Table 2

Incidence rates and HRs for type 2 diabetes according to BMI by history of HDP in parous middle-aged women without history of gestational diabetes mellitus

Incidence rates
Normal weight (18.5–24.9 kg/m2)Overweight (25.0–29.9 kg/m2)Obesity class I (30.0–34.9 kg/m2)Obesity class II–III (≥35.0 kg/m2)Total
Crude incidence
 No HDP
  Events/person-years*60/193,169221/113,891313/50,566443/29,3061,037/386,932
  Incidence per 1,000 person-years0.311.96.215.12.7
 History of HDP
  Events/person-years*10/15,57340/15,36096/9,934158/8,534304/49,401
  Incidence per 1,000 person-years0.642.69.718.56.2
HR (95% CI)
Normal weight (18.5–24.9 kg/m2)Overweight (25.0–29.9 kg/m2)Obesity class I (30.0–34.9 kg/m2)Obesity class II–III (≥35.0 kg/m2)Ptrend
Basic Cox regression model
 No HDP1.00 (Ref)6.18 (4.65, 8.23)19.60 (14.85, 25.87)46.94 (35.79, 61.56)<0.001
 History of HDP1.00 (Ref)§3.96 (1.98, 7.92)14.73 (7.67, 28.28)29.60 (15.60, 56.17)<0.001
Main Cox regression model
 No HDP1.00 (Ref)5.89 (4.42, 7.85)18.20 (13.72, 24.13)44.6 (33.56, 59.25)<0.001
 History of HDP1.00 (Ref)§3.83 (1.91, 7.67)14.44 (7.50, 27.80)28.78 (15.06, 54.98)<0.001
  • Ref, reference group. Women categorized as underweight (BMI <18.5 kg/m2) or with BMI >50 kg/m2 are excluded. Basic models include adjustment for age, race/ethnicity (white, Latina, African American, Asian, or other), and parity (1, 2, or ≥3 births). Main models additionally include DASH diet score (quartiles), physical activity (quartiles), BMI at age 18 years, smoking (nonsmoker, current smoker, or former smoker), alcohol intake (none, 1–15 g/day, or >15 g/day), menopausal status (premenopausal, postmenopausal, or unknown), parental history of diabetes (yes/no), and interaction terms between HDP and BMI categories.

  • *Rounded to year.

  • †Continuous BMI included in the models instead of categorical BMI.

  • ‡Separate Cox proportional hazards models by HDP history.

  • §The same model as for “no HDP” except that women with prior HDP and BMI 18.5–24.9 kg/m2 constitute the reference group.