Table 2.

Adjusted odds ratios (ORs) with associated 95% confidence interval (CI) of gestational diabetes mellitus

	Age at menarche
	8–12 years (n = 7770)		13 years (n = 18,419)		14 years (n = 22,585)		15 years (n = 26,285)		16 -19 years (n = 26,285)		P trend
	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI
Crude model	1.09	1.02–1.16	1.08	1.02–1.13	1	referent	0.97	0.92–1.02	0.99	0.93–1.05	0.001
Model 1	1.08	1.02–1.15	1.07	1.03–1.14	1	referent	0.97	0.92–1.02	0.99	0.94–1.05	0.001
Model 2	1.08	1.01–1.16	1.10	1.05–1.17	1	referent	0.97	0.92–1.02	0.98	0.92–1.04	0.001
Model 3	1.03	0.95–1.13	1.07	0.99–1.14	1	referent	0.96	0.89–1.03	1.02	0.95–1.10	0.113
Model 4	0.93	0.85–1.03	1.02	0.95–1.08	1	referent	0.97	0.91–1.05	1.06	0.99–1.18	0.094

Model 1 adjusted for family history of diabetes

Model 2 adjusted for variables in model 1 plus education levels, age at delivery, chronic hepatitis B virus status

Model 3 adjusted for variables in model 2 plus systolic blood pressure, diastolic blood pressure

Model 4 adjusted for variables in model 3 plus pre-pregnancy BMI