Table 4.

Co-sibling analyses of women’s pregnancy duration and subsequent risk of stroke.

	Cases	HR (95% CI)*	P
0-43 years after delivery
Preterm (<37 wks)	1,738	1.41 (1.29-1.55)	<0.001
Early term (37-38 wks)	3,680	1.15 (1.08-1.22)	<0.001
Full-term (39-41 wks)	12,707	Reference
Per additional week (trend)		0.95 (0.94-0.96)	<0.001
<10 years after delivery
Preterm (<37 wks)	313	1.78 (1.19, 2.67)	0.005
Early term (37-38 wks)	637	1.07 (0.81, 1.40)	0.63
Full-term (39-41 wks)	1,674	Reference
Per additional week (trend)		0.93 (0.88, 0.98)	0.006
10-19 years after delivery
Preterm (<37 wks)	367	1.32 (1.03, 1.70)	0.03
Early term (37-38 wks)	731	1.12 (0.94, 1.34)	0.22
Full-term (39-41 wks)	2,225	Reference
Per additional week (trend)		0.95 (0.92, 0.98)	0.004
20-29 years after delivery
Preterm (<37 wks)	510	1.25 (1.04, 1.50)	0.02
Early term (37-38 wks)	1,174	1.28 (1.12, 1.46)	<0.001
Full-term (39-41 wks)	3,994	Reference
Per additional week (trend)		0.96 (0.94, 0.99)	0.006
30-43 years after delivery
Preterm (<37 wks)	548	1.38 (1.12, 1.69)	0.002
Early term (37-38 wks)	1,138	1.11 (0.96, 1.29)	0.16
Full-term (39-41 wks)	4,814	Reference
Per additional week (trend)		0.95 (0.92, 0.98)	<0.001

^*Adjusted for shared familial (genetic and/or environmental) factors, and additionally for maternal age (as Cox model time scale), year of delivery, parity, education, employment, income, BMI, smoking, preeclampsia, other hypertensive disorders, and diabetes prior to delivery.