Estimating Asthma Prevalence and Cases in 2019

Researchers, co-led by Peige Song and Davies Adeloye, aimed to provide global and regional estimates of asthma prevalence and cases in 2019. In their report, published in the Journal of Global Health, they ultimately concluded that, “although varying approaches to case identification in different settings make epidemiological estimates of asthma very difficult, this analysis reaffirms asthma as a common global respiratory condition before the COVID-19 pandemic in 2019, with higher prevalence than previously reported in many world settings.”

The authors’ analysis included 220 population-based studies carried out prior to December 31, 2019 across 88 countries. Asthma was divided into four epidemiological case definitions: current wheezing, ever wheezing, current asthma, and ever asthma. Multilevel multivariable mixed-effects meta-regression models, random-effects meta-analysis, and a “risk factor-based model” were used to assess associations between asthma and study-level variables, risk factors for current wheezing and asthma, and regional asthma prevalence and case numbers in 2019, respectively. A follow-up analysis was also performed to estimate regional and national distributions of prevalence and cases for the current wheezing and ever asthma statuses.

2019 Global and Regional Prevalence of Asthma Findings

The authors estimated a global prevalence of current wheezing, ever wheezing, current asthma, and ever asthma of 11.5% (95% CI, 9.1-14.3), 17.9% (95% CI, 14.2-22.3), 5.4% (95% CI, 3.2-9.0), and 9.8% (95% CI, 7.8-12.2), respectively, in people aged 5-69 years in 2019. This equated to 754.6 million (95% CI, 599.7-943.4), 1,181.3 million (95% CI, 938.0-1,471.0), 357.4 million (95% CI, 213.0-590.8), 645.2 million (95% CI, 513.1-806.2) cases, respectively.

Reportedly, the African Region had the highest prevalence of current wheezing at 13.2% (95% CI, 10.5-16.5), while the Americas Region had the lowest at 10.0% (95% CI, 8.0-12.5). Comparatively, the estimated prevalence of ever asthma was also highest in the African Region at 11.3% (95% CI, 9.0-14.1), but was lowest in the South-East Asia Region at 8.8% (95% CI, 7.0-11.0).

Ultimately, the authors concluded that, “asthma, based on whichever definition is used, was more common than previously estimated” prior to the COVID-19 pandemic, and they proposed that their findings “should be particularly useful for planning a national and sub-national response to asthma and will complement other international research efforts.”

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