Birth weight and risk of cardiovascular disease in a cohort of women followed up since 1976

Objective: To examine the association between birth weight and non-fatal adult cardiovascular disease while controlling for potential confounders such as socioeconomic group and adult lifestyle. Design: Retrospective self report of birth weight in an ongoing longitudinal cohort of nurses followed up by postal questionnaire every two years. Setting: Nurses' health study, a cohort of 121 700 women followed up since 1976. Main outcome measures: Non-fatal cardiovascular disease, including myocardial infarction, coronary revascularisation, and stroke. Results: Among the 70 297 women free of cardiovascular disease at baseline who reported birth weight in the 1992 questionnaire there were 1309 first cases of non-fatal cardiovascular disease. Increasing birth weight was associated with decreasing risk of non-fatal cardiovascular disease. There were 1216 first cases of non-fatal cardiovascular disease among women who were singletons and had been born full term; their relative risks adjusted for several cardiovascular risk factors were 1.49 (95% confidence interval 1.05 to 2.10) for birth weight < 2268 g (< 5 lb 0 oz); 1.25 (0.98 to 1.61) for birth weight 2268-2495 g (5 lb 0 oz to 5 lb 8 oz); 1.12 (0.98 to 1.27) for birth weight > 2495-3175 g (> 5 lb 8 oz to 7 lb 0 oz); 1.00 (referent) for birth weight >3175-3856 g(>7 lb 0 oz to 8 lb 8 oz); 0.96 (0.80 to 1.15) for birth weight > 3856-4536 g (> 8 lb 8 oz to 10 lb 0 oz); and 0.68 (0.46 to 1.00) for birth weight > 4536 g (> 10 lb 0 oz) (P value for trend = 0.0004). The inverse trend was apparent for both coronary heart disease and stroke. Conclusions: These data Provide strong evidence of an association between birth weight and adult coronary heart disease and stroke.