Background. Day-care attendance has been associated with an increased risk of hospitalization for lower respiratory tract illnesses (LRIs). This study examines, in a health maintenance organization population of children, the associations between child day care and the occurrence of LRIs in the first 3 years of life. Smoking by caregivers and a possible protective effect of longer day-care enrollment in relation to LRIs are also addressed.
Methods. Information on day-care arrangements was elicited from 1006 parents of infants for five age intervals in the first 3 years of life: birth through 3 months, 4 to 6 months, 6 to 12 months, 1 to 2 years, and 2 to 3 years. Data on LRIs in the first 3 years of life were recorded by pediatricians at the time of the acute illnesses.
Results. After controlling for other risk factors, the presence of three or more unrelated children in the care setting was associated with significant risks of LRI of up to twofold or more from 4 months of age to 3 years. Type of care setting was not a significant risk factor during this time period. In the third year of life, the risk of wheezing LRI in the presence of a smoking caregiver was more than threefold for those in another residential home setting. No significant protective effect against LRIs in the third year of life associated with longer prior day-care enrollment was demonstrated.
Conclusion. The presence of three or more unrelated children in the care setting and the presence of a smoking caregiver were significant independent risk factors for LRIs during the first 3 years of life. Prolonged day-care did not protect against LRIs in the third year of life.