title: Prevalence and risk factors for anal squamous intraepithelial lesions in women.
abstract: BACKGROUND
  Anal cancers are thought to arise from squamous intraepithelial lesions in the anal canal, and women infected with human immunodeficiency virus-1 (HIV) may be at higher risk of anal cancer. Our aim was to determine the prevalence of human papillomavirus (HPV)-related abnormalities of the anal canal in women and to characterize risk factors for these lesions.
  
  
  METHODS
  We evaluated HPV-related abnormalities in 251 HIV-positive and in 68 HIV-negative women. We completed physical examinations and obtained questionnaire data on medical history and relevant sexual practices. Univariate and adjusted relative risks (RRs) and 95% confidence intervals (CIs) were computed using the Mantel-Haenszel procedure and regression techniques. All statistical tests were two-sided.
  
  
  RESULTS
  Abnormal anal cytology, including atypical squamous cells of undetermined significance, low-grade squamous intraepithelial lesions, or high-grade squamous intraepithelial lesions (HSILs), was diagnosed in 26% of HIV-positive and in 8% of HIV-negative women. HSILs were detected by histology or cytology in 6% of HIV-positive and in 2% of HIV-negative women. HIV-positive women showed increased risk of anal disease as the CD4 count decreased (P<.0001) and as the plasma HIV RNA viral load increased (P =.02). HIV-positive women with abnormal cervical cytology had an increased risk of abnormal anal cytology at the same visit (RR = 2.2; 95% CI = 1.4 to 3.3). Abnormal anal cytology in HIV-positive women was associated with anal HPV RNA detected by the polymerase chain reaction and by a nonamplification-based test (RR = 4.3; 95% CI = 1.6 to 11). In a multivariate analysis, the history of anal intercourse and concurrent abnormal cervical cytology also were statistically significantly (P =.05) associated with abnormal anal cytology.
  
  
  CONCLUSIONS
  HIV-positive women had a higher risk of abnormal anal cytology than did HIV-negative women with high-risk lifestyle factors. These data provide strong support for anoscopic and histologic assessment and careful follow-up of women with abnormal anal lesions.
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco 94143-1228, USA. eaholly@epi.ucsf.edu
authors.forename: E A
authors.initials: EA
authors.lastname: Holly
authors.forename: M L
authors.initials: ML
authors.lastname: Ralston
authors.forename: T M
authors.initials: TM
authors.lastname: Darragh
authors.forename: R M
authors.initials: RM
authors.lastname: Greenblatt
authors.forename: N
authors.initials: N
authors.lastname: Jay
authors.forename: J M
authors.initials: JM
authors.lastname: Palefsky
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000473:pathology; D000704:Analysis of Variance; D001005:Anus Neoplasms / Q000453:epidemiology*; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology*; D016001:Confidence Intervals; D004522:Educational Status; D005006:Ethnicity; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000453:epidemiology; D018023:HIV Seronegativity; D006679:HIV Seropositivity / Q000453:epidemiology; D006801:Humans; D007182:Income; D017533:Marital Status; D008487:Medical History Taking; D008875:Middle Aged; D027383:Papillomaviridae / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000150:complications* / Q000453:epidemiology; D015995:Prevalence; D044469:Racial Groups; D012044:Regression Analysis; D012306:Risk; D012307:Risk Factors; D012495:San Francisco / Q000453:epidemiology; D012725:Sexual Behavior; D012959:Socioeconomic Factors; D019966:Substance-Related Disorders / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014412:Tumor Virus Infections / Q000150:complications / Q000453:epidemiology