Abstract A01: Independent and combined effects of dietary weight loss and aerobic exercise on leukocyte telomere length in overweight and obese postmenopausal women
Authors: Mason Caitlin , Risques Rosa-Ana , Xiao Liren , Duggan Catherine R. , Imayama Ikuyo , Campbell Kristin L. , Kong Angela , Foster-Schubert Karen E. , Wang Ching-Yun , Alfano Catherine M. , Blackburn George L. , Rabinovitch Peter S. , McTiernan Anne 
Published: January 2014

Abstract
The purpose of this study was to investigate the effects of 12 months of dietary weight loss and/or aerobic exercise on leukocyte telomere length in overweight and obese postmenopausal women. Four hundred and thirty nine women (50-75 y) were randomized to one of four groups: i) dietary weight loss (N=118); ii) moderate-to-vigorous aerobic exercise (N=117), iii) diet + exercise (N=117), or iv) control (N=87). The diet intervention was a group-based reduced-calorie program with a 10% weight loss goal. The exercise intervention was 45 mins/day, 5 days/week of moderate-to-vigorous intensity 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). Telomere length was calculated as the ratio of telomeric DNA divided by a single-copy control gene. Mean changes were compared between groups (intent-to-treat) using generalized estimating equations. At baseline, leukocyte telomere length was not significantly correlated with body mass index (r=0.02, p=0.68) or % body fat (r=-0.003, p=0.95), but was inversely associated with age (r=-0.12 p&lt;0.01) and positively associated with VO2max (r=0.11, p=0.03). Mean telomere length (SD) was not significantly different between overweight and obese women [1.045 (0.184) vs. 1.057 (0.201); p=0.63]. After 12 months, mean weight changes were -2.4% (p=0.03) in the exercise group, -8.5% (p&lt;0.001) in the diet group, and -10.8% (p&lt;0.001) in the diet + exercise group, compared to -0.8% among controls. No significant changes in leukocyte telomere length were detected in any of the intervention groups compared to controls, nor was the magnitude of weight loss associated with telomere length changes after 12 months. Over 12-months there was a net increase (mean T/S ratio: 0.124, range: 0.002-0.736) in telomere length among 48% (n=190) of women. The proportion of women who experienced a net 12-month increase was not significantly different between groups (χ2 p=0.90). Although telomere shortening represents a compelling link between genetics, accumulated lifestyle exposures and cancer, leukocyte telomere length is not significantly changed by 12 months of dietary weight loss and/or aerobic exercise intervention in postmenopausal women.
Citation Format: Caitlin Mason, Rosa-Ana Risques, Liren Xiao, Catherine R. Duggan, Ikuyo Imayama, Kristin L. Campbell, Angela Kong, Karen E. Foster-Schubert, Ching-Yun Wang, Catherine M. Alfano, George L. Blackburn, Peter S. Rabinovitch, Anne McTiernan. Independent and combined effects of dietary weight loss and aerobic exercise on leukocyte telomere length in overweight and obese postmenopausal women. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A01.