The impact of sleep quality on asthma incidence in middle-aged and older adults: evidence from a prospective cohort study

Background Sleep disorders represent a growing public health burden, while asthma persists as a predominant chronic respiratory condition globally. Although suboptimal sleep quality correlates with diverse adverse health outcomes, its prospective association with asthma incidence in middle-aged and older adults remains inadequately characterized. Methods Utilizing data from the English Longitudinal Study of Ageing (ELSA), this cohort study included 4,578 asthma-free participants aged ≥50 years at baseline. Baseline sleep quality was quantified via a validated questionnaire, classifying participants into high, moderate, and low quality strata; nocturnal sleep duration was concurrently assessed. Incident asthma diagnoses over a 10-year follow-up period constituted the primary endpoint. Multivariable Cox proportional hazards regression models estimated hazard ratios (HRs) for asthma risk, adjusting for demographic, lifestyle, and comorbidity covariates. Results Among 4,578 participants, 156 incident asthma cases (3.41%) emerged during follow-up. Following comprehensive adjustment, baseline sleep quality demonstrated a significant dose–response relationship with asthma risk (P for trend < 0.001). Relative to the high-quality reference group, moderate- and low-quality groups exhibited 63% (HR = 1.63; 95% CI: 1.09–2.42) and 84% (HR = 1.84; 95% CI: 1.16–2.92) elevations in asthma risk, respectively. No statistically significant association emerged between sleep duration and asthma incidence. Conclusion This large-scale prospective cohort study demonstrates that poor sleep quality is an independent risk factor for the development of asthma in middle-aged and older adults, independent of sleep duration. The findings highlight the potential importance of optimizing sleep quality (rather than simply extending sleep duration) in asthma primary prevention. Improving sleep quality may represent a novel intervention target to reduce asthma incidence in this population and provide evidence for public health strategies.