title: Multivariate Analyses of Urinary Calculi Composition: A 13-Year Single-Center Study.
abstract: BACKGROUND
  The incidence and prevalence of urinary stone are increasing throughout the world. Compared to the past, recent demographics of patient with urolithiasis compositions are strikingly different. Furthermore, recent clinical studies implied that seasonal cyclicity might influence the distribution of stone composition.
  
  
  METHODS
  We sought to determine the trends in pathogenesis of urolithiasis based on urinary stone analyses. Between 2002 and 2014, a total of 2,383 eligible urinary stone samples from different patients were collected in our center. Infrared spectroscopy was used for urinary calculi analysis. A logistic regression analysis was used to investigate the relationship between urinary calculi composition and calendar month (season), gender, and age in north China during the past 13 years.
  
  
  RESULTS
  Calcium-containing calculi were the most frequent with an overall incidence of 84.1%. Calcium phosphate (CaP) or magnesium ammonium phosphate (MAP) stones were more frequent in females, while monohydrate calcium oxalate (COM), dihydrate calcium oxalate (COD), or uric acid (UA) stones were more common in males. Older individuals were associated with an increased risk of UA stones and a decreased risk of COD, CaP, or cystine stones. Additionally, from 2002 to 2014, the frequency of COD and MAP stone increased, whereas the trend of CaP, UA and cystine stones decreased. However, calendar month (season) was not significantly associated with differences in composition.
  
  
  CONCLUSIONS
  This study provides the present distribution of urolithiasis compositions in China. From 2002 to 2014, age and gender were significantly associated with stone composition, whereas calendar month was not.
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Xiong
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Changwen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Shiyong
authors.initials: S
authors.lastname: Qi
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Qiduo
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Chunyu
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Kuo
authors.initials: K
authors.lastname: Yang
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: E
authors.initials: E
authors.lastname: Du
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Urology, Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People's Republic of China. prof.yongxu@hotmail.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002129:Calcium Oxalate / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002681:China; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012044:Regression Analysis; D012621:Seasons; D012737:Sex Factors; D000069877:Struvite / Q000032:analysis; D014545:Urinary Calculi / Q000737:chemistry* / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D002130:Calcium Phosphates; D002129:Calcium Oxalate; C020243:calcium phosphate; D000069877:Struvite
keywords: China; age groups; seasons; sex; urolithiasis