Figures
- Fig. 1.—
Time trends in the prevalence of asthma in the three surveys (1974, 1992 and 1998) in a) males, b) females and c) the total population by children's birth-yr. ▒: prevalence of asthma in younger children (6–9.9 yrs); □: prevalence of asthma in older children (10–13 yrs).
Tables
- Table 1—
Demographic socioeconomic characteristics of the children studied in the three surveys according to urban area of residence
Surveys 1974 1992 1998 Area A Area B Area A Area B Area A Area B Subjects n 2259 1229 1139 Demography Sex M 1154 (51.1) 635 (51.7) 561 (49.2) F 1105 (48.9) 594 (48.3) 579 (50.8) Age yrs <9.9 1098 (48.6) 611 (49.7) 620 (54.4) >10 1161 (51.4) 618 (50.3) 518 (45.6) Socio economic characteristics Living in house with >4 rooms 5.8 31.7 9.8 44.8 10.3 45.1 Father's nonmanual activity 5.6 30.0 9.2 34.8 9.6 37.7 Habitually engaging in organized sport 32.6 57.7 37.6 64.2 39.6 61.4 Household smoking (% of families consuming the given no. of cigarettes·day−1) 0–19 76.2 77.4 65.5 67.7 65.4 72.8 20–39 17.7 16.7 26.1 24.4 26.7 20.3 >39 6.1 5.9 8.4 8.0 7.9 6.9 Data are presented as n (%) or %
Urban area A: intensive housing, high buildings, chemical industries, heavy traffic, scarce green areas (lower standard of living)
Urban area B: lower and widely spaced buildings, no chemical industries, light traffic, wide green areas (higher standard of living)
significant difference between urban areas, (p<0.05, Chi-squared test)
- Table 2—
Prevalence of positive answers to questions concerning wheezing, dyspnoea and asthma
Survey year 1974 1992 1998 Subject n 2259 1229 1139 Q1 Physician diagnosis of asthma or asthmatic bronchitis 5.0 11.6 11.0 Q2 Dyspnoea on effort more easily than other children 0.9 2.6 4.1 Q3 Parent reported asthmatic attacks (attacks of breathlessness and audible wheezing) 3.6 10.8 9.4 Q4 Parent reported asthmatic attacks during the past year 1.6 4.0 3.7 Asthma 5.5 12.2 12.0 Data are presented as per cent of total population
affirmative answer to question 1 or to question 2 and 3
p<0.0001, Chi-squared test
p=ns
- Table 3—
Prevalence of asthma by environmental factors
Environmental factor Asthma prevalence % 1974 1992 1998 Household smoking habits no. cigarettes·day−1 0–19 5.1 11.3 11.6 20–39 7.0 14.1 10.3 >39 10.9 16.3 13.8 Father' occupation level Requiring university degree 5.4 12.7 13.9 Qualified, nonmanual 5.8 11.6 12.7 Manual 5.4 10.7 10.3 Number of persons in the household ≥3 7.1 12.2 10.3 4–5 5.3 12.3 12.3 ≤6 6.5 13.3 17.4 Number of rooms in the house 1–2 4.5 11.6 13.7 3–4 6.4 11.9 11.7 ≥5 6.0 13.4 10.8 Housing conditions Central heating no damp rooms 5.5 11.8 11.6 No central heating or damp rooms 6.8 13.3 19.7 No central heating and damp rooms 11.4 21.5 18.7 Area of residence A 5.1 11.6 12.7 B 6.1 11.9 12.1 Urban area A: intensive housing, highbuildings, chemical industries, heavy traffic, scarce green areas (lower standard of living)
urban area B: lower and more widely spaced building, no chemical industries, light traffic, wide green areas (higher standard of living)
significant difference, p<0.05, Chi-squared test
