Prevalence of Asthma and Allergic Rhinitis and Their Association With Chronotype Among Adolescents in Ernakulam District: A School-Based Cross-Sectional Study.

Background and objectives Asthma and allergic rhinitis are common non-communicable diseases that cause chronic respiratory issues, poor sleep, and reduced academic performance among adolescents. Hence the objective of this study was to (1) estimate the prevalence of asthma and allergic rhinitis and (2) to determine its association with chronotype among adolescents in Ernakulam district, Kerala. Methods A school-based cross-sectional study was conducted between February and December, 2024, among adolescents aged 13 to 14 years from a selected school in urban Ernakulam using convenience sampling. The minimum calculated sample size with 95% confidence and an absolute precision of 5 was 303. Data were collected using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and the Ultra-Short Version of the Munich Chronotype Questionnaire. Logistic regression was done to identify the independent predictors for asthma and allergic rhinitis and results were reported as adjusted odds ratios (aOR) with 95% confidence intervals. Results Among the 313 participants interviewed, the prevalence of asthma was 15% (95% CI: 10.9-19.4), and allergic rhinitis was 24% (95% CI: 19.4-29.2). Most participants were of evening chronotype, 67% (95% CI: 61.8-72.6), followed by intermediate chronotype, 27% (95% CI: 22.1-32.1). The independent predictors for asthma were found to be morning chronotype [aOR:7.53 (2.4-23.4)] and household tobacco use [aOR: 5.21 (2.4-11.0)]. While the different chronotypes did not show any association with allergic rhinitis (p = 0.62), family history of asthma/allergy [aOR: 3.84 (2.0-7.2)] and larger family size [aOR: 1.89 (1.0-3.3)] were found to be independent predictors for allergic rhinitis. Conclusion The prevalence of asthma and allergic rhinitis was found to be high in our survey, with environmental factors and family history playing key roles. Asthma is linked to chronotype, while allergic rhinitis is not. It is recommended to implement preventive measures focusing on modifiable risk factors like tobacco use and the early detection of high-risk chronotypes.