Associations between nocturnal bedtime and asthma among adults in the United States

Background Sleep disorders have a significant impact on asthma. The aim of this study was to explore the association between nocturnal bedtime and asthma among adults in the United States. Methods This study was a cross-sectional analysis involving 11,475 participants from the National Health and Nutrition Examination Survey (NHANES) during the period of 2015-2018. Nocturnal bedtime was categorized into three distinct groups: 2100 h or earlier, between 2100 h and 2300 h, and 2300 h or later. The association between night bedtime and asthma was detected using multivariable logistic regression analyses. Additionally, subgroup analyses were conducted to assess the impact of subgroups. Results After adjustment for confounders, a positive association was revealed between later bedtime (after 2300 h) and the prevalence of asthma (OR = 1.20, 95%CI: 1.01-1.43). In the subgroup analysis, the following factors were associated with increased risk: 18-39 years (OR = 1.23, 95%CI: 1.02-1.48); female sex (OR = 1.30, 95%CI: 1.01-1.68); Hispanic patients (OR = 1.66, 95%CI: 1.17-2.37); heavy drinkers (OR = 1.52, 95%CI: 1.17-1.96); Body Mass Index (BMI) (< 25 kg/m(2)) (OR = 1.45, 95%CI: 1.13-1.87); vigorous physical activity (OR = 1.32, 95%CI: 1.05-1.65);Significant interactions were found between nocturnal bedtime and asthma based on age, sex, eosinophils (EOS) percent and depression (P (Interaction )< 0.05). Conclusion Our results confirmed a moderately increased risk of asthma attributed to later bedtime, especially in 18-39 years, women and patients of Hispanic ethnicity. Future studies should investigate the underlying mechanisms of this association and explore the clinical implications for asthma management.