Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways, leading to symptoms like wheezing, coughing, shortness of breath, and chest tightness. This article explores the worldwide and regional prevalence of asthma, highlighting the percentage of people affected. Understanding these statistics offers insight into the public health impact of asthma across diverse populations.
Global and National Asthma Prevalence
In 2019, an estimated 262 million people worldwide were impacted by asthma, resulting in 455,000 deaths. The global prevalence of doctor-diagnosed asthma in adults was around 4.3% across 70 countries, with variations ranging from 0.2% in China to 21.0% in Australia. A broader definition, including clinical or treated asthma, showed a global prevalence of 4.5%.
In the United States, asthma is a major health concern. As of 2021, approximately 24.9 million people in the U.S. had asthma, accounting for 7.7% of the total population. This figure includes 4.7 million children and 20.3 million adults. The Centers for Disease Control and Prevention (CDC) provides these national statistics.
Variations in Asthma Rates
Asthma prevalence is not uniform across demographic groups or geographic locations. In childhood, asthma rates are higher among boys (11.9%) compared to girls (7.5%). This trend reverses in adulthood, where women experience higher rates (9.6%) than men (6.3%).
Socioeconomic factors also play a role. Individuals with lower annual household incomes or less than a high school education show increased rates of current asthma. Geographically, while overall prevalence in adults did not differ greatly between broad regions, specific countries exhibit wide variations. Australia, Sweden, and the UK reported some of the highest rates, while countries like Vietnam and China had much lower figures.
Factors Contributing to Asthma Prevalence
Asthma prevalence is influenced by environmental exposures, genetic predispositions, and lifestyle choices. Environmental triggers such as air pollution, indoor allergens like dust mites and mold, and exposure to tobacco smoke contribute to the development and exacerbation of asthma. Long-term exposure to heavily trafficked areas, for example, is associated with an increase in asthma incidence.
Genetic factors also play a role in susceptibility. If one parent has asthma, a child’s risk increases by 25%, rising to 50% if both parents are affected. While no single gene is solely responsible, several gene complexes can interact with environmental factors to increase the likelihood of developing asthma. Lifestyle factors, such as obesity, can further influence asthma prevalence and severity, as excess weight may trigger related conditions like acid reflux and obstructive sleep apnea, impacting respiratory health.