Is there a sex difference in the association between birth weight and systolic blood pressure in later life? Findings from a meta-regression analysis.

The aim of this study was to determine whether a sex difference exists in the association between birth weight and systolic blood pressure. A meta-analysis of all observational studies (n = 57) in which the study population contained both males and females and the association between birth weight and blood pressure was presented as a linear regression coefficient was undertaken. There were no differences in the pooled regression coefficients between males and females combining all studies; the regression of blood pressure on birth weight for males was -1.27 (95% confidence interval: -1.77, -0.77) mmHg/kg and for females was -1.24 (95% confidence interval: -1.90, -0.58) mmHg/kg. When studies in which blood pressure had been measured in childhood were considered separately from those in which it was measured in adulthood, there were no sex differences in either age group. The pooled regression coefficient tended to be weaker in studies reporting sex-specific results than in those reporting combined results. These findings suggest that reports of sex differences in the association between birth weight and blood pressure are chance findings.