Outcome of childhood asthma in mid-adult life
BMJ 1994; 309 doi: https://doi.org/10.1136/bmj.309.6947.95 (Published 09 July 1994) Cite this as: BMJ 1994;309:95
- Helmut Oswald,
- Peter D Phelan,
- Anna Lanigan,
- Marienne Hibbert,
- Glenn Bowes,
- Anthony Olinsky
- Correspondence to: Professor Peter D Phelan, Department of Paediatrics, University of Melbourne, Royal Children's Hospitals, Parkville, Victoria 3052, Australia. Department of Thoracic Medicine, Royal Children's Hospital, Melbourne, Australia Helmut Oswald, research fellow Anna Lanigan, research nurse Anthony Olinsky, director Department of Paediatrics, University of Melbourne, Melbourne, Australia Peter D Phelan, Stevenson Professor Centre for Adolescent Health, Royal Children's Hospital, Melbourne, Australia Marienne Hibbert, head of adolescent health research unit Glenn Bowes, professor of adolescent health.
- Accepted 7 April 1994
A prospective 28 year follow up of 7 year old children with wheezing and asthma began in 1963 in Melbourne, Australia.1 2 We aimed to describe the outcome of childhood asthma at 35 and the changes since the last review, at 28.3
Subjects, methods, and results
The children who were selected at 7, on the basis of parents’ responses to a questionnaire, had been classified in terms of wheeze as those who had never wheezed (controls) (n = 106); those with fewer than five episodes associated with apparent respiratory infection (mild wheezy bronchitis) (n = 75); those with five or more episodes associated with an apparent respiratory infection (wheezy bronchitis) (n = 107); and those with wheezing not associated with respiratory infection (asthma) (n = 113). A fifth group of children, with severe asthma (n = 79), was selected at age 10 from the same age cohort.
During 1992 we followed up 401 of the 480 subjects; 101 answered a telephone questionnaire, and 300 were examined physically. Eleven subjects had died since the study began. The follow up rate was therefore 86%. The subjects were classified as those who had been controls at age 7 (controls) (n = 85); those who had not wheezed in the previous three years (no recent asthma) (n = 132); those who had wheezed in the previous three years but not in the previous three months (infrequent wheeze) (n = 132); those who had not wheezed in the previous three months but less than once a week (frequent asthma) (n = 45); and those who wheezed at least once a week in the previous three months (persistent asthma) (n = 91).
The table shows the pattern of asthma at age 35 in relation to the initial classification. The presence of atopy at age 7 in the children with mild wheezy bronchitis or wheezy bronchitis did not influence the outcome.
Distribution of asthma in 401 subjects aged 35 according to whether they had had bronchitis or asthma as children. Values are numbers (percentages) of subjects
In all, 330 of the 371 (89%) subjects seen at 28 were reviewed at 35; 60% (46/75) of the subjects with persistent asthma at 28 had persistent asthma at 35, and 77% (70/91) of the subjects with no symptoms at 28 were symptom free at 35. Only 26% (15/59) of the subjects with infrequent asthma and 20% (12/60) of the subjects with frequent asthma remained stable.
Tobacco smoking among the controls and the four groups of subjects was similar in terms of whether they had ever smoked (range 40-46%), the number of pack years (1 pack year = 20 cigarettes/day for 1 year) smoked (> 10 pack years) (28-33%), and those who were current smokers (24-34%). Hay fever at the age of 35 occurred in 57 (85%) of the subjects who had been in the group with severe asthma; 72 (73%) of the subjects who had been in the group with asthma; 51 (59%) of the subjects who had been in the group with wheezy bronchitis; 40 (62%) of the subjects who had been in the group with mild wheezy bronchitis; and 36 (43%) of the controls.
Comment
Our results confirm the findings of earlier reviews of this cohort— namely, that many children do not grow out of asthma, and the more troublesome their asthma is, the less likely they are to do so.3 4 Just over a third of subjects who had had childhood wheezy bronchitis had asthmatic symptoms at 35. Our findings support Williams and McNichol's suggestion that wheezy bronchitis and asthma are different labels for the same disease.1 By the time their children were 7 some parents might have forgotten a few minor episodes of wheeze; we may therefore have overestimated the percentage of children with wheeze associated with respiratory infection who continued to wheeze as adults.
Between the ages of 28 and 35 no substantial changes occurred in the pattern of asthma. Subjects with infrequent or frequent asthma were less stable in their pattern of asthma than those with no recent asthma or with persistent asthma, which may reflect less precision in the classification of the groups in the midrange of the severity scale.