Introduction

Asthma and allergic rhinitis (AR) are highly prevalent chronic respiratory disorders, affecting millions globally. Both conditions impair quality of life, causing sleep disturbances, fatigue, and academic decline. Circadian rhythms regulate physiological processes, including airway tone and immune function. In adolescents, delayed sleep-wake cycles create evening chronotypes, misaligning biological and social schedules. Chronotype reflects preferred sleep timing, categorized as morning, intermediate, or evening, influencing alertness patterns and respiratory health outcomes. Circadian rhythms influence symptom severity, with asthma worsening at night due to bronchomotor tone changes. Evening chronotype and disrupted melatonin secretion may exacerbate airway inflammation, linking circadian misalignment to increased asthma and AR risk.

Aim

To assess the prevalence of asthma and AR among adolescents in Ernakulam district, Kerala and to evaluate the correlation with chronotype.

Method

Study Design

Treatment Strategy 

• The cohort comprised adolescents aged between 13 to 14 years from a selected school in urban Ernakulam using convenience sampling
• The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to capture the physician-diagnosed asthma and AR
• The Ultra-Short Version of the Munich Chronotype Questionnaire (μMCTQ) assessed the chronotype based on sleep and wake times for school days and free days
• Chronotype was determined using sleep-corrected mid-sleep on free days (MSFsc), calculated from sleep patterns
• Participants were classified as morning (<3:00 AM), intermediate (3:00–5:00 AM), or evening (>5:00 AM) chronotypes based on MSFsc values
• The independent predictors of asthma and AR were identified using logistic regression models

Endpoints

• Prevalence of asthma
• Prevalence of AR
• Predictors of asthma
• Predictors of AR

Results

• A total of 313 adolescents were included in the study
• The prevalence of asthma and AR was 15% and 24% respectively
• Majority of adolescents (67.4%) were of evening chronotype, followed by intermediate chronotype, 26.8% and morning chronotype, 5.8%
• Morning chronotype (aOR:7.53) and household tobacco use (aOR: 5.21) independently increased the risk of asthma
• There was no significant correlation between AR and factors such as chronotype and household tobacco use
• Family history of asthma/allergy (aOR: 3.84) and larger family size (aOR: 1.89) were identified as independent predictors for AR

Conclusion

• This study in an Ernakulam school found a significant burden of asthma and allergic rhinitis among adolescents, linked to chronotype, environmental exposures, and family history.
• Findings suggest exploring sleep hygiene and chronotype awareness programs, alongside targeted education on modifiable risks like tobacco exposure.

Cureus. 2025 Aug 12;17(8):e89928. Doi: 10.7759/cureus.89928.