PREVENTIVE
MEDICINE
5,
63-69 (1976)
Smoking and Respiratory Symptoms in Two Groups of Schoolchildren1 R. BEWLEY AND J.M. BLAND
BEULAH
Department of Community Medicine, Saint Thomas’s Hospital Medical School, London, S.E.1. The effects of early cigarette smoking on respiratory symptoms have been studied in two large populations of schoolchildren (lO-12M years). Both studies were carried out in 1971in two different areas of the United Kingdom. The smoking prevalence rates and respiratory symptoms were similar for both groups. Boys and girls in each area who smoked, reported more respiratory symptoms than nonsmokers, whether they attended urban or rural schools. The prevalence rate of smoking was similar in children in the final year of primary school (IO-lllh years) to those in the first year of secondary school (1 I-12!4 years). Among the secondary schoolchildren, those attending secondary modem schools smoked more than those at grammar schools.
INTRODUCTION
Children who smoke cigarettes report more respiratory symptoms than those who do not. This has been found among secondary schoolchildren in England (8,9), and among final year primary schoolchildren (3). It has also been found that urban children reported more respiratory symptoms than did rural children (3, 9). This paper reports a study of smoking and respiratory symptoms in final year primary and first year secondary schoolchildren in Kent. Part of this study replicates an early study in Derbyshire, already reported elsewhere (3) and the Kent findings are compared with those from Derbyshire. METHOD
The Kent study took place in November 1971. The population was 5355 children, aged 10-1255 years, in the final year of primary school or the first year of secondary school. Four areas of Kent were studied: Rochester M.B., Tonbridge U.D., Malling R.D. and Cranbrook R.D., Tenterden R.D. and Romney R.D.2 In Derbyshire 8682 children aged lO-11% years were surveyed in March 1971, in their final year of primary school (3). In each study, the children completed a short self-administered questionnaire in the classroom. These questionnaires were then sealed in individual envelopes and returned to St. Thomas’ Hospital. The following questions were asked about respiratory symptoms: 1 This work was supported, in part, by a grant from the Medical Research Council and the Depattment of Health and Social Security. * MB. = municipal borough; U.D. = urban district; and R.D. = rural district. 63 Copyright All ri&ts
@ 1976 by Academic Rcss, Inc. of reproduction in any Fomt reserved.
64
HEWLEY
AND
BLAND
1. Do you usually cough first thing in the morning? 2. Do you usually cough during the day or at night? If you answer YES to question 1 or question 2, please answer question 3. 3. Do you cough like this on most days for as much as three months each year?
YES/NO YES/NO YES/NO
In Derbyshire, the children were then asked: Do you smoke? If YES, how many cigarettes do you smoke per week? If NO, have you ever smoked cigarettes? If YES, do you smoke cigarettes at all now? If YES, how many cigarettes do you smoke per week?
In Kent a slightly different question was used: Have you eversmoked a cigarette? (Even a few puffs.) Do you still smoke cigarettes? How many cigarettes do you smoke in a week?
YES/NO YES/NO YES/NO
YES/NO YES/NO
A smoker was defined as a child who smoked at least one cigarette a week; and smoker as one who had smoked at some time, but did not smoke as much as one cigarette per week; and a nonsmoker as a child who had never smoked. Children were grouped as urban or rural by the location of the school they attended, according to the classification used by the General Registry Office (5, 6). This defined an area as urban if there were 10 or more people per acre. The educational system of England and Wales for children aged 5-16 years or over, is divided into primary and secondary education (7). Although children in primary and secondary education vary from county to county in England and Wales, broadly speaking, primary schools cater for children aged 5-11 years, and secondary schools for children aged 11-16 years or over. The “secondary modern” schools are nonselective secondary schools and the “grammar schools” selective secondary schools. In Derbyshire and Kent there are also “comprehensive” secondary schools, that is, nonselective secondary schools which admit all children from their area without regard to selection or exclusion based on ability.
