Association of obesity and sleep problems among breast cancer survivors: results from a registry-based survey study.

Purpose: Sleep-related complaints are common among breast cancer survivors. However, the risk factors underlying sleep disturbances in this population are not completely understood. Some studies have shown that maintaining normal weight can result in a reduced risk of cancer-related symptoms, including sleep problems; however, data from published studies are not consistent. This study examined the associations between body mass index (BMI) and sleep-related complaints in breast cancer survivors.

Methods: Self-reported survey data from 861 breast cancer survivors at a single institution were analyzed. BMI was calculated based on self-reported weight and height at the time of the survey. Daytime sleepiness was assessed using the Epworth Sleepiness Scale. Average sleep duration was calculated based on the reported hours of sleep on a typical weekday and weekend. Associations between BMI and the sleep outcomes were estimated using multivariable logistic regression.

Results: In adjusted models, BMI was not significantly associated with either excessive daytime sleepiness or "short" sleep pattern (≤ 6 h) in our sample of breast cancer survivors. Younger age, presence of strong acute pain, and lower level of education were independent risk factors for excessive daytime sleepiness. African American race, presence of strong acute pain, and lower level of education were independent risk factors for being a short sleeper.

Conclusions: Findings from this study indicate that BMI is not independently associated with sleep-related outcomes among breast cancer survivors. More research is needed to identify cancer survivors who are at increased risk for sleep disturbances as well as the mechanisms that underlie such disturbances.