Secular Trends in Height, Weight, and Body Mass Index Among Tibetan Children and Adolescents in the Tibet Autonomous Region, China, From 2005 to 2019.

objectiveThis study aimed to characterize growth and development patterns among children and adolescents in the Tibet Autonomous Region and to interpret their human biological significance through the interaction between hypoxic exposure and improvements in nutrition, healthcare, and socioeconomic conditions.

methodsData were drawn from the 2005, 2010, 2014, and 2019 Chinese National Survey on Students' Constitution and Health. The study included Tibetan school students aged 7-18 years from testing sites in and around Lhasa, Tibet Autonomous Region, China, at an altitude of approximately 3600 m. Height and weight were measured using standardized protocols, and BMI was calculated. Sex-specific and age-specific means and standard deviations were reported by survey year. Differences across years were assessed using one-way analysis of variance, with temporal trend tests also performed.

resultsFrom 2005 to 2019, Tibetan children and adolescents showed an overall upward trend in height, weight, and BMI. For height, significant differences across survey years were observed in most age groups among both boys and girls, except for the group aged 16 years (p < 0.05). The greatest height gains occurred among boys aged 13 years and girls aged 10 years, indicating age-specific heterogeneity in secular growth changes. Weight followed a broadly similar pattern: mean body weight in 2019 exceeded that in 2005 in most sex and age-specific groups, with particularly marked increases among boys aged 13 years and girls aged 10 years. BMI increased gradually, with more evident gains in some age groups after 2010, although the magnitude of BMI change was smaller than that observed for height and weight. Concurrently, the number of participants classified as having height-related growth retardation declined from 150 in 2005 to 35 in 2019, suggesting a substantial reduction in the burden of low stature and an overall improvement in population-level growth status.

conclusionDespite continuous exposure to high altitude hypoxia, Tibetan children and adolescents experienced measurable improvements in physical growth between 2005 and 2019. These findings indicate that although hypoxia remains a key ecological constraint on growth at high altitude, its adverse effects may be partly buffered by enhanced nutritional security, school-based dietary support, improved healthcare resources, and broader socioeconomic development.