Gestational diabetes associated with risks later in life, but lifestyle makes a difference, studies find
A review found increased risks of cardiovascular and cerebrovascular disease in women who had gestational diabetes, while another study showed that five markers of a healthy lifestyle were associated with a significant reduction in risk of developing type 2 diabetes after gestational diabetes.
Two recent studies looked at long-term outcomes in women with gestational diabetes.
The first, a systematic review and meta-analysis, found that a history of gestational diabetes was associated with increased risks of cardiovascular and cerebrovascular diseases that were not solely attributed to conventional cardiovascular risk factors or subsequent diabetes.
Of 513,324 women with gestational diabetes in 15 observational studies, 9,507 developed cardiovascular and cerebrovascular disease. Of more than 8 million women without gestational diabetes who were used as controls, 78,895 developed cardiovascular and cerebrovascular disease. Compared with women without gestational diabetes, women with a history of the condition had an increased risk of cardiovascular disease (risk ratio [RR], 1.72; 95% CI, 1.40 to 2.11), cerebrovascular disease (RR, 1.40; 95% CI, 1.29 to 1.51), or both (RR, 1.45; 95% CI, 1.36 to 1.53). Results were published Sept. 21 by BMJ.
Women with gestational diabetes also had increased risk of several specific conditions: coronary artery disease (RR, 1.40; 95% CI, 1.18 to 1.65), myocardial infarction (RR, 1.74; 95% CI, 1.37 to 2.20), heart failure (RR, 1.62; 95% CI, 1.29 to 2.05), angina pectoris (RR, 2.27; 95% CI, 1.79 to 2.87), cardiovascular procedures (RR, 1.87; 95% CI, 1.34 to 2.62), stroke (RR, 1.45; 95% CI, 1.29 to 1.63), and ischemic stroke (RR, 1.49; 95% CI, 1.29 to 1.71). Their risk of venous thromboembolism was also higher (RR, 1.28; 95% CI, 1.13 to 1.46). The association with cardiovascular and cerebrovascular diseases was attenuated among women who did not develop subsequent overt diabetes but remained significant (RR, 1.09; 95% CI, 1.06 to 1.13).
The study authors wrote that the excess risk cannot be solely attributed to conventional cardiovascular risk factors, which were partially mediated by the outcome of subsequent diabetes. “Our results highlight the need for early intervention in women at high risk of gestational diabetes, and for continuous monitoring of women with gestational diabetes,” they wrote.
Another study, published the same day by BMJ, found that among women with a history of gestational diabetes, each of five modifiable risk factors was associated with an incrementally lower risk for type 2 diabetes, even among individuals who were overweight, obese, or at greater genetic susceptibility.
Researchers used data from the Nurses' Health Study II to follow 4,275 women with a history of gestational diabetes, with repeated measurements of weight and lifestyle factors between 1991 and 2009. Five modifiable risk factors were assessed: body mass index less than 25.0 kg/m2, high-quality diet (top two-fifths of the modified Alternate Healthy Eating Index), regular exercise (≥150 min/wk of moderate intensity or ≥75 min/wk of vigorous intensity), moderate alcohol consumption (5.0 to 14.9 g/d), and no current smoking. Genetic susceptibility to type 2 diabetes was characterized by a genetic risk score.
Over a median of 27.9 years of follow-up, 924 women developed type 2 diabetes, and risk was directly associated with the five modifiable factors. Hazard ratios for type 2 diabetes for those who met one, two, three, four, and five of the factors compared with none were 0.94 (95% CI, 0.59 to 1.49), 0.61 (95% CI, 0.38 to 0.96), 0.32 (95% CI, 0.20 to 0.51), 0.15 (95% CI, 0.09 to 0.26), and 0.08 (95% CI, 0.03 to 0.23), respectively (P<0.001).
Researchers highlighted the finding that women who had optimal levels of all five factors had a more than 90% lower risk for developing type 2 diabetes compared with those who had no optimal levels. “Importantly, the lower risk of type 2 diabetes associated with optimal levels of modifiable risk factors was evident even among high risk women who were overweight or obese or who had higher genetic susceptibility,” they wrote.