The incidence of adult T-cell leukemia/lymphoma among human T-lymphotropic virus type 1 carriers in Japan

Abstract

Human T-lymphotropic virus type 1 (HTLV-1) is highly endemic in the Kyushu/Okinawa region of Japan. A nationwide investigation verified the frequency of HTLV-1 carriers among first-time blood donors and the occurrence of newly diagnosed adult T-cell leukemia/lymphoma (ATL) cases from 2007 through 2008. After adjusting for differences in capture rate between areas, the age-, sex- and area-specific incidence of ATL among carriers was determined. Annual ATL incidence among 10 000 carriers was 7.7 and 8.7 for the Kyushu and non-Kyushu/Okinawa regions, respectively. The incidence increased sharply for men from their 40s to their 70s, but the rate in females remained unchanged through their 40s to 70s. ATL incidence in middle-aged females was still low, even if female carrier frequency was assumed to be identical to that of males. Patients with ATL in their 60s and 70s will comprise two-thirds of all patients with ATL for the next 15 years in Japan.

Keywords::

• Adult T-cell leukemia/lymphoma
• disease incidence
• epidemiology
• human T-lymphotropic virus type 1
• virus carrier

Acknowledgements

This work was supported by a grant for the Study Project for Emerging and Re-emerging Infectious Diseases from the Ministry of Health, Labor and Welfare of Japan. The authors gratefully acknowledge the physicians who participated in this study for their efforts in registering patients with ATL and B-NHL.

Potential conflict of interest

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