Exposure–Response Associations of Household Air Pollution and Buccal Cell Telomere Length in Women Using Biomass Stoves

摘要

Background: Telomere shortening is associated with early mortality and chronic disease. Recent studies indicate that environmental exposures, including urban and traffic-related air pollution, may shorten telomeres. Associations between exposure to household air pollution from solid fuel stoves and telomere length have not been evaluated. Methods: Among 137 rural Chinese women using biomass stoves ( mean = 55 y of age), we measured 48-h personal exposures to fine particulate matter [PM ≤ 2.5 μ m in aerodynamic diameter ( PM 2.5 )] and black carbon and collected oral DNA on up to three occasions over a period of 2.5 y. Relative telomere length (RTL) was quantified using a modified real-time polymerase chain reaction protocol. Mixed effects regression models were used to investigate the exposure–response associations between household air pollution and RTL, adjusting for key sociodemographic, behavioral, and environmental covariates. Results: Women’s daily exposures to air pollution ranged from 13 – 1,136 μ g / m 3 for PM 2.5 ( mean = 154 ) and 0.1 – 34 μ g / m 3 for black carbon ( mean = 3.6 ). Natural cubic spline models indicated a mostly linear association between increased exposure to air pollution and shorter RTL, except at very high concentrations where there were few observations. We thus modeled the linear associations with all observations, excluding the highest 3% and 5% of exposures. In covariate-adjusted models, an interquartile range (IQR) increase in exposure to black carbon ( 3.1 μ g / m 3 ) was associated with shorter RTL [all observations: ? 0.27 (95% CI: ? 0.48 , ? 0.06 ); excluding highest 5% exposures: ? 1.10 (95% CI: ? 1.63 , ? 0.57 )]. Further adjustment for outdoor temperature brought the estimates closer to zero [all observations: ? 0.15 (95% CI: ? 0.36 , 0.06); excluding highest 5% exposures: ? 0.68 (95% CI: ? 1.26 , ? 0.10 )]. Models with PM 2.5 as the exposure metric followed a similar pattern. Conclusion: Telomere shortening, which is a biomarker of biological aging and chronic disease, may be associated with exposure to air pollution in settings where household biomass stoves are commonly used.