title: Rise in ambient temperature predisposes aging, male Japanese patients to renal colic episodes due to upper urolithiasis.
abstract: OBJECTIVE
  Urolithiasis is a common urological problem, and its incidence has been increasing worldwide, including in Japan. Relationships between stone etiology and rise in ambient temperature have been reported, but it remains unclear how age and gender affect these relationships.
  
  
  METHODS
  A retrospective examination was conducted of the medical archives of 1005 patients (aged ≥15 years) with acute renal colic diagnosed with urolithiasis upon image examination who consecutively visited emergency departments in three hospitals. The patients were categorized into six groups according to age: younger than 30, 30-39, 40-49, 50-59, 60-69, and 70 years and older. The net difference and fold increase in the number of patients in summer (July to September) versus in winter (December to February) were calculated.
  
  
  RESULTS
  Overall, the actual number of the patients varied according to the temperature rise throughout the year and among the age groups. Net increases in the number of patients were observed in all age groups for both genders, apart from 30-39-year-old women. The age group of 50-59 years considerably outnumbered all other groups. A significant statistical correlation was detected between the fold increase and male aging using Spearman's rank correlation analysis (ρ = 0.94, p = 0.017), but not in females (ρ = -0.03, p = 1).
  
  
  CONCLUSIONS
  These results support a positive association between ambient temperature rise and increase in the incidence of renal colic due to urolithiasis in Japan, and indicate that aging and gender affect the association differently.
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Ichiyanagi
authors.affiliation: b Department of Urology , Nihonkai General Hospital , Sakata City , Yamagata Prefecture , Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Fukuhara
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Sei
authors.initials: S
authors.lastname: Naito
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Nishida
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kurokawa
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ito
authors.affiliation: b Department of Urology , Nihonkai General Hospital , Sakata City , Yamagata Prefecture , Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kakizaki
authors.affiliation: c Department of Urology , Yamagata Prefectural Shinjo Hospital , Shinjo City , Yamagata Prefecture , Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Muto
authors.affiliation: c Department of Urology , Yamagata Prefectural Shinjo Hospital , Shinjo City , Yamagata Prefecture , Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kato
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nagaoka
authors.affiliation: a Department of Urology , Yamagata University Faculty of Medicine , Yamagata City , Yamagata Prefecture , Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Tsuchiya
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015984:Causality; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D007669:Kidney Calculi / Q000150:complications*; D007682:Kidney Pelvis; D008297:Male; D008875:Middle Aged; D056844:Renal Colic / Q000453:epidemiology* / Q000209:etiology*; D012189:Retrospective Studies; D012621:Seasons; D012737:Sex Factors; D013696:Temperature; D014514:Ureteral Calculi / Q000150:complications*
keywords: Elderly; male; renal colic; temperature; urinary stone