The relationship between insulin, insulin resistance, parathyroid hormone, cortisol, testosterone, and thyroid function tests in the presence of nephrolithiasis: a comprehensive analysis

INTRODUCTION Previous studies have shown that hormonal factors such as levels of insulin, cortisol, testosterone, and insulin resistance are related with increased nephrolithiasis (NL). However, no previous study has evaluated the relationship between insulin, insulin resistance, thyroid hormones, cortisol, intact parathyroid hormone and testosterone levels with the presence of NL in a comprehensive manner. MATERIALS AND METHODS ALL PATIENTS UNDERWENT THE FOLLOWING PROCEDURES: history taking, physical examination, biochemical analysis [including measurement of levels of insulin, thyroid hormones, cortisol, and total testosterone (for male patients only)], urine analysis, 24-hour urine collection to measure urinary protein, sodium excretion, and creatinine clearance. Insulin resistance was evaluated by the homeostasis model assessment index (HOMA-INDEX). The presence of NL was determined by ultrasonography. RESULTS The study was composed of 136 patients. In total, 30 patients had NL. Patients with NL were more likely to be older, male, obese, and smokers. Uric acid and HOMA-INDEX were also higher in patients with NL. In the whole group, only insulin (Odds ratio:1.128, CI:1.029-1.236, P:0.01) but not other hormones, and HOMA-INDEX were related with the presence of NL. In males, none of the hormones including total testosterone were associated with NL. CONCLUSIONS Only levels of insulin, but not other hormones were associated with the presence of NL in a group of patients with suspicion of NL. More studies are needed to highlight the mechanisms regarding NL and hormone levels.