DOI 10.1007/s00345-007-0177-4ORIGINAL ARTICLE Type of renal calculi: variation with age and sex

Abstract The aim of this paper is to study the variations in the percentage of the diVerent types of renal stones with age and sex. Renal calculi were classiWed according to their composition and structure. Stone formers were divided according to age and sex, and the percentage of each kind of calculi in the diVerent considered age periods for men and women were determined. It was found that calcium oxalate dihydrate calculi decreased with age, but only in men. These calculi were also clearly predominant in men. Hydroxyapatite calculi decreased with age in both men and women, but they were predominant in women. Uric acid calculi increased with age in both men and women, but were predominant in men. Finally, it was found that cal-cium oxalate monohydrate unattached calculi increased with age in both men and women. As a main novelty, the study here presented demonstrates the importance of distin-guishing between calcium oxalate monohydrate papillary stones and calcium oxalate monohydrate unattached stones, since the etiologic factors responsible for their origin must be clearly diVerent