Human T-lymphotropic virus type-I infection, survival and cancer risk in southwestern Japan: a prospective cohort study.
OBJECTIVE
This study prospectively evaluated the associations of human T-lymphotropic virus type-I (HTLV-I) infection with survival and cancer incidence.


METHODS
The study base comprised 4297 adults (aged 40-69 years in 1993) who had either visited the outpatient clinic or who had received annual health check-ups at the A Hospital, Nagasaki, Japan, between 1985 and 1992 (HTLV-I seropositivity = 24.7%). During the follow-up period (1993-1999 or 2000), 290 deaths and 261 cases of malignant neoplasms occurred, including ten deaths and six incident cases of adult T-cell leukemia/lymphoma (ATL).


RESULTS
After adjustment for gender, age and other covariates, HTLV-I seropositivity was associated with an increased mortality from all-causes excluding ATL (rate ratio, RR = 1.3, 95% confidence interval, CI = 1.0-1.7), all non-neoplastic diseases (RR = 1.5, 95% CI = 1.0-2.3) and heart diseases. HTLV-I infection was not found to be associated with an increased risk of developing total cancers other than ATL (RR = 0.98, 95% CI = 0.74-1.3), colorectal cancers, liver cancer or lung cancer, but was associated with a reduced risk of gastric cancer (RR = 0.42, 95% CI = 0.17-0.99).


CONCLUSIONS
HTLV-I infection is associated with increased mortality from all-causes excluding ATL and all non-neoplastic diseases. HTLV-I carriers may not be at increased general cancer risk, but at reduced risk of gastric cancer.
Arisawa
Kokichi
K
Division of Molecular Epidemiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. k-iwata@net.nagasaki-u.ac.jp
Sobue
Tomotaka
T
Yoshimi
Itsuro
I
Soda
Midori
M
Shirahama
Satoshi
S
Doi
Hiroshi
H
Katamine
Shigeru
S
Saito
Hiroshi
H
Urata
Minoru
M
D000368:Aged; D002423:Cause of Death; D015331:Cohort Studies; D005247:Feeding Behavior; D005260:Female; D015490:HTLV-I Infections / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000453:epidemiology / Q000209:etiology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D016019:Survival Analysis