Secular change in heights of rural adults in west-central poland between 1986 and 2016: The transition from pre- to post-communism.

Secular change in the heights of adult men and women resident in ten rural communities in west-central Poland in four decennial surveys between 1986 and 2016 is considered. The adults were parents of children attending schools in rural communities in the province of Poznań. During each survey, parents of school children were asked to complete a questionnaire which requested their ages, heights and completed levels of education. Ages were reported in whole years. The self-reported heights were adjusted for the tendency of individuals to overestimate height. Height loss among of individuals 35+ years was estimated with sex-specific equations and was added to the adjusted heights. Secular gains in heights of adult males across the 30 year interval, and across the 1986-1996 and 2006-2016 surveys were, on average, larger than corresponding gains in heights of adult females; the sex difference between 1996 and 2006 surveys was negligible. When heights were regressed on year of birth, heights of males and females born before 1950 (prior to World War II and shortly after) showed minimal and non-significant secular changes, while heights of those born post-1950 showed larger and significant secular gains, more so in males than in females. The results highlight significant secular trends in the heights of rural adults over a 30-year interval. Consistent with other studies in Poland, the positive trends likely reflected political, educational and socio-economic changes and by inference improved nutritional and health conditions across generations.