Group day care and the risk of serious infectious illnesses

Group day care attendance has been associated with an increased risk of infectious illnesses. With the exception of illnesses caused by Haemophilus influenzae type b (H. influenzae) and Neisseria Meningitidis (N. meningitidis), most studies have examined relatively mild illnesses. A matched case-control study was conducted to study the association between group day care attendance and serious infectious illnesses (requiring hospitalization). Cases were children aged 3 months to 59 months hospitalized for an infectious illness at Yale-New Haven Hospital from June 1984 through November 1986. Each case was matched to a control by date of birth and regular pediatrician, and their parents were interviewed. Data from 193 matched pairs were analyzed using conditional logistic regression. The matched odds ratio (OR) for the association between group day care attendance and serious infectious illness was 1.39 (95% confidence interval (CI) 0.87-2.20). For pairs in which the case had an H. influenzae infection (n = 46), the odds ratio was 8.00 (95% CI 1.00-63.85), and for N. meningitidis (n = 9) the odds ratio was 2.00 (95% CI 0.39-10.27). In the remaining 138 pairs, the odds ratio was 1.27 (95% CI 0.76-2.12). In infants less than 12 months of age (n = 64) the odds ratio for group day care and illnesses (excluding H. influenzae and N. meningitidis) was 1.66 (95% CI 0.73-3.80) and it was 1.06 (95% CI 0.55-2.05) for older children (n = 74). The data suggested an association between day care attendance and invasive bacterial infections other than H. influenza and N. meningitidis, OR = 2.00 (95% CI 0.81-4.94) but not for local bacterial infections, OR = 1.00 (95% CI 0.25-4.00) or infections of presumed viral etiology, OR = 1.00 (95% CI 0.49-2.05). Important predictors of serious infections (excluding H. influenzae and N. meningitidis) were passive smoking (OR = 3.96, 95% CI 2.16-7.24) and sharing a bedroom (OR = 2.31, 95% CI 1.23-4.33). These findings do not suggest that group day care attendance poses a large risk of serious infections (other than H. influenzae or N. meningitidis) to young children; however, at least one preventable factor, passive smoking, may.