Journal of Epidemiology and Community Health, 1978, 32, 79-85
A national study of asthma in childhood CATHERINE PECKHAM From the Charing Cross Hospital Medical School, London NEVILLE BUTLER From the University of Bristol
A history of asthma was obtained in 3.5 % of a representative national sample of children aged years. A further 8.8% had a history of wheezy bronchitis. In the 12 months before the interview, 2 % had experienced attacks of asthma and a further 2.9 % attacks of wheezy bronchitis. Both conditions were significantly more common among boys than girls, and a history of asthma was reported more frequently among children from non-manual than from manual social classes. Children with frequent attacks of wheezing had lower mean relative weights. A history of eczema and hay fever was more frequently discovered in children with reported asthma than in those with wheezy bronchitis, whereas migraine or recurrent headaches, recurrent abdominal pain, and recurrent throat or ear infections were more commonly associated with wheezy bronchitis than with asthma. The modified Rutter home behaviour scale, which reflects the parental view of the child's behaviour, was significantly raised among children with a history of wheezing, but their school behaviour as judged by the Bristol social adjustment guide showed no such difference. In spite of increased absence from school because of illness, no differences were found in educational attainment between children with a history of asthma or wheezy bronchitis and those with neither condition.
SUMMARY
Introduction Previous studies on asthma in childhood have been restricted mainly to local or selected samples from the population. The present study is an attempt to overcome the bias introduced by variations in size and characteristics of sample population by examining the prevalence of childhood asthma and wheezy bronchitis in a nationally representative sample of children. The nature of this sample has allowed comparisons to be made between the medical history, social background, and educational progress of children with a history of asthma and/or wheezy bronchitis and those who had no history of either complaint. Method
Information has been compiled from the results of the National Child Development Study conducted by the National Children's Bureau. This study is a longitudinal survey of all children in England, Scotland, and Wales who were born in one week in March, 1958 (Davie et al., 1972). It originated from
the 17 000 children in the National Birthday Trust Fund's Perinatal Mortality Survey (Butler and Alberman, 1969). Medical, social and educational data were obtained from three main sources when the children were seven and 11 years old. Parents were interviewed in the home, school doctors carried out medical examinations, and teachers filled in a questionnaire at school. The children completed a number of tests and a questionnaire at the age of 11. The educational tests at the age of 11 included a reading comprehension test, developed along the lines of the Watts Vernon test (Start and Wells, 1972), an arithmetic test, and a test of general ability. These tests were constructed and standardised for children aged 11 by the National Foundation for Educational Research. As a measure of the child's behaviour in the home, parents were asked about 17 'behaviour items' from the Rutter home behaviour scale (Rutter et al., 1970). Information on school behaviour was obtained from the Bristol social adjustment guide (Stott, 1963) which was completed for each child by the teacher. 79
Catherine Peckham and Neville Butler
80
Selection of children The health visitor asked parents of children aged 11 'Has your child ever had attacks of asthma; of wheezy bronchitis; or neither of these conditions'? If the answer to the first two questions was 'yes', parents were then asked about the frequency of attacks, categorised as follows: at least once a week; usually less than once a week but can expect one a month; at least one attack in past year but less frequently than once a month; had attacks in the past year but don't know frequency; no attacks at all in past year but had attacks when younger. The terms asthma and wheezy bronchitis were both included in the parental questionnaire since it is often difficult to distinguish precisely between them. However, a history of asthma has been shown to be a good indicator of impaired ventilatory function (Hamman et al., 1975), whereas bronchitis with associated wheezing has been less well validated, although recent evidence suggests that both asthma and wheezy bronchitis constitute part of one disease entity, differing only in degree (Williams and McNicol, 1969).
