HealthDay News — Children experience a median of 14 infections during their first three years of life, though there is large variation in incidence, according to a study published online May 24 in Pediatrics.
Nadja Hawwa Vissing, M.D., Ph.D., from the University of Copenhagen in Denmark, and colleagues assessed the frequency and risk factors of childhood infections during the first three years of life among 334 children participating in the Copenhagen Prospective Studies on Asthma in Childhood 2000 birth cohort.
The researchers found that children experienced a median of 14 infectious episodes (range two to 43) from ages 0 to 3 years. The number of children in the day care and the physical space per child in the day care were associated with the overall rate of infections (adjusted incidence rate ratio [aIRR], 1.09 and 0.96, respectively) and upper respiratory infections (aIRR, 1.11 and 0.95, respectively). Lower respiratory infections were associated with cesarean section (aIRR, 1.49), maternal smoking (aIRR, 1.66), older siblings (aIRR, 1.54), and the age at entry to day care (aIRR, 0.77).
“Environmental exposures only explained a small fraction of the variation, suggesting host factors as major determinants of infectious burden,” the authors write.