Age, Sex, and Season of Onset of Juvenile Diabetes in Different Geographic Areas

Abstract

Age, sex and estimated time of onset of insulin-dependent diabetes were determined for children in Pittsburgh [Pennsylvania, USA] (N = 673), Gainesville [Florida, USA] (N = 976), Galveston [Texas, USA] (N = 741) and Melbourne [Australia] (N = 851). The USA cities had a decrease in new cases during the summer and peak incidence in Jan. through April. In Melbourne, monthly trends were reversed; there were more cases during May through Aug. In USA cities, but not in Melbourne, children less than 6 yr old showed a greater variation by season than children 6 yr old and older. Observations of the same fall and winter onset (in different calendar months) of insulin-dependent diabetes in Australia and the USA, and exaggeration of seasonal differences in young USA children, suggest that onset of insulin-dependent diabetes is associated with seasonally varying viral diseases. Mumps and rubella infections do not seem responsible for much of the seasonal variation. Seasonal peaks of mumps and rubella are later than those observed for insulin-dependent diabetes, and immunization with live mumps and rubella viruses is not associated with changes in incidence of insulin-dependent diabetes. An increase in disease incidence in boys over girls below age 6 yr and in girls over boys at ages 6-11 yr was consistently observed but not explained.