Gender and Age Characteristics of the Mineral Composition of Urinary Stones in Patients with Urolithiasis
Authors:   Kharkiv National Medical University. 4, Nauky Avenue, Kharkiv 61022, Ukraine, Kolupayev S. M. , Bereznyak E. P. ,   National Science Center Kharkov Institute of Physics and Technology. 1, Akademicheskaya St., Kharkov, 61108, Ukraine
Published: December 2020

The paper presents the results of studying the features of the mineral composition of urinary stones obtained after spontaneous passage, as well as the use of minimally invasive surgical techniques. Material and methods. The study involved 61 patient with urolithiasis, depending who were examined depending on the sex and age of the patients. Infrared spectroscopy in the spectral range of 4000-400 cm-1 was used as a method for assessing the mineral composition of the stone. The next stage of the study consisted of analyzing the occurrence of stones of various mineral types in groups of patients with different gender and age characteristics. Results and discussion. Infrared spectroscopy identified a wide range of chemical compounds in urinary stones, in which calcium oxalate in the form of monohydrate (vevelite) or dihydrate (vedelite), calcium phosphate in the form of hydroxylapatite and uric acid were most often identified. Calcium carbonate, aragonite, struvite, ammonium urate, and cystine were detected in single samples. 45 patients (73.77%) had a mixed composition of the stone, consisting of two or more mineral components. Depending on the prevailing component, which is more than 50% vol. the sample, urinary stones were classified into 3 mineral types: type 1 – calcium oxalate calculi, the prevailing component of which is calcium oxalate in the form of monohydrate (vevellite) or dihydrate (veddelite); Type 2 – calcium phosphate, in which more than 50% vol. represented by apatite, hydroxylapatite or fluorapatite; Type 3 – stones, the dominant substance of which is uric acid or uric acid dihydrate. Most of the urinary stone samples were represented by type 1 stones, which were significantly more often detected in males. The study of gender dependence in the prevalence of stones of types 2 and 3, corresponding to these minerals, was not identified. Type 1 urinary stones were observed in all age categories, with a predominance in patients aged 30-39 years (41.38%). The age distribution of stones of type 2 had similar characteristics, while the maximum number of patients with this type of stone was noted in the age range of 40-49 years (40%), followed by a decrease in this indicator in older age groups. The minimum number of cases of type 3 stone formation was registered among patients aged 30-39 years (8.33%). In the following age periods, the quantitative presence of this type of stones increased with a maximum value in the age range of 50-59 years (41.67%). Conclusion. The mineral composition of urinary stones has features, depending on the sex and age of patients. The formation of oxalate-calcium urinary stones is most characteristic of men, the peak incidence occurs at the age of 40-49 years. Gender features of the distribution of stones, the dominant components of which are calcium phosphate and uric acid were not detected. The frequency of detection of uric acid stones increases with age, the inverse relationship is characteristic of the age distribution of phosphate-calcium stones