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

1.2.6
Natural Radiation and Radioactivity

1.2.6.2
Natural Background: Populations

"Wei and Wang compared the health of 77,000 Chinese peasants living in a world average background radiation level, with 73,000 peasants living in a background radiation which was three times higher (1995). This study involved 2,500,000 person years. They found the non-leukemia cancer mortality rate of the 40-70 years age group to be statistically lower in peasants living in the high background radiation level than in peasants of the control cohort . . ."

"An earlier summary suggests the background radiation group benefited in several parameters of health (Luckey 1991, 1992). When both populations were compared, cancer mortality rate, lung cancer mortality, and the leukemia mortality were lower in the high-background population, p=0.05. In the high-background population, infertility was lower, p<0.05 neonatal mortality was only 76 percent that of the controls, p=NS, and life expectancy of people over 40 years old was longer, p<0.05."

Figure 2

"The negative correlation between natural levels of ionizing radiation and cardiovascular, respiratory and cancer death rates in the United States (Fig. 2) is good evidence that low level irradiation is not a major cause of these diseases (Sauer 1982). Although altitude, oxygen and air pressure were also negatively correlated.

"This study found no correlation between the high death rates in the southeastern area of the United States and about 40 environmental, social, economic or racial factors. A similar correlation between background radiation and leukemia mortality has been noted in many studies for the population of the United States (Luckey 1991). In contrast, the negative correlation between radiation and cancer death rates in India are not related to altitude or air pressure. The results from the United States and India are supported by the more rigorous studies with Chinese peasants. In each of the three countries there was a three-fold difference in radiation levels between low and high dose populations.

Figure 4

"The most well studied populations are two groups of Chinese peasants, about 70,000 each, in the Yangjiang Provence (Wei 1994). Leukemia and total cancer mortality rates appear to be lower for peasants living in the high background area. A correlation of leukemia deaths with age (Fig. 4) suggests an important difference in radiation sensitivity between infantile and adult leukemia.