Daycare attendance has been associated with an increased occurrence of respiratory illness, but little is known about which children are at particular risk. Our objectives were to determine the association between the incidence of respiratory illness and attendance in daycare, and to determine if the risk is modified by selected sociodemographic factors. Using a prospective study design, 185 newborns in Prince Edward Island, Canada, were recruited between January 1997-March 2000. They were followed for 2 years or until the end-date of the study in September 2000. Information on daycare attendance and respiratory illness was collected twice monthly by telephone interviews of the parent. Comparing those who were ever in daycare more than 1 day per week (daycare group) to those who were not, the association between daycare and illness was stronger among children 15 months of age compared to those less than 3 months of age (P < 0.001), and stronger among those without siblings than those with siblings (P < 0.001). Among those not in daycare, family income was inversely related to the proportion of days with an illness episode: 9.8% (CI, 6.0, 13.6) if family income was < $30,000 vs. 5.2% (CI, 4.1, 6.3) if > or = $30,000 (P = 0.003). However, in the daycare group, income did not influence illness, with respective values of 14.6% (CI, 12.4, 16.8) vs. 13.2% (CI, 12.1, 14.3) (P = 0.21). In conclusion, younger children and those with siblings may be less susceptible to illness associated with daycare, and daycare attendance may negate a protective effect of higher income on respiratory illness.
Copyright 2004 Wiley-Liss, Inc.