Asthma and Allergy Comorbidity Among the US Population Aged 2 Years or Older, National Health Interview Survey, 2021

Asthma has substantial morbidity and impact on quality of life. Symptoms can worsen when asthma coexists with allergy. We assessed the prevalence of asthma-allergy comorbidity in a nationally representative sample.

We used 2021 National Health Interview Survey data for 7343 children and adolescents aged 2 to 17 years and 29 329 adults aged ≥18 years to estimate the prevalence of asthma, allergy symptoms, and lifetime allergy diagnosis. We assessed associations between asthma-allergy comorbidity and characteristics (sex, age group, race and ethnicity, family income, region, urbanicity) and between asthma attacks and allergy by using logistic regression.

Almost 8% of people aged ≥2 years had asthma, and 52.3% had allergy symptoms. Among children and adolescents, boys had a higher prevalence of asthma-allergy comorbidity than girls (6.2%; 95% CI, 5.3%-7.2% vs 5.0%; 95% CI, 4.2%-5.9%). Among adults, men had a lower prevalence of asthma-allergy comorbidity than women (4.9%; 95% CI, 4.5%-5.4% vs 8.3%; 95% CI, 7.7%-8.8%). The prevalence of asthma-allergy comorbidity was higher among people with low income (<100% vs ≥200% federal poverty level) and non-Hispanic Black (vs non-Hispanic White) people. Among people with asthma, 82.1% had allergy symptoms and 67.3% had a lifetime allergy diagnosis. The prevalence of allergy symptoms differed by sex among adults with asthma but not among children and adolescents with asthma. Among adults with asthma, asthma attacks were associated with allergy symptoms (adjusted prevalence ratio = 1.23; 95% CI, 1.04-1.46).

Disparities in asthma-allergy comorbidity exist by sex, family income, and race and ethnicity. These findings support national asthma management guidelines on the importance of identifying and treating comorbid allergies among people with asthma.