title: Are patients with psoriasis susceptible to the classic risk factors for actinic keratoses?
abstract: BACKGROUND
  An increased prevalence of benign solar damage (eg, facial wrinkles) but not neoplastic lesions was observed among patients with psoriasis who were exposed to Dead Sea climatotherapy compared with controls.
  
  
  OBJECTIVE
  To compare the prevalence of actinic keratosis in psoriatic patients and controls and to assess whether known risk factors behave similarly in both groups.
  
  
  METHODS
  Multicenter cross-sectional study.
  
  
  METHODS
  Dermatology clinics in 4 participating Israeli hospitals and at a Dead Sea clinic.
  
  
  METHODS
  Adult subjects (n = 460) with plaque-type psoriasis were recruited from the Israel Psoriasis Association (volunteer sample) and from dermatology clinics (convenience sample). The control group (n = 738) consisted of nonimmunosuppressed patients attending these clinics for benign conditions unrelated to sun exposure, such as atopic or contact dermatitis.
  
  
  METHODS
  Prevalence and distribution of actinic keratoses and odds ratios associated with skin, hair, and eye color and propensity or history of sunburn adjusted for age, ethnicity, and sun exposure.
  
  
  RESULTS
  Actinic keratoses were observed in 200 controls (27%) and 51 subjects (11%) (P<.001). This increased prevalence occurred in both sexes, participants aged 35 years or older, all ethnic groups, smokers, and nonsmokers. The anatomical distribution of lesions did not substantially differ between subjects and controls. In multivariate analysis, psoriasis conferred a protective effect (odds ratio, <1), as did dark skin, dark eyes, and a history of severe sunburn in childhood. However, significant interactions were observed between psoriasis and hair color as well as psoriasis and propensity to sunburn, whereby a linear association was observed for controls but not for patients with psoriasis.
  
  
  CONCLUSIONS
  Psoriasis confers protection against actinic keratosis. Hair color and propensity to sunburn exert differential effects among psoriatic patients and controls.
authors.affiliation: School of Public Health, Hadassah-Hebrew University Medical Center, PO Box 12000, Jerusalem, Israel 91120. ora@vms.huji.ac.il
authors.forename: Ora
authors.initials: O
authors.lastname: Paltiel
authors.forename: Bella
authors.initials: B
authors.lastname: Adler
authors.forename: Klilah
authors.initials: K
authors.lastname: Herschko
authors.forename: Boris
authors.initials: B
authors.lastname: Tsukrov
authors.forename: Michael
authors.initials: M
authors.lastname: David
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D006200:Hair Color; D006801:Humans; D007557:Israel / Q000453:epidemiology; D007642:Keratosis / Q000150:complications / Q000453:epidemiology* / Q000208:ethnology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011565:Psoriasis / Q000150:complications / Q000453:epidemiology* / Q000208:ethnology; D012307:Risk Factors; D012720:Severity of Illness Index