Increased all-cause and cancer mortality in HTLV-II infection.
BACKGROUND
Human T-lymphotropic virus (HTLV)-I and HTLV-II cause chronic human retroviral infections, but few studies have examined the impact of either virus on survival among otherwise healthy individuals. The authors analyzed all-cause and cancer mortality in a prospective cohort of 155 HTLV-I, 387 HTLV-II, and 799 seronegative subjects.


METHODS
Vital status was ascertained using death certificates, the US Social Security Death Index or family report, and causes of death were grouped into 9 categories. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models.


RESULTS
After a median follow-up of 15.9 years, there were 105 deaths: 22 HTLV-I, 41 HTLV-II, and 42 HTLV-seronegative. Cancer was the predominant cause of death, resulting in 8 HTLV-I, 17 HTLV-II, and 15 HTLV-seronegative deaths. After adjustment for confounding, HTLV-I status was not significantly associated with increased all-cause mortality, though there was a positive trend (HR: 1.6, 95% CI: 0.8 to 3.1). HTLV-II status was strongly associated with increased all-cause (HR: 2.4, 95% CI: 1.4 to 4.4) and cancer mortality (HR: 3.8, 95% CI: 1.6 to 9.2).


CONCLUSIONS
The observed associations of HTLV-II with all-cause and cancer mortality could reflect biological effects of HTLV-II infection, residual confounding by socioeconomic status or other factors, or differential access to health care and cancer screening.
Blood Systems Research Institute, San Francisco, CA 94118, USA.
Hope H
HH
Biswas
Zhanna
Z
Kaidarova
George
G
Garratty
Joan W
JW
Gibble
Bruce H
BH
Newman
James W
JW
Smith
Alyssa
A
Ziman
Joy L
JL
Fridey
Ronald A
RA
Sacher
Edward L
EL
Murphy
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D005260:Female; D015491:HTLV-II Infections / Q000150:complications* / Q000401:mortality*; D015367:Human T-lymphotropic virus 2; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications* / Q000401:mortality*; D014481:United States / Q000453:epidemiology; D055815:Young Adult