Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.2.4
Radium Body-Burden

1.2.4.3
Mortality/Longevity

"When the numbers of deaths from different causes in the radium-dial painters are compared with those in the control group; the observed: expected ratio for deaths from all causes is 0.88 (p <0.05 (Table 4.13). [See Section 1.2.4.2 above] This means that the study group of radium-dial painters, which excluded the workers who died of cancer due to internally deposited radium, showed significant reduction in the mortality from all causes compared with the control group.

"A similar survey of 1203 radium luminizers in the UK were carried out by Baverstock and Papworth (1989), who also found significantly lower rates of death from all causes except cancer among luminizers than among controls (Table 4.14). [See Section 1.2.4.2 above] No death from leukemia was observed among the British luminizers, although at least one case of leukemia would have been expected on the basis of the usual incidence rate."

"Table 4.15 summarizes the temporal trend after exposure in mortality of British radium luminizers who had worked for two or more years. In the first 20 years after exposure, the ratio of observed:expected numbers of non-cancer deaths was 0.31-0.47, indicating a beneficial effect of radiation on the life span of the workers. The ratio gradually increased thereafter, indicating diminution of the benefit of radiation with time, reaching 1.02 (disappearance of benefit) 40-50 years after exposure.

"The temporal trend in reduction of mortality in the luminizers (Table 4.15) is reminiscent of the observation that mortality from non-cancer deaths among atomic bomb survivors exposed to low to intermediate doses of radiation was reduced in the early period after the bombings, and thereafter gradually increased with time [See Section 1.2 Kondo 1993 Table I]. The observed:expected ratio for non-cancer deaths among women who worked for less than two years as luminizers, however, was 2.21, with p value of 0.004 for the period 0-10 years after first exposure although the overall ratio for the period 0-50 years after first exposure for this group is close to one (Baverstock and Papworth, 1989), an indication that the women had a shortened life span during the first 10 years after first exposure. If this effect was due to radiation, we must conclude that a short period (<2 years) of exposure to radiation has harmful effects, whereas long periods (>2 years) has a beneficial effect (see discussion of Table 4.15). This conclusion is, however, hardly compatible with data of bomb survivors (See 1.2 Kondo 1993 Table I). My interpretation is that most of the women in the group that worked for <2 years retired from luminizing work due to illness shortly after they started and that a considerable number of them died within 10 years as a result of progression of their illness.

"The British radium luminizer population is unique in that the women worked for a limited period under fairly uniform conditions of exposure at low external gamma dose rates (5-20 rad/year), resulting in accumulated doses of up to more than 100 rad (average, 40 rad) and 80% of them are still alive (Baverstock and Papworth, 1989). Radium-dial painters are an irreplaceable resource for elucidating important questions about the risk of low-level radiation. I hope that the follow-up surveys on the UK and USA study populations will be continued."