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This is a draft for Chernobyl disaster#Assessing the disaster's effects on human health.

Assessing the disaster's effects on human health

Demonstration on Chernobyl day near WHO in Geneva

Controversial nature of assessments

The levels of illness and fatality due to radioactive fallout are controversial, with widely varying estimates.

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has conducted scientific and epidemiological research on the effects of the Chernobyl accident since it occurred, and given its assessment in a series of reports. Apart from the 57 direct deaths in the accident itself, UNSCEAR originally predicted up to 4,000 additional cancer cases due to the accident. UNSCEAR now state:

Among the residents of Belarus, the Russian Federation and Ukraine, there had been up to the year 2005 more than 6,000 cases of thyroid cancer reported in children and adolescents who were exposed at the time of the accident, and more cases can be expected during the next decades. Notwithstanding the influence of enhanced screening regimes, many of those cancers were most likely caused by radiation exposures shortly after the accident. Apart from this increase, there is no evidence of a major public health impact attributable to radiation exposure two decades after the accident. There is no scientific evidence of increases in overall cancer incidence or mortality rates or in rates of non-malignant disorders that could be related to radiation exposure. The incidence of leukaemia in the general population, one of the main concerns owing to the shorter time expected between exposure and its occurrence compared with solid cancers, does not appear to be elevated. Although those most highly exposed individuals are at an increased risk of radiation-associated effects, the great majority of the population is not likely to experience serious health consequences as a result of radiation from the Chernobyl accident. Many other health problems have been noted in the populations that are not related to radiation exposure.

UNSCEAR does also raise the possibility of long term genetic defects, pointing to a doubling of radiation-induced minisatellite mutations among children born in 1994, though there is some dispute over the control groups in this study and the long term effects are not clear. The IAEA states that there has been no increase in the rate of birth defects or abnormalities, or solid cancers (such as lung cancer).

The Chernobyl Forum is a regular meeting of IAEA, other UN organizations and the governments of Belarus, Russia, and Ukraine, that issues regular scientific assessments of the evidence for health effects of the Chernobyl accident. The Chernobyl Forum has concluded from studies of the Russian Registry from 1991 to 1998 that "of 61,000 Russian workers exposed to an average dose of 107 mSv about 5% of all fatalities that occurred may have been due to radiation exposure."

Social and political changes in the region since 1990 pose a significant difficulty in assessing the disaster's impact on the population at large. These changes have had numerous impacts on the administration of health care, socio-economic stability, and even the manner in which statistical data is collected. A report outlining some of these difficulties states, among other things, that:

"...there is clear evidence of weaknesses in cause-of-death registration, especially among those >70 which has, historically, led to underestimation of cancer mortality especially in rural populations. Against this background, the rapid increase in cancer mortality among the elderly in Russia and Ukraine in the late 1980s and its striking further rise in Ukraine in 1989-1990 seems to be due, in large part, to an increase in completeness of registration of cancer as an underlying (or primary) cause of death. The decline in cancer mortality at older ages in the 1990s, which is particularly striking in Ukraine, seems likely to represent a return to previous approaches to registration."

Another study critical of the Chernobyl Forum report was commissioned by Greenpeace, which asserts that "the most recently published figures indicate that in Belarus, Russia and Ukraine alone the accident could have resulted in an estimated 200,000 additional deaths in the period between 1990 and 2004." The Scientific Secretary of the Chernobyl Forum criticized the report's exclusive reliance on non-peer reviewed locally produced studies (in fact, most of the study's sources are from peer-reviewed journals, including many Western medical journals, or from proceedings of scientific conferences), while Gregory Härtl (spokesman for the WHO) suggested that the conclusions were motivated by ideology.

Chernobyl: Consequences of the Catastrophe for People and the Environment is an English translation of the 2007 Russian publication Chernobyl. It was published online in 2009 by the New York Academy of Sciences in their Annals of the New York Academy of Sciences. It presents an analysis of scientific literature and concludes that medical records between 1986, the year of the accident, and 2004 reflect 985,000 deaths as a result of the radioactivity released. The authors suggest that most of the deaths were in Russia, Belarus and Ukraine, but others were spread through the many other countries the radiation from Chernobyl struck. The literature analysis draws on over 1,000 published titles and over 5,000 internet and printed publications discussing the consequences of the Chernobyl disaster. The authors contend that those publications and papers were written by leading Eastern European authorities and have largely been downplayed or ignored by the IAEA and UNSCEAR; they also state that the conclusions of those bodies do not acknowledge large gaps in the available data: early levels and spread of radiation from Chernobyl are not known, because it took weeks before measurements started to be taken over wide geographical areas; also, for the first three years after the accident, Soviet doctors were officially forbidden from diagnosing diseases as radiation-related, and all data on contamination was classified. One of the authors, Alexy V. Yablokov, was also one of the general editors on the Greenpeace report.

