Early-life protective effects associated with attending day care at a young age, seen in children with parents with a history of atopy, also begin early.
Protection against atopy likely begins by two years of age but, a similar protective effect against wheezing could be delayed until the children are four years old.
United States researchers explain early day-care attendance is associated with increased risks for both upper respiratory tract infection (URI) and lower respiratory tract infection (LRI) in early life. Such illnesses may be partly responsible for the observed protective effect of day care attendance on the development of childhood asthma.
Investigators from Brigham and Women's Hospital, Beth Israel Deaconess Medical Centre and Harvard University in Boston, Massachusetts say, "Among children with a parental history of atopy, the association between illnesses of the respiratory track in the first year of life and wheezing in the first four years of life may be due to infections and/or may be the early manifestation of an atopic predisposition."
The researchers examined exposure to day care as well as both URIs and LRIs in 505 infants enrolled in a prospective birth study in Boston. Participants' parents had a history of asthma or allergy. Children were enrolled between September 1994 and August 1996.