Apparently beneficial effect of low to intermediate doses of A-bomb radiation on human lifespan.

Among about 100,000 A-bomb survivors registered at Nagasaki University School of Medicine, 290 male subjects exposed to 50-149 cGy showed significantly lower mortality from non-cancerous diseases than age-matched unexposed males. This was deduced from the fitting of a U-shaped dose-response relationship. Reasons for this effect in males, but not in females, are discussed with reference to selection of individuals and to hormesis.