Diabetic nephropathy: natural history and declining incidence in diabetic children.

This report reviews data regarding diabetic nephropathy and proliferative retinopathy (PR) that were derived from three inception cohorts of insulin dependent diabetics (IDDM) under the age of 21 years at the onset of diabetes mellitus in the index years 1939, 1949, and 1959. Nephropathy occurred in only a subsegment of this population and was age dependent rather than dependent on the duration of diabetes. It occurred earlier and was more aggressive in those with poorer control of the diabetes. The cumulative incidence of nephropathy decreased significantly between 1939 and the 1949 and 1959 cohorts. Possible reasons for this decline are discussed. Similarities and differences between the occurrence of nephropathy and PR are reviewed. The findings suggest that different etiologic factors are involved in the pathogenesis of these two microvascular complications.