Regular exercise can help in cutting down the risk of breast cancer in women. As compared to sedentary peers, women who stay active are less likely to develop breast cancer. The benefits of physical activity exist irrespective of whether a woman was slim, normal weight, or overweight; whether or not she had a family history of breast cancer; and whether or not she had reached menopause. Epidemiologic studies have shown that breast cancer risk is reduced 30% to 40% in highly physically active compared with inactive women. However, the effects of moderate activities, timing of activities, and intervening effects of other risk factors remain less clear. To assess the benefits of exercise in preventing breast cancer, researchers at the Nofer Institute of Occupational Medicine in Lodz, Poland, compared 2,176 women with breast cancer and 2,346 healthy controls. These women were asked about their level of recreational and occupational physical activity throughout their adult lives. Using unconditional logistic regression analyses, the researchers calculated odds ratios and confidence intervals associated with physical activity levels (measured by average metabolic equivalents of energy expenditure hours per week), controlling for potential confounders. The results showed that women can cut their breast cancer risk by being physically active. The women with the highest total adult lifetime activity were 20 percent less likely to have developed breast cancer than the least active women. Being in the top fourth of the group based on moderate-to-vigorous recreational physical activity conferred a 26 percent lower risk of the disease compared to being in the bottom fourth. It was found that women who spent more time in moderate-to-vigorous recreational activities in their 50s than they had in their 20s, 30s and 40s were 34 percent less likely to develop breast cancer, while those who increased their activity the most were at 41 percent lower risk. The researchers urge moderate-to-vigorous activities to help reduce breast cancer risk in women.
Epidemiology,
March 2008