A cross-sectional assessment of ambient air pollution exposure and leukocyte telomere length in US women

摘要

Background: Telomeres are repetitive sequences of nucleotides at the end of chromosomes that function to maintain structural integrity. Telomere length varies considerably among individuals and typically decreases with age, and telomere shortening has been shown to be accelerated by oxidative stress and inflammation. Shorter telomere length has been associated with decreased life-expectancy and increased rates of cardiovascular disease (CVD) and cancer, similar to ambient air pollution. To date, however, only a few studies have examined the association of telomere length and exposures to ambient or occupational air pollution. Aims: We aimed to determine if ambient air pollution exposures were associated with shorter leukocyte telomere length (LTL) in US women. Methods: Information on LTL from a real time PCR assay was available for 9,074 members of the Nurses' Health Study. All blood samples were collected 1989-1990 from women free of disease. To adjust for batch-to-batch variability in LTL, we log-transformed each measurement and calculated a batch-specific z-score. Spatiotemporal model predictions were used to determine the average concentrations of PM2.5, PM10, NO2, and SO2 in 1988 for each participant based on her residential address. We also calculated the distance in meters to the nearest major roadway as a measure of exposure to traffic. Robust regression with adjustment for known lifestyle predictors of LTL was used to determine the percent difference in LTL for each standard deviation increase in air pollution, or to compare women within 50m of a major road to those further away. Results: In adjusted models, there was no association of LTL with distance to road, PM10, NO2, or SO2. However, each 1 SD increase in PM2.5 (4 μg/m3), was associated with a 3.4% (95%CI: 1.0-5.9%) increase in LTL; the equivalent association in nonsmokers was 4.5% (95%CI: 0.9-8.3%). Conclusions: In cross-sectional analyses, LTL was not associated with measures of traffic or air pollution, with the exception of a positive association with PM2.5.