Table 3—

Prevalence of asthma by environmental factors

Environmental factorAsthma prevalence %
Household smoking habits no. cigarettes·day−1
Father' occupation level
 Requiring university degree5.412.713.9
 Qualified, nonmanual5.811.612.7
Number of persons in the household
Number of rooms in the house
Housing conditions
 Central heating no damp rooms5.511.811.6
 No central heating or damp rooms6.813.319.7
 No central heating and damp rooms11.421.518.7
Area of residence
  • 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