Secular Change in Body Proportions of Macao Children and Adolescents Aged 3–19 Years Across Four Surveys, 2005–2020
Xiang Pan, Yibo Gao, Koya Suzuki, Mingzhe Li, Deqiang Zhao, Lupei Jiang, Yanfeng ZhangABSTRACT
Objectives
To describe how the secular stature gain was divided between sitting height and leg length across survey intervals and ages, and whether the age at the sitting‐height ratio minimum changed.
Methods
We designed and conducted four rounds (2005–2020) of the Macao Citizens Physical Fitness Monitoring Survey, a stratified cluster sample of kindergartens and schools, and analyzed 21 919 records of residents aged 3–19 years. Changes were adjusted for age and sex, with standard errors clustered on institution; the age at the ratio minimum was located on penalized‐spline curves, with cluster‐bootstrap intervals.
Results
Height was 1.97 cm (95% confidence interval [CI] 1.48–2.47) greater in 2020 than in 2005: leg length 0.91 cm (0.66–1.15) and sitting height 1.06 cm (0.77–1.36). Between 2005 and 2010 both segments increased, leg length by more (0.63 cm) than sitting height (0.30 cm), and the ratio fell 0.13 percentage points (−0.19, −0.06); between 2015 and 2020 sitting height rose 0.46 cm, leg length showed no statistically detectable change (0.04 cm; −0.22, 0.30), and the ratio rose 0.13 percentage points (0.04–0.22). Gains were largest at 10–14 years. The age at the ratio minimum did not change detectably (2015 vs. 2005: boys −0.30 years, −0.70 to 0.27; girls −0.93 years, −1.92 to 0.08).
Conclusions
Across successive survey populations, the stature gain came mainly from the legs in the earliest interval and from sitting height in the latest, without a detectable change in the age at the ratio minimum.