Height, health, and hazards: Reconstructing secular trends in cohort height from cross-sectional data with applications to China.

摘要

This dissertation reconstructs and attempts to explain trends in cohort height and health in twentieth century China. It seeks to make contributions in three areas. Theoretically, adult height is viewed as a “cohort crystal ball,” reflecting the condensed early life conditions and various hazards experienced by cohort members during their growing years since conception. Analytically, a model, whose principles have general applications, is developed to reconstruct cohort mean height from more commonly available cross-sectional data. Empirically, a series of mean height by birth cohort in China is estimated, and stratified differential analyses are conducted using the China Health and Nutrition Survey.; To address the lack of long-series height data, the proposed model is used to decompose cross-sectional age patterns in height into three parts: secular trends (“cohort effect”), height shrinkage with age (“aging effect”), and differential mortality by height (“selection effect”). Through an innovative non-parametric approach, I estimate the secular trends in maximum adult height for all birth cohorts since the turn of the century in China. Reconstructed cohort height differs dramatically from the cross-sectional values especially for older cohorts.; In general, the height series agrees well with other indicators of health status and may better represent the impact of early life conditions. However, there also exist a few anomalies that leave room for future research and verification. Cohort height is found to increase in tandem with improvement in health and survival in twentieth century China. For males, little or no increase in the mean height for cohorts born between 1915 and 1945 contrasts with more rapid increase for cohorts born since 1946. The trends for females show moderate increase for the early cohorts, more rapid increase for the late 1940s and the 1950s cohorts, and a downward trend for the mid- and-late 1960s cohorts. Historical events such as the famine during the “Great Leap Forward,” 1959–1962, and the “Cultural Revolution,” 1966–1969, left measurable marks in the average population height. Height differentials by sex, urban/rural residence, region, and education are substantial. The trends and differentials make sense in light of bio-physiological theories, historical events, and early life experiences of these cohorts.