Older adults with asthma also have at least one allergy, according to researchers from Mount Sinai School of Medicine. The research contradicts existing studies on allergen sensitization in older adult asthma patients, which was thought to be significantly less than in youth adult asthma patients, according to the study.

Researchers analyzed the records of 2573 people included in the National Health and Nutrition Examination Survey (NHANES) 2005-2006 to assess immunoglobulin E–mediated (IgE) sensitization rates in adults with asthma. The investigators compared the prevalence of sensitization between two age groups: adults aged 20 to 40 years and adults aged 55 years or older.

Of the 1623 younger patients, the researchers identified 108 (6.7%) individuals who had physician-diagnosed cases of asthma. Among the 950 older patients, the investigators identified 43 (4.5%) individuals with asthma. In the younger group, 75.4% of the individuals with asthma had at least 1 allergen sensitization, as did 65.2% of the older adults with asthma. The difference between the 2 groups did not reach statistical significance.

Older patients with asthma most often were sensitized to dust mite (Dermatophagoides pteronyssinus, 36.3%) and rye grass (33.1%), with 50.2% being sensitized to at least 1 indoor allergen and 39.3% to at least 1 outdoor allergen. Younger patients with asthma were most often sensitized to dog (49.5%) and dust mite (D pteronyssinus [44.8%] and D farinae [41.4%]), with 60.2% being sensitized to at least 1 indoor allergen and 53.3% to at least 1 outdoor allergen.

“Allergists have known the prevalence of allergies among asthmatic children is high at 60 to 80 percent, but it was thought allergies were not as common in asthmatic adults,” lead author Paula J. Busse, MD, said in a news release. “These findings are important, and can help lead to proper diagnosis and treatment.”

Although the literature suggests the prevalence of asthma may range from 3.5% to 7.5% in adults older than 60 years, this study finds that 4.5% of the NHANES 2005-2006 population aged 55 years and older had physician-diagnosed asthma, the researchers write. Asthma was more common in women with higher body mass indexes.

“Physicians providing care for older patients with asthma should consider testing for allergic sensitization and counseling about environmental control practices, particularly among those with poorly controlled asthma,” researchers concluded.