Associations of Insulin Resistance and Glycemic Control with the Risk of Kidney Stones

Objective: The associations of insulin resistance and glycemic control with the risk of kidney stones were explored.

Methods: Generally healthy Japanese (n=2,171) who visited Saiseikai Central Hospital (Tokyo, Japan) for a health check were included in a cross-sectional study. We calculated odds ratios (OR) of having kidney stones in terms of four measures: fasting serum insulin, homeostasis model assessment of insulin resistance (HOMA-IR), fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c), adjusting for possible risk factors for kidney stones.

Results: Fasting serum insulin and HOMA-IR were non-significantly associated with the risk of kidney stones, whereas FPG and HbA1c were significantly associated. Compared with those with an FPG of <100 mg/dL, the ORs in those with an FPG of 100 to <126 mg/dL and ≥126 mg/dL were 1.38 (95% confidence interval [CI] =0.95-2.00) and 1.83 (95% CI =1.09-3.06) (p for trend =0.016). In relation to those with an HbA1c of <5.5%, the ORs in those with an HbA1c of 5.5 to <6.0%, 6.0% to <6.5% and ≥6.5% were 1.16 (95% CI =0.76-1.79), 1.25 (95% CI =0.70-2.23) and 1.98 (95% CI =1.11-3.52), respectively (p for trend =0.027). The significant associations between glycemic control measures and the risk of kidney stones were preserved even after the adjustment for factors related to insulin resistance.

Conclusion: Glycemic control could be an independent risk factor for kidney stones.