The relatively small contribution of birth weight to blood pressure at age 49-51 years in the Newcastle Thousand Families Study.

Background: Whereas a large number of previous studies suggest an association between birth weight and later blood pressure, others do not. Controversy surrounds the relative importance of these associations, in particular in relation to more modifiable factors in later life. The aim of this study was to investigate the relative contributions of a range of factors from across life to variations in SBP and DBP in the Newcastle Thousand Families Study.

Methods And Results: Detailed information was collected prospectively during childhood, including birth weight, duration breast fed and socioeconomic conditions. At age 49-51 years, 574 study members returned self-completion questionnaires and 412 underwent clinical examination, including measurement of DBP and SBP. These data were analysed using linear regression and path analyses. After adjustment for all other significant variables, decreased birth weight, standardized for sex and gestational age (P = 0.035), increased BMI (P < 0.001) and being male (P = 0.034) were independently associated with raised SBP and DBP. Social class at birth (P = 0.044) was also independently associated with DBP. BMI was found to be the most important predictor, with a small relative contribution of standardized birth weight.

Conclusion: Adult blood pressure is influenced by numerous factors, acting both directly and indirectly during an individual's lifetime. Inverse associations of standardized birth weight, although statistically significant, were of relatively small importance, with the majority of variation being explained by more modifiable factors in adulthood, in particular adult BMI.