Health, height, height shrinkage and SES at older ages: Evidence from China

Adult height, as a marker of childhood health, has recently become a focus in understanding the relationship between childhood health and health outcomes at older ages. However, measured height of the older individuals is contaminated by height shrinkage from aging. Height shrinkage, in turn may be correlated with health conditions and socio-economic status from throughout the life-cycle. In this case it would be problematic to use measured height directly in regressions without considering such an effect. In this paper, we tackle this problem by using upper arm length and lower leg length to estimate a pre-shrinkage height function for a younger population that should not have started their shrinkage. We then use these estimated coefficients to predict pre-shrinkage heights for an older population, for which we also have upper arm and lower leg lengths. We then estimate height shrinkage for this older population and examine the associations between shrinkage and socio-economic status variables. We provide evidence that height shrinkage for both men and women is negatively associated with better current SES and early life conditions and, for women, positively with pre-shrinkage height. We then investigate the relationships between pre-shrinkage height, height shrinkage and a rich set of health outcomes of older respondents, finding that height shrinkage is positively associated with poor health outcomes across a variety of outcomes, with results for older age cognition being especially strong. Indeed height shrinkage is more strongly associated with later life outcomes than is pre-shrinkage height, suggesting that later life conditions are especially important correlates for these outcomes.