Epidemiologic studies of Reye's syndrome: cases seen in Pittsburgh, October 1973-April 1975.

Twenty-seven cases of Reye's syndrome (RS) were admitted over a 19-month period to one urban hospital. All lived in a suburban or rural location and 23 cases occurred during two influenza outbreaks. Two to three months following the last cases of RS, 24 families of RS cases and 21 control families representing neighbors or friends were interviewed for factors which could predispose to RS. Children with RS had an illness immediately preceding the onset of RS more frequently than did controls (p less than .001). No other clinical, familial, or environmental factors distinguished RS children and families from controls. Water samples, collected during the interviews, from 34 homes showed no potential toxins. The geographic pattern of RS cases with localization exclusively to rural areas suggests that an as yet unidentified environmental factor may be related to the development of RS.