Low birth weight has been found to be associated with cardiovascular mortality and morbidity and with an adverse profile of several cardiovascular risk factors. The inverse association between birth weight and blood pressure was consistently reported from many populations. Using longitudinal data from the Bogalusa Heart Study (Louisiana), the authors investigated the association between birth weight and progression of blood pressure through early adulthood, comparing that relation between African Americans and Whites. Birth data of 2,275 participants, screened two or more times in the Bogalusa Heart Study between 1973 and 2001, were retrospectively obtained from birth certificates and were linked to their clinical, laboratory, and socioeconomic and lifestyle data in the Bogalusa Heart Study data sets. Birth weight was inversely associated with systolic blood pressure, diastolic blood pressure, and pulse pressure (p<or=0.01 for all). For every 1-kg increase in birth weight, systolic blood pressure dropped by 1.9 mmHg (95% confidence interval: -2.6, -1.3), diastolic blood pressure by 0.7 mmHg (95% confidence interval: -1.2, -0.2), and pulse pressure by 1.2 mmHg (95% confidence interval: -1.7, -0.7). The interaction of birth weight with ethnicity was not significant for any outcome. Birth weight was inversely associated with later blood pressure. The strength of that association did not differ between African Americans and Whites.