Review of Epidemiological Finding in Study of Medical Consequences of theChernobyl Accident in Ukrainian Population
Anatoly Ye. PRYSYAZHNYUK, Volodymir G. GRISHTSHENKO,
Zoya P. FEDORENKO*, Ludmila O. GULAK*, Mykola. M. FUZIKScientific Center for Radiation Medicine of Academy of Medical Science of the Ukraine,
53, Melnikov str., Kiev, 04050, Ukraine. E-mail root@ucr.kiev.ua*Institute of Oncology of Academy of Medical Science of the Ukraine,
33/43, Lomonosov str., Kiev, 03022, Ukraine. E-mail root@ucr.kiev.ua

Abstract
Evaluation of the health status of different groups of the Ukrainian population affected by the
Chernobyl accident is one of the most important problems in elimination of the consequences of theChernobyl disaster. A lot of scientific researches devoted to study of health effects and based on
established registers of victims of the Chernobyl accident had drawn conclusion about worsening ofhealth of main groups of the affected population: Chernobyl accident recovery operation workers,
evacuees from Prypyat city and 30km zone, and residents of the most contaminated with radionuclides
territories. Most remarkable stochastic effect of radiation due to the Chernobyl accident is increase of
thyroid cancer incidence rate in the above-mentioned groups of the Ukrainian population. For female
breast cancer and some other solid cancers there are suggestions of increases. Further observation isneeded for long term stochastic and non-stochastic effects.

1. Introduction
The accident at the Chernobyl Nuclear Power Plant on April 26th, 1986 is an unprecedented
complicated and large-scale disaster in views of its origin, spreading of radionuclides on relatively large
territories and the number of affected population. The release of dangerous radioactive substances diffusedover the wide areas of Ukraine, Belarus and Russia. Chernobyl accident recovery operation workers(CAROW), who participated in elimination of the consequences of the accident, as well as inhabitants ofterritories neighbouring Chernobyl received substantial dose of radiation.
According to National Report (2001) [1], during 15 years after the accident the rural population of the
Ukraine received 46.21 thousand person-Sv of accumulated collective dose. Average external dose in therural inhabitants during that period constituted 0.6-41 mSv. Average accumulated external and internal dose
per person in the territories with a density of nuclear fall-out more than 555 kBq/m2 exceeded 70 mSv.
Average external effective dose to the evacuated inhabitants of the 30-km zone formed 20-30 mSv;
Prypyat city - 10-12 mSv and Chernobyl city - 20 mSv. Taking into account the internal component, thisevaluation should be doubled. The main group of CAROW who participated in elimination of the accident
consequences in 1986 have received mean dose of 100-200 mSv, and CAROW in 1987 - 50-100 mSv.
Doses to thyroid for the population of the contaminated territories have shown significant burden on
this organ, especially in children. Estimated average of thyroid dose equivalent in the most contaminatedareas constituted 187 - 220 mSv in adults and children, while 877-1360 mSv only in children. Collective
dose to thyroid in Ukrainian children is estimated to be 400,000 person-Gy, and in the most contaminateddistricts - 57,000 person-Gy [2].
Evaluation of health status of the population affected by the Chernobyl accident is one of the mostimportant problem in elimination of the consequences of the Chernobyl disaster. According to regulation of188Ukrainian government, there was established State Registry of Ukraine of persons affected by the Chernobyl
accident (SRU). In 2000 there were registered 1,258,241 persons, including 249,000 CAROW, 71,510
evacuees and 193,250 children [1]. Health care system in Ukraine and principles of activity of SRU aredescribed in details by [3].
To follow up haematological and thyroid cancer consequences two special registries are in operation;
