Abstract
The Atomic Bomb Survivor Database at Nagasaki University has been storing medical information on Nagasaki atomic bomb survivors. As of March 2009, the mean age of atomic bomb survivors was 75.4 years old (73.2 years old in males and 76.7 years old in females). We assessed health conditions of atomic bomb survivors using trends in their mortality by the distance from hypocenter.
As of April 1, 1970, the number of atomic bomb survivors registered was 76,806, among whom 65,273 were directly exposed. The number of deaths observed during 1970-2004 in directly exposed survivors was 26,159. Death from cancer was observed in 6,744, cerebrovascular diseases in 4,351, and heart diseases in 4,400. We divided observation period into 7 periods: 1970-74, 1975-79, 1980-84, 1985-89, 1990-94, 1995-99 and 2000-04. We also categorized the distance from hypocenter as 0-1.9 km, 2.0-2.9 km, and 3.0 km or over. We calculated age-adjusted mortality rates using Japanese standard population constructed from 1985 national census.
The mortality from all causes showed a tendency to decrease with year in both sexes for all distance groups; in males, the mortality after 1980 showed a tendency to be slightly higher in those exposed within 1.9 km compared to the other groups, and in females, similar tendency was observed during 1970-79 and after 1990.
The mortality from cancer showed in males a tendency to be higher after 1985 in those exposed within 1.9 km compared to the other groups, while in females, although higher until 1979 in those exposed within 1.9 km compared to other groups, no difference among distance groups was observed after 1979.
