High Salt Intake is Associated with Renal Involvement in Japanese Patients with Type 2 Diabetes Mellitus

OBJECTIVE: The aim of our study was to investigate clinical and nutritional factors associated with renal involvement in patients with type 2 diabetes. PATIENTS: We performed a cross-sectional study of 71 patients with type 2 diabetes who were being educated at our hospital from September 2006 to February 2008. The patients were divided into two groups; Group I consisted of 40 patients with both an estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m(2) and normoalbuminuria, and Group II consisted of 31 patients with either microalbuminuria/overt proteinuria or an eGFR of <60 mL/min/1.73 m(2). We compared the age, body mass index (BMI), blood pressure, duration from onset of diabetes, use of hypoglycemic agents and insulin, biochemistry data, including HbA1c, pulse wave velocity corrected by blood pressure (PWVc) and the daily intake of several nutrients between the two groups. A multivariate logistic regression analysis was performed to identify factors independently associated with renal involvement. RESULTS: Group II had significantly higher values for BMI, the duration of diabetes, triglycerides, uric acid and PWVc than Group I. Group II tended to have a high salt intake compared to Group I. The multivariate logistic analysis revealed that the daily salt intake, PWVc and uric acid were independent factors associated with renal involvement (odds ratio, 1.15, 1.84 and 2.00; 95% confidence interval, 1.02-1.31, 1.04-3.27 and 1.04-3.85, respectively). CONCLUSION: Our data suggest that a high salt intake, in addition to arteriosclerosis, is associated with renal involvement in our cohort with type 2 diabetes.