SEX-SPECIFIC MORTALITY FROM ADULT T-CELL LEUKEMIA AMONG HUMAN T-LYMPHOTROPIC VIRUS TYPE I CARRIERS

Abstract

SP-25 Perinatal infection with human T-lymphotropic virus type I (HTLV-I) is a risk factor for adult T-cell leukemia (ATL). Incidence of ATL is generally higher in males than in females, perhaps partly due to younger average age of infection among males. Since age of infection is rarely identifiable for individual carriers, gender difference in risk of ATL among perinatally-infected HTLV-I carriers is hard to quantify. We estimated the sex-specific ATL mortality among perinatally-infected HTLV-I carriers in the population-based, prospective Miyazaki Cohort Study. Six ATL deaths (4 males, 2 females) occurred among 549 HTLV-I carriers. The overall ATL age-adjusted mortality of 226.8 and 57.2 per 105 person-years for males and females, respectively, with a relative risk (RR) of 4.4 for males (p = 0.004). The estimated ATL mortality rates among perinatally-infected HTLV-I carriers were 3 to 4-fold higher than the overall rates, 676.7 and 219.1 per 105 person-years for males and females, respectively (RR = 3.6, p < 0.001) for males. The RR for males compared to females remained significantly elevated after adjustment for person-years attributable to perinatal infection, suggesting that the male predominance in ATL occurrence may not be entirely due to earlier age of HTLV-I infection among males. Gender itself may play a role in the development of ATL.