Reye's syndrome: incidence and time trends in Olmsted County, MN, 1950-1981.

Incidence and time trends of Reye's syndrome have been determined in Olmsted County, MN, using the facilities of the Rochester Epidemiology Program Project at Mayo Clinic. Incidence rates in individuals under 18 years of age were 1.1 per 100,000 person-years in the 1970-75 time interval and 1.7 in the 1976-81 interval. Failure to identify any case in the earliest time interval yields a rate of zero, and an incidence higher than 0.6 per 100,000 can be excluded with 95% probability. This finding is consistent with an increasing incidence over time in this community and does not exclude the possibility that Reye's syndrome did not exist in Olmsted County before 1970.