Exposure to ambient air pollution and changes in leukocyte telomere length in US women

Abstract

Background: Telomeres are repetitive sequences of nucleotides at the end of chromosomes that function to maintain structural integrity. Shorter telomere length has been associated with decreased life-expectancy and increased rates of cardiovascular disease (CVD) and cancer. Ambient air pollution has been related to similar outcomes. A few studies have shown associations between increases in pollution and decreases in telomere length, however fewer have been able to examine the effects of air pollution on longer term changes in telomere length. Aims: We aimed to determine if ambient air pollution exposures were associated with 10 year changes in leukocyte telomere length (LTL) in US women. Methods: Repeated measures of LTL from a real time PCR assay were available for 272 members of the Nurses’ Health Study. Blood samples were collected 1989-1990 and again in 2000-2001. Change in telomere length over the 10 year period (and the percent change) was calculated for each woman. Spatiotemporal model predictions were used to determine the average concentrations of PM2.5, PM10, NO2, and SO2 1990-2000 for each participant based on her residential address history. Linear regression with adjustment for known lifestyle predictors of LTL and change in LTL was used to determine the change in LTL for each standard deviation increase in air pollution. Results: In adjusted models, the 10 year average levels of all pollutants were associated with decreases in LTL. However, only associations with PM2.5 and PM10 were statistically significant. Each 6 µg/m3 increase in PM10 was associated with a 4.0% decrease (SE=1.9) in LTL and each 3 µg/m3 increase in PM2.5 was associated with 3.6% (SE=1.8) decrease. Conclusions: Average particulate matter pollution in the 10 years between blood draws was associated with an accelerated rate of telomere length shortening in US women.