Long- and short-term air pollution exposure shortens telomere length in a population of hypersusceptible subjects

Abstract

BACKGROUND AND AIM: Reduction in telomere length (TL) has been documented in subjects affected by age-related diseases (e.g., cancer, cardiovascular diseases) and has been associated to oxidative stress and systemic inflammation, claimed also as potential mechanisms underlying health effects of air pollution exposure, especially particulate matter (PM). We aim to determine the effects of both short- and long-term exposure to PM ≤10µm (PM10) on TL in a well-characterized population (SPHERE project). METHODS: About 1,800 subjects with overweight/obesity were recruited in Milan (Italy) in 2010-2015, completed a questionnaire and donated a 15 mL blood sample. TL was measured (as T/S ratio) by real-time PCR. Each subject was assigned air pollution and meteorological daily data based on his/her residential address. Multivariate mixed-effects linear models with a random intercept on PCR plate were applied. RESULTS:We observed a -2.8% change in TL [95% confidence interval (CI): -5.3; -0.8) per 10 µg/m3 increase in PM10 at the day of blood sampling (lag0). A similar pattern was apparent up to 12 days before recruitment (lag12), with the highest reduction observed at lag6 (-4.3, 95%CI: -6.9; -1.7). When considering moving averages of exposure levels in days preceding recruitment, we observed percent changes in TL ranging from -2.1 (lag0-1) to -8.5 (lag0-12). Long-term PM10 exposure was associated to a -14.9% TL reduction (95%CI: -29.4; -0.5) per 10 µg/m3 increase in annual average PM10 levels. The association between short-term exposure and TL remained practically unchanged when we additionally adjusted for long-term exposure (-6.2%, 95%CI: -11.2; -1.3 at lag0-14). CONCLUSIONS:Our results consistently show that both long- and short-term air pollution exposure shortens TL in a population of hypersusceptible subjects, thus shedding light on the potential mechanisms responsible for the excess of age-related diseases that is known to be associated with air pollution exposure. KEYWORDS: air pollution, particulate matter (PM), telomere length (TL), overweight, obesity, hypersusceptible