a megacity in southern India) to examine pregnancy period exposures to PM2.5 and PAHs through
personal monitoring and biomarker measurements and examine associations with birthweight. The proposed
research builds on the extensive capacities at the host institution created through previous NIH supported
projects. The study will recruit 300 pregnant women from outpatient clinics of Sri Ramachandra Hospital
(applicants host institute), conduct 24-hour personal exposure measurements for PM2.5 and PAHs three times,
once during each trimester using a wearable sampler and assess the oxidative potential of the PM2.5 fractions
(PM-OP) by acellular assays and its relationship with PM2.5 and PAHs. Urinary levels of PAH metabolites (2-
naphthol and 1-hydroxypyrene) and 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-OHdG), a biomarker of oxidative
damage will be measured during each trimester and leukocyte telomere length (LTL) will be measured in cord
blood. This will allow an evaluation of the individual and interactive associations between PM2.5, PAHs, PM-OP,
urinary biomarkers (PAH metabolites and 8-OHdG) and telomere length. On a 100-person subset of the
cohort, Fresh Air wristbands will be used to provide a measure of personal exposure to PAHs and will be
evaluated with other measures of exposure and effect. Finally, the differential effects of PM2.5 and PAHs on
term low-birth weight will be examined using single, two and multipollutant models. The study will strengthen
the limited available exposure-response evidence for prenatal PM2.5 and PAH exposures and birthweight in
India while also identifying potential vulnerable exposure windows. Career development activities will focus on
advanced training in novel exposure assessment techniques, mass spectrometry-based techniques for
biomarker analysis, regression analysis and multipollutant modeling. The increased investigator capacities will
allow research beyond traditional PM mass-related health effects to address multiple environmental exposures
that predominate in high exposure settings of urban India.