experimental
RESULTS Response Rates
Completed forms were obtained from 4804 children in Kent (90%) and from 7115 children in Derbyshire (82%). Nonresponders were children whose headteachers or parents refused to allow them to take part in the study, were absent from school on the day of the questionnaire, or who did not return completed forms. Smoking
The prevalence of smoking reported in both studies is shown in Table 1. Significantly more Kent than Derbyshire children were experimental smokers; although the Kent children were older, age was not the factor causing this difference. More boys smoked than girls; 54% of the Kent boys and 43% of Derbyshire boys had tried a cigarette, compared to 35 and 24% of Kent and Derbyshire girls, respectively. Only six girls reported smoking more than one cigarette a day, but 39 (1.6%) of the Kent boys and 29 (0.8%) of the Derbyshire boys were doing so. This difference between the sexes was not age-dependent.
SMOKING
AND
RESPIRATORY
SMOKING
HABITS
SYMPTOMS
TABLE 1 AS REPORTED BY
65
IN CHILDREN
CHILDREN
Smokers (At least one cigarette per week) N %
Experimental smokers (Smoked at least once) N %
Boys Kent Derbyshire
172 253
7.3 6.9
1109 1294
46.8 35.6
1087 2087
45.9 57.4
1 2
Girls Kent Derbyshire
56 91
2.3 2.6
793 732
32.6 21.0
1579 2654
64.8 76.3
Total Kent Derbyshire
228 344
4.7 4.8
1902 2026
39.6 28.5
2666 4741
55.5 66.6
Nonsmokers (Never smoked) N %
Not known N %
Totals N
%
0.0 0.1
2369 3636
100.0 100.0
7 2
0.3 0.1
2435 3479
100.0 100.0
8 4
0.2 0.1
4804 7115
100.0 100.0
Table 2 shows the smoking habits of children in urban and rural schools. In Kent, significantly more rural than urban boys reported smoking, and more rural than urban girls also reported smoking, but this was not significant. In Derbyshire there was no significant difference between smoking prevalence in urban and rural schools for boys or girls. In Kent, the children were attending three types of school: primary, grammar, and secondary modem. The smoking habits of these three groups are shown in Table 3. Boys attending secondary schools reported more smoking than those at primary schools, although the difference was small. The difference between types of secondary schools was much greater; 60% of the boys at secondary modem schools had tried smoking, compared to 45% at grammar schools. There was no difference between girls from primary and secondary schools, but more girls attending secondary modern schools reported smoking than those at grammar schools. Respiratory
Symptoms
Morning cough was reported by 10% of Kent children and 7% of Derbyshire children, day or night cough by 26% in Kent and 23% in Derbyshire, and cough for 3 months by 7 and 4%, respectively. The relationship between respiratory symptoms and smoking habits, sex, and area of residence of Kent children is given in Table 4. There is a significant interaction between these factors which makes interpretation difficult. Smoking was consistently associated with a higher prevalence of respiratory symptoms in boys and girls in urban and rural schools, whereas there were no consistent associations of symptoms with sex or area of residence. The corresponding data from Derbyshire are presented in Table 5. Within each
66
BEWLEY AND BLAND TABLE 2 SMOKINGHABIT BY URBANORRURALSCHCOL’
Smoker N % Boys Kent Urban Rural Derbyshire Urban Rural Girls Kent Urban Rural Derbyshire Urban Rural Total Kent Urban Rural Derbyshire Urban Rural
Experimental smoker N %
Nonsmoker % N
Not known N %
Totals N
%
89 83
6.1 9.2
674 435
46.0 48.1
701 386
47.9 42.7
1 0
0.1 0.0
1465 904
100.0 loo.0
200 53
6.9 7.4
1035 259
35.5 35.9
1678 409
57.6 56.7
2 0
0.1 0.0
2915 721
100.0 100.0
32 24
2.0 2.9
522 271
32.2 33.2
1060 519
65.5 63.6
5 2
0.3 0.2
1619 816
100.0 100.0
74 17
2.7 2.3
5% 136
21.7 18.6
2075 579
75.6 79.0
1 1
0.0 0.1
2746 733
100.0 100.0
121 107
3.9 6.2
11% 706
38.8 41.0
1761 905
57.1 52.6
6 2
0.2 0.2
3084 1720
100.0 100.0
274 70
4.8 4.8
1631 395
28.8 27.2
3753 988
66.3 68.0
3 1
0.1 0.1
5661 1454
100.0 100.0
o X2test for association between urban or rural school and smoking-Boys: Kent X” d.f.=2 = 11.2, P < 0.005; Derbyshire X” d.f. = 2 = 0.3, P < 0.1; Girls: Kent X2d.f. = 2 = 2.6, P < 0.1; Derbyshire X2d.f. = 2 = 4.0. P < 0.1.