Former Deputy of the Supreme Soviet Alla Yaroshinskaya, taking advantage of the general anarchy surrounding the dissolution of the Soviet Union, managed to obtain a copy of a secret report to the Central Committee, dating from the early weeks of the Chernobyl accident: "When I read these documents I discovered everything happened differently. I realised just how huge a lie the Party leaders told. Decree number 12 stated that on the 12th of May 1986, 10,198 people had already been hospitalised; 345 showed signs of radio lesions. Yet at the same time they were telling us everything was fine, that it was nothing serious, and I realised the scope of the lies." According to Yaroshinskaya, another passage reveals that authorities arbitrarily raised the "acceptable" radiation dose for humans by a factor of five: "suddenly people were miraculously cured. They were released from the hospital and sent home."

Acute radiation syndrome

The Chernobyl Forum concluded that twenty-eight emergency workers ("liquidators") died from acute radiation syndrome including beta burns.

Thyroid cancer

Thyroid cancer incidence in children and adolescents from Belarus after the Chernobyl accident.
Yellow: Adults over the age of 46
Blue: 20–46 Years old
Red: Children

Thyroid cancer has increased dramatically, as a result of radioactive iodine absorbed from the atmosphere in the first days after the accident, or consumed through milk (iodine tends to accumulate in milk glands). A 1994 study counted 527 cases of thyroid cancer in Belarussian, Ukrainian and Russian children, over 65% of them from Belarus; the World Health Organization directly attributes these to fallout from Chernobyl. Belarus also reports an increase in non-cancerous tumors in children, from a previous average of one per year to an annual rate of over 60. UNSCEAR has reported 6000 cases of thyroid cancer among children and adolescents due to radioactive iodine exposure, and expects more cases in decades to come. Thyroid cancer is generally treatable. With proper treatment, the five-year survival rate of thyroid cancer is 96%, and 92% after 30 years, suggesting there may be up to 500 early deaths from this cause.

The Chernobyl Forum concluded that 15 patients died from Chernobyl-related thyroid cancer by 2005.

The German affiliate of the International Physicians for the Prevention of Nuclear War (IPPNW) argued that more than 10,000 people are today affected by thyroid cancer and 50,000 cases are expected in the future.

Iodine-131, because of its relatively short half-life, was initially viewed with less concern than cesium-137 and strontium-90, the other two most harmful radionucleides spread from Chernobyl; it now appears that iodine has caused the most severe health problems over the widest area.

General health

In June 1986 the Ukrainian health minister declared that there was "no cause for alarm whatsoever" outside the 30-km exclusion zone: "Doctors have checked tens of thousands of people, and thousands of tests have been carried out in the laboratories. Their results give us grounds to say that there is no danger to people's health." By 1993, however, the Ukrainian health ministry estimated that only 28–32% of adults and 27–31% of children were in good health, with large increases in respiratory, blood and nervous system diseases. This claim is probably exaggerated. Radiation-related illness must be distinguished from illness related to poor health care and sanitation in Belarus and Ukraine; for instance, cases of tuberculosis and diptheria are much higher than in most of Europe, and in 1995 polluted water caused a cholera outbreak in southern Ukraine. In 1991 US bone marrow specialist Robert Gale expressed doubt that the large number of people hospitalised in Kiev was a result of fallout. Disadvantaged children around Chernobyl suffer from health problems that are attributable not only to the Chernobyl accident, but also to the poor state of post-Soviet health systems.

Other cancers

The Chernobyl Forum have roughly estimated that cancer deaths caused by Chernobyl may reach a total of about 4,000 among the 5 million persons residing in the contaminated areas. The report projected cancer mortality "increases of less than one per cent" (~0.3%) on a time span of 80 years, cautioning that this estimate was "speculative" since at the time of the report they had only linked a few tens of cancer deaths to the Chernobyl disaster. Fred Mettler, a radiation expert at the University of New Mexico, estimates about 4000 fatal radiation-induced cancers among the 600,000 liquidators and another 5000 in more peripheral populations, saying "the number is small (representing a few percent) relative to the normal spontaneous risk of cancer, but the numbers are large in absolute terms".

