Lifestyle change lowers T2D risk in women with gestational diabetes mellitus history

Each additional optimal modifiable factor among women with a history of gestational diabetes mellitus (GDM) significantly contributes to a reduction in type 2 diabetes (T2D) risk, suggests a recent study. These associations are also present among individuals who are overweight/obese or are at greater genetic susceptibility to T2D.

“Participants who had optimal levels of all five modifiable factors after the index pregnancy had a more than 90-percent lower risk for developing T2D compared with those who did not have any,” the researchers said.

This prospective cohort study included a total of 4,275 women with a history of GDM from the Nurses’ Health Study II, with repeated measurements of weight and lifestyle factors and followed up between 1991 and 2009.

The researchers assessed the following modifiable risk factors: not being overweight or obese (body mass index [BMI] <25.0 kg/m²), high quality diet (top two-fifths of the modified Alternate Healthy Eating Index), regular exercise (≥150 min/week of moderate intensity or ≥75 min/week of vigorous intensity), moderate alcohol consumption (5.0‒14.9 g/day), and no current smoking.

Genetic susceptibility for T2D was defined by a genetic risk score based on 59 single nucleotide polymorphisms associated with T2D in a subset of participants (n=1,372).

Of the participants, 924 developed T2D over a median 27.9 years of follow-up. Women with optimal levels of all five factors had >90-percent lower T2D compared with those without optimal levels of any of the risk factors. [BMJ 2022;378:e070312]

For women with one, two, three, four, and five optimal levels of modifiable factors, the hazard ratios (HRs) of T2D were 0.94 (95 percent confidence interval [CI], 0.59‒1.49), 0.61 (95 percent CI, 0.38‒0.96), 0.32 (95 percent CI, 0.20‒0.51), 0.15 (95 percent CI, 0.09‒0.26), and 0.08 (95 percent CI, 0.03‒0.23), respectively, compared with none (p_trend<0.001).

The benefit with having optimal modifiable factors was also evident in participants who were overweight/obese or with higher genetic susceptibility (p_trend<0.001).

The HR for having optimal levels of the other four risk factors among women with BMI ≥25 kg/m² (n=2,227) was 0.40 (95 percent CI, 0.18‒0.91). Among those with higher genetic susceptibility, the HR for achieving four optimal factors was 0.11 (95 percent CI, 0.04‒0.29). Of note, no T2D events occurred in those with optimal levels of all five factors.

“Our findings are … consistent with a subgroup analysis of women with a history of GDM (n=350) in the Diabetes Prevention Programme, where an intensive lifestyle intervention involving weight loss through diet and increased physical activity reduced the risk of T2D by 50 percent after 3 years of follow-up compared with placebo,” the researchers said. [J Clin Endocrinol Metab 2008;93:4774-4779]

“Updated findings from the main Diabetes Prevention Programme study supported the long-term effectiveness of the lifestyle interventions on preventing T2D over 15 years of follow-up,” they added. [Lancet Diabetes Endocrinol 2015;3:866-875]