A Growing Social Divide in Body Mass Index, Strength, and Fitness of Swedish Male Conscripts
by Lauren Lissner, K Mehlig et al, Journal of Adolescent Health, vol 65,(2019) p 232-238; all authors from Goteborg, Sweden.

This is a report of the health of over 1 million conscripts with complete data examined during 36 years, from 1968 to 2005, at the initial screening for military service.
Obesity became increasingly associated with low parental education over the years. But muscular strength reversed.Those with parents with lower education became weaker and those with parents with higher education became stronger. Cardiovascular fitness was better in those with parents of higher education, and this relationship did not change over the years.
The men in this study will be followed to investigate the relationship, if any, of their health at 18-19 years and future health.