title: Lichen sclerosus: epidemiological distribution in an equal access health care system.
abstract: OBJECTIVE
  The incidence and demographics of lichen sclerosus range from 1/300 (0.3%) to 1/1,000 individuals (0.1%). We analyzed the incidence of lichen sclerosus in an equal access health care system, hypothesizing that it is more common in older white males.
  
  
  METHODS
  We reviewed the Department of Defense electronic medical record, Armed Forces Health Longitudinal Technology Application, to determine the number of unique male patients diagnosed with lichen sclerosus between 2003 and 2009. After removing duplicate visits we determined patient age and race, and the regional distribution and overall incidence of lichen sclerosus.
  
  
  RESULTS
  Of the 42,648,923 unique male patients in the electronic medical record in this period 604 were diagnosed with lichen sclerosus (0.0014% or 1.4/100,000 visits). Age distribution was similar in the first 3 decades of life but more than doubled in the fourth through sixth decades with the highest prevalence at ages 61 or older (4.4/100,000 patients diagnosed per 100,000 visits, Pearson chi-square p <0.0001). Race distribution was Asian or Pacific Islander 0.9, black 1.4, other 1.7 and white 2.1 patients diagnosed per 100,000 visits (Pearson chi-square p = 0.003). There was a trend in the regional distribution across the United States, as defined by the Department of Health and Human Services, ranging from 0.3 diagnoses per 100,000 visits in Region 2, New York to 2.2/100,000 in Seattle (Pearson chi-square p <0.0001).
  
  
  CONCLUSIONS
  In this equal access health care system the incidence of male lichen sclerosus is 1.4 patients per 100,000 visits. It is more common in white men after the third decade of life. There is an association between region and the diagnosis of lichen sclerosus with the highest incidence in the northwestern United States.
authors.affiliation: Madigan Army Medical Center, Tacoma, Washington, USA.
authors.forename: Dayne M
authors.initials: DM
authors.lastname: Nelson
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Peterson
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D017677:Age Distribution; D000368:Aged; D052798:Balanitis Xerotica Obliterans / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology; D016009:Chi-Square Distribution; D016208:Databases, Factual; D057286:Electronic Health Records; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006801:Humans; D018459:Lichen Sclerosus et Atrophicus / Q000175:diagnosis* / Q000453:epidemiology* / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000706:statistics & numerical data; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data