Randomized controlled trial of weight loss versus usual care on telomere length in women with breast cancer: the lifestyle, exercise, and nutrition (LEAN) study.

Purpose: Some studies suggest that telomere shortening may be associated with increased breast cancer risk and mortality. Obesity is also associated with increased breast cancer risk and mortality. Few studies have examined changes in telomere length in overweight or obese breast cancer survivors. The purpose of our study was to examine the effect of a 6-month diet- and exercise-induced weight loss intervention versus usual care on telomere length in breast cancer survivors.

Methods: 151 breast cancer survivors with body mass index (BMI) ≥ 25 kg/m were randomly assigned to a 6-month weight loss intervention (n = 93) or to usual care (n = 58). Fasting blood samples, height, weight, physical activity, and diet were measured at baseline and 6-months. Relative telomere length (RTL) was measured by quantitative-polymerase chain reaction (qPCR) done on buffy coat-extracted genomic DNA. Mean baseline to 6-month changes were compared between groups (intention-to-treat) using generalized estimating equations.

Results: Complete telomere data were available in 125 participants. Women were 58 ± 8 years, with BMI 33.0 ± 6.2 kg/m and were 2.9 ± 2.5 years from diagnosis; 90% were non-Hispanic white, and 76% had stage 0/I breast cancer. After 6 months, women randomized to weight loss had 3% telomere lengthening compared to 5% shortening in the usual care group (p = 0.12). Among women with stage 0/I, the intervention group experienced 7% telomere lengthening compared to 8% shortening in the usual care group (p = 0.01). No intervention effect was observed in women with stage II/III breast cancer.

Conclusion: Our findings suggest a weight loss intervention in stage 0 and 1 breast cancer survivors may lead to telomere lengthening, compared to a shortening in their usual care counterparts.