Introduction. Abdominal obesity has been considered an important risk factor for the development of urolithiasis in recent years. In this paper, we investigated the influence of the degree of obesity in patients with urolithiasis on metabolic parameters and the frequency of detection of urinary stones of various chemical compositions.
Materials and methods. the mineral composition of 701 urinary concretions (from 302 men and 399 women aged 16 to 81 years) was studied by infrared spectroscopy. The degree of obesity was assessed by the body mass index (BMI) according to WHO criteria.
Results. In comparison between patients of normal body weight and patients with overweight (pre-obesity) and obesity patients showed a progressive increase in the frequency of uric acid stones as the severity of obesity increased. Thus, the frequency of uric acid stones increased from 6.4% (BMI 18.5-24.9 kg/m2 ) to 18.1% in overweight (BMI 25.0-29.9 kg/m2 ), to 31.3% in 1 obesity 1 degree (BMI 30.0-34.9 kg/m2 ), to 35.0% among patients with 2-3 degrees obesity (BMI 35.0-57.3 kg/m2 , p<0.0005). Relative to these changes, the frequency of oxalate and carbonatapatite stones decreased. In contrast to patients of normal weight, in the groups of men with overweight, obesity of the 1st degree and obesity of the 2nd3rd degree, relative risk (RR) of the formation of uric ac1id stones were 6.1, 8.9 and 10.0, respectively (p <0.0001), while in women the RR values in such groups were significantly lower (1.5,2.8 and 2.8, respectively, p <0.005). Compared with female patients, the urinary excretion of calcium, uric acid, phosphates and magnesium in male patients was significantly higher (by 1.38-1.52 times) and correlated with the degree of obesity. The dynamics of the decrease in urine pH values as the degree of obesity increases in men and women was similar. As the degree of obesity increases, men have an increase in the level of uric acid in the blood, but lower values of phosphatemia, compared with women.
Conclusion. The risk of developing the formation of uric acid stones is significantly higher in men and manifests itself already at the stage of pre-obesity (BMI 25.0-29.9 kg/m2 ), exceeding this indicator by 4 times compared to women. Metaphylaxis of uric acid urolithiasis in men with various degrees of obesity should include, in addition to measures to normalize body weight, measures to eliminate the influence of metabolic lithogenic factors caused by obesity.