Table 2.

Age adjusted hazard ratios with 95% confidence intervals for the association of birth weight with stroke, nurses' health study, 1976-2000

	Birth weight (g)
	<2268	2268-2495	>2495-3175	>3175-3856	>3856-4536	>4536	Per kg, across all categories
Total stroke
Events	37	59	393	514	120	41	1,164
Person years	26 605	78 162	491 999	733 963	181 780	38,854	1,551,362
Hazard ratio	1.74 (1.24 to 2.44)	1.14 (0.87 to 1.50)	1.16 (1.02 to 1.33)	1.00	0.86 (0.70 to 1.05)	1.19 (0.86 to 1.64)	0.84 (0.76 to 0.93)
Ischaemic stroke
Events	17	35	190	252	61	21	576
Hazard ratio	1.56 (0.95 to 2.56)	1.43 (1.00 to 2.04)	1.14 (0.95 to 1.38)	1.00	0.86 (0.65 to 1.14)	1.18 (0.76 to 1.85)	0.83 (0.71 to 0.96)
Haemorrhagic stroke
Events	6	8	70	78	20	7	189
Hazard ratio	1.85 (0.80 to 4.28)	0.96 (0.47 to 2.00)	1.34 (0.97 to 1.86)	1.00	1.00 (0.61 to 1.64)	1.48 (0.68 to 3.23)	0.86 (0.66 to 1.11)