Table 3

Statistics for additive interaction between postpregnancy BMI and history of HDP in multivariable-adjusted models of incident type 2 diabetes in parous women without history of gestational diabetes mellitus

Additive interaction statisticBMI category (kg/m2)
Normal weight (18.5–24.9)Overweight (25.0–29.9)Obesity class I (30.0–34.9)Obesity class II–III (≥35.0)
RERI (95% CI), null = 0Reference*0.98 (−1.92, 3.87)10.69 (3.67, 17.70)14.02 (2.83, 25.22)
Attributable proportion (95% CI), null = 0Reference*0.12 (−0.22, 0.46)0.36 (0.13, 0.59)0.24 (0.05, 0.42)
Synergy index (95% CI), null = 1Reference*1.16 (0.72, 1.60)1.59 (1.34, 1.83)1.31 (1.12, 1.51)
  • *The reference group is women with BMI 18.5–24.9 kg/m2 and no history of HDP.

  • †The proportion of risk that is attributable to the additive interaction between postpregnancy BMI and history of HDP.