Table 1—

Descriptive characteristics of women with and without type 1 diabetes

	Type 1 diabetes	Without diabetes			P
	Type 1 diabetes			Sisters	P	Control subjects
n	143	186	158
Mean age at exam (years)	42.6 ± 5.4	42.4 ± 8.3	41.2 ± 6.4	0.22
Age at menarche (years)	13.5 ± 1.9	12.5 ± 1.4	12.6 ± 1.4	<0.001
Ever oral contraceptive use (%)	44.0	79.0	79.8	<0.001
Ever pregnant (%)	76.8	83.9	70.3	0.01
Mean number of pregnancies*	2.3 ± 1.6	2.9 ± 1.4	2.6 ± 1.4	<0.001
Infertility (%)	16.9	17.7	16.6	0.96
Miscarriages (%)*	31.2	32.1	27.9	0.76
Stillbirths (%)*	10.1	0.6	0.9	<0.001
Natural menopause (%)	12.5	12.7	9.8	0.69
Mean age at natural menopause (years)†	41.6 ± 10.6	49.9 ± 6.1	47.8 ± 4.6	0.06
Ever smoked (%)	41.8	48.4	50.0	0.33
College attendance (%)	64.6	65.6	75.9	0.06
Income ≥$40,000 (%)	40.8	59.1	52.7	0.006
Mean BMI (kg/m²)	24.6 ± 4.5	25.2 ± 5.3	27.4 ± 7.3	0.003
Hashimoto’s thyroiditis (%)	42.7	30.4	19.6	<0.001
Age Hashimoto’s detected (years)	38.1 ± 9.3	42.0 ± 10.2	39.2 ± 9.7	0.14

Data are mean ± SD.
*
↵* These analyses excluded women that had never been pregnant;
†
↵† these analyses excluded women with a premenopausal hysterectomy or bilateral oophorectomy and were based on 120, 165, and 143 women, respectively, of whom 15, 21, and 14 experienced natural menopause.