The analyses were directed at the following: 1) Time spent in day-care and the incidence and severity of respiratory illnesses; 2) Breast-feeding and the incidence and severity of respiratory illnesses during the first six months of life; 3) Determinants of wheezing and wheezing illnesses; 4) Determinants of a physician-diagnosis of asthma; 5) Exposure to woodsmoke and incidence and severity of respiratory illnesses; 6) Household demographics, including ethnicity, and incidence and severity of respiratory illnesses; 7) Determinants of the duration of respiratory illnesses; 8) The validity of retrospective parental reports of respiratory illness; 9) Parental perceptions of the risks of indoor and outdoor air pollution; 10) Clinical findings on assessment of ill children in the community.