title: Seasonal variability in the biophysical properties of forehead skin in women in Guangzhou City, China.
abstract: BACKGROUND
  Skin appearance is influenced by biophysical parameters. Seasonal changes affect the condition of normal skin and may trigger cutaneous disorders.
  
  
  OBJECTIVE
  This study was undertaken to measure the effects of seasonal changes on biophysical parameters in the skin of female subjects living in Guangzhou City in southern China.
  
  
  METHODS
  A cross-sectional study was conducted in 178 healthy, adult Chinese women in whom forehead skin was examined in all four seasons between March 2007 and February 2008. Commercially available, non-invasive devices were used to measure skin hydration, sebum content, pH, and transepidermal water loss (TEWL) in a closed environment under controlled and constant conditions of temperature and humidity. Correlations between skin parameters and climate conditions were investigated.
  
  
  RESULTS
  There were significant seasonal changes in TEWL and pH (autumn and winter > spring and summer), skin hydration (spring and summer > autumn and winter), and sebum content (spring and summer > autumn and winter). Skin hydration was correlated with average temperature and humidity. Skin TEWL and skin pH were correlated with average temperature, humidity, and ultraviolet (UV) radiation levels. Skin sebum content was correlated with average humidity.
  
  
  CONCLUSIONS
  Facial skin physiology showed seasonal variations in China. The reasons for the changes may refer to seasonal changes in temperature, humidity, and UV radiation.
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Miao-Jian
authors.initials: MJ
authors.lastname: Wan
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Su
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Zi-Jian
authors.initials: ZJ
authors.lastname: Gong
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Jin-Ling
authors.initials: JL
authors.lastname: Yi
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Guan
authors.affiliation: Department of Dermatology, Third Affiliated Hospital of Sun Yat-San University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Lai
mesh_terms: D000328:Adult; D055592:Biophysical Phenomena; D002681:China; D003430:Cross-Sectional Studies; D005260:Female; D005546:Forehead; D006801:Humans; D006813:Humidity; D006863:Hydrogen-Ion Concentration; D012621:Seasons; D012629:Sebum / Q000378:metabolism; D012867:Skin / Q000737:chemistry / Q000378:metabolism*; D012879:Skin Physiological Phenomena; D013696:Temperature; D014867:Water / Q000378:metabolism*; D014870:Water Loss, Insensible; D055815:Young Adult
chemical_list: D014867:Water