Comparative Study of Serum Calcium, 24-hour Urinary Calcium, and Body Mass Index in Patients with Urolithiasis and Their First Degree Relatives

BackgroundUrolithiasis is a major public health concern worldwide, with a rising incidence in Kazakhstan. Early detection of metabolic abnormalities among first-degree relatives of affected patients may improve prevention strategies. ObjectivesTo evaluate the diagnostic significance of hypercalcemia, hypercalciuria, and body mass index (BMI) in patients with urolithiasis and their first-degree relatives as potential predictors of stone formation. MethodsA retrospective study was conducted including 180 patients with radiologically confirmed urolithiasis and 315 of their siblings. Serum calcium and 24-hour urinary calcium were measured using standard biochemical analyzers. Hypercalcemia was defined as serum calcium >2.65 mmol/L, and hypercalciuria as urinary calcium excretion >7.5 mmol/24 h in men and >6.5 mmol/24 h in women. BMI was categorized according to WHO criteria. Statistical analyses included descriptive statistics and chi-square testing (p<0.05). Written informed consent was obtained from all participants; for minors, consent was provided by their parents or legal guardians. ResultsHypercalcemia was observed in 82 patients (45.6%) and hypercalciuria in 78 (43.3%). Among siblings, hypercalcemia occurred in 32.7% and hypercalciuria in 17.1%, indicating subclinical metabolic alterations. Simultaneous hypercalcemia and hypercalciuria were detected in 64.5% of siblings of patients with hypercalcemia. Obesity/overweight was found in 80% of patients but only in 12% of siblings. Male patients with hypercalcemia showed particularly high concordance with their brothers calcium abnormalities. ConclusionsHypercalcemia, hypercalciuria, and elevated BMI are frequent abnormalities among patients with urolithiasis. A substantial proportion of siblings also exhibit latent metabolic risk factors, underscoring the role of genetic predisposition. Routine biochemical screening of first-degree relatives could aid in early detection and prevention of urolithiasis.