Table 3. Association Between Mode of Delivery With the Risk of Type 2 Diabetes.

Characteristic	HR (95%CI)		P value
	Vaginal delivery	Cesarean delivery
Cases of type 2 diabetes, No.	1927	87	NA
Person-time, Person-years	1 852 102	61 876	NA
Incidence rate of type 2 diabetes, per 10 000 person-years	10.4	14.1	NA
Crude	1 [Reference]	1.42 (1.14-1.76)	.002
Adjusteda	1 [Reference]	1.46 (1.18-1.81)	.001
Additional analyses
Marginal structural model estimate	1 [Reference]	1.19 (0.96-1.50)	.12
Treating maternal BMI as continuous variableb	1 [Reference]	1.47 (1.18-1.82)	.001
Log-binomial model for risk ratio	1 [Reference]	1.49 (1.19-1.87)	<.001
Additional adjustment for offspring characteristics
Breastfeeding	1 [Reference]	1.45 (1.17-1.80)	.001
Updated BMI	1 [Reference]	1.34 (1.08-1.67)	.008

Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); HR, hazard ratio; NA, not applicable.

^aAdjusted models included terms for maternal age at delivery, race/ethnicity (white or other), maternal educational level (≥high school or ≥college), maternal prepregnancy BMI group (<18.5, 18.5-24.99, 25-29.99, or ≥30), gestational weight gain (<9.1 kg or ≥9.1 kg), maternal height, gestational diabetes (yes or no), preeclampsia (yes or no), pregnancy-induced hypertension (yes or no), year of birth (1946-1951, 1952-1961, or 1962-1964), gestational age at delivery (<37, 37-39, 40-42, or ≥43 weeks), birth weight group (<2.3, 2.3-3.1, 3.2-3.8, 3.9-4.4, or ≥4.5 kg), smoking during pregnancy (no, first trimester, second and third trimesters, or current), and region of residence at birth (Northeast, Midwest, West, or South).

^bAdjusted model modeling prepregnancy BMI as a continuous variable with a linear term and a quadratic term.