Occurrence and recurrence of acute otitis media among children.

The occurrence and recurrence of acute otitis media among 37 570 Finnish children at risk who were under 15 years of age were studied. During a one-year period, 4 337 of the children experienced a total of 6 249 attacks of acute otitis media, giving an annual incidence rate of 16.6%. The highest incidence, 75.5%, was found among infants 6--11 months old. 50% of Finnish children had experienced at least one ear infection before their third birthday and 75% before the age of 10, and among this latter group the total number of otitis attacks per child-year during a lifetime was 0.71. Among children under 10, half of the index attacks were recurrences, and among children under 16, 28% of the index attacks were followed by recurrences during the study year. The highest relative recurrence rate was found during the second year of life. Before the second birthday both incidence and recurrence rates were significantly (p less than 0.001) higher among boys. Acute otitis media was most common in the higher social class families and the lowest incidence and recurrence rates were found among children of farmers.