SOCIOECONOMIC-STATUS AND LUNG-FUNCTION AMONG PRIMARY-SCHOOL CHILDREN IN CANADA

We examined the relationship of lung function level to socioeconomic s tatus (SES) using a cross-sectional design among 989 primary school ch ildren selected from 18 Montreal schools and studied between April 199 0 and November 1992. Information on each child's health, demographics, home exposure to tobacco smoke, pets, and cooking and heating fuel us ed in the child's home was collected by questionnaire. Spirometry was performed at school. Parental occupation was used to establish SES. Af ter adjusting for personal, familial, and environmental factors, in bo ys but not in girls, FEV(1) and FVC were progressively larger in highe r categories of SES (p < 0.001 for linear trend). After taking into ac count the effect of multiple comparisons and adjusting for personal, f amilial, and environmental factors, boys from families in the lowest c ategory of SES were found to have an FEV(1) lower by 8.2% (95% CI, -13 .8 to -2.1) and an FVC lower by 8.1% (95% CI, -13.4 to -2.6) when comp ared with the most advantaged. These results provide evidence that soc ioeconomic status, independent of common indoor exposures, is a risk f actor for lower FEV(1) and FVC among boys.