Independent and combined effects of dietary weight loss and exercise on leukocyte telomere length in postmenopausal women

Objective Investigate the effects of 12 months of dietary weight loss and/or aerobic exercise on leukocyte telomere length in postmenopausal women. Design and Methods Four hundred and thirty nine overweight or obese women (50‐75 years) were randomized to: (i) dietary weight loss (N = 118); (ii) aerobic exercise (N = 117), (iii) diet + exercise (N = 117), or (iv) control (N = 87). The diet intervention was a group‐based program with a 10% weight loss goal. The exercise intervention was 45 min day−1, 5 days week−1 of moderate‐to‐vigorous aerobic activity. Fasting blood samples were taken at baseline and 12 months. DNA was extracted from isolated leukocytes and telomere length was measured by quantitative‐polymerase chain reaction (qPCR). Mean changes were compared between groups (intent‐to‐treat) using generalized estimating equations. Results Baseline telomere length was inversely associated with age (r = −0.12 P < 0.01) and positively associated with maximal oxygen uptake (r = 0.11, P = 0.03), but not with BMI or %body fat. Change in telomere length was inversely correlated with baseline telomere length (r = −0.47, P < 0.0001). No significant difference in leukocyte telomere length was detected in any intervention group compared to controls, nor was the magnitude of weight loss associated with telomere length at 12 months. Conclusions Twelve months of dietary weight loss and exercise did not change telomere length in postmenopausal women.