title: Epidemiological studies on the prevalence of upper urinary calculi in Taiwan.
abstract: BACKGROUND
  A nationwide survey was conducted to investigate the prevalence of upper urinary calculi in Taiwan.
  
  
  METHODS
  A postal questionnaire was mailed to 27,758 people, 0.2% of the adults in Taiwan.
  
  
  RESULTS
  Of the 4,588 valid respondents, 440 had at least one episode of upper urinary calculus disease. The overall prevalence was 9.6% (14.5% in males and 4.3% in females). Men were more prone to nephrolithiasis than women (age-adjusted prevalence of 12.2% in men and 3.1% in women, p = 0). The 'stone belt' was localized in the Midwest region of Taiwan. A gender- and age-adjusted multivariate analysis revealed that alcohol consumption and family history of kidney stone were significant risk factors for stone occurrence. Compared with general population, the odds ratios for stone disease in inhabitants whose father, mother and both parents with stone history were 3.44 [95% confidence interval (CI), 2.33-5.07], 4.79 (95% CI, 2.85-8.07) and 10.40 (95% CI, 3.75-28.84), respectively. The subtropical temperature and gradually higher socioeconomic standards of living may contribute to the high prevalence. Inhabitants in the Midwest region have higher risk to develop stones.
  
  
  CONCLUSIONS
  Further studies are needed to investigate the exact cause of these regional variations of stone prevalence. Nevertheless, the present study provides an additional piece of information on worldwide epidemiology of urolithiasis.
authors.affiliation: Division of Urology, Department of Surgery, Veterans General Hospital, Kaohsiung, Taiwan/ROC. yhlee@isca.vghks.gov.tw
authors.forename: Ying-Huei
authors.initials: YH
authors.lastname: Lee
authors.forename: Wann-Chu
authors.initials: WC
authors.lastname: Huang
authors.forename: Jeng-Yu
authors.initials: JY
authors.lastname: Tsai
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Lu
authors.forename: Wei-Chuan
authors.initials: WC
authors.lastname: Chen
authors.forename: Ming-Huei
authors.initials: MH
authors.lastname: Lee
authors.forename: Huei-Shing
authors.initials: HS
authors.lastname: Hsu
authors.forename: Jong-Khing
authors.initials: JK
authors.lastname: Huang
authors.forename: Luke S
authors.initials: LS
authors.lastname: Chang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013624:Taiwan / Q000453:epidemiology; D014545:Urinary Calculi / Q000453:epidemiology*