area, smokers reported more symptoms than nonsmokers for both boys and girls. Within smoking groups, urban children reported more symptoms than rural children. When smoking and area were taken into account, there was no difference in the frequency of symptoms between boys and girls.
DISCUSSION These two studies of the smoking habits and respiratory symptoms of schoolchildren aged 1&12?4 years have shown very similar results. The prevalence of smoking in Kent was close to that in Derbyshire although more children in Kent had tried a cigarette at least once. In both, more boys than girls were smoking, and in both smoking was linked to respiratory symptoms. Differences between urban and rural schools in Derbyshire were not found in Kent. In Kent, these differences were small and inconsistent, whereas in Derbyshire, urban children consistently
SMOKING
AND
RESPIRATORY
SYMPTOMS
67
IN CHILDREN
TABLE 3 KENT SCHOLL
Type of School
CHILDRENBY
Experimental smoker N %
Smoker N %
Boys Primary Secondary Modem Grammar AU secondary
DIFFERENT
TYPES OF SCHOOLS AND SMOKING
Nonsmoker N %
’
Not known N %
Total N
%
87
7.0
550
44.4
602
48.6
0
0.0
1239
100.0
80 5 85
8.6 2.5 7.6
473 86 559
51.1 42.2 49.5
372 113 485
40.2 55.4 42.9
1 0 1
0.1 0.0 0.1
926 204 1130
100.0 loo.0 100.0
26
2.3
372
32.9
729
64.4
4
0.3
1131
100.0
30 0 30
3.0 0.0 2.3
349 72 421
34.6 24.3 32.3
627 223 850
62.2 75.3 65.2
2 1 3
0.2 0.3 0.2
1008 2% 1304
100.0 100.0 loo.0
Girls Primary Secondary Modem Grammar AU secondary
0 X* tests for association between smoking and school type-Boys: primary vs secondary modem vs grammar X* d.f. = 4, = 29.94, P < 0.001; primary vs all secondary X” = 9.96, P < 0.01; grammar vs secondary modem X’ = 19.98, P < 0.001. Girls: primary vs secondary modem vs grammar X’ = 22.47, P < 0.001; primary vs all secondary X’(2) = 0.12, 0.6 < p < 0.8, grammar vs secondary modem = x2 d.f. = 2, = 22.36, P c 0.001.
TABLE 4 RESPIRATORY
SYIWTOMS
BY SEX. AREA, AND SMOKING
HABIT.
REPORTED BY KENT SCHOOLCHILDREN
urban
Rural
Smoking Symptom
SCX
Smoker N%N%N%
Experimental smoker
Nonsmoker
Significance ’
Smoker N%N%N%
EXpCrilllelltal smoker
Nonsmoker
Dot known
Significance
N
l *
7.8
Boys Girls
I2 IO
13.5 31.3
72 51
10.7 9.8
60 73
a.6 6.9
0.1 < P < 0.3 P < 0.001
I6 6
19.3 25.0
63 39
14.5 14.4
30 59
Il.4
P < 0.01 0.1 < P 4 0.3
0 0
Cough during day or night
Boys Girls
31 I7
34.8 53.1
181 146
26.8 2a.o
I68 I95
24.0 la.4
P < 0.05 P < 0.001
32 9
38.6 37.5
1311 91
31.7 33.6
90 I54
23.3 29.7
P < 0.01 O.I
MEDICINE
5,
63-69 (1976)
Smoking and Respiratory Symptoms in Two Groups of Schoolchildren1 R. BEWLEY AND J.M. BLAND
BEULAH
Department of Community Medicine, Saint Thomas’s Hospital Medical School, London, S.E.1. The effects of early cigarette smoking on respiratory symptoms have been studied in two large populations of schoolchildren (lO-12M years). Both studies were carried out in 1971in two different areas of the United Kingdom. The smoking prevalence rates and respiratory symptoms were similar for both groups. Boys and girls in each area who smoked, reported more respiratory symptoms than nonsmokers, whether they attended urban or rural schools. The prevalence rate of smoking was similar in children in the final year of primary school (IO-lllh years) to those in the first year of secondary school (1 I-12!4 years). Among the secondary schoolchildren, those attending secondary modem schools smoked more than those at grammar schools.
