The prevalence of obesity has increased markedly in the U.S. in recent years. According to a new study by researchers from Boston University Slone Epidemiology Center's Black Women's Health Study (BWHS), the risk of becoming obese among young African-American women decreased with increasing levels of vigorous activity. The investigators focused on younger women because most weight gain occurs before middle age.
The findings are online and will appear in the September 2013 issue of the American Journal of Preventive Medicine.
The assessment of exercise in relation to obesity was based on data from the BWHS, an ongoing follow-up study of African-American women from across the U.S. The researchers followed 20,259 African-American women who were less than 40 years old and not obese at the start of the study for 14 years, from 1995-2009. Information on weight was updated every two years and information on exercise and walking was updated four times during follow-up. The investigators found that incidence of obesity decreased as the level of vigorous exercise increased. The risk of obesity was 23 percent lower among women who exercised seven or more hours per week relative to women who participated in little or no exercise. The reduction of obesity incidence among women who exercised was evident both among those with healthy weights at baseline and among those who were overweight at baseline. There were suggestive reductions in the incidence of obesity among women who walked briskly for exercise or transport but there were no clear trends.
According to Lynn Rosenberg, PhD, lead investigator of the study, effective approaches to reduce weight gain and obesity are very much needed in view of the increased incidence of type 2 diabetes and other serious illnesses associated with obesity. "Our study suggests that increased exercise would help in that effort," she said.