[Prevalence and risk factors for nephrolithiasis among young rural residents]

To determine the prevalence of nephrolithiasis, assess the significance of known risk factors, and identify new risk factors for nephrolithiasis among young rural residents.

This cross-sectional study was conducted in 5 settlements of the Irkutsk rural district of the Irkutsk region and involved 408 inhabitants (93 men, 315 women) aged from 18 to 47 years. The selection of candidates for the study was randomized. The response of the population was 81.6%. Diagnostic evaluation included clinical examination, renal ultrasound, urinalysis and questionnaires; drinking water hardness was determined.

The prevalence of nephrolithiasis was 10.0% (95% CI 7.1-12.9). The men-to-women ratio for the prevalence of nephrolithiasis in was 0.69. No kidney stones were found in participants younger than 20 years, but after 20 years of age, there was a statistically significant (p=0.04) trend in increasing prevalence of nephrolithiasis. Calculi were detected only in participants with acidic urine and were absent in individuals with alkaline urine (p=0.001). A higher prevalence of nephrolithiasis was found in individuals using hard water (12.5%), compared to those using water of medium hardness (1.6%) (p=0.019). The odds ratio of nephrolithiasis in persons using hard water was 8.9 (95% CI 1.2-66.6).

and conclusions 1.The incidence of nephrolithiasis in the Irkutsk rural area was 10.0%, which is comparable to that in populations of Europe and North America; 2. The primary risk factors for nephrolithiasis were age, acidic urine and the hardness of drinking water, which is consistent with the data of other authors; 3. Difficulties in measuring, grading and controlling subjective risk factors for nephrolithiasis (fluid intake, diet, heredity, and past diseases) make it difficult to analyze them in cross-sectional studies and prevent direct comparison with other studies.