In 1995, lung cancer among evacuees from the exclusion zone was four times the national average for Belarus. The IAEA states there has been no increase in lung cancer or other solid cancers due to radiation.

Leukaemia

Rates of leukaemia in Ukraine and Belarus are high compared with most of Europe, but are actually lower than they were in the 1970s, and the disease's prevalence is attributed by some to industrial pollution.

Diabetes

By 1995, some attributed a dramatic increase in type 1 diabetes to the Chernobyl accident; Gomel province, the most heavily contaminated region, also has the largest incidence of childhood diabetes. Yet there is no known scientific link between radiation and diabetes.

Mental health

The IAEA report went into depth about the risks to mental health of exaggerated fears about the effects of radiation:

The designation of the affected population as “victims” rather than “survivors” has led them to perceive themselves as helpless, weak and lacking control over their future. This, in turn, has led either to over cautious behavior and exaggerated health concerns, or to reckless conduct, such as consumption of mushrooms, berries and game from areas still designated as highly contaminated, overuse of alcohol and tobacco, and unprotected promiscuous sexual activity.

Fred Mettler commented that 20 years later:

The population remains largely unsure of what the effects of radiation actually are and retain a sense of foreboding. A number of adolescents and young adults who have been exposed to modest or small amounts of radiation feel that they are somehow fatally flawed and there is no downside to using illicit drugs or having unprotected sex. To reverse such attitudes and behaviors will likely take years although some youth groups have begun programs that have promise.

Genetic defects

In West Berlin, Germany, prevalence of Down syndrome (trisomy 21) peaked 9 months following the main fallout.[11, 12] Between 1980 and 1986, the birth prevalence of Down syndrome was quite stable (i.e., 1.35–1.59 per 1,000 live births [27–31 cases]). In 1987, 46 cases were diagnosed (prevalence = 2.11 per 1,000 live births). Most of the excess resulted from a cluster of 12 cases among children born in January 1987. The prevalence of Down syndrome in 1988 was 1.77, and in 1989, it reached pre-Chernobyl values. The authors noted that the isolated geographical position of West Berlin before reunification, the free genetic counseling, and complete coverage of the population through one central cytogenetic laboratory support completeness of case ascertainment; in addition, constant culture preparation and analysis protocols ensure a high quality of data.

Reports of structural chromosomal aberrations in people exposed to fallout in Belarus and other parts of the former Soviet Union, Austria, and Germany argue against a simple dose-response relationship between degree of exposure and incidence of aberrations. These findings are relevant because a close relationship exists between chromosome changes and congenital malformations. Inasmuch as some types of aberration are almost specific for ionizing radiation, researchers use aberrations to assess exposure dose. On the basis of current coefficients, however, it is not certain that the calculated individual exposure doses resulting from fallout would not induce measurable rates of chromosome aberrations.

Other developmental problems

• Neural tube defects (NTDs) in Turkey. During the embryonic phase of fetal development, the neural tube differentiates into the brain and spinal cord (i.e., collectively forming the central nervous system). Chemical or physical interactions with this process can cause NTDs. Common features of this class of malformations are more or less extended fissures, often accompanied by consecutive dislocation of central nervous system (CNS) tissue. NTDs include spina bifida occulta and aperta, encephalocele, and—in the extreme case—anencephaly. The first evidence in support of a possible association between CNS malformations and fallout from Chernobyl was published by Akar et al.. in 1988. The Mustafakemalpasa State Hospital, Bursa region, covers a population of approximately 90,000. Investigators have documented the prevalence of malformations since 1983. The prevalence of NTDs was 1.7 to 9.2 per 1,000 births, but during the first 6 months of 1987 increased to 20 per 1,000 (12 cases). The excess was most pronounced for the subgroup of anencephalics, in which prevalence increased 5-fold (i.e., 10 per 1,000 [6 cases]). In the consecutive months that followed (i.e., July–December 1987), the prevalence decreased again (1.3 per 1,000 for all NTDs, 0.6 per 1,000 for anencephaly), and it reached pre-Chernobyl levels during the first half of 1988 (all NTDs: 0.6 per 1,000; anencephaly: 0.2 per 1,000). This initial report was supported by several similar findings in observational studies from different regions of Turkey.

Approximately 100,000km² of land was contaminated, the worst hit regions being in Belarus, Ukraine and Russia. Slighter levels of contamination fell on large areas of Europe.