title: A population-based study on the association between urinary calculi and kidney cancer.
abstract: BACKGROUND
  Using a nationwide population-based dataset and case-control study design, we investigate the association between urinary calculi (UC) and kidney cancer (KC) in Taiwan.
  
  
  METHODS
  The data for this case-control study were sourced from the Taiwan National Health Insurance program. The cases included 1308 incident patients pathologically diagnosed with KC. This study also used 6540 randomly selected subjects as controls. Conditional logistic regression was used to examine the associations between KC and patients previously diagnosed with UC.
  
  
  RESULTS
  Of the sampled patients, 1262 (16.1 %) had previously been diagnosed with UC; 415 (31.7 % of the patients with KC) and 847 controls (13.0 % of patients without KC). After adjusting for monthly income, geographic location, urbanization level, hypertension, diabetes, renal disease, obesity, cystic kidney disease, tobacco use disorder, and alcohol abuse, we found that patients with KC were likely to have been previously diagnosed with UC than controls (odds ratio [OR] 3.18, 95% confidence interval [CI] 2.75-3.68, p < 0.001). In addition, the magnitude of the observed associations were stronger among females (females OR 3.59; 95% CI 2.87-4.48 vs. males OR 2.93, 95% CI 2.42-3.55) and transitional cell carcinoma patients (transitional cell carcinoma, OR 3.96; 95% CI 3.23-4.86 vs. renal cell carcinoma OR 2.76, 95% CI 2.31-3.29).
  
  
  CONCLUSIONS
  We conclude that there is an association between KC and prior UC, especially in females and patients with transitional cell carcinoma.
authors.affiliation: Division of Urology, Department of Surgery, Far Eastern Memorial Hospital, Ban Ciao, Taipei, Taiwan; ; Sleep Research Center, Taipei Medical University Hospital, Taipei, Taiwan;
authors.forename: Shiu-Dong
authors.initials: SD
authors.lastname: Chung
authors.forename: Shih-Ping
authors.initials: SP
authors.lastname: Liu
authors.forename: Herng-Ching
authors.initials: HC
authors.lastname: Lin