Ukrainian Haematological Registry at Scientific Centre for Radiation Medicine, and Morphological Registryof Thyroid Cancer at Kiev Research Institute of Endocrinology and Metabolism.
The main cancer epidemiological studies related to the Chernobyl consequences are based on a database of National Cancer Registry (NCR), which was established in 1989 and covers all territory of Ukraine.
Personal information about all cancer cases is collected in NCR using a network of regional and city cancer
registries [4, 5, 6]. In the last years joint efforts between Research Institute of Oncology and Scientific
Centre for Radiation Medicine allowed to establish a frame of special sub-registry of NCR: cancer patientsfrom the sufferers by the Chernobyl accident (CAROW, evacuees, and people still living in thecontaminated territories). Before these registries, in Ukraine since 1953 there existed a system of cancer
registration based on paper documents which were filled in all cancer hospitals (oncological dispensaries).
Results of studies in the above-mentioned institutes have been published in periodical medical
literatures in Russian, Ukrainian languages as well as in proceedings in national and international symposia,
conferences, congresses and another scientific forums. The main purpose of the current paper is review ofpublications performed and devoted to epidemiological researches of health status, especially about
leukaemia and solid cancer in the groups of the Ukrainian population affected by the Chernobyl accident.
2. Somatic disorders in the main groups of population affected by the Chernobyl accident
2.1. Health status of residents in the contaminated territories with radionuclides
There were observed significant changes of health status of the population still living in thecontaminated territories with radionuclides [7]. During 1988-1999 prevalence and incidence of diseases inthese people increased by more than 2 times (from 620.9 to 1275.6 ‰ and from 305.5 to 746.0 ‰,respectively). Increases of morbidity were observed in almost all diseases classes, especially blood andblood circulation classes (10.8-15.4 times), endocrine pathology (4.1-8.1 times), neurological system andsense organs (3.8-5.0 times), skin and underskin cellulose (4.0-4.6 times). There were also observed morethan two fold increases in the level of morbidity of digestive organs, urinarygenital and muscular-skeletal
systems. It should be pointed out that the level of morbidity in the contaminated areas has exceeded the
Ukrainian population level since 1993-1994.
There was observed a tendency that morbidity in inhabitants of the contaminated areas depends on thelevel of contamination. Since 1988 through 1997 the most remarkable increase was observed in the
population of the territories with the highest level of contamination (so-called the 2nd zone of “obligatory
resettlement”) - by 4.2 times. In the areas with the intermedium level of contamination (so-called the 3rdzone of “guaranteed voluntary resettlement”) morbidity increased by 2.3 times. And in the areas with thelowest level of contamination (so-called the 4th zone of “enhanced radiation control”) - only by 1.4 times.
Only in the 2nd zone, however, there was observed significantly higher level of pathology in comparison
with the Ukrainian population level. Such difference in the levels of morbidity of inhabitants in the different
zones was demonstrated for almost all diseases classes. Attention should be drawn to the higher excess ofmental disorders in all contaminated territories. In the 2nd zone the maximal level of mental disorders
incidence reached 69.7 ‰ rather 4.4-5.4 ‰ in the Ukrainian adult population.
There was performed an incidence cohort study of inhabitants in the contaminated territories withdifferent dose of thyroid gland irradiation [7], which registered high relative risks of blood circulationdiseases, especially cerebrovascular pathology and muscular-skeletal system.
189

