Objectives. The physical stature of a population is a useful supplementary indicator of the living standards of children and youth insofar as it is sensitive to income and medical care. It is, thus, somewhat of a conundrum that U.S. heights tended to stagnate between around the mid-1950s to the mid-1970s birth cohorts, an otherwise economically prosperous period. Because of the controversial nature of the finding based on the NHANES data sets we seek independent corroborating evidence.
Methods. The height of U.S.-born army personnel is analyzed in order to explore ethnic and second-generation effects on height, in particular if these affect the trend among the birth cohorts of the 1950s and 1960s. We limit the regression analysis to U.S.-born (non-Hispanic) blacks and whites, controlling for ethnicity (own, mother's, and father's), foreign-born parents, and region of their birth within the United States stratified by race and gender.
Results. We find that none of the above variables affect the trend meaningfully: the height of U.S. military personnel tended to stagnate during the period considered. Only black males showed some improvement in height. Hence, the army data support the trends obtained from the civilian population, which cannot be controlled for second-generation effects.
Conclusion. The quality of nutritional intake and of medical care was not improving among children and youth in these decades in spite of the fact that the income of their parents was increasing.