Association of Diet Quality and Physical Activity on Obesity-Related Cancer Risk and Mortality in Black Women: Results from the Women's Health Initiative

• Published in: Cancer epidemiology, biomarkers & prevention Vol. 29; no. 3; pp. 591 - 598
• Main Authors: Chebet, Joy J, Thomson, Cynthia A, Kohler, Lindsay N, Ehiri, John E, Luo, Juhua, Cheng, Ting-Yuan David, Pan, Kathy, Chlebowski, Rowan T, Nassir, Rami, Sealy-Jefferson, Shawnita, Manson, JoAnn E, Saquib, Nazmus, Bell, Melanie L
• Format: Journal Article
• Language: English
• Published: United States 01-03-2020
• Subjects: African Americans - statistics & numerical data; Aged; Body Mass Index; Exercise; Feeding Behavior; Female; Follow-Up Studies; Health Status Disparities; Humans; Incidence; Life Style; Middle Aged; Mortality; Neoplasms - epidemiology; Obesity - epidemiology; Proportional Hazards Models; Prospective Studies; Risk Assessment - methods; Risk Factors; United States - epidemiology; United States
• ISSN: 1055-9965; 1538-7755
• DOI: 10.1158/1055-9965.EPI-19-1063

Obesity-related cancers disproportionately affect the Black community. We assessed the relationship between diet quality, physical activity, and their combined effect on obesity-related cancer risk and mortality in Black women enrolled in the Women's Health Initiative (WHI).
Data from postmenopausal (50-79 years of age) Black women enrolled in WHI clinical trials or observational studies were analyzed. Exposure variables included baseline physical activity [metabolic equivalent of tasks (MET)-hours/week of moderate-to-vigorous physical activity (MVPA)] and diet quality [Healthy Eating Index (HEI)-2015]. Outcomes included adjudicated obesity-related cancer incidence and mortality. Cox proportional hazard models were used to evaluate the association between MVPA and HEI-2015 and obesity-related cancer risk and mortality.
The analytical sample included 9,886 Black women, with a baseline mean body mass index (BMI) of 31.1 kg/m
(SD = 6.8); mean HEI-2015 score of 63.2 (SD = 11.0, possible range 0 to 100); and mean MVPA of 5.0 (SD = 9.4) MET-hours/week. Over an average of 13 years of follow-up, 950 (9.6%) obesity-related cancer cases were observed, with 313 (32.9%) resulting in death. Physical activity [HR, 1.05; 95% confidence interval (CI), 0.86-1.30], diet quality (HR, 0.99; 95% CI, 0.92-1.08), and their combination (HR, 1.05; 95% CI, 0.85-1.29) were not associated with risk for any or site-specific obesity-related cancers. Similarly, these health behaviors had no association with mortality.
Diet quality, physical activity and their combined effect, as measured, were not associated with obesity-related cancer risk and mortality in Black women enrolled in WHI.
Other social, behavioral, and biological factors may contribute to racial disparities observed in obesity-related cancer rates.