title: Increased mortality associated with HTLV-II infection in blood donors: a prospective cohort study.
abstract: BACKGROUND
  HTLV-I is associated with adult T-cell leukemia, and both HTLV-I and -II are associated with HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Several published reports suggest that HTLV-I may lead to decreased survival, but HTLV-II has not previously been associated with mortality.
  
  
  RESULTS
  We examined deaths among 138 HTLV-I, 358 HTLV-II, and 759 uninfected controls enrolled in a prospective cohort study of U.S. blood donors followed biannually since 1992. Proportional hazards models yielded hazard ratios (HRs) for the association between mortality and HTLV infection, controlling for sex, race/ethnicity, age, income, educational level, blood center, smoking, injection drug use history, alcohol intake, hepatitis C status and autologous donation. After a median follow-up of 8.6 years, there were 45 confirmed subject deaths. HTLV-I infection did not convey a statistically significant excess risk of mortality (unadjusted HR 1.9, 95%CI 0.8-4.4; adjusted HR 1.9, 95%CI 0.8-4.6). HTLV-II was associated with death in both the unadjusted model (HR 2.8, 95%CI 1.5-5.5) and in the adjusted model (HR 2.3, 95%CI 1.1-4.9). No single cause of death appeared responsible for the HTLV-II effect.
  
  
  CONCLUSIONS
  After adjusting for known and potential confounders, HTLV-II infection is associated with increased mortality among healthy blood donors. If replicated in other cohorts, this finding has implications for both HTLV pathogenesis and counseling of infected persons.
authors.affiliation: University of California San Francisco and Blood Systems Research Institute, San Francisco, CA, USA. orland@itsa.ucsf.edu
authors.forename: Jennie R
authors.initials: JR
authors.lastname: Orland
authors.forename: Baoguang
authors.initials: B
authors.lastname: Wang
authors.forename: David J
authors.initials: DJ
authors.lastname: Wright
authors.forename: Catharie C
authors.initials: CC
authors.lastname: Nass
authors.forename: George
authors.initials: G
authors.lastname: Garratty
authors.forename: James W
authors.initials: JW
authors.lastname: Smith
authors.forename: Bruce
authors.initials: B
authors.lastname: Newman
authors.forename: Donna M
authors.initials: DM
authors.lastname: Smith
authors.forename: Edward L
authors.initials: EL
authors.lastname: Murphy
mesh_terms: D001782:Blood Donors / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005843:Geography; D015490:HTLV-I Infections / Q000401:mortality; D015491:HTLV-II Infections / Q000401:mortality*; D006801:Humans; D011446:Prospective Studies; D014481:United States / Q000453:epidemiology