title: Combined effects of HLA-Cw6, body mass index and waist-hip ratio on psoriasis vulgaris in Chinese Han population.
abstract: BACKGROUND
  Psoriasis is a chronic inflammatory skin disease associated with an HLA-Cw6 allele. Higher waist-hip ratio (WHR) and body mass index (BMI) may increase the risk of psoriasis vulgaris, but, to our knowledge, no evidence of the combined effects of HLA-Cw6 and BMI, WHR are available.
  
  
  OBJECTIVE
  To evaluate the combined effect of HLA-Cw6, BMI and WHR on psoriasis vaulgaris.
  
  
  METHODS
  The data of 466 patients and 177 controls were investigated and analyzed by a hospital-based case-control study and non-condition logistic regress model.
  
  
  RESULTS
  There was a graded positive association of WHR and BMI with psoriasis vulgaris. Compared with a WHR of 0.80 or less than 0.80, the odds ratio (OR) was 2.36 (p < 0.01) for WHR 0.80-0.85, and 2.74 (p < 0.01) for WHR greater than 0.85. Compared with subjects with a BMI of 20 or less than 20, the multivariate OR of psoriasis were 1.20 (p > 0.05) for a BMI of 20-25, 1.84 (p < 0.05) for a BMI of more than 25 corresponding overweight (p for trend, <0.01). We found not only the risk of psoriasis for the individual with HLA-Cw6+ was 8.33 times greater than that for individual with HLA-Cw6(-) but also the risk increased approximately 35 times in individuals with HLA-Cw6+ and a overweight as compared with one with HLA-Cw6(-) and a non-overweight, and 17-fold when the individuals with HLA-Cw6+ and a WHR of more than 0.80 were compared with individuals with HLA-Cw6(-) and a WHR of 0.80 or less than 0.80, displaying the combined effect of HLA-Cw6, BMI and WHR (all p < 001).
  
  
  CONCLUSIONS
  This study suggested that HLA-Cw6, overweight and higher waist-hip ratio are material risk factors of psoriasis vulgaris, specially the combined effects of HLA-Cw6 and BMI, WHR on psoriasis vulgaris in Chinese population.
authors.affiliation: Institute of Dermatology and Department of Dermatology at the First Affiliated Hospital, Anhui Medical University, Hefei, China.
authors.forename: Yongtang
authors.initials: Y
authors.lastname: Jin
authors.forename: Fengyu
authors.initials: F
authors.lastname: Zhang
authors.forename: Sen
authors.initials: S
authors.lastname: Yang
authors.forename: Yunming
authors.initials: Y
authors.lastname: Kong
authors.forename: Fengli
authors.initials: F
authors.lastname: Xiao
authors.forename: Yong
authors.initials: Y
authors.lastname: Hou
authors.forename: Xing
authors.initials: X
authors.lastname: Fan
authors.forename: Xuejun
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D044466:Asian People / Q000208:ethnology / Q000235:genetics; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002681:China; D005260:Female; D020022:Genetic Predisposition to Disease / Q000208:ethnology / Q000235:genetics; D015236:HLA-C Antigens / Q000235:genetics*; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000208:ethnology; D011565:Psoriasis / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics; D012307:Risk Factors; D049629:Waist-Hip Ratio / Q000706:statistics & numerical data*
chemical_list: D015236:HLA-C Antigens; C528994:HLA-C*06 antigen