title: Demographic determinants of syphilis seroprevalence among U.S. blood donors, 2011-2012.
abstract: BACKGROUND
  No cases of transfusion-transmitted syphilis have been described for over four decades. While there is mandatory transfusion screening for syphilis, the absence of transmission is in part ascribed to a low prevalence of syphilis in the blood donor population, the concomitant use of antibiotics in a high proportion of transfusion recipients, allied with poor survival of T. pallidum during refrigerated storage of blood products.
  
  
  METHODS
  A cross-sectional retrospective data analysis was conducted to ascertain the prevalence of Treponema pallidum antibodies in U.S. blood donors by demography and geography. Routine blood donation testing data and demographics were extracted from the data warehouse of a large network of U.S. blood centers. Crude and adjusted prevalence of T. pallidum antibodies and active syphilis infection were calculated, and GIS mapping was used to illustrate geographic distribution.
  
  
  RESULTS
  The prevalence of T. pallidum seropositivity and active syphilis in first time donors was 162.6 (95% CI 145.5-181.2) per 100,000 donors and 15.8 (95% CI 10.8-22.3) per 100,000 donors, respectively. The odds of T. pallidum seropositivity were significantly elevated in African American (OR = 18.9, 95% CI 14.2-25.2), and Hispanic (OR = 2.8, 95% CI 2.0-3.8) as compared to Caucasian donors. Similarly, the odds of active T. pallidum infections were significantly higher in African American (OR 15.0, 95% CI 7.0-32.3) and Hispanic (OR = 5.8, 95% CI 2.9-11.6) as compared to Caucasian donors. Syphilis seropositivity was associated with first time blood donation, increasing age, lower education, birth outside the US, and positive tests for HIV and HCV. Geographically, T. pallidum seropositivity was increased in southern and western regions of the US.
  
  
  CONCLUSIONS
  Given the low seroprevalence of syphilis in blood donors, continued screening remains debatable; however it may provide a public health benefit through surveillance of at-risk populations.
authors.affiliation: School of Public Health, University of California Berkeley, Berkeley, CA, USA. mkane11@berkeley.edu.
authors.forename: Mark Andrew
authors.initials: MA
authors.lastname: Kane
authors.affiliation: Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA, 94118, USA. ebloch@bloodsystems.org.|Department of Laboratory Medicine, University of California San Francisco, 270 Masonic Avenue, San Francisco, CA, 94118, USA. ebloch@bloodsystems.org.
authors.forename: Evan Martin
authors.initials: EM
authors.lastname: Bloch
authors.affiliation: Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA, 94118, USA. rbruhn@bloodsystems.org.
authors.forename: Roberta
authors.initials: R
authors.lastname: Bruhn
authors.affiliation: Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA, 94118, USA. zkaidarova@bloodsystems.org.
authors.forename: Zhanna
authors.initials: Z
authors.lastname: Kaidarova
authors.affiliation: Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA, 94118, USA. murphy@ucsf.edu.|Department of Laboratory Medicine, University of California San Francisco, 270 Masonic Avenue, San Francisco, CA, 94118, USA. murphy@ucsf.edu.|Department of Epidemiology/Biostatistics, University of California San Francisco, 270 Masonic Avenue, San Francisco, CA, 94118, USA. murphy@ucsf.edu.
authors.forename: Edward Laurence
authors.initials: EL
authors.lastname: Murphy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001782:Blood Donors / Q000706:statistics & numerical data*; D001803:Blood Transfusion / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology; D006526:Hepatitis C / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D016036:Seroepidemiologic Studies; D013587:Syphilis / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D014481:United States / Q000453:epidemiology