Table 1.

Relative risk (95% CI) of GDM according to age at menarche among 42,109 pregnancies in the Nurses’ Health Study II (1,404 GDM events)

Age at menarche	GDM (events/pregnancies)	Multivariate model 1	Multivariate model 2	Multivariate model 3
≤11 years	361/8,730	1.39 (1.19–1.63)	1.36 (1.16–1.60)	1.34 (1.14–1.58)
12 years	405/12,335	1.13 (0.97–1.32)	1.13 (0.97–1.31)	1.13 (0.97–1.31)
13 years	381/11,980	1.10 (0.95–1.29)	1.11 (0.95–1.29)	1.11 (0.95–1.29)
≥14 years	257/9,064	Reference	Reference	Reference
P for trend		<0.0001	0.0003	0.0005

Data are reported as RR (95% CI), unless otherwise indicated. Model 1, covariates include age (continuous), family history of diabetes (yes, no), and race/ethnicity (Caucasian, African American, Asian American, Hispanic, other); model 2, covariates include those in model 1, birth weight (<5.5, 5.5–6.9, 7.0–8.4, 8.5–10.0, or >10.0 pounds), somatotype at age 5 years (1, 2, 3, 4, 5+), and somatotype at age 10 years (1, 2, 3, 4, 5+); and model 3, covariates include those in model 2, and alcohol consumption (4 categories, grams/day), smoking status (4 categories), Alternate Healthy Eating Index 2010 (quintiles), total physical activity (quintiles of METs/week), marital status (yes vs. no), and oral contraceptive use (yes vs. no).