THE INDOOR AIR AND CHILDRENS HEALTH STUDY - METHODS AND INCIDENCE RATES

The Indoor Air and Children's Health Study is a prospective cohort stu dy of the relation between indoor air pollution and lower respiratory illness (LRI) during the first 2 years of life. information on family and household characteristics was obtained from a health maintenance o rganization for 1,424 infants enrolled at birth. Data on LRI were abst racted from medical records. The incidence of all LRI was 48.4 per 100 child-years. Wheezing associated respiratory illness (WARI)/asthma wa s the most common specific LRI, with an incidence of 11.5 per 100 chil d-years. Total LRI incidence was lowest during the first 5 months of l ife. Girls had lower incidence than boys [rate ratio (RR) = 0.8; 95% c onfidence interval (CI) = 0.7-0.8)]. With the exception of croup, all LRI were most common during February and March. These results are comp arable with those of other prospective studies. Consistent with other studies, self-reported maternal smoking demonstrated an RR of 1.5 (95% CI = 1.2-1.8) for total LRI, but the association varied for specific LRIs from 2.3 (95% CI = 1.5-3.0) for WARI/asthma to 1.0 (95% CI = 0.7- 1.6) for bronchitis.