Adult height and childhood disease

Taller populations are generally richer populations, and taller individuals live longer and earn more, perhaps reflecting their superior cognitive abilities. Understanding the determinants of adult height has thus become a focus in understanding the relationship between health and wealth. We investigate the childhood determinants of adult height in populations, focusing on the respective roles of income and of disease. Across a range of European countries and the United States, we find a strong inverse relationship between postneonatal (one month to one year) mortality, interpreted as a measure of the disease and nutritional burden in childhood, and the mean height of those children as adults. In pooled birth-cohort data over 31 years for the United States and eleven European countries, postneonatal mortality in the year of birth accounts for more than 60 percent of the combined cross-country and cross-cohort variation in adult heights. The estimated effects are smaller but remain significant once we allow for country and birth-cohort effects. The decline in postneonatal mortality from 1950 to 1980 can account for almost all of the increase in adult height for those born in those years, and explains 20 to 30 percent of the 2 cm shortfall of 30 yearold Americans relative to 30-year old Swedes in 2000. Consistent with these findings, we develop a model of selection and stunting, in which the early life burden of nutrition and disease is not only responsible for mortality in childhood but also leaves a residue of long-term health risks for survivors, risks that express themselves in adult height, as well as in late-life disease. The model predicts that, at sufficiently high mortality levels, selection can dominate scarring, leaving a taller population of survivors. We find evidence of this effect in the poorest and highest mortality countries of the world, supplementing recent findings on the effects of the Great Chinese famine.