INTRODUCTION
Children who smoke cigarettes report more respiratory symptoms than those who do not. This has been found among secondary schoolchildren in England (8,9), and among final year primary schoolchildren (3). It has also been found that urban children reported more respiratory symptoms than did rural children (3, 9). This paper reports a study of smoking and respiratory symptoms in final year primary and first year secondary schoolchildren in Kent. Part of this study replicates an early study in Derbyshire, already reported elsewhere (3) and the Kent findings are compared with those from Derbyshire. METHOD
The Kent study took place in November 1971. The population was 5355 children, aged 10-1255 years, in the final year of primary school or the first year of secondary school. Four areas of Kent were studied: Rochester M.B., Tonbridge U.D., Malling R.D. and Cranbrook R.D., Tenterden R.D. and Romney R.D.2 In Derbyshire 8682 children aged lO-11% years were surveyed in March 1971, in their final year of primary school (3). In each study, the children completed a short self-administered questionnaire in the classroom. These questionnaires were then sealed in individual envelopes and returned to St. Thomas’ Hospital. The following questions were asked about respiratory symptoms: 1 This work was supported, in part, by a grant from the Medical Research Council and the Depattment of Health and Social Security. * MB. = municipal borough; U.D. = urban district; and R.D. = rural district. 63 Copyright All ri&ts
@ 1976 by Academic Rcss, Inc. of reproduction in any Fomt reserved.
64
HEWLEY
AND
BLAND
1. Do you usually cough first thing in the morning? 2. Do you usually cough during the day or at night? If you answer YES to question 1 or question 2, please answer question 3. 3. Do you cough like this on most days for as much as three months each year?
YES/NO YES/NO YES/NO
In Derbyshire, the children were then asked: Do you smoke? If YES, how many cigarettes do you smoke per week? If NO, have you ever smoked cigarettes? If YES, do you smoke cigarettes at all now? If YES, how many cigarettes do you smoke per week?
In Kent a slightly different question was used: Have you eversmoked a cigarette? (Even a few puffs.) Do you still smoke cigarettes? How many cigarettes do you smoke in a week?
YES/NO YES/NO YES/NO
YES/NO YES/NO
A smoker was defined as a child who smoked at least one cigarette a week; and smoker as one who had smoked at some time, but did not smoke as much as one cigarette per week; and a nonsmoker as a child who had never smoked. Children were grouped as urban or rural by the location of the school they attended, according to the classification used by the General Registry Office (5, 6). This defined an area as urban if there were 10 or more people per acre. The educational system of England and Wales for children aged 5-16 years or over, is divided into primary and secondary education (7). Although children in primary and secondary education vary from county to county in England and Wales, broadly speaking, primary schools cater for children aged 5-11 years, and secondary schools for children aged 11-16 years or over. The “secondary modern” schools are nonselective secondary schools and the “grammar schools” selective secondary schools. In Derbyshire and Kent there are also “comprehensive” secondary schools, that is, nonselective secondary schools which admit all children from their area without regard to selection or exclusion based on ability.
