Wednesday, February 24, 2016

Longevity of Nagasaki Survivors

In an earlier study, Mine had compared the observed deaths of the survivors with the expected number and found all age groups from forty-five year to eighty-plus-years had significantly longer life expectancies - just the opposite of what had been predicted by the LNT.

Figure 14 is plotted from "Observed and expected annual rates of deaths (1970-76) from all causes among atomic bomb survivors in Nagasaki." [Note for Figure 14: Longevity of Nagasaki Survivors: By definition, the ratio of observed to expected deaths in the general population is 1. In this example, only 38% of the expected number of survivors above eighty years old died, as compared with 100% of a similar group in the general population. Source: Mine, M., Nakamura, T., Mori, H., Kondo, H. and Okajima, S. The current mortality rates of A-bomb survivors in Nagasaki City, Japan Journal of Public Health, 28, p337, 1981. (In Japanese with an English abstract.)]

The vertical axis gives the ratio of the observed deaths of male survivors compared with the expected deaths from the general population (who are assumed to be unexposed). Except for the age range of fifty-five to fifty-nine - which had a mortality 12% above the general population - all age groups older than forty-five have less than expected mortality, with the effect increasing with increasing age. [Data from Mine et al. The current mortality rates of A-bomb survivors in Nagasaki City, Japan Journal of Public Health, 28, 337, 1981. N values for data starting at 45-49 are 113, 87, 184, 299, 508, 816, 825, 869.]

Returning to Kondo: "The ratio of observed to expected numbers of deaths shows that the mortality of exposed people was slightly lower than or equal to that of unexposed people at all four low to intermediate doses, 1-49, 50-99, 100-149 and 150-199 rad, and that a significant increase in deaths occurred only in the high dose range, 200-599."

This confirms what we already know - that radiation in huge doses is not something to trifle with. But it also suggests that low-level exposure poses no danger and may be helpful.