The risk for diabetic nephropathy is low in young adults in a 17-year follow-up from the Diabetes Incidence Study in Sweden (DISS). Older age and higher BMI at diabetes onset can be important risk factors.

Aims: The main objective of this study was to estimate the occurrence of diabetic nephropathy in a population-based cohort of patients diagnosed with diabetes as young adults (15-34 years).
Methods: All 794 patients registered 1987-1988 in the Diabetes Incidence Study in Sweden (DISS) were invited to a follow-up study 15-19 years after diagnosis, and 468 (58%) participated. Analysis of islet antibodies was used to classify type of diabetes.
Results: After median 17 years of diabetes, 15% of all patients, 14% T1DM and 25% T2DM, were diagnosed with diabetic nephropathy. Ninety-one percent had microalbuminuria and 8.6% macroalbuminuria. Older age at diagnosis (HR 1.05; 95% CI 1.01-1.10 per year) was an independent and a higher BMI at diabetes diagnosis (HR 1.04; 95% CI 1.00-1.09 per 1 kg/m²), a near-significant predictor of development of diabetic nephropathy. Age at onset of diabetes (p = 0.041), BMI (p = 0.012) and HbA1c (p < 0.001) were significant predictors of developing diabetic nephropathy between 9 and 17 years of diabetes. At 17 years of diabetes duration, a high HbA1c level (OR 1.06; 95% CI 1.03-1.08 per 1 mmol/mol increase) and systolic blood pressure (OR 1.08; 95% CI 1.05 1.12 per 1 mmHg increase) were associated with DN.
Conclusions: Patients with T2DM diagnosed as young adults seem to have an increased risk to develop diabetic nephropathy compared with those with T1DM. Older age and higher BMI at diagnosis of diabetes were risk markers for development of diabetic nephropathy. In addition, poor glycaemic control but not systolic blood pressure at 9 years of follow-up was a risk marker for later development of diabetic nephropathy.
(Copyright © 2014 John Wiley & Sons, Ltd.)