Determinants of telomere attrition over one year in healthy older women: Stress and health behaviors matter

Telomere length, a reliable predictor of disease pathogenesis, can be affected by genetics, chronic stress, and health behaviors. Cross-sectionally, highly stressed post-menopausal women have shorter telomeres, but only if they are inactive. However, no studies have prospectively examined telomere length change over a short period, and if rate of attrition is affected by naturalistic factors such as stress and engagement in healthy behaviors. Here we followed healthy women over one year to test if major stressors that occurred over the year predicted telomere shortening, and whether engaging in healthy behaviors during this period mitigates this effect. In 239 post-menopausal, non-smoking, disease-free women, accumulation of major life stressors across a one-year period predicted telomere attrition over the same period - for every major life stressor that occurred during the year, there was a significantly greater decline in telomere length over the year of 35 base pairs (p < .05). Yet, these effects were moderated by health behaviors (interaction B = 0.19, p = .04). Women who maintained relatively higher levels of health behaviors (one standard deviation above the mean) appeared to be protected when exposed to stress. This finding has implications for understanding malleability of telomere length, as well as expectations for possible intervention effects. This is the first study to identify predictors of telomere length change over the short period of a year.