The Impact of Baseline Sleep as a Potential Moderator of Weight Loss Intervention in Breast Cancer Survivors: Results From the POWER-Remote Trial.

[OBJECTIVE] We evaluated whether sleep disturbance moderates weight loss in breast cancer survivors. We hypothesized that poor sleep prior to behavioral weight loss (BWL) would be associated with less weight reduction than better sleep.

[METHODS] Women with prior stage 0-III breast cancer with BMI ≥ 25 kg/m were randomized to BWL (n = 47) or self-directed approach (n = 46). Weight and self-reported sleep (NIH PROMIS Adult Sleep Disturbance Short Form) were collected at baseline and at 6 and 12 months. In the full sample and cohorts stratified by baseline sleep, multiple regression analyses evaluated associations of study arm, age, baseline sleep, and BMI with weight loss.

[RESULTS] There was significant interaction between baseline sleep and treatment (BWL vs. self-directed) for weight loss at 6 (p = 0.024) and 12 months (p = 0.019). Weight loss among better sleepers was -6.16% (SE 1.42%) in BWL versus self-directed arms and -7.53% (SE 2.02%) at 6 (p < 0.001) and 12 months (p = 0.001), respectively. Among poor sleepers, weight loss was -3.15% (SE: 1.58%) and -2.44% (SE: 2.40%) at 6 (p = 0.056) and 12 months (p = 0.321), respectively. BWL had a greater effect among better sleepers but minimal effect among poor sleepers.

[CONCLUSIONS] BWL has greater effects in breast cancer survivors with better versus worse sleep. Studies should evaluate whether sleep disturbance treatment augments weight loss.

[TRIAL REGISTRATION] ClinicalTrials.gov identifier NCT01871116.