Prevalence, Trends, and Associated Factors of Underweight Among Taiwanese Adolescents
1
Health Promotion Administration, Ministry of Health and Welfare, Taipei City, Taiwan, Province of China
Popul. Med. 2026;8(Supplement Supplement 1):A2053
ABSTRACT
BACKGROUND:
Malnutrition, including undernutrition and overnutrition, contributes to adverse health outcomes. In Taiwan, most research has focused on obesity, while underweight remains understudied. Underweight in adolescence may reflect inadequate nutrient intake or unhealthy lifestyle patterns and is associated with multiple health concerns. This study examined the prevalence and trends of underweight among Taiwanese adolescents and identified associated factors.
METHODS:
A cross-sectional study was conducted using data from the 2017, 2019, 2021, and 2023 Adolescent Smoking and Health Behavior Surveys of high school students. Underweight was defined using the body mass index (BMI) recommendations from the Taiwan Ministry of Health and Welfare. Prevalence was analyzed overall and stratified by demographic factors. Trends were assessed using logistic regression. Multivariable logistic regression identified demographic and lifestyle factors associated with underweight.
RESULTS:
Underweight prevalence increased from 10.8% in 2017 to 12.9% in 2023 (P-trend < 0.05), with similar increases among females, older adolescents, and first- and third-grade students. In 2023, females had a higher risk of underweight than males (OR: 1.60). The risk of underweight increased with age (OR: 1.74, 1.95, and 4.56 for adolescents aged 16, 17, and ≥18 years compared with ≤15 years). Engaging in physical activity ≤2 days per week was associated with higher underweight risk (OR: 1.36). Weight-control behaviors also differed, as adolescents trying to lose or maintain weight were less likely to be underweight, while those trying to gain weight had the highest odds.
CONCLUSIONS:
Underweight among Taiwanese adolescents showed a modest upward trend, though interpretation should consider COVID-19-related declines in response rates and survey changes, suggesting a need for continued monitoring. Higher risk was observed among females, older adolescents, and those with low physical activity. Moreover, weight-control behaviors differed by perceived body size. These findings support development of interventions to promote healthy weight in adolescents.
Malnutrition, including undernutrition and overnutrition, contributes to adverse health outcomes. In Taiwan, most research has focused on obesity, while underweight remains understudied. Underweight in adolescence may reflect inadequate nutrient intake or unhealthy lifestyle patterns and is associated with multiple health concerns. This study examined the prevalence and trends of underweight among Taiwanese adolescents and identified associated factors.
METHODS:
A cross-sectional study was conducted using data from the 2017, 2019, 2021, and 2023 Adolescent Smoking and Health Behavior Surveys of high school students. Underweight was defined using the body mass index (BMI) recommendations from the Taiwan Ministry of Health and Welfare. Prevalence was analyzed overall and stratified by demographic factors. Trends were assessed using logistic regression. Multivariable logistic regression identified demographic and lifestyle factors associated with underweight.
RESULTS:
Underweight prevalence increased from 10.8% in 2017 to 12.9% in 2023 (P-trend < 0.05), with similar increases among females, older adolescents, and first- and third-grade students. In 2023, females had a higher risk of underweight than males (OR: 1.60). The risk of underweight increased with age (OR: 1.74, 1.95, and 4.56 for adolescents aged 16, 17, and ≥18 years compared with ≤15 years). Engaging in physical activity ≤2 days per week was associated with higher underweight risk (OR: 1.36). Weight-control behaviors also differed, as adolescents trying to lose or maintain weight were less likely to be underweight, while those trying to gain weight had the highest odds.
CONCLUSIONS:
Underweight among Taiwanese adolescents showed a modest upward trend, though interpretation should consider COVID-19-related declines in response rates and survey changes, suggesting a need for continued monitoring. Higher risk was observed among females, older adolescents, and those with low physical activity. Moreover, weight-control behaviors differed by perceived body size. These findings support development of interventions to promote healthy weight in adolescents.
| eISSN: | 2654-1459 |
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