A new study published in JAMA Internal Medicine finds that increased physical activity can lower the risk of gestational diabetes mellitus progressing to type 2 diabetes mellitus.
A common complication of pregnancy, gestational diabetes mellitus (GDM) is defined as glucose intolerance that occurs or is first recognized during pregnancy. About one third of women of reproductive age with type 2 diabetes mellitus (T2DM) have a history of GDM.
T2DM is now defined as an escalating worldwide epidemic, so diagnosing GDM is important in that it allows women to recognize the risk of T2DM and to take action to try and prevent it.
In order to take action that might prevent GDM from progressing to T2DM, though, it is necessary for research to identify what risk factors in this high-risk population are modifiable. The researchers behind the new study had established in previous work that a healthful diet is associated with a lower risk of T2DM in women with a history of GDM.
Glycemic control may be regulated by physical activity, which also facilitates weight loss and weight maintenance, so the researchers wondered if regular physical activity could prevent or delay the onset of T2DM.
Using data from the Nurses' Health Study II, the study looked at 4,554 women with a history of GDM who were followed between 1991-2007. The study captured information on the women's physical activity and sedentary activity, such as watching TV. Within this group, 635 of the women went on to get T2DM.
The researchers calculated that every increase in increments of 100 minutes per week of moderate-intensity physical activity (or 50 minutes per week of of vigorous-intensity activity) was associated with a 9% lower risk of T2DM.
Women who increased their physical activity by the federal government recommendation of 150 minutes per week of moderate-intensity physical activity (or 75 minutes per week of vigorous-intensity activity) were found to have a 47% lower risk of T2DM.
Sedentary lifestyle increases women's risk for type 2 diabetes
However, the researchers also found that an increase in the amount of time watching TV was associated with a greater risk of T2DM. The researchers stress, though, that T2DM risk is not raised by TV watching per se, but that an unhealthy lifestyle highly correlated with TV watching could influence risk.
Women who increased their physical activity by the federal government recommendation of 150 minutes per week of moderate-intensity physical activity (or 75 minutes per week of vigorous-intensity activity) had a 47% lower risk of T2DM.
"For example," the authors write, "TV watching typically acts as a sedentary replacement for physical activity leading to a reduction in energy expenditure, and TV watching is associated with 'mindless' eating, increasing food and total energy intake. Finally, while watching TV, women may be influenced by commercial food advertisements for nutrient-poor, high-calorie foods."
This study included a large sample of participants who were studied over a long period of time.
However, as the participants were all nurses, it is possible that the results could be confounded by the nurses being more health conscious or by having different access to health care than the general population.
Also, the participants were mostly white American women, so it may not be possible to generalize the results to other groups.
The authors conclude their study by writing:
"Our results from a large prospective study indicate that increasing physical activity may help lower the risk of progression from GDM to T2DM. These findings suggest a hopeful message to women with a history of GDM, although they are at exceptionally high risk for T2DM, promoting an active lifestyle may lower the risk."
Last November, Medical NewsToday reported on new guidelines for diagnosing gestational diabetes.