HETEROSEXUAL TRANSMISSION OF HUMAN T-CELL LEUKEMIA LYMPHOMA VIRUS TYPE-I AMONG MARRIED-COUPLES IN SOUTHWESTERN JAPAN - AN INITIAL REPORT FROM THE MIYAZAKI COHORT STUDY

To identify factors that may modify the heterosexual transmission of human T cell leukemia/lymphoma virus type I (HTLV-1), 534 married couples enrolled in the Miyazaki Cohort Study between November 1984 and April 1989 were studied: 95 husband HTLV-I-seropositive (H+)/wife seropositive (W+), 33 H+/W-, 64 H-/W+, and 342 H-/W-. After 5 years of follow-up, seven seroconversions occurred and clustered significantly among serodiscordant pairs (relative risk [RR] = 41.2); the rate of transmission was 3.9 times higher if the carrier spouse was male (P = .19). Among H+/W- couples, husband's age greater-than-or-equal 60 years strongly predicted seroconversion in the wives (RR = 11.5). All 4 carrier husbands whose wives seroconverted had HTLV-1 titers greater-than-or-equal-to 1: 1 024 (P = .04) and were anti-tax antibody positive (P = .06). In cross-sectional analysis, total parity also was independently associated with wife's serostatus but only length of marriage with husband's. Overall, sexual transmission of HTLV-1 was primarily from older infected husbands to their wives, with husbands' viral status being an important factor.