Obesity, ethnicity, and quality of life among breast cancer survivors and women without breast cancer: the long-term quality of life follow-up study.

Purpose: The purpose of this study was to examine the relationship between obesity and quality of life (QOL) among Hispanic and non-Hispanic white breast cancer survivors and population-based controls from the 'Long-Term Quality of Life Study'--a 12- to 15-year follow-up study of breast cancer cases/survivors and controls from New Mexico (n = 451).
Methods: Using multiple linear regressions, obesity measures [body mass index (BMI) ≥ 30 kg/m(2)] at baseline and follow-up interview were modeled with composite scores for physical and mental health from the SF-36 Quality of Life Survey. Interaction between ethnicity and BMI and change in BMI were evaluated. All models were adjusted for age, ethnicity, Charlson Index, depression, fatigue, and physical activity.
Results: Baseline obesity (β = -6.58, p = 0.04) was significantly associated with decreased mental health among survivors, but not among controls. Obesity at baseline and follow-up were significantly associated with decreased physical health among survivors (baseline β = -10.51, p = 0.004; follow-up β = -7.16, p = 0.02) and controls (baseline β = -11.07, p < 0.001; follow-up β = -5.18, p = 0.04). No significant interactions between ethnicity and BMI were observed.
Conclusions: Our findings provide unique information about a diverse population of breast cancer survivors and controls and the impact of obesity on the mental and physical aspects of QOL.