Secular change in height and weight of rural school children and youth in west-central Poland: 1986 to 2016.

OBJECTIVE To evaluate secular changes in the heights and weights of rural school youth in west-central Poland across decennial surveys of the same communities spanning 1986 and 2016. METHODS Heights and weights of school youth 7 to 15 years in 10 rural communities in the vicinity of the city of Poznan were measured in 1986 (1417 boys, 1326 girls), 1996 (979 boys, 947 girls), 2006 (871 boys, 843 girls), and 2016 (1189 boys, 1105 girls). Descriptive statistics for sex-specific single year chronological age groups were calculated by survey, while the sample was partitioned into three age groups (7-9, 10-12, 13-15 years) for detailed analysis of changes across surveys using sex-specific ANCOVA with age and age2 as covariates. Pairwise post hoc comparisons between specific surveys, adjusted for multiple comparisons (Bonferroni), were evaluated. RESULTS Heights and weights of rural school youth increased significantly between 1986 and 2016, but estimated secular gains between adjacent surveys were variable and not linear over time. CONCLUSION Significant secular changes occurred in the heights and weights of rural school children in the 10 rural communities between 1986 and 2016, but estimated rates of change across sequential decennial surveys were variable. The results were generally consistent with corresponding studies of Polish youth.