The age a person develops asthma may help explain their disease more clearly. A new study finds people who are diagnosed with asthma as children have a different disease than those who develop it as an adult. Researchers say the patients suffered different symptoms and disease progression based on the age of onset.
Eighty patients with severe asthma that could not be controlled by steroids participated in the study. They were divided into two groups including those diagnosed before 12 years old and those who developed the disease later in life. The participants were evaluated for differences in allergic response, symptoms, lung function and pathology.
Researchers found that patients whose asthma began in childhood were more frequently allergic than those whose asthma began as adults, while adult-onset asthma was associated with more rapid loss of lung function. Researchers say they were surprised to find that many patients showed no signs of inflammation, generally considered a hallmark of the asthma, yet they still had severe airflow limitation and many asthma symptoms. Specifically, researchers say more than 75 percent of patients who developed asthma before 12 say they wheezed most or all of the time when exposed to dust or pollens. In contrast, only 40 percent of patients diagnosed after 12 reported the same scenario.
Even though the early onset patients had had the disease for a longer period. Researchers also found that the lung function was worse in the adult-onset group. This suggests patients diagnosed later suffer a more rapid loss of lung function. The study also found late-onset patients were more likely to have inflammatory cells known as eosinophils in their airways, despite treatment.
Thus researchers conclude saying it is clear asthma is not a single disease, but a group of syndromes with different origins and biological characteristics. They hope defining these subsets will help in asthma diagnosis, treatment and future research.