# Cross-country health inequality in the asthma burden: findings from the global burden of disease study 2021

## TL;DR

The study finds that asthma rates have decreased globally, but inequalities persist, especially in low-income regions.

## Contribution

This study evaluates global asthma burden inequality using decomposition analysis and inequality indices.

## Key findings

- Asthma incidence decreased with higher socio-demographic index, but prevalence increased.
- Inequality in asthma incidence and prevalence decreased, but high BMI-related asthma deaths concentrated in lower SDI regions.
- Aging and population growth increased asthma deaths, while epidemiological changes reduced asthma incidence and DALYs.

## Abstract

Changes in inequality in the total and risk factor-specific incidence, prevalence, deaths, and disability-adjusted life years (DALYs) of asthma have not been evaluated.

Asthma incidence, prevalence, deaths, and DALYs, and risk factors-related deaths and DALYs rates were extracted from the Global Burden of Disease study 2021. We employed decomposition analysis, encompassing aging, population growth, and epidemiologic changes, to investigate factors influencing incidence, prevalence, deaths, and DALYs of asthma. Besides, the slope inequality index (SII) and relative concentration index (RCI) were used to assess the inequality in the total and risk factor-specific incidence, prevalence, deaths, and DALYs of asthma.

Global rates of asthma incidence, prevalence, deaths, and DALYs declined from 1990 to 2021. People aged < 5 years exhibited the highest asthma incidence, and those aged ≥ 70 years old had the highest prevalence, death, and DALYs rates of asthma. Leading drivers of increased number of asthma deaths were aging (127.48%) and population growth (138.99%), but epidemiological change contributed mostly to decreased numbers of asthma incidence, prevalence, and DALYs. Asthma incidence decreased with raising socio-demographic index (SDI), but asthma prevalence increased with increasing SDI. Inequality in asthma incidence and prevalence decreased as indicated by SII and RCI. Besides, asthma deaths and DALYs rates were concentrated in lower SDI regions. Inequality in high body mass index-related asthma death increased and concentrated in lower SDI regions, but inequality in risk factor-specific asthma DALYs all decreased.

Our findings imply that rates of asthma incidence, prevalence, deaths, and DALYs decreased, but age-specific distribution was not essentially changed. Inequality in asthma incidence and prevalence narrowed, but high body mass index-related asthma death concentrated in lower SDI regions and inequality widened. Healthcare system reforms should focus on primary risk factor and lower SDI regions.

The online version contains supplementary material available at 10.1186/s12889-025-25149-y.