Increases in Height among Chinese Children and Adolescents by Gender: An Age-Period-Cohort Analysis.

Objective: To examine increases in average height among Chinese children and adolescents.

Methods: The data were obtained from the China Health and Nutrition Survey conducted during the period 1989-2015. A stratified multistage cluster sampling method was utilized to select participants aged 2-22 years in each province. Linear regression was used to examine the effects of age, birth cohort, and survey period on height.

Results: A total of 15,227 males and 13,737 females were included in the final analysis. Age (A) showed a continuous effect on height. The average heights of the investigated groups increased continuously during the investigation period. By 2015, the average height of the overall group increased by 7.87 cm compared to the average height during the 1989 survey. Moreover, birth year (cohort, C) also had a stable effect on height. Using the height of individuals born in or before 1975 as a reference, the average height of each birth cohort increased in comparison to the previous birth cohort.

Conclusions: The height of Chinese children and adolescents was affected by age, period, and cohort effects, and this effect is governed by certain rules. The age-period-cohort model can be used to analyze the trends of children's and adolescent's heights. The findings provide a scientific basis for the formulation of children's and adolescents' growth and development policies in China.