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 (beta = -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 beta = -10.51, p = 0.004; follow-up beta = -7.16, p = 0.02) and controls (baseline beta = -11.07, p < 0.001; follow-up beta = -5.18, beta = 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.