Dietary caffeine intake and current asthma among U.S. children and adolescents: a cross-sectional study based on NHANES 2011–2020

Evidence regarding the association between dietary caffeine intake and asthma in pediatric populations remains limited and inconsistent. This study aimed to examine the association between dietary caffeine intake and current asthma prevalence among U.S. children and adolescents. We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) 2011–2020. A total of 8,812 participants aged 3–19 years were included. Current asthma was defined according to standardized NHANES respiratory questionnaire responses. Dietary caffeine intake was assessed using up to two 24-hour dietary recalls, expressed as energy-adjusted caffeine intake (mg/1000 kcal), and log-transformed for continuous analyses. Survey-weighted logistic regression models and restricted cubic spline analyses were performed after adjustment for potential confounders. Among 8,812 participants, 1,013 (11.5%) had current asthma. In fully adjusted models, energy-adjusted caffeine intake was not significantly associated with current asthma prevalence. The adjusted OR per unit increase in ln-transformed caffeine intake was 0.95 (95% CI: 0.89–1.02; P = 0.141). Compared with non-consumers, the ORs across increasing tertiles were 1.13 (0.80–1.59), 0.91 (0.69–1.20), and 0.87 (0.67–1.12), respectively (P for trend = 0.113). Restricted cubic spline analyses showed no significant overall or nonlinear association. Sensitivity analyses, including multiple imputation and additional adjustment for dietary variables and survey cycle, yielded similar results. Dietary caffeine intake was not significantly associated with current asthma prevalence among U.S. children and adolescents. However, a modest association cannot be excluded given the limited exposure variability and confidence intervals observed. Further prospective studies with repeated exposure assessment and objective asthma measurements are warranted. This study is an observational cross-sectional analysis using de-identified NHANES data and does not involve any intervention or prospective participant assignment. Therefore, it does not meet the criteria for a clinical trial, and clinical trial registration is not required.