The influence of high body mass index on asthma: A study integrating GBD 2021 and Mendelian randomization

Elevated body mass index (BMI) represents a significant adjustable risk element for asthma, posing a considerable worldwide health concern. This research was designed to assess the worldwide impact of asthma due to high BMI between 1990 and 2021, forecast patterns through 2050, and use 2-sample Mendelian randomization (MR) to examine whether elevated BMI is genetically associated with asthma risk, in order to guide preventive approaches. The data for this study were obtained from the global burden of disease 2021 study and the integrative epidemiology unit OpenGWAS project. We employed decomposition analysis, Joinpoint regression, and the Bayesian age-period-cohort model to analyze asthma-related mortality and disability-adjusted life years (DALYs) by age, sex, and socio-demographic index region. Additionally, a bidirectional 2-sample MR analysis was performed to investigate the association between genetically predicted BMI and asthma risk. From 1990 to 2021, the global age-standardized mortality rate and age-standardized DALY rate for asthma attributable to high BMI declined. In contrast, the absolute number of deaths and DALYs increased by 63.9% and 45.7%, respectively. The most significant decline occurred between 1996 and 2000, while low-middle socio-demographic index regions experienced consistent increases. Projections to 2050 indicate a continued decline in age-standardized mortality rate but a slight increase in age-standardized DALY rate. Notably, females and older adults carried a higher disease burden. The MR analysis identified a positive, genetically supported association between elevated BMI and asthma risk (inverse-variance weighted odds ratio = 1.389, 95% confidence interval: 1.303-1.479). However, substantial heterogeneity across genetic variants suggests that this estimate should be interpreted with caution. The asthma burden related to high BMI is forecast to increase in the coming decades, mainly fueled by population growth, population aging, and socioeconomic inequalities. MR further supports a unidirectional, genetically supported association between higher BMI and asthma risk. These results highlight the critical necessity for implementing focused and fair public health strategies across the globe to tackle elevated BMI and reduce the associated asthma burden.