The effect of rainfall during gestation and early childhood on adult height in a foraging and horticultural society of the Bolivian Amazon.

Recent research documents the effects of adverse conditions during gestation and early childhood on growth responses and health throughout life. Most research linking adverse conditions in early life with adult health comes from industrial nations. We know little about the plasticity of growth responses to environmental perturbations early in life among foragers and horticulturalists. Using 2005 data from 211 women and 215 men 20+ years of age from a foraging-horticultural society of native Amazonians in Bolivia (Tsimane'), we estimate the association between (a) adult height and (b) rainfall amount and variability during three stages in the life cycle: gestation (year 0), birth year (year 1), and years 2-5. We control for confounders such as height of the same-sex parent. Rainfall amount and variability during gestation and birth year bore weak associations with adult height, probably from the protective role of placental physiology and breastfeeding. However, rainfall variability during years 2-5 of life bore a negative association with adult female height. Among women, a 10% increase in the coefficient of variation of rainfall during years 2-5 was associated with 0.7-1.2% lower adult height (1.08-1.93 cm). Environmental perturbations that take place after the cessation of weaning seem to leave the strongest effect on adult height. We advance possible explanations for the absence of effects among males.