Physical activity attenuated the association of air pollutants with telomere length in rural Chinese adults

Background: Exposure to air pollutants (nitrogen dioxide (NO2) and particulatematters (PMs)) or physical inactivity is linked to telomere length (TL) shortening. However, there is a lack of research on combined effects of either NO2 or PMs and physical activity (PA) on TL. This study aimed to explore the joint associations of air pollutants (NO2 or PMs) and PA with relative TL in rural Chinese adults. Methods: This study was conducted among 2704 participants aged 18-79 years in rural China. Concentrations of NO2 and PMs (PM with an aerodynamics diameter <= 1.0 mu m (PM1), <= 2.5 mu m (PM2.5) or <= 10 mu m (PM10)) were estimated using random forest models incorporated with satellites data, meteorological data, and land use information. Relative TL of each participant was measured by a quantitative real-time polymerase chain reaction. Linear regression models were applied to examine the independent associations between PA, NO2 or PMs and relative TL. Interaction plots were used to depict the altered associations between NO2, PM1, PM2.5, or PM10 and relative TL along with increasing PA levels. Results: Each 1 mu g/m(3) increment in NO2, PM1, PM2.5, or PM10 was associated with a 0.038 (95% confidence intervals (CI):-0.044,-0.033), 0.036 (95% CI: -0.041, -0.031), 0.052 (95% CI: -0.059,-0.045), or 0.022 (95% CI: -0.025, -0.019) decrease in relative TL among all participants; similar findings were observed among normal glucose tolerance or impaired fasting glucose (IFG) participants as well as type 2 diabetes mellitus (T2DM) patients. PA at certain levels counteracted the association of air pollutants (NO2, PM1, PM2.5, and PM10) with relative TL among IFG participants or T2DM patients. Conclusions: Long-term exposure to NO2 and PMs was associated with relative TL shortening and these effects may be counteracted by PA at certain levels in IFG participants or T2DM patients. (C) 2020 Elsevier B.V. All rights reserved.