Machine learning forecasts bluetongue outbreaks up to six months ahead
A study of 8,812 children and teenagers in the United States found no statistically significant link between how much caffeine they got from food and drinks and whether they currently had asthma. The participants were 3–19 years old and took part in the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2020. Among them, 1,013, or 11.5%, met the survey's definition of current asthma. The study looked at caffeine intake and asthma at a single point in time. It cannot show whether caffeine causes asthma, prevents it, or affects the risk of developing it.
Researchers estimated how much caffeine each participant consumed using up to two 24-hour food and drink reports. They measured caffeine in milligrams per 1,000 kilocalories to account for differences in how much energy participants consumed. They then used a logarithmic transformation of these values for analyses that treated caffeine intake as a continuous measure. The researchers determined whether participants currently had asthma from their answers to a standard NHANES questionnaire about breathing and respiratory health. They used statistical models that accounted for the survey design to estimate the link between caffeine intake and current asthma, while adjusting for other factors that could affect the results. They also used restricted cubic spline analyses to examine the relationship across different levels of caffeine intake.
The model that adjusted for all selected factors found no statistically significant link. For each one-unit increase in the log-transformed caffeine measure adjusted for energy intake, the adjusted odds ratio for current asthma was 0.95. The 95% confidence interval was 0.89–1.02, and the P value was 0.141. Because the confidence interval included 1.00, the result did not meet the usual standard for statistical significance. However, this does not prove that there is no link or rule out a small effect. The authors also warned that caffeine intake varied only within a limited range in the study and that the confidence intervals were wide enough that a small association could not be ruled out with certainty.
When the researchers grouped participants by caffeine intake, the results led to the same overall conclusion. Compared with participants who consumed no caffeine, those in the lowest third of caffeine intake had an adjusted odds ratio for current asthma of 1.13. Those in the middle third had an odds ratio of 0.91, and those in the highest third had an odds ratio of 0.87. The corresponding 95% confidence intervals were 0.80–1.59, 0.69–1.20, and 0.67–1.12. The P value for the trend across these groups was 0.113. This means the results did not show a statistically significant pattern linking caffeine intake levels with current asthma. The restricted cubic spline analyses also found no statistically significant overall relationship or nonlinear relationship.
Additional checks produced similar results. Analyses that used multiple imputation to handle missing data, adjusted for more dietary factors, or accounted for the NHANES survey cycle did not substantially change the findings. The study covered only the measured dietary caffeine intake and current asthma status of the 8,812 participants included in NHANES from 2011 to 2020. It was an observational study that examined data collected at one point in time, using de-identified survey information. The researchers did not give participants an intervention or assign them to different caffeine-intake groups and follow them over time. The authors called for future studies that follow participants over time, measure their caffeine intake repeatedly, and use objective measures of asthma. They noted that the current findings cannot rule out a small association. The appropriate conclusion is that estimated dietary caffeine intake was not significantly linked to current asthma in this group of children and teenagers, not that caffeine has no effect on childhood asthma.
Subject of Research: The relationship between dietary caffeine intake and current asthma in children and teenagers in the United States
Article Title: Dietary caffeine intake and current asthma among U.S. children and adolescents: a cross-sectional study based on NHANES 2011–2020
Article References: Zhang, M., Zhang, Y., Tian, Y., Zhang, X., Chen, Y., Zhang, C., Han, S., Ren, X., & Liu, R. (2026). Dietary caffeine intake and current asthma among U.S. children and adolescents: a cross-sectional study based on NHANES 2011–2020. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07601-z
Image Credits: AI Generated
DOI: 10.1186/s12887-026-07601-z
Keywords: childhood asthma, adolescent health, dietary caffeine, NHANES, cross-sectional study, dietary recalls, odds ratios, pediatric epidemiology, diet, caffeine, intake, current