About one in five women in Singapore develop a temporary form of diabetes as a complication during pregnancy. While their blood sugar levels usually return to normal soon after childbirth, they are ten times more susceptible to go on to develop type 2 diabetes later in life compared with other women. Worldwide, this condition, known as gestational diabetes, arises in seven to ten per cent of all pregnancies.
While the five modifiable risk factors of diabetes—body-mass index (BMI), diet, amount of physical activity, alcohol consumption, and smoking—have been studied individually, the combined impact of all of them on the long-term risk of diabetes had not been fully examined, much less so among women who had developed gestational diabetes.
Using the Nurses’ Health Study II data set, a team from the National University of Singapore, led by Professor Zhang Cuilin, Director of the Global Centre for Asian Women’s Health (GloW) at the Yong Loo Lin School of Medicine, along with researchers from the National Institutes of Health and Harvard T.H. Chan School of Public Health determined that women who had developed gestational diabetes and who subsequently maintained optimal levels of the five modifiable risk factors, namely a normal BMI (18.5-24.9), high-quality diet, regular exercise, not smoking, and moderate alcohol consumption, benefitted from a 90 per cent relative reduction in the risk of developing type 2 diabetes. Their findings were published in the British Medical Journal.
“The major findings from the study convey a hopeful and powerful message to women at exceptionally high risk, and women with a history of gestational diabetes. Adopting a healthy diet and lifestyle can lower the risk of type 2 diabetes up to 90 per cent risk and even alleviate the high genetic risk of type 2 diabetes.”
Professor Zhang Cuilin
The study population in the Nurses’ Health Study II is a predominantly white female cohort based in the United States with a history of gestational diabetes who were followed up for 28 years since 1989. Among the 4,275 participants, 924 of them developed type 2 diabetes during the follow-up period.
Each additional risk factor that was kept in check led to a further lowering of this risk, even in women who were overweight, or at a greater genetic susceptibility for developing diabetes.
“Although causal relationships cannot be established given the observational nature of the study, ample evidence consistently supports the effectiveness of healthy lifestyles in preventing obesity or type 2 diabetes, and on improving cardiometabolic health among diverse populations,” said first author Dr Jiaxi Yang, a research fellow at GloW and Department of Obstetrics and Gynaecology, NUS Medicine.
Prof Zhang Cuilin (left) and Dr Yang Jiaxi were part of a team that looked at the combined impact of modifiable risk factors of diabetes on the long-term risk of diabetes in women with a history of gestational diabetes.
“With the alarmingly high prevalence of diabetes, and gestational diabetes in particular, in Asia, further studies among high-risk Asian women are needed to build upon the present findings. But one thing is clear—it is never too late to make these lifestyle changes. Adapting and maintaining a healthy diet and lifestyle should be encouraged as life-long efforts and should start young, which will not only benefit women themselves, but also the family and the next generation,” emphasised Zhang, whose team at GloW is now working on endeavours to help women at a reproductive age improve their diet and lifestyle with the aim of advancing women’s health over the life-span, and across generations.
Adapted and expanded by Sruthi Jagannathan from Healthy lifestyle lowers risk of Type 2 diabetes by up to 90% in women with gestational diabetes during pregnancy