A randomized trial of exercise and diet on health-related quality of life in survivors of breast cancer with overweight or obesity

Background: Obesity is a chronic, relapsing, and progressive disease; it is associated with poor health-related quality of life (HRQOL) in survivors of breast cancer. Methods: In this 2 × 2 factorial trial, 351 survivors of breast cancer with overweight or obesity were randomized to 1 of 4 treatment groups for 52 weeks: control, exercise alone, diet alone, or exercise plus diet. HRQOL end points were measured at baseline and at week 52 using the 36-Item Medical Outcomes Survey-Short Form (SF-36). Repeated measures analysis of covariance quantified the estimated treatment difference (ETD). Results: At baseline, participants had a mean (SD) age of 59.4 years (8.7), body mass index of 34.0 kg/m² (5.9), and 71 participants (20.2%) self-reported fair or poor general health. After 52 weeks, compared with control, the exercise plus diet improved the physical health summary score (ETD: 5.39; 95% CI, 0.55-10.22); exercise alone (ETD: –1.91; 95% CI, –6.60 to 2.79) and diet alone (ETD: 3.16; 95% CI, –1.52 to 7.83) did not change the physical health summary score. Compared with control, exercise alone (ETD: –0.27; 95% CI, –6.60 to 2.79), diet alone (ETD: 3.25; 95% CI, –1.41 to 7.91), and the exercise plus diet (ETD: 1.75; 95% CI, –2.90 to 6.39) did not change the mental health summary score. Exercise alone did not impact any HRQOL subscale; diet alone improved the vitality subscale; exercise plus diet improved the physical functioning, role—physical and vitality subscales. Conclusion: In survivors of breast cancer with overweight or obesity, exercise plus diet improved select HRQOL end points at week 52.