Diabetic nephropathy: a risk factor for diabetes mellitus in offspring.

Both non-insulin-dependent diabetes mellitus and diabetic nephropathy show familial aggregation. If diabetes and renal disease have independent determinants (genetic or otherwise), offspring of parents with diabetic renal disease should have a similar risk of diabetes to those offspring of parents with diabetes alone. To test this hypothesis, the prevalence of diabetes was examined in a population-based pedigree study in Pima Indian offspring of three mutually exclusive parental types: 1) diabetic with renal disease, 2) diabetic, but without renal disease and 3) non-diabetic. Among offspring of one diabetic parent and one non-diabetic parent (n = 320) the prevalence of diabetes at ages 15-24 years and 25-34 years was 0% and 11%, respectively if the diabetic parent did not have renal disease compared with 6% and 28% respectively if the diabetic parent did have renal disease. Corresponding rates for offspring of two diabetic parents (n = 121) were 10% and 17%, respectively if neither parent had renal disease compared with 30% and 50%, respectively if one parent did have renal disease. The presence of renal disease in a parent with diabetes relative to diabetes alone was associated with 2.5 times the odds of diabetes (95% confidence interval 1.4-4.3) in the offspring controlled for age, age at onset of parental diabetes and diabetes in the other parent using logistic regression. These findings provide support for parental diabetic renal disease, independent of age at onset of parental diabetes, conferring an increased risk for diabetes in the offspring.(ABSTRACT TRUNCATED AT 250 WORDS)