Table IV.

History of laparoscopically confirmed endometriosis and risk of incident infertility among married women in Nurses' Health Study II from 1989 to 2005, includes women concurrently diagnosed with endometriosis and infertility.

Laparoscopically confirmed endometriosis	Total population			Primary infertility			Secondary infertility			P-het
	No	Yes	P-value	No	Yes	P-value	No	Yes	P-value
Cases, n	4206	406		1968	265		2238	141
Person-years	351 318	10 901		42 135	1880		309 183	9021
Age-adjusted HR (95% CI)	1.00 (ref)	4.02 (3.55–4.55)	<0.0001	1.00 (ref)	3.70 (3.17–4.33)	<0.0001	1.00 (ref)	2.65 (2.12–3.32)	<0.0001
Multivariate-adjusted HRa (95% CI)	1.00 (ref)	3.23 (2.85–3.67)	<0.0001	1.00 (ref)	3.68 (3.15–4.31)	<0.0001	1.00 (ref)	2.57 (2.06–3.22)	<0.0001	0.09
Laparoscopically confirmed endometriosis				Age <35 years			Age 35–39 years			P-het
				No	Yes	P-value	No	Yes	P-value
Cases, n				2731	279		1475	127
Person-years				155 399	3978		195 917	6923
Age-adjusted HR (95% CI)				1.00 (ref)	4.02 (3.55–4.55)	<0.0001	1.00 (ref)	2.44 (2.03–2.92)	<0.0001
Multivariate-adjusted HRa (95% CI)				1.00 (ref)	3.21 (2.83–3.64)	<0.0001	1.00 (ref)	1.83 (1.52–2.20)	<0.0001	<0.001
Laparoscopically confirmed endometriosis				BMI <25 kg/m2			BMI 25+ kg/m2			P-het
				No	Yes	P-value	No	Yes	P-value
Cases, n				2922	315		1273	90
Person-years				237 944	7127		112 358	3722
Age-adjusted HR (95% CI)				1.00 (ref)	4.46 (3.87–5.14)	<0.0001	1.00 (ref)	2.95 (2.25–3.87)	<0.0001
Multivariate-adjusted HRa (95% CI)				1.00 (ref)	3.42 (2.96–3.95)	<0.0001	1.00 (ref)	2.72 (2.06–3.59)	<0.0001	0.05

^aAdjusted for age (months), age interaction term (except for age stratified analysis), questionnaire cycle, age at menarche, menstrual cycle length between ages 18 and 22 years, current BMI, total physical activity, smoking status, cumulatively updated average AHEI diet score, parity (number of children).