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NEW YORK (Reuters Health) - Women who become diabetic during pregnancy may be able to avoid later developing type 2 diabetes with exercise, according to a new U.S. study.
Among women who had so-called gestational diabetes, those who upped their exercise by a little more than 20 minutes a day after giving birth had half the longer-term diabetes risk of women who didn't change their activity levels.
“This is kind of a hopeful message because they may think they are at a high risk of type 2 diabetes, but this shows they shouldn’t give up,” Dr. Cuilin Zhang said. “Exercise more. It can help.”
Zhang, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, in Rockville, Maryland, is the study’s lead author.
Women – especially those who are older, heavier and not white – are at risk of developing gestational diabetes, because of changes in the body during pregnancy. Gestational diabetes affects between 2 percent and 10 percent of U.S. pregnancies.
While women with gestational diabetes may experience symptoms typical of type 2 diabetes including increased thirst and urge to urinate, most women find out from their doctors.
If blood sugar isn't controlled during pregnancy, gestational diabetes puts babies at risk of being born earlier and heavier than normal. It also puts women at increased risk of high blood pressure and preeclampsia, another serious pregnancy complication.
Although gestational diabetes may disappear after childbirth, a woman who has had it is at increased risk of developing type 2 diabetes, especially within the next five years.
“Pregnancy is like a stress test," Zhang said. “Pregnancy can unveil the high susceptibility of type 2 diabetes later in their lives.”
For the new study, the researchers used 16 years' worth of data on 4,554 adult women who had a history of gestational diabetes. By the end of the study period, 635 had developed type 2 diabetes.
Based on behaviors like exercise and time spent watching television, the researchers calculated the women's risk of developing type 2 diabetes.
Among the one-fifth of women who exercised the least, about 19 percent developed diabetes later on, compared to about 9 percent among the one-fifth who exercised the most.
The researchers found that a woman’s risk of developing type 2 diabetes fell by about 9 percent for every additional 100 minutes of moderate-intensity exercise added per week.
Overall, women who increased their exercise by 150 minutes a week had just 53 percent of the diabetes risk of women who didn't change their activity levels after pregnancy.
Watching television, in contrast, was tied to an increased risk of developing type 2 diabetes. For instance, women who watched 11 to 20 hours of TV a week had 1.4 times the diabetes risk of women who watched 0 to 5 hours a week.
Those results don’t mean that watching television is the problem, the researchers write in JAMA Internal Medicine. Instead, it’s more likely that people who watch a lot of television are generally less healthy than those who don’t.
They caution that the study’s results may not apply to all women because their data primarily come from white women living in the U.S.
Monique Hedderson told Reuters Health that the healthcare system needs to do a better job of understanding what works at preventing type 2 diabetes among high-risk women.
"It’s a challenging time for women during the post partum period when they have a baby," she said.
Hedderson co-authored a commentary accompanying the new study. She is a research scientist at the Kaiser Permanente Division of Research in Oakland, California.
"It’s important for young women to be physically active before, during and after pregnancy," she said. "That is the bottom line."
Zhang said the ultimate goal of their research is to identify how medicine, lifestyle and genetics come together to influence risk among women with a history of gestational diabetes.
SOURCE: bit.ly/WiwDtv JAMA Internal Medicine, online May 19, 2014.