Healthy Lifestyle Habits Lower Risk of Type 2 Diabetes among Women with a History of Gestational Diabetes - NUS Medicine

Issue 45
Jan 2023

SCIENCE OF LIFE

Women with a history of diabetes during pregnancy can still reduce their chances of developing Type 2 diabetes substantially by sticking to a healthy lifestyle.

Gestational Diabetes Mellitus (GDM), or diabetes during pregnancy, is a common pregnancy complication. Women who developed GDM are nearly 10 times more at risk of developing type 2 diabetes compared to the general population.

In particular, Asian women have the highest risk of developing GDM across all racial and ethnic groups. It’s no surprise that in Singapore, up to one in five pregnant women are at risk of GDM. This calls for more public health and research efforts in identifying and developing effective interventions to prevent or delay the progression of type 2 diabetes.

The five modifiable risk factors of type 2 diabetes, such as weight control, diet, amount of physical activity, alcohol consumption and smoking, have thus far been examined individually. However, the combined associations of these risk factors on the long-term risk of developing type 2 diabetes are less well understood, particularly among women who developed GDM.

Women who developed GDM are nearly
10 times
more at risk of developing type 2 diabetes compared to the general population

Investigating this, Professor Zhang Cuilin, Director of Global Centre for Asian Women’s Health (GloW), and a Professor from the Department of Obstetrics and Gynecology at the NUS Yong Loo Lin School of Medicine, led a team of NUS researchers, in collaboration with the National Institutes of Health and Harvard T.H. Chan School of Public Health. They examined the associations of adhering to optimal levels of five major modifiable risk factors, with the risk of developing type 2 diabetes among women with a history of GDM.

Lifestyle factors trumps genetic susceptibility

Yet another aspect of investigation was the risk factor associations among a subset who were further predisposed by a greater genetic susceptibility and were overweight (BMI>25.0 kg/m²).

Diabetes developing among this group of women may have been considered at greater risk.

Published in the British Medical Journal (BMJ), the study showed promising findings on the beneficial roles of optimal modifiable factors in lowering type 2 diabetes risk among these high-risk women.

Major findings from the study convey a hopeful and powerful message to these women. Eating healthily, exercising regularly, not smoking, and maintaining an optimal body weight can lower the risk of type 2 diabetes by up to 90% and even alleviate the high genetic risk of type 2 diabetes. Those who are overweight may also benefit from adopting these healthful lifestyle practices after their GDM-complicated pregnancy.

Study findings hold relevance for Asian populations

The study population consisted of 4,275 women with a history of GDM from the Nurses’ Health Study II, a longitudinal predominantly white female cohort in the United States that has been followed up with since 1989. These participants were included as part of the Diabetes & Women’s Health Study initiated and led by Prof Zhang for investigating modifiable and genetic risk factors for type 2 diabetes and comorbidities following pregnancies complicated by GDM.

In the study, 924 women developed type 2 diabetes over 28 years of follow-up. After adjusting for other major diabetes risk factors, the researchers found that having optimal levels of the five modifiable risk factors, namely a normal BMI (18.5-24.9), high-quality diet, regular exercise, abstinence from smoking, and moderate alcohol consumption, was associated with a relative reduction of more than 90% in the risk of type 2 diabetes, compared to those who did not have any. Each additional optimal modifiable factor was associated with an incrementally lower risk of the condition.

Having optimal levels of the five modifiable risk factors, namely a normal BMI (18.5-24.9), high-quality diet, regular exercise, abstinence from smoking, and moderate alcohol consumption, was associated with a relative reduction of more than 90% in the risk of type 2 diabetes, compared to those who did not have any.

Asked about the relevance of this study to the Singaporean population, Prof Zhang answered, “Although data of the present study came from predominantly Caucasian women in the United States, accumulating evidence has suggested benefits of adopting a healthy lifestyle in the prevention of cardio-metabolic diseases including type 2 diabetes.”

“We believe the biology and mechanisms underpinning the roles of healthy lifestyle on the prevention of type 2 diabetes should be similar across populations. Thus, they should work among Singaporeans, although the magnitude of effectiveness and their interactions with genetic susceptibility to type 2 diabetes could be different,” said Prof Zhang.

Indubitably, this means future studies on women who developed diabetes in pregnancy, within the Singaporean population, are needed—for the development and precise application of medicine and prevention initiatives.

Given the multi-ethnic composition of the Singapore society and possibly different underlying genetic profiles, future studies examining health outcomes among Singaporeans should account for its populational heterogeneity.

At the same time, ethnicity specific intervention approaches should be explored. With that being said, Prof Zhang and her team are eager to conduct such studies within the Singaporean population in the near future.

The first author of the study, Dr Jiaxi Yang, a research fellow in the Global Centre for Asian Women’s Health and Department of Obstetrics and Gynecology at NUS Medicine, commented, “Although causal relationships cannot be established given the observational nature of the study, ample evidence consistently support the effectiveness of healthy lifestyles in preventing obesity or type 2 diabetes, and on improving cardiometabolic health among diverse populations.”

In view of the alarmingly high prevalence of GDM in Asia broadly and in Singapore particularly, and the ongoing diabetes epidemic in Asia, future studies among high-risk Asian women are warranted to further expand findings from the study. But as of now, the findings are encouraging for women at risk of developing type 2 diabetes.

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