Introduction: Prevalence of the kidney stones (renal calculi) increase in several countries in parallel with the increase of overweight, diabetes (type 2 diabetes) and hypertension. Goal: The goal of our research was to evaluate the connection between the calcium nephrolithiasis and overweight, as quantified using the Body Mass Index (BMI) of the adult population, with a particular reflection on the age groups within it. Material and methods: The research was prospective and it was implemented at the Clinical Center of Banja Luka, at the Urology Clinic in the period from 1st April 2012 to 1st January 2013. The trial encompassed 120 patients with calcium nephrolithiasis of the upper part of the urinary tract and 120 patients without nephrolithiasis. A group of patients with the calcium nephrolithiasis presented a working group, while a group of patients without nephrolithiasis presented a control group. The BMI obtained on the basis of bodily weight and height of the patient, where the age and sex of specific reference values of the BMI were developed by the Center for Disease Control and Prevention (CDC) were not used in the calculation of the BMI. Results: Analyzing the values of the BMI in relation to age groups, where there was a statistically significant difference in the working group, whereas in the control group there was a statistically high significant difference, testing of statistical significance of the average value of the BMI was done by observed age groups of working and control group, as well as to the total sample of work and control group using the ChiSquare test and Ttest for independent samples. Having observed the age group of 2040 years, statistically significant differences have been noted at the level of risk of 10%, which confirms that there is a connection between the categories of the BMI and the group, which the patient comes from (ChiSquare test p0.05), that is, Ttest has shown that the values are different at the level of 10%, i.e. p0.05 (ttest p=0.314). In addition to this, the average BMI values are not significantly different, p>0.05 (ttest p=0.871). Having observed the age group of the older than 60, there was no dependency between the category of the BMI and the group, that is, the differences are not statistically significant, p>0.05 (Chisquare test p=0.167). Having observed the total sample of the working and control group, there was no dependency of the category of the BMI and the group (or urolithiasis), p>0.05 (ChiSquare test p=1.208), whereas the results of the Ttest showed that there was no statistically significant difference of the arithmetic mean values of the BMI working group and control group, p>0.05 (ttest p=0.620). Conclusion: Overweight in younger age groups of adult population may be connected to the
Key words: urolithiasis, calcium kidney stone (renal calculi), overweight, Body Mass Index.
