Air pollution, Telomere length and Mortality- A systemic review

Abstract

BACKGROUND AND AIM: Adverse effects of air pollution on cardiovascular morbidity, mortality, and all-cause mortality have been demonstrated over the last few decades. Acceleration of biological aging by air pollution could be a plausible underlying mechanism. Telomeres are tandem repetitive DNA complexes, considered as one of the critical markers of aging. This study sought to review the existing literature on the association between air pollution and telomere length (TL) as well as the association between TL and mortality to elucidate the underlying mechanism between air pollution and mortality. METHODS: We have searched on electronic databases including PUBMED, SCOPUS, and WEB OF SCIENCE using keywords “air pollution,” “telomere length,” and “all-cause mortality” from 2003-2017. RESULTS:A total of 20 articles remained for final review with 10,488 subjects to explore the association between air pollution and telomere length. Most of the observational studies were cross-sectional (12), remaining studies were cohort (5) and case-control (3). Eighteen (90%) assessed leukocyte telomere length (LTL), of which 15 found associations between air pollution and shorter TL, 2 with longer TL, and 1 had no association. Only two studies found shorter TL from saliva was associated with household air pollutants. Particulate matter was investigated in 70% of articles (14), and the remainder assessed black carbon (BC), Ozone, benzene, and NO2. We have found 21 published articles to explore the association between TL and all-cause mortality. Of which 11 studies found an association between shorter TL and all-cause mortality. The remainder found no association. However, we could not perform a quantitative meta-analysis due to discordance in the reporting formats. CONCLUSIONS:Most of the studies support the association of air pollution with shorter TL as well as mortality with shorter TL- that suggested a possible explanation of how environmental stress may promote earlier onset of age-related diseases and mortality if the observed associations are causal. KEYWORDS: Air pollution, Telomere length, All-cause mortality