Trends and Associated Factors of Malnutrition Among Adolescents With Diarrhoea in Bangladesh: A Retrospective Cross‐Sectional Surveillance Study Using Adaptive LASSO

ABSTRACT Background and Aims Adolescence is a critical phase of rapid growth with long‐term health implications. We aimed to examine the trends and associated factors of malnutrition among adolescents with diarrhoea in urban Bangladesh. Methods We conducted a retrospective cross‐sectional study and analysed data from 1597 adolescents aged 10–19 years enrolled in the Diarrhoeal Disease Surveillance System at icddr,b's Dhaka Hospital between 2012 and 2023. Nutritional status was defined using WHO standards. Trends were assessed using the Jonckheere–Terpstra test. Logistic regression models were developed after variable selection with least absolute shrinkage and selection operator. Results The pooled prevalence of stunting, thinness, and overweight across 2012–2023 was 473/1597 (29.6%), 388/1597 (24.3%), and 106/1597 (6.6%), respectively. Stunting declined significantly from 40.8% in 2012 to 25.7% in 2023, while thinness increased from 21.8% to 24.3%. In adjusted models, stunting was positively associated with age (aOR: 1.06; 95% CI: 1.02–1.10) and negatively with maternal post‐primary education (aOR: 0.71; 95% CI: 0.53–0.94) and rich households (aOR: 0.66; 95% CI: 0.46–0.96). Thinness was less likely among females (aOR: 0.46; 95% CI: 0.35–0.60), older adolescents (aOR: 0.90; 95% CI: 0.86–0.94), and the richest households (aOR: 0.52; 95% CI: 0.30–0.90). Overweight was inversely associated with age (aOR: 0.92; 95% CI: 0.86–0.99) but increased with post‐primary maternal education (aOR: 3.22; 95% CI: 2.09–4.96) and richest households (aOR: 2.72; 95% CI: 1.13–6.55). Conclusion Adolescent stunting decreased while thinness increased over the 12‐year period, highlighting a dual burden of malnutrition. Male adolescents and those from socioeconomically disadvantaged households remain particularly vulnerable to malnutrition. These findings underscore the need for integrated adolescent nutrition strategies within diarrhoeal disease management and urban health programmes in Bangladesh.