experimental
RESULTS Response Rates
Completed forms were obtained from 4804 children in Kent (90%) and from 7115 children in Derbyshire (82%). Nonresponders were children whose headteachers or parents refused to allow them to take part in the study, were absent from school on the day of the questionnaire, or who did not return completed forms. Smoking
The prevalence of smoking reported in both studies is shown in Table 1. Significantly more Kent than Derbyshire children were experimental smokers; although the Kent children were older, age was not the factor causing this difference. More boys smoked than girls; 54% of the Kent boys and 43% of Derbyshire boys had tried a cigarette, compared to 35 and 24% of Kent and Derbyshire girls, respectively. Only six girls reported smoking more than one cigarette a day, but 39 (1.6%) of the Kent boys and 29 (0.8%) of the Derbyshire boys were doing so. This difference between the sexes was not age-dependent.
SMOKING
AND
RESPIRATORY
SMOKING
HABITS
SYMPTOMS
TABLE 1 AS REPORTED BY
65
IN CHILDREN
CHILDREN
Smokers (At least one cigarette per week) N %
Experimental smokers (Smoked at least once) N %
Boys Kent Derbyshire
172 253
7.3 6.9
1109 1294
46.8 35.6
1087 2087
45.9 57.4
1 2
Girls Kent Derbyshire
56 91
2.3 2.6
793 732
32.6 21.0
1579 2654
64.8 76.3
Total Kent Derbyshire
228 344
4.7 4.8
1902 2026
39.6 28.5
2666 4741
55.5 66.6
Nonsmokers (Never smoked) N %
Not known N %
Totals N
%
0.0 0.1
2369 3636
100.0 100.0
7 2
0.3 0.1
2435 3479
100.0 100.0
8 4
0.2 0.1
4804 7115
100.0 100.0
Table 2 shows the smoking habits of children in urban and rural schools. In Kent, significantly more rural than urban boys reported smoking, and more rural than urban girls also reported smoking, but this was not significant. In Derbyshire there was no significant difference between smoking prevalence in urban and rural schools for boys or girls. In Kent, the children were attending three types of school: primary, grammar, and secondary modem. The smoking habits of these three groups are shown in Table 3. Boys attending secondary schools reported more smoking than those at primary schools, although the difference was small. The difference between types of secondary schools was much greater; 60% of the boys at secondary modem schools had tried smoking, compared to 45% at grammar schools. There was no difference between girls from primary and secondary schools, but more girls attending secondary modern schools reported smoking than those at grammar schools. Respiratory
Symptoms
Morning cough was reported by 10% of Kent children and 7% of Derbyshire children, day or night cough by 26% in Kent and 23% in Derbyshire, and cough for 3 months by 7 and 4%, respectively. The relationship between respiratory symptoms and smoking habits, sex, and area of residence of Kent children is given in Table 4. There is a significant interaction between these factors which makes interpretation difficult. Smoking was consistently associated with a higher prevalence of respiratory symptoms in boys and girls in urban and rural schools, whereas there were no consistent associations of symptoms with sex or area of residence. The corresponding data from Derbyshire are presented in Table 5. Within each
66
BEWLEY AND BLAND TABLE 2 SMOKINGHABIT BY URBANORRURALSCHCOL’
Smoker N % Boys Kent Urban Rural Derbyshire Urban Rural Girls Kent Urban Rural Derbyshire Urban Rural Total Kent Urban Rural Derbyshire Urban Rural
Experimental smoker N %
Nonsmoker % N
Not known N %
Totals N
%
89 83
6.1 9.2
674 435
46.0 48.1
701 386
47.9 42.7
1 0
0.1 0.0
1465 904
100.0 loo.0
200 53
6.9 7.4
1035 259
35.5 35.9
1678 409
57.6 56.7
2 0
0.1 0.0
2915 721
100.0 100.0
32 24
2.0 2.9
522 271
32.2 33.2
1060 519
65.5 63.6
5 2
0.3 0.2
1619 816
100.0 100.0
74 17
2.7 2.3
5% 136
21.7 18.6
2075 579
75.6 79.0
1 1
0.0 0.1
2746 733
100.0 100.0
121 107
3.9 6.2
11% 706
38.8 41.0
1761 905
57.1 52.6
6 2
0.2 0.2
3084 1720
100.0 100.0
274 70
4.8 4.8
1631 395
28.8 27.2
3753 988
66.3 68.0
3 1
0.1 0.1
5661 1454
100.0 100.0
o X2test for association between urban or rural school and smoking-Boys: Kent X” d.f.=2 = 11.2, P < 0.005; Derbyshire X” d.f. = 2 = 0.3, P < 0.1; Girls: Kent X2d.f. = 2 = 2.6, P < 0.1; Derbyshire X2d.f. = 2 = 4.0. P < 0.1.
