Sex-specific mortality from adult T-cell leukemia among carriers of human T-lymphotropic virus type I

Perinatal infection with human T-lymphotropic virus type I (HTLV-I) is cons idered a risk factor far adult T-cell leukemia (ATL). Incidence of ATL in j apan is generally higher in males compared with females, perhaps partly due to an earlier average age of infection among males. We estimated sex-speci fic ATL mortality among perinatally-infected HTLV-I carriers in the prospec tive Miyazaki Cohort Study in japan. Based on the approximated proportion o f perinatally-infected carriers, the relative risk (RR) of ATL for males co mpared with females was calculated. Six ATL deaths (4 males, 2 females) occ urred among the 550 HTLV-I carriers in the cohort during 13 years of follow -up. The overall ATL mortality was 190.5 (95% CI 51.9-487.7) per 10(5) pers on-years for males and 51.7(6.3-186.8) per 105 person-years for females (ag e-standardized RR = 3.9, p = 0.02). By approximating the number of persons who acquired infection perinatally, the estimated mortality among those per inatally-infected HTLV-I carriers was 209.1 (57.0-535.2) per 105 person-yea rs for males and 60.9 (7.4-2 19.9) per 10(5) person-years for females (age- standardized RR 3.7, p = 0.02). The adjusted RR changed minimally from the unadjusted RR, suggesting that earlier age of infection alone is unlikely t he explanation for the male predominance in ATL. Based on the small number of cases available for analysis, aspects of gender itself appear to play a role in the development of this malignancy. (C) 2001 Wiley-Liss, Inc.