As pointed out [8, 9] since 1990-1991 a sign of demographical crisis has been observed, peculiarities ofwhich are a significant decrease of birth-rate and a steep increase of mortality, including a high level of
infant mortality. That happened in the negative radiation-ecological situation due to the Chernobyl disasterand its consequences. Forecasting calculation suggests worsening of the main demographical indexes in thecontaminated territories. It is difficult, however, to estimate the size of load due to ionising radiation in theworsening demographical situation.
2.2. Health status of Chernobyl accident recovery operation workers (CAROW)
During the last period of time there were registered significant changes toward worse health status of
CAROW [10, 11]. The proportion of healthy persons among this relatively young and healthy population at
the moment of participation in elimination of the Chernobyl consequences decreased from 78.7% to 10.3%.
In the people who have received external dose of radiation more than 250 mSv the percentage of healthy
persons decreased to 7.2% due to increase of non-cancer chronic pathology which is the leading cause in
their invalidity and mortality. There were observed increases of morbidity due to neurological diseases,
diseases of sense organs, endocrine system, blood circulation, digestive organs, urinogenital system, andblood and haemopoetic system. The levels of these pathologies exceeded the incidence figures in the adult
population of Ukraine.
There was observed a high level of psychiatric disorders incidence, especially in 1990-1993 [12]. In the
structure of all diseases priority belongs to digestive organs pathology, system of blood circulation,neurological system and sense organs [13]. These three diseases classes compose 85-87% from all causes ofinvalidisation.
According to epidemiological cohort studies [14] the most significant increase of prevalence andincidence of chronic non-cancer diseases was observed in CAROW of 1986-1987 in comparison withpersons who participated in the later period of time. Fourteen years follow-up of CAROW who had acuteradiation disease demonstrated high risks of leukaemia and combined forms of immunodeficit. In a third ofthese patients there were observed relapse of skin lesions. In clinical symptomatology there was observed
domination of radiation cataracts, hypothyreoidism, organic pathology of nervous system. About 90% ofrecovered patients from acute radiation diseases are severe invalids. The main cause of death of them issudden heart death. Obtained data [13] suggest a relationship between dose of irradiation and chronic noncancer morbidity among CAROW.
In CAROW there were observed annual increase of mortality. The level of CAROW mortality
approximated to figures of the mortality in the Ukrainian population of labourable ages [12]. In the last six
years there was observed two fold annual increase of death rate of blood circulation system diseases,
respiratory, digestive systems and endocrine pathology. In the structure of causes of death the first placebelongs to pathology of blood circulation system.
2.3. Health status of the adult population of evacuees
According to State Registry of the Ukraine (SRU) [15, 16], in the adult population of evacuees from
Prypyat city and the 30-km zone around Chernobyl NPP there were observed negative tendency of healthstatus. Since 1988 through 1999 the percentage of healthy persons decreased from 67.7 % to 29.0 %. In thesame time the relative frequency of pathology increase from 31.5 % to 71.0 %. During the above-mentioned
period of time the prevalence of diseases increased by more than 3 times, and the incidence - by 2 times.
The morbidity level was higher rather than the population level for the next classes of diseases:
pathology of endocrine system, blood and haemopoetic system, mental disorders, neurological system andsense organs, system of blood circulation, digestive, and muscular-skeletal systems.
In evacuees there was observed 1.5 fold increased incidence of thyroid gland pathology due to the190acquired hypothyreoidism, thyreoidite and non-toxical nodular goiter. Annual level of thyroid pathology infemale was higher rather than in male. There is an increase of this pathology with age, and more significant
increase was observed in the people older 30.
There are some peculiarities in the structure of evacuees’ morbidity. In the early post-accidental period
the leading role was mental disorders which relative frequency reached 14%. In the following years theleading places belonged to blood circulation diseases, respiratory, neurology systems and sense organs, anddigestive organs.
There was performed a special cohort study of evacuees’ morbidity [16] with different terms ofevacuation from Prypyat city and the 30-km zone around Chernobyl NPP: the first twenty four hours, 8-12
days and 19-50 days. The highest level of morbidity was observed in Prypyat inhabitants of the earliest
evacuation, the prevalence figure of which in 1988-1998 composed 7780 ± 212.4 ‰. The lowest level ofmorbidity was observed in the sub-cohort of evacuees during 19-50 days after the accident. The level ofprevalence was 3124 ± 108.8 ‰, two times lower than the earliest sub-cohort. The intermedium level wasobserved for 8-12 days evacuees; 5436.6 ± 62.2 ‰ of prevalence.
A study of evacuees’ mortality pointed out that at the present time its level does not exceed the
population level. Nevertheless, in separate years (1993, 1994) the mortality level in teenagers (15-17 years
old) was higher than in 18-29 years and corresponded with the mortality in older population groups. In the
structure of death causes the highest relative frequency was observed due to blood circulation diseases(47.6-83.1 %), neoplasms (7.4-16.5 %), and traumas and poisoning (2.7-19%).
2.4. Health status of children affected by the Chernobyl accident
The percentage of healthy children who were evacuated or born from CAROW decreased from 30% in
the first post-accidental years to 2.8 - 5.0% [17]. The percentage of invalid children affected by the
Chernobyl accident by four times exceeds the Ukrainian population level
There was revealed an increase of somatic diseases prevalence during the follow-up period. In 1999 thelevel of all diseases prevalence (49,967 per 10,000 children) was twice the figure in 1987-1988 (25,948 per
10,000 children). The most remarkable changes were registered in index of prevalence of digestive organs
diseases (4,659 in 1988 and 10,122 in 1999 per 10,000 children), nervous system diseases (2,369 and 4,350
per 10,000 children, correspondingly).
Comparison of morbidity figures with those in the identical age groups of non-affected children
suggests a significant difference between two groups (in 1999 by 3 times higher in the affected children). A
tendency of increase was determined distinctly in digestive organs pathology, nervous system and thediseases in pathogenesis of which the main the role belongs to changes of immune system [17, 18, 19].
There was denoted that the main risk of health damage in children living in the contaminated territories
were connected with blood diseases, haemopoetic system, endocrine system pathology, digestive organs
disorders and mental disorders [19].
The increased level of morbidity may be related with both radiological and non-radiological factors(contamination of soil with radionuclides, heavy metals, pesticides, chemical composition drinking waterand so on). Portion of ionising radiation contributing to the increased morbidity is considered from 2 to
20 %.
The most unfavourable changes were observed in the children with high dose of irradiation of thyroid
gland (over 200 cGy) and in utero irradiated children. Among them the percentage of practically healthy
does not exceed 2.6-5.0 % [13].Since 1986 there were observed determined effects of irradiation on thyroid
gland: primary functional reaction observed in 1986-1987, beginning of formation chronical autoimmunal
thyreoiditis in 1990-1992, and clinical realisation of diseases - in 1992-1993.
In the latest period after the Chernobyl accident the forecasting of health status of the children affected191