area, smokers reported more symptoms than nonsmokers for both boys and girls. Within smoking groups, urban children reported more symptoms than rural children. When smoking and area were taken into account, there was no difference in the frequency of symptoms between boys and girls.
DISCUSSION These two studies of the smoking habits and respiratory symptoms of schoolchildren aged 1&12?4 years have shown very similar results. The prevalence of smoking in Kent was close to that in Derbyshire although more children in Kent had tried a cigarette at least once. In both, more boys than girls were smoking, and in both smoking was linked to respiratory symptoms. Differences between urban and rural schools in Derbyshire were not found in Kent. In Kent, these differences were small and inconsistent, whereas in Derbyshire, urban children consistently
SMOKING
AND
RESPIRATORY
SYMPTOMS
67
IN CHILDREN
TABLE 3 KENT SCHOLL
Type of School
CHILDRENBY
Experimental smoker N %
Smoker N %
Boys Primary Secondary Modem Grammar AU secondary
DIFFERENT
TYPES OF SCHOOLS AND SMOKING
Nonsmoker N %
’
Not known N %
Total N
%
87
7.0
550
44.4
602
48.6
0
0.0
1239
100.0
80 5 85
8.6 2.5 7.6
473 86 559
51.1 42.2 49.5
372 113 485
40.2 55.4 42.9
1 0 1
0.1 0.0 0.1
926 204 1130
100.0 loo.0 100.0
26
2.3
372
32.9
729
64.4
4
0.3
1131
100.0
30 0 30
3.0 0.0 2.3
349 72 421
34.6 24.3 32.3
627 223 850
62.2 75.3 65.2
2 1 3
0.2 0.3 0.2
1008 2% 1304
100.0 100.0 loo.0
Girls Primary Secondary Modem Grammar AU secondary
0 X* tests for association between smoking and school type-Boys: primary vs secondary modem vs grammar X* d.f. = 4, = 29.94, P < 0.001; primary vs all secondary X” = 9.96, P < 0.01; grammar vs secondary modem X’ = 19.98, P < 0.001. Girls: primary vs secondary modem vs grammar X’ = 22.47, P < 0.001; primary vs all secondary X’(2) = 0.12, 0.6 < p < 0.8, grammar vs secondary modem = x2 d.f. = 2, = 22.36, P c 0.001.
TABLE 4 RESPIRATORY
SYIWTOMS
BY SEX. AREA, AND SMOKING
HABIT.
REPORTED BY KENT SCHOOLCHILDREN
urban
Rural
Smoking Symptom
SCX
Smoker N%N%N%
Experimental smoker
Nonsmoker
Significance ’
Smoker N%N%N%
EXpCrilllelltal smoker
Nonsmoker
Dot known
Significance
N
l *
7.8
Boys Girls
I2 IO
13.5 31.3
72 51
10.7 9.8
60 73
a.6 6.9
0.1 < P < 0.3 P < 0.001
I6 6
19.3 25.0
63 39
14.5 14.4
30 59
Il.4
P < 0.01 0.1 < P 4 0.3
0 0
Cough during day or night
Boys Girls
31 I7
34.8 53.1
181 146
26.8 2a.o
I68 I95
24.0 la.4
P < 0.05 P < 0.001
32 9
38.6 37.5
1311 91
31.7 33.6
90 I54
23.3 29.7
P < 0.01 O.I
