title: Age and gender specific prevalence of HTLV-1.
abstract: BACKGROUND
  The seroprevalence of Human T-cell Leukemia Virus Type 1 (HTLV-1) is female predominant despite the higher incidence of Adult T-cell Leukemia (ATL) in males. If the mother-to-child transmission of HTLV-1 is more common for male infants than in female infants, longer exposure to the virus for males may explain the paradoxically higher incidence of ATL.
  
  
  OBJECTIVE
  To test the hypothesis that the seroprevalence of HTLV-1 is male predominant during adolescence.
  
  
  METHODS
  The presence of HTLV-1 antibody in 272,043 blood samples donated to a regional blood bank in an HTLV-1 high-endemic region was assessed.
  
  
  RESULTS
  The entire population of female donors had a significantly higher seroprevalence compared to males (2.05% and 1.80%, respectively, p<0.0001). However, compared with male donors, the carrier rate for female donors was lower for the youngest subgroup (16-19 years, p=0.0011); was similar for the next two age subgroups (20-29 years and 30-39 years); and was significantly higher for the last two age subgroups (40-49 years and over 50-64 years, both p<0.0001). In general, older age subgroups led to higher seroprevalence in both genders.
  
  
  CONCLUSIONS
  HTLV-1 infection is more common for males until after age 20, when male to female sexual transmission becomes likely. This suggests that mother-to-child transmission is more common for males.
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
authors.forename: Nobuoki
authors.initials: N
authors.lastname: Eshima
authors.forename: Osuke
authors.initials: O
authors.lastname: Iwata
authors.forename: Sachiko
authors.initials: S
authors.lastname: Iwata
authors.forename: Minoru
authors.initials: M
authors.lastname: Tabata
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Toyojiro
authors.initials: T
authors.lastname: Matsuishi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Karukaya
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D015490:HTLV-I Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D012737:Sex Factors; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral