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the group were1: V. Bebeshko, Ukraine; E. Bromet, USA; D. Darroudi, Netherlands; A. Grakovich, Belarus; J. Havenaar, Netherlands; E. Kapitonova, Belarus; N. Korol, Ukraine; V. Ivanov, Russian Federation; F. Mettler, USA; K. Neriishi, Japan; Y. Shibata, Japan; G. Soushkevich, Russian Federation; B. Worgul, USA.

The expert group acknowledged and used a number of documents as a historical basis including the report of the International Chernobyl Project [1], the proceedings of the IAEA/WHO/EC [2], the WHO IPHECA report [3], and the 2000 UNSCEAR report [4]. The group also reviewed several recent books on health effects from experts in the Russian Federation [5] and Ukraine [6].

The topics included for review are diverse and have different underlying biological mechanisms. Many of the papers and studies that we reviewed only had descriptive or subjective rather than objective findings. In other studies, the diagnostic criteria used to make a diagnosis were inconsistent or not presented. The data were sometimes presented without a useful context. For example, a percentage increase may have been found but the exact number, the baseline and the timeframe were often not available. Appropriate control groups were only available in some studies. Most studies did not have a dose response analysis and some did not even provide organ dose estimates at all.

The data were commonly also only available from one country. For example, most infant health data was available from the Ukraine, malformation data from Belarus and liquidator data from the Russian Federation. A final issue that has complicated data analysis in a number of areas is the reduction in lifespan which has occurred over the last decade in the three affected countries due to factors unrelated to the Chernobyl accident. The average lifespan in 2000 for males in the Russian Federation was 58.4, Belarus 62.6 and Ukraine 66.7 years compared to 70.6 years in nearby Poland (Table 1). As a result of the above caveats, the conclusions regarding non-cancer effects are scientifically less rigorous than the cancer and leukaemia data presented by the other expert groups.

The group was not able to review every alleged health effect due to the accident. A number of non-cancer topics were chosen as they were felt to have the most information and to be the most important for public health. They were:

—Cataracts;

—Cardiovascular disease;

1Observers included: M. Balonov, IAEA; E. Bodnar, USA; B. Greenebaum, USA; J. Hendry, IAEA; R. Lee, USA; Z. Carr, WHO; S. Yamashita, WHO.

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TABLE 1. COMPARATIVE POPULATION DEMOGRAPHICS FOR BELARUS, THE RUSSIAN FEDERATION, UKRAINE AND POLAND*

*US Census Bureau International data base (www.census.gov/ipc/www/idbnew.html) and WHO (www.who.int/countries) as of 2000.

—Cytogenetic markers;

—Immunological effects;

—Heritable, reproductive effects and children’s health;

—Psychological mental and nervous system effects;

—Mortality due to the accident;

—Medical programmes and medical monitoring.

2.CATARACTS

Clinically significant radiation-induced cataracts after high doses have been known for many years. The current Chernobyl and other data suggest that early lens opacities can be found at lower doses (perhaps as low as 0.25 Gy) when the studies use coherent criteria, well-trained observers and good equipment. Some difficulties remain in determining the actual dose to the lens of the eye (especially from beta particles). In addition, the questions of the ultimate clinical effect and whether there is significant progression of the lesions still needs more research. The expert group has recommended continued ocular follow-up of liquidators and highly exposed radiation workers, and to continue the studies on those subjects already recruited. Ocular examinations of the public living in contaminated areas was felt to be unwarranted and possibly wasteful of resources.

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3.CARDIOVASCULAR DISEASE

Changes to the heart, coronary arteries and small vessels has also been well documented after high radiation doses (particularly after radiation therapy of the chest). Most data relative to cardiovascular disease is potentially confounded by tobacco use. Most people are not aware that smoking causes more cardiovascular deaths than lung cancer deaths.

Data from the atomic bomb survivors has suggested a possible relation between radiation exposure and cardiovascular disease. The only Chernobyl data on cardiovascular disease available to the expert group was for the Russian liquidators [5] and the data had not been evaluated for potential smoking bias. While there was a slight increase reported for cardiovascular mortality for the group as a whole, there was no correlation with subsets of the data (i.e. myocardial infarction and ischemic heart disease) which one might reasonably expect would be associated with mortality.

The conclusion was that the acute radiation sickness survivors may well be at an increased risk of cardiovascular disease. The Russian liquidator findings need to be validated and further evaluated. A radiation effect was not fully substantiated but a small effect could not be excluded. Further studies of liquidators in other countries with appropriate control groups, individual dosimetry, standardized protocols and common diagnostic criteria were suggested.

4.CYTOGENETIC MARKERS

There are a number of markers that can be found in the genetic material of peripheral circulating lymphocytes which are related to radiation bone marrow dose. These include dicentrics and to a lesser extent miniand microsatellite mutations. These methods have been used for years to perform biodosimetry. Both dicentric and fluorescent in situ hybridization (FISH) analysis can detect doses as low as 0.25 Gy. The reviewed Chernobyl data regarding miniand microsatellite mutations was inconsistent.

The main question posed to the expert group was: “Are there any clinically significant effects associated with these genetic changes?” The group concluded that there is no evidence of current clinical effects directly attributable to these changes. It is clear, however, that since the changes are a marker of absorbed dose, they do provide an indication of the magnitude of potential risk for some future effects (such as cancer).

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