Guerra S, Wright AL, Morgan WJ, Sherrill DL, Holberg CJ, Martinez FD. Am J Respir Crit Care Med. 2004;170:78–85
Purpose of the Study.
To evaluate factors the may influence the persistence or remission of childhood asthma after the onset of puberty.
A subset of the birth cohort (n = 1246) enrolled in the Tucson Children’s Respiratory Study between 1980 and 1984.
The population underwent a series of evaluations and questionnaires at years 2, 3, 6, 8, 11, 13, and 16. Questions regarding the onset of puberty appeared at years 13 and 16. Questions were also asked about the presence and frequency of wheezing. Onset of puberty was defined by parental report of early signs; asthma was defined by frequent wheezing or any wheezing with a physician-confirmed diagnosis. Infrequent wheezing was defined by <3 episodes in the previous year. The category of “unremitting” was applied if any wheezing was reported after the onset of puberty and “remitting” if no wheezing was reported.
Information on wheezing before and after the onset of puberty was available for 781 subjects. In this cohort, 401 (51%) never experienced wheezing, and 83 (11%) reported wheezing after the onset of puberty. Of the 297 who were wheezing before puberty, 131 (17%) had only infrequent wheezing, and 166 (21%) fulfilled the definition for asthma. Most children (92 of 131 [70%]) with infrequent wheezing experienced remission after puberty. Of those children with the diagnosis of asthma in the prepubertal period, 97 (58%) of the 166 had wheezing episodes after the onset of puberty, and 69 (42%) had remitting asthma. The early onset of puberty was associated with the persistence of asthma into adolescence and with children in the unremitting-wheezing and asthma groups having the onset of puberty significantly earlier than children in the corresponding remitting groups (unremitting wheezing/unremitting asthma = 11.74/11.95 years versus remitting wheezing/remitting asthma = 12.34/12.7 years). The mean body mass index was significantly higher in unremitting-wheezing/asthma groups compared with remitting groups at each point over 10 years of surveys. Other factors associated with the persistence of symptoms included the amount of wheezing in the per-pubertal period and the presence of active sinus disease and rhinitis in the year before the survey. There were a limited number for whom a measure of airway hyperresponsiveness was available. In the unremitting-wheezing group, 27% had a positive methacholine challenge, and in the unremitting-asthma group, 68% were positive. Persistence of wheezing and asthma into adolescence was also associated with a positive skin test to the mold Alternaria. Children sensitized before puberty were 1.6 to 2.0 as likely to experience unremitting wheezing/asthma into adolescence.
Overall, 30% of children with infrequent wheezing and 60% of children with asthma in the prepubertal period will keep experiencing wheezing in the first 4 years after the onset of puberty. The prepubertal risk factors for the persistence of asthma include presence of frequent or continuous wheezing, obesity, early-onset puberty, active sinus disease, and skin-test sensitization.
How often has it been said that a child will “outgrow” their asthma during adolescence? Where is the evidence that supports such a statement? This study challenges that notion. This is an excellent and very informative work by a group that has continued to advance our understanding of the natural history of wheezing and asthma in children. A potential limitation is that these findings may be “population specific.” As most good studies do, this one begs for verification in other populations and regions in the country.