RISK-FACTORS FOR PRIMARY INVASIVE PNEUMOCOCCAL DISEASE AMONG CHILDRENIN FINLAND

Objective.-To study risk factors for invasive pneumococcal disease amo ng children. Design.-A population-based, case-control study of 149 cas es and 284 controls matched for age, sex, and place of residence. Sett ing.-Finland, November 1986 through November 1989. Patients and Contro ls.-Patients were identified from a prospective nationwide surveillanc e for invasive bacterial diseases among children (0 to 15 years of age ) through a network of bacteriologic laboratories. Two matched control s were selected for 135 of the cases and one matched control for 14 of the cases from the respective cases' child health center or school. Q uestionnaires evaluating potential risk factors were mailed to familie s of cases and controls. Results.-An increased risk for invasive pneum ococcal disease among children younger than 2 years was associated wit h day care center attendance (odds ratio [OR]=36; 95% confidence inter val [CI], 5.7 to 233), family day care (OR=4.4; 95% CI, 1.7 to 12), an d history of frequent otitis media (OR=8.8; 95% CI, 2.5 to 31). For th ose at least 2 years of age, existence of siblings younger than school -age indicated increased risk for invasive pneumococcal disease (OR=2. 2; 95% CI, 1.1 to 4.4). Conclusions.-Day care center attendance is a m ajor risk factor for invasive pneumococcal disease for children younge r than 2 years, with significantly higher risk than the risk associate d with family day care.