摘要：Objectives. We calculated the percentage of gestational diabetes mellitus (GDM) attributable to overweight and obesity. Methods. We analyzed 2004 through 2006 data from 7 states using the Pregnancy Risk Assessment Monitoring System linked to revised 2003 birth certificate information. We used logistic regression to estimate the magnitude of the association between prepregnancy body mass index (BMI) and GDM and calculated the percentage of GDM attributable to overweight and obesity. Results. GDM prevalence rates by BMI category were as follows: underweight (13–18.4 kg/m2), 0.7%; normal weight (18.5–24.9 kg/m2), 2.3%; overweight (25–29.9 kg/m2), 4.8%; obese (30–34.9 kg/m2), 5.5%; and extremely obese (35–64.9 kg/m2), 11.5%. Percentages of GDM attributable to overweight, obesity, and extreme obesity were 15.4% (95% confidence interval [CI] = 8.6, 22.2), 9.7% (95% CI = 5.2, 14.3), and 21.1% (CI = 15.2, 26.9), respectively. The overall population-attributable fraction was 46.2% (95% CI = 36.1, 56.3). Conclusions. If all overweight and obese women (BMI of 25 kg/m2 or above) had a GDM risk equal to that of normal-weight women, nearly half of GDM cases could be prevented. Public health efforts to reduce prepregnancy BMI by promoting physical activity and healthy eating among women of reproductive age should be intensified. Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance leading to hyperglycemia with onset or first recognition during pregnancy. 1 GDM affects 1% to 14% of pregnancies, depending on the population studied and the diagnostic tests used. 1 , 2 It has been associated with maternal, fetal, and infant complications, including infant macrosomia and birth trauma, infant hypoglycemia, cesarean section, and increased medical costs. 3 – 7 Although some women with diagnosed GDM will have persistent abnormal glycemia, most women will revert to normal carbohydrate metabolism after delivery. 8 However, women with a history of GDM remain at increased risk of developing type 2 diabetes mellitus in the future. 9 GDM and type 2 diabetes share many common risk factors, including overweight and obesity, and GDM is considered by many to be a precursor of type 2 diabetes. 10 In addition, evidence suggests that the incidence of GDM increased in the 1990s. 11 , 12 This rise, which was concurrent with the growing prevalence of prepregnancy obesity (a 69.3% increase between 1993–1994 and 2002–2003) 13 and increases in type 2 diabetes in the general population (a 48.8% increase from 1994 through 2002), 14 was independent of other risk factors such as maternal age and parity. 13 Although GDM risk increases substantially with increasing prepregnancy body mass index (BMI; defined as weight in kilograms divided by height in meters squared), 15 the percentage of GDM specifically attributable to overweight and obesity is currently unknown. Population-based risk estimates are needed to calculate the percentage of GDM cases that could potentially be prevented if all women who are overweight or obese had a GDM risk equivalent to that of women of normal weight. We sought to calculate the percentage of pregnancies affected by GDM and the percentage of GDM attributable to overweight and obesity as a means of better understanding the potential effects of weight management on GDM prevalence.
