Objective: To determine the influence on blood pressure of relative weight from birth through adulthood in non-obese and juvenile obese men.
Design: Case-cohort study of obesity in Danish men, identified at age (mean+/-s.d.) 19.8+/-1.6 y at draft board examination, who participated in at least one of two follow-up studies in adulthood (age 36.8+/-6.7 and 47.9+/-6.8 y at first and second follow-up, respectively). Birth weight and weight and height from the age of 7-13 y were collected from school health records.
Subjects: Three hundred and twenty-seven non-obese men (controls) selected as 0.5% of the draft board population and 285 obese men with body mass index (BMI)> or =31 kg/m(2) at draft board examination.
Main outcome measures: Systolic and diastolic blood pressure measured twice in adulthood adjusted for current age.
Results: Birth weight was inversely related to systolic blood pressure at first and second follow-up, but only significantly so when adjusted for current BMI (regression coefficients in mmHg per unit Z-score (95% confidence interval (CI))-1.2 (-2.3, -0.1) and -1.6 (-3.1, 0.0)). Change in Z-score from birth weight to BMI at the age of 7 y was significantly positively related to systolic blood pressure, but the relationship weakened by adjustment for current BMI (0.8 (0.1, 1.6) and 0.6 (-0.4, 1.6), respectively). If both birth weight and change until 7 y were included in the same model, their effects were both positive and significant, but they weakened and became not significant when adjusted for current BMI. BMI since the age of 7 y had no significant effect on blood pressure beyond that of current BMI.
Conclusion: In a wide range of adult BMI in men, the birth weight was inversely related to systolic blood pressure, even when controlled for BMI since the age of 7 y. However, the effect may reflect the weight change between birth and 7 y of age. After that age BMI had no additional effect on blood pressure beyond the effect of current BMI.