1000 children aged 11 were having wheezy attacks of some kind at least monthly. Eleven children were receiving special teaching because of their asthma (eight were classified as delicate and three as physically handicapped). One death had been ascribed to asthma in a girl aged 11. Children reported by parents to have had asthma or wheezy bronchitis in the year before the interview at the age of 11 were designated as having current attacks and comprised 4 9 % of the total sample. The children whose attacks were reported to have taken place before, but not during, the preceding year, are subsequently refered to as having past attacks. This group comprised 7 '4% of the total sample and includes 29 children with a history of asthma and 51 with a history of wheezy bronchitis for whom there was no information about whether attacks had occurred in the past year. The remaining 1 I-year-old children (87 7 %), who had no history of asthma or wheezy bronchitis, were categorised as having neither condition. BOYS AND GIRLS
Attacks of asthma and wheezy bronchitis, both current and past, were more common in boys than girls. This difference was more marked in the Results asthma group, where there were nearly twice as many boys as girls, but it was still significant in the PREVALENCE OF ASTHMA AND wheezy bronchitis group (Table 2). Twenty of the WHEEZY BRONCHITIS 29 children shown in Table 1 as having attacks at BY THE AGE OF 11 A history of asthma with or without wheezy least weekly were boys. bronchitis was reported by parents in 3-5% of 13 509 children from whom information was Table 2 Prevalence of asthma and wheezy bronchitis available relating specifically to asthma or wheezy by sex Total Boys Girls bronchitis. A further 8 8 % were reported to have a No. % No. % No. % history of wheezy bronchitis only. The proportions in whom asthma or wheezy bronchitis had occurred Asthma 177 (2-6) 93 ( 1-4) 270 (2-0) Current attacks in the year before the interview at the age of 11 are 199 (1S5) 69 ( 1'1) 130 ( 19) Past attacks bronchitis Wheezy set out in Table 1. This shows that 2% had suffered 394 (2-9) 165 (2'5) 229 ( 3'3) Current attacks 801 ( 59) 357 ( 54) 444 ( 6'4) Past attacks from asthma attacks during the previous year and a Neither condition 5953 (85 9) 5892 (89'6) 11 845 (87?7) further 2-9% from wheezy bronchitis. One or more Total 13 509 (100) 6933 (100) 6576 (100) attacks of asthma or wheezy bronchitis a month Asthma (current and past) vs. neither condition P
A national study of asthma in childhood CATHERINE PECKHAM From the Charing Cross Hospital Medical School, London NEVILLE BUTLER From the University of Bristol
A history of asthma was obtained in 3.5 % of a representative national sample of children aged years. A further 8.8% had a history of wheezy bronchitis. In the 12 months before the interview, 2 % had experienced attacks of asthma and a further 2.9 % attacks of wheezy bronchitis. Both conditions were significantly more common among boys than girls, and a history of asthma was reported more frequently among children from non-manual than from manual social classes. Children with frequent attacks of wheezing had lower mean relative weights. A history of eczema and hay fever was more frequently discovered in children with reported asthma than in those with wheezy bronchitis, whereas migraine or recurrent headaches, recurrent abdominal pain, and recurrent throat or ear infections were more commonly associated with wheezy bronchitis than with asthma. The modified Rutter home behaviour scale, which reflects the parental view of the child's behaviour, was significantly raised among children with a history of wheezing, but their school behaviour as judged by the Bristol social adjustment guide showed no such difference. In spite of increased absence from school because of illness, no differences were found in educational attainment between children with a history of asthma or wheezy bronchitis and those with neither condition.
