Study on specificity of leukemia among the second generation of A-bomb survivors

The title specificity was studied and discussed for the leukemia (L) of 5 cases of the second generation who had lived in Osaka (Report 1977) in comparison with published statistic data of the second generation's 15 L cases in a life-span investigation (2003) and of 5,098 L cases in a nationwide report (2003). The A-bomb survivors were exposed in either Hiroshima or Nagasaki. The Osaka cases (4/5 boys) were morbid during 1958-1975, had acute L (myeloid L 3 cases, and unidentified type L 2) and died at ages of 10-19 y. Their parents were exposed to A-bomb directly (2 cases) or due to entrance in the city (3), and 1 father, 3 mothers and 1 couple of parents were exposed. Parent(s) in the life-span investigation were classified in high dose exposure (within 2 km distance from the city) and zero exposure (2.5 km afar from the city and other) groups. Their second generation (13/20 boys) were morbid during 1952-1969 at average age of 9.7 y (high dose group) and 8.3-7.2 y (zero group), and had acute myeloid L (8 cases), acute lymphocytic L (5) and other L. Exposure was to their 12 mothers, 4 fathers and 4 both parents. The nationwide statistics showed L of <18 years old pediatric patients (1986-2000) involving 56.7% boys, of morbid age peak of 3-4 y and of acute lymphocytic L in 68.8%. As above, it seemed that, in the second generation, their mothers were mostly exposed relative to fathers, the morbid sex ratio was higher in boys, morbid age was higher than general, and acute myeloid L was more frequent than general. L of the second generation thus seemed to be somehow specific, particularly in the higher age of morbidity and frequency of acute myeloid L. (T.T.)