March 15, 2006

Exercise Lowers Pregnancy-related Diabetes Risk

By Anne Harding

NEW YORK (Reuters Health) - Women who are physically active before pregnancy are less likely to develop diabetes during pregnancy, a new study shows. It also indicates that the risk rises with the amount of pre-pregnancy television viewing.

While smaller studies have suggested that exercise can reduce the risk of so-called gestational diabetes, the current study is among the largest and best-designed that has examined this relationship to date, lead investigator Dr. Cuilin Zhang of the Harvard School of Public Health in Boston told Reuters Health.

Zhang and her colleagues looked at 21,765 women participating in the Nurses Health Study II who had at least one pregnancy between 1990 and 1998. A total of 1428 cases of gestational diabetes were identified. The women had completed questionnaires assessing their level of physical activity and sedentary behavior.

After the researchers took account of body mass index, diet and other factors, they found that women with the highest levels of vigorous physical activity were 23 percent less likely to develop gestational diabetes than those who were the least active.

Women who walked briskly but did not perform vigorous exercise were 34 percent less likely to develop gestational diabetes than those who walked at an easy pace. Walking briskly for more than 30 minutes daily or climbing 15 flights of stairs every day also lowered gestational diabetes risk for women who did not exercise vigorously, according to the report in the Archives of Internal Medicine.

The researchers also found that women who watched at least 20 hours of television each week and did not exercise vigorously were 2.3-times more likely to develop gestational diabetes than active women who watched less than 2 hours of TV a week.

Given that gestational diabetes is a risk factor for subsequently developing type 2 diabetes, Zhang said, the findings underscore the importance of physical activity for young women. There's also evidence that gestational diabetes can increase a child's later risk of obesity and diabetes, she added.

"From the public health view, it is important for women of reproductive age to keep an active lifestyle," she said.

SOURCE: Archives of Internal Medicine, March 13, 2006.