SUMMARY
Introduction Previous studies on asthma in childhood have been restricted mainly to local or selected samples from the population. The present study is an attempt to overcome the bias introduced by variations in size and characteristics of sample population by examining the prevalence of childhood asthma and wheezy bronchitis in a nationally representative sample of children. The nature of this sample has allowed comparisons to be made between the medical history, social background, and educational progress of children with a history of asthma and/or wheezy bronchitis and those who had no history of either complaint. Method
Information has been compiled from the results of the National Child Development Study conducted by the National Children's Bureau. This study is a longitudinal survey of all children in England, Scotland, and Wales who were born in one week in March, 1958 (Davie et al., 1972). It originated from
the 17 000 children in the National Birthday Trust Fund's Perinatal Mortality Survey (Butler and Alberman, 1969). Medical, social and educational data were obtained from three main sources when the children were seven and 11 years old. Parents were interviewed in the home, school doctors carried out medical examinations, and teachers filled in a questionnaire at school. The children completed a number of tests and a questionnaire at the age of 11. The educational tests at the age of 11 included a reading comprehension test, developed along the lines of the Watts Vernon test (Start and Wells, 1972), an arithmetic test, and a test of general ability. These tests were constructed and standardised for children aged 11 by the National Foundation for Educational Research. As a measure of the child's behaviour in the home, parents were asked about 17 'behaviour items' from the Rutter home behaviour scale (Rutter et al., 1970). Information on school behaviour was obtained from the Bristol social adjustment guide (Stott, 1963) which was completed for each child by the teacher. 79
Catherine Peckham and Neville Butler
80
Selection of children The health visitor asked parents of children aged 11 'Has your child ever had attacks of asthma; of wheezy bronchitis; or neither of these conditions'? If the answer to the first two questions was 'yes', parents were then asked about the frequency of attacks, categorised as follows: at least once a week; usually less than once a week but can expect one a month; at least one attack in past year but less frequently than once a month; had attacks in the past year but don't know frequency; no attacks at all in past year but had attacks when younger. The terms asthma and wheezy bronchitis were both included in the parental questionnaire since it is often difficult to distinguish precisely between them. However, a history of asthma has been shown to be a good indicator of impaired ventilatory function (Hamman et al., 1975), whereas bronchitis with associated wheezing has been less well validated, although recent evidence suggests that both asthma and wheezy bronchitis constitute part of one disease entity, differing only in degree (Williams and McNicol, 1969).
1000 children aged 11 were having wheezy attacks of some kind at least monthly. Eleven children were receiving special teaching because of their asthma (eight were classified as delicate and three as physically handicapped). One death had been ascribed to asthma in a girl aged 11. Children reported by parents to have had asthma or wheezy bronchitis in the year before the interview at the age of 11 were designated as having current attacks and comprised 4 9 % of the total sample. The children whose attacks were reported to have taken place before, but not during, the preceding year, are subsequently refered to as having past attacks. This group comprised 7 '4% of the total sample and includes 29 children with a history of asthma and 51 with a history of wheezy bronchitis for whom there was no information about whether attacks had occurred in the past year. The remaining 1 I-year-old children (87 7 %), who had no history of asthma or wheezy bronchitis, were categorised as having neither condition. BOYS AND GIRLS
Attacks of asthma and wheezy bronchitis, both current and past, were more common in boys than girls. This difference was more marked in the Results asthma group, where there were nearly twice as many boys as girls, but it was still significant in the PREVALENCE OF ASTHMA AND wheezy bronchitis group (Table 2). Twenty of the WHEEZY BRONCHITIS 29 children shown in Table 1 as having attacks at BY THE AGE OF 11 A history of asthma with or without wheezy least weekly were boys. bronchitis was reported by parents in 3-5% of 13 509 children from whom information was Table 2 Prevalence of asthma and wheezy bronchitis available relating specifically to asthma or wheezy by sex Total Boys Girls bronchitis. A further 8 8 % were reported to have a No. % No. % No. % history of wheezy bronchitis only. The proportions in whom asthma or wheezy bronchitis had occurred Asthma 177 (2-6) 93 ( 1-4) 270 (2-0) Current attacks in the year before the interview at the age of 11 are 199 (1S5) 69 ( 1'1) 130 ( 19) Past attacks bronchitis Wheezy set out in Table 1. This shows that 2% had suffered 394 (2-9) 165 (2'5) 229 ( 3'3) Current attacks 801 ( 59) 357 ( 54) 444 ( 6'4) Past attacks from asthma attacks during the previous year and a Neither condition 5953 (85 9) 5892 (89'6) 11 845 (87?7) further 2-9% from wheezy bronchitis. One or more Total 13 509 (100) 6933 (100) 6576 (100) attacks of asthma or wheezy bronchitis a month Asthma (current and past) vs. neither condition P
