Secular Trends in Height Among Children During 2 Decades

Objective: To examine trends in height among 5- to 17-year-old children between 1973 and 1992. Design: A panel design consisting of 7 cross-sectional surveys. Participants: All schoolchildren residing in Bogalusa, La, were eligible. A total of 24 070 examinations were performed. Results: During the study period, the mean height of schoolchildren increased by 0.70 cm per decade independently of race, sex, and age. Trends were most pronounced among preadolescents, blacks, and boys, with 9- to 12-year-old black boys showing a height increase of 1.8 cm per decade. We observed a decrease in the number of relatively short children ([is less than] 10th percentile of height) and an increase in the number of tall children ([is greater than] 90th percentile of height). Because a secular trend was not seen among the 15- to 17-year-old children, our findings likely reflect an acceleration of maturation. Conclusions: It has generally been assumed that secular increases in height among schoolchildren in the United States ceased by the mid-1900s. Our findings, which may be due to various environmental factors, demonstrate that care must be taken when using nonconcurrent reference data to assess the growth of children. Additional study is needed to determine if these secular trends are continuing and to examine possible explanations and consequences of these trends. Arch Pediatr Adolesc Med. 2000; 154:155-161
After dramatic increases in the height of children and adults over the previous century, the increases were considered to stop in the 1950's and 1960's, but that may have only been a temporary pause. Between 1973 and 1992, trends toward height increase returned. The largest increases were among African-American boys between five and eight years old, and both boys and girls between nine and 12 years old. Increases among white children were half as large. However, there was no significant increase for children of any race or sex in the 13- to 17-year-old range.