The demographic profile of urolithiasis in Iran: a nationwide epidemiologic study.

OBJECTIVE: The marked variations in urinary stone disease prevalence by age, gender, race, and geographic location may provide clues to their etiology and prevention. We investigated the demographic profile of urolithiasis across Iran to draw out implications for national healthcare policies.

MATERIALS AND METHODS: In a nationwide multi-center epidemiologic study from September 2006 to August 2007, a multi-stage stratified sampling was taken in 12 ecologic zones across Iran during four seasons. 6,089 imaging-proven cases were identified out of 117,956 referrals to the radiologic centers. The demographic characteristics of positive cases were determined by a detailed questionnaire. Target population characteristics were derived from the most recent formal national census (2006).

RESULTS: Male-to-female ratio was 1.38 (male: 58%, female: 42%). Uneducated people ratio was significantly greater among stone formers. (Mean difference = 10.4%, 95% CI = 9-12%).Mean age at presentation was 41.5 years +/- 16.3 and the peak incidence range was between 55 and 65 years. The most frequent co-existence diseases were hypertension (15.8%) and diabetes (11.4%). It ranged from 2.8 to 21.3 for diabetes and 6.1 to 30.4 for hypertension compared to 1 to 4.2% and 4 to 7.7, respectively, in the general population. Surprisingly, the number of current smokers among stone formers was significantly less than the general population. BMI failed to show a significant correlation.

CONCLUSIONS: The putative risk factors for urinary stone disease were male gender, hypertension, diabetes mellitus, and lack of education. Preventive strategies based on indigenous demographic data may have a role in public healthcare policies.