The shifting landscape of asthma in the United States: An over 20-year analysis of prevalence, severity, and medication paradigms, 1999–2023

Background Asthma remains a substantial public health burden in the United States, warranting updated estimates of prevalence, morbidity, and medication use across population subgroups. Methods This study analyzed data from 114,505 participants in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2023. Asthma status (lifetime, current, attack, emergency visit) and medication use were assessed through self-reports and prescription data. Weighted prevalence trends were evaluated across demographic subgroups. Results Among 114,505 participants (median age 37 years; 51.2% male) in NHANES 1999–2023, the prevalence of lifetime and current asthma was 14.7% and 8.8%, respectively. Lifetime asthma prevalence increased from 11.2% to 15.8%, and current asthma from 6.5% to 9.3%, by 0.41% (95%CI: 0.28 to 0.54) and 0.24% (0.09–0.38) per NHANES cycle, respectively. Prevalence was consistently higher in women, non-Hispanic Black individuals, and those with lower socioeconomic status. Adolescents had the highest lifetime asthma prevalence (19.3%). Asthma attacks and emergency visits among those with current asthma declined significantly, by −0.99% (−1.94 to −0.03) and −1.94% (−2.96 to −0.93) per NHANES cycle, respectively. During the study period, the prevalence of asthma medication use showed a biphasic trend: an overall increase from 1999 to 2000 to a peak in 2007–2008, followed by a significant decline through 2020–2023. Lower education and income levels were associated with higher medication usage. Conclusion Over the past 2 decades, asthma prevalence increased at the population level, whereas the prevalence of asthma attacks and asthma-related emergency visits among individuals with current asthma declined.