title: Climatic conditions and the onset of primary spontaneous pneumothorax: an investigation of the influence of solar terms.
abstract: OBJECTIVE
  To study the correlation between climatic changes and the development of primary spontaneous pneumothorax (PSP).
  
  
  METHODS
  We retrospectively studied the relationship between 337 patients with conservatively treated PSP and meteorological conditions during a 3-year period in the urban area of Xi'an, China. The comparison was made depending on solar terms and on different aspects of atmospheric pressure, outdoor temperature, relative humidity, and wind speed.
  
  
  RESULTS
  Significant differences were found between PSP and non-PSP days depending on daily mean values of outdoor temperature and atmospheric pressure (p = 0.001 and p < 0.001, respectively). However, no obvious differences of meteorological factor variations between the 'PSP day' and the 'pre-PSP day' on days with and without PSP were found. The occurrence of PSP was associated with the solar terms Spring Equinox (p < 0.05) and End of Heat (p < 0.01).
  
  
  CONCLUSIONS
  Among the factors examined in our study, daily mean outdoor temperature and atmospheric pressure showed a strong correlation with the occurrence of PSP. The solar terms Spring Equinox and End of Heat were found to be closely related with PSP development, which shed light on a new way for PSP incidence evaluation.
authors.affiliation: Department of Thoracic Surgery, The First Affiliated Hospital, Xi'an Jiao Tong University, 277 Yanta West Road, Xi'an, China.
authors.forename: Guang-Jian
authors.initials: GJ
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Gao
authors.forename: Jun-Ke
authors.initials: JK
authors.lastname: Fu
authors.forename: Xin
authors.initials: X
authors.lastname: Jin
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D001274:Atmospheric Pressure; D002681:China / Q000453:epidemiology; D002980:Climate; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D011030:Pneumothorax / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012621:Seasons; D013696:Temperature; D014919:Wind