Obesity as the predominant contributor to asthma burden: insights from GBD and NHANES analyses

This study describes the global asthma burden trends from 1990 to 2021 and identifies key risk factors contributing to changes in asthma burden, focusing on the impact of obesity on asthma burden.

We extracted asthma incidence, mortality, and Disability-Adjusted Life Years (DALYs) from the Global Burden of Disease (GBD) database (1990-2021), stratifying by age, sex and Socio-demographic Index (SDI). Temporal trends were evaluated using Joinpoint regression. Decomposition analysis quantified contributions of population growth, aging, and age-specific rates to DALY changes. Frontier analysis evaluated SDI regions' effectiveness in reducing asthma burden. To evaluate the impact of obesity, we further analyzed risk-attributable DALYs and, using National Health and Nutrition Examination Survey (NHANES) data (2021-2023), performed multivariable logistic regression examining associations between body-mass index (BMI) and asthma outcomes.

Although age-standardized incidence and mortality rates declined, asthma remained prevalent in 2021 with an estimated 37 million new cases and 21.4 million DALYs, disproportionately affecting children (0-14 years) and older adults (55-74 years). Decomposition analysis attributed most DALY increases to demographic changes, particularly population growth and aging. Frontier analysis showed that while high-SDI regions achieved notable reductions in burden, rising obesity rates expanded the at-risk population even in these areas. High BMI emerged as the leading global risk factor for asthma-related DALYs-ranking first in high-SDI regions and, since the late 2010s, in low-SDI regions as well. NHANES analyses confirmed that individuals with asthma exhibited significantly higher BMI (Non- Asthma: 29.4 ± 7.32, Asthma: 31.2 ± 8.48, P < 0.001) Adjusted regression demonstrated that obesity independently predicted asthma onset and progression across all age groups (BMI Adjusted Odds Ratio (aOR): 1.41; 95% confidence interval (CI): 1.17-1.68.) CONCLUSION: Despite declines in standardized rates, asthma continues to impose a heavy global burden, concentrated in vulnerable age groups, especially among the young and elderly. Obesity has emerged as the foremost modifiable risk factor worldwide. Tailored public health strategies focusing on weight management are urgently needed to curb asthma incidence and severity.