The association between telomere length and mortality in Bangladesh

Abstract

Telomeres are tandem repeat sequences at the end of chromosomes that bind proteins to protect chromosome ends. Telomeres shorten with age, and shorter leukocyte telomere length (TL) has been associated with overall mortality in numerous studies. However, this association has not been tested in populations outside of Europe and the U.S. We assessed the association between TL and subsequent mortality using data on 744 mortality cases and 761 age-/sex-matched controls sampled from >27,000 participants from three longitudinal Bangladeshi cohorts: Health Effects of Arsenic Longitudinal Study (HEALS), HEALS Expansion (HEALS-E), and Bangladesh Vitamin E and Selenium Trial (BEST). We used conditional logistic regression to estimate odds ratios (ORs) for the association between a standardized TL variable and overall mortality, as well as mortality from chronic diseases, respiratory diseases, circulatory diseases, and cancer. In HEALS and BEST, we observed an association between shorter TL and increased overall mortality (P=0.03 and P=0.03), mortality from chronic disease (P=0.01 and P=0.03) and mortality from circulatory disease (P=0.03 and P=0.04). Results from pooled analyses of all cohorts were consistent with HEALS and BEST. This is the first study demonstrating an association between short TL and increased mortality in a population of non-European ancestry.

Keywords: Bangladesh; arsenic; circulatory disease; mortality; telomere length.

Figure 1. Forest plots of the odds ratios (ORs) and 95% confidence intervals for the association between telomere length and mortality in HEALS, HEALS-E, and BEST cohorts

ORs correspond to a 1 standard deviation difference in telomere length.

Figure 2. Odds ratios (ORs) and 95% confidence intervals for the association between TL quartiles and mortality outcomes in pooled analyses of all three cohorts

TL is divided into quartiles based on the distribution in controls. The reference group is the longest quartile of TL. The OR corresponding to each quartile compares the odds of mortality of the given quartile to the odds of mortality in the longest quartile.