Is the effect of low birth weight on cardiovascular mortality mediated through high blood pressure?

Objective To explore whether the inverse association between birth weight a nd mortality from circulatory diseases is mediated through blood pressure i n men aged 50-75 years. Design Cohort study with retrospectively collected data on size at birth. Subjects and setting The study included 1334 men born during 1920-1924, liv ing in Uppsala, Sweden, who were examined at the ages of 50 and 60 years, a nd followed-up to the end of 1995. Main outcome measures Mortality from circulatory diseases based on routine death registration. Results Birth weight showed a specific, inverse association with mortality from circulatory diseases: the rate ratio was 0.67 (95% confidence interval 0.50 to 0.89) per 1000 g increase in birth weight. This association was no t appreciably affected by adjustment for sociodemographic characteristics o r smoking, but was strengthened slightly by adjustment for body mass index at the ages of 50 and 60 years. Adjustment for systolic blood pressure at t he age of 50 years only slightly reduced the strength of the inverse associ ation between birth weight and mortality from ischaemic heart disease, and did not affect the inverse association between birth weight and mortality f rom stroke. Adjustments for systolic and diastolic blood pressure and hyper tension treatment at the ages of 50 and 60 years did not reduce the strengt h of the association between birth weight and mortality from circulatory di seases at the age of 60-75 years. Conclusions The inverse association between birth weight and mortality from circulatory diseases in men aged 50-75 years is independent of adult socio demographic characteristics, smoking and adult obesity and does not seem to be mediated through an increased blood pressure in those with low birth we ight. J Hypertens 1999, 17:19-25 (C) Lippincott Williams & Wilkins.