Women Who Exercise Have Lower Breast Cancer Risk
Above average lifetime physical activity linked to 20% lower breast cancer risk in black and white women
FRIDAY, Nov. 18 (HealthDay News) -- A lifetime of recreational exercise is associated with a lower risk of breast cancer in both black and white women, according to a study published in the Nov. 16 issue of the Journal of the National Cancer Institute.
Leslie Bernstein, Ph.D., of the University of Southern California in Los Angeles, and colleagues collected detailed histories of lifetime recreational exercise among 4,538 newly diagnosed breast cancer patients and 4,649 controls. The women were aged 35 to 64, and were all from the Women's Contraceptive and Reproductive Experiences Study. About a third of the women in each group were black.
The researchers found that in all women, lower breast cancer risk was associated with increased lifetime exercise levels, or metabolic equivalents of energy expenditure (MET-hours) per week per year. A greater than average annual lifetime exercise level was associated with a 20% lower breast cancer risk compared to inactive women, the researchers found.
The inverse association held for both black women and white women, the researchers found.
"What remains unclear is the amount of lifetime activity necessary to reduce risk (if the association is causal), whether the benefits of activity vary by age, and whether the reduction in risk is observed in all population subgroups," the authors write.