Table 2.

Incident type 2 diabetes in relation to reproductive-period duration, timing of menopause and menarche, and period regularity among postmenopausal women in the Women’s Health Initiative

Exposure	Factor Level	# Diabetes Events (Person Years Follow-up)	Age Adjusted^a HR (95% CI)	Age Adjusted p	Fully^b Adjusted HR (95% CI)	p^c
Reproductive Period Duration	<30	2142 (232,670)	1.37 (1.30, 1.45)	<0.0001	1.07 (1.01, 1.14)	0.04
	30–35	2815 (386,257)	1.09 (1.03, 1.14)		1.02 (0.97, 1.07)
	36–40	3934 (585,514)	1.00 (Ref.)		1.00 (Ref.)
	41–45	1939 (259,544)	1.11 (1.05, 1.17)		1.06 (1.00, 1.12)
	45+	432 (52,070)	1.23 (1.12, 1.37)		1.09 (0.99, 1.21)
Menopause Timing	< 46 years	3523 (411,286)	1.25 (1.20, 1.30)	<0.0001	1.04 (0.99, 1.09)	0.02
	46 to 55 years	6189 (90,3007)	1.00 (Ref.)		1.00 (Ref.)
	> 55 years	1550 (201,762)	1.12 (1.06, 1.19)		1.08 (1.01, 1.14)
Menarche Timing	< 12 years	2,796 (328,602)	1.14 (1.08, 1.20)	<0.0001	1.01 (0.95, 1.06)	0.89
	12 years	2966 (397,946)	1.00 (Ref.)		1.00 (Ref.)
	> 12 years	5,500 (789,507)	0.93 (0.89, 0.97)		0.99 (0.95, 1.04)
Cycle Regularity	Not Regular	935 (113707)	1.11 (1.04, 1.19)	0.008	1.04 (0.97, 1.11)	0.46
	Sometime s Regular	1074 (146085)	1.00 (0.94, 1.06)		1.02 (0.96, 1.08)
	Regular	9253 (1,256,262)	1.00 (Ref.)		1.00 (Ref.)

Cox proportional hazards techniques were used to estimate associations.

Fully adjusted model includes age, race, baseline BMI, hormone therapy (HT) intervention arm membership, baseline physical activity, baseline alcohol consumption, baseline smoking history, education, baseline marital status, number of term pregnancies, family history of diabetes, years since menopause at baseline, baseline waist circumference, history of oral contraceptive use at baseline, and baseline metformin use.

p values correspond to the fully adjusted models and reflect likelihood ratio tests of significance for the indicated exposure variable.