Background Radiation and Cancer Mortality in Bavaria: An Ecological Analysis

Abstract

The authors investigated a possible association between background gamma radiation (BGR) and cancer and infant mortality rates. In an in-country ecological study, they performed a population-weighted linear regression of cancer (infant) mortality rates on BGR, adjusted for unemployment rate and population density. Crude cancer rates showed a highly significant increase with BGR: 38 excess cases per 100,000 person-years per millisievert/year (p < .0001). After adjusting for unemployment rate and population density, the authors found that the excess absolute risk reduced to 23.6 cases per 100,000 person-years per mSv/year (p = .0014). The corresponding excess relative risk was 10.2% (95% confidence interval = 3.9-16.7) per mSv/year. The excess relative risk for infant mortality rates was 24% (95% confidence interval = 9-42) per mSv/year. The cancer risk derived from this ecological study is 0.24/Sv, which compares with an International Commission on Radiological Protection value of 0.05/Sv. However, because they are based on highly aggregated data, the results should be interpreted with caution.

The effects of natural variation in background radioactivity on humans, animals and other organisms

“…This implies that elevated incidence of disease in contaminated areas may be caused by effects of radiation on the immune system rather than being a consequence of increased mutation rates directly causing disease. Three epidemiological studies link cancer to elevated levels of background radiation, even after controlling for potentially confounding variables (Ujeno, ; Tao et al ., ; Körblein & Hoffmann, ). These findings about disease incidence and natural variation in background radiation have implications for studies of the effects of radiation accidents such as Chernobyl, Fukushima Daiichi and Three Mile Island.…”

“…If several effects were reported, we used the effect that controlled for confounding variables such as age or smoking in order to be conservative. In five studies included in the mean effect size calculations see Table we conservatively used the number of populations rather than the number of subjects because the latter was not reported; in cases of cancer deaths (Körblein & Hoffmann, ) use of the size of the underlying total population would seriously distort our study findings towards the effect size in those studies. Therefore, for these five studies we used the number of populations to be conservative.…”

“…For each effect size we also extracted information on the mean level of background radiation and report these as mSv per year in Table . We assumed that 1 R = 10 mSv (Körblein & Hoffmann, …”

A Review and Critical Analysis of the “Effective Dose of Radiation” Concept

“…Figure 4 shows positive correlation between mortality from all types of cancer and levels of natural γ-radiation from the Earth's crust (t-value 5.9, df = 94, p < 0.0001), regardless of age or gender. 27 The differences in the levels of natural radiation in different areas in Bavaria are just fractions of mSv per year. The difference in indicators of cancer mortality for these territories is statistically significant, even when accounting for population density and unemployment rates.…”

Cancer Mortality Among People Living in Areas With Various Levels of Natural Background Radiation

“…The data set of Körblein and Hoffmann (2006) , which was also a part of previously described meta-analysis by Mœller and Mousseau (2013) , covers a relatively large collection of observations on incidence of cancer and γ-radiation level in 96 districts of Bavaria, Germany. These studies are of great interest, as they intended to show that the risk of cancer increases even at the lowest dose rates.…”