Birth weight and adult health in historical perspective: evidence from a New Zealand cohort, 1907-1922.

We provide new historical evidence on the developmental origins of health and disease in a cohort of boys born between 1907 and 1922 in Wellington, New Zealand. Using a dataset of 1523 birth records that include birth weight and length we find 852 (58%) of the adult cohort in World War II records measuring stature, body mass and blood pressure. On average, the boys weighed 3.5 kg at birth, similar to Australian and American babies of the era, and nearly identical to full-term New Zealand babies in the 1990s. Using OLS regression models we estimate the effect of birth weight on adult stature and systolic blood pressure. We find an increase in birth weight of 1 kg is associated with an increase in stature of 2.6 cm (95% confidence interval [CI] 1.6 cm-3.6 cm), and a decrease in systolic blood pressure of 2.1 mm/Hg (95% CI - 5.00 to 0.67). This is the earliest cohort by fifty years for whom the fetal origins hypothesis has been examined in early adulthood. Our estimates of the effect of birth weight on blood pressure are towards the upper end of the range of published estimates in modern cohorts.