Trends in Height and Body Mass Among Adolescents Between 2002–2003 and 2019–2021 in Hong Kong Special Administrative Region, China

Objective To assess secular trends in height and body mass among adolescents from 2002–2003 to 2019–2021 in the Hong Kong Special Administrative Region, China. Methods Height and body mass data for Hong Kong adolescents aged 12–17 years were obtained from the Survey on Physical Fitness Status of Hong Kong School Pupils in 2002–2003, 2004–2005, 2009–2010, 2014–2015, and 2019–2021. Gender‐specific two‐way analysis of variance with age and wave as main factors, and age‐by‐wave as the interaction, was used to estimate the differences. The pace of secular trends was expressed as the changes every five years across adjacent waves. Results During the entire period, the average height increased by 2.0 cm (95% confidence interval [CI]: 1.4 to 2.6 cm) among boys and 1.8 cm (95% CI: 1.3 to 2.3 cm) among girls, while average body mass increased by 4.4 kg (95% CI: 3.4 to 5.5 kg) and 2.1 kg (95% CI: 1.4 to 2.9 kg), respectively. Significant increases were observed in most age groups. The greatest increases in height occurred between 2002–2003 and 2004–2005 among boys and between 2014–2015 and 2019–2021 among girls. The greatest increases in body mass among boys occurred between 2014–2015 and 2019–2021. The increases in body mass among girls were relatively stable. Conclusion The height and body mass have increased among Hong Kong adolescents during the past nearly two decades. The downward trend in height and the upward trend in body mass among boys is concerning, and future health promotion strategies should prioritize them.