by radiation is unfavourable [20]. The higher proportion of these children has developed pathology in mostorgans and systems: thyroid gland - 32.6 % (15.4 % in the control group, P<0.05), respiratory system 26.0 % (13.7 % in the control group, P<0.05), heart-vessel system (including vegeto-vessel distonia) 57.8 % (31.8 % in the control group, P<0.05), gastro-intestinal tract - 18.9 % (8.9 % in the control group,P<0.05), immunological deficiency - 43.5 % (28.0 % in the control group, P<0.05), and endocrine infertility
in girls - 32.0 % (10.5 % in the control group, P<0.05).
3. Cancer incidence rates in main groups of population affected by Chernobyl accident.
Cancer incidence rates after the Chernobyl accident were studied in the population of the territories ofKiev and Zhytomir regions neighbouring with the nuclear power plant. The most contaminated districts
included in the study were Narodichy and Ovruch districts of Zhytomir region, Ivankov, Polesskoye andnow unpopulated former Chernobyl districts. At the moment of the Chernobyl accident these five districts
accounted 274 thousand of population including 59,200 children. In 2000 the four most contaminateddistricts (without unpopulated Chernobyl district) had 125,000 residents (including 21,600 children). During
the period of observation for 1980-2000 there were registered 11,400 cases of cancer and leukaemia,
including 126 cases in children [21].
Cancer incidence rates for the period of 1990-1997 were studied in Chernobyl accident recovery
operation workers (CAROW) of 1986 and 1987 years who were chosen from 6 regions of Ukraine:
Dnepropetrovsk, Donetsk, Kharkov, Kiev, Lugansk regions and Kiev city [22]. The sample population
containing the records on 95,000 CAROW as of 1990 was constructed based on the data acquired from theState Registry of Ukraine of persons affected due to the Chernobyl accident (SRU). Cancer incidence in the
Ukrainian evacuees was studied based on the data base contained in SRU. In 1990 there were accounted
51,500 evacuees [22, 23].
3.1. Cancer incidence rates in residents of the most contaminated territories
Cancer incidence rates in the population living in various regions are illustrated in Figure I for theperiod 1980-2000 [21]. Cancer rates in the populations still living in the most contaminated districts wereconsistently lower than for the overall Ukraine or for Kiev and Zhytomir regions. Cancer incidence rates inall four groups show a similar pattern of temporal increase. Regression coefficients, which characterise theincrement per year, do not differ significantly [21, 22, 23, 24].
Comparison of standardised incidence ratios (SIR) for all cancers in the most contaminated districts isshown in Table 1 for various periods of observation. Irrespective of the sub-periods for 1990-1993, 19941997 and 1998-2000, there is no significantly increased cancer incidence for all cancers in the residents ofAge-adjusted incidence rates (10-5)

300

250

200

150

UkraineKiev region
Zhytomir region
Most contaminated districts

100

50

0
1980

1985

1990

1995

2000

Fig. I. Incidence rates for all cancers in various regions of the Ukraine. Males and females.
192

Table 1. Standardised incidence ratios for various cancers in residents of the most contaminateddistricts in Zhytomyr and Kiev regions.
Observed
Expected
Years of
Number of personnumbers of
numbers of
SIR (%)
95% CI
observation
years of observation
cases
cases
All cancers (ICD-IX 140-208), males and females
1990-2000
1660971
5378
6781
79.3
77.2 - 81.4
1990-1993
654501
2143
2607
82.2
78.8 - 85.7
1994-1997
556631
1820
2283
79.7
76.1 - 83.4
1998-2000
449839
1415
1891
74.8
70.9 - 78.7
Leukaemia and lymphoma (ICD-IX 200-208), males and females
1990-2000
1660971
310
295.7
104.8
93.2 - 116.5
1990-1993
654501
127
114.1
111.3
92.8 - 131.5
1994-1997
556631
100
98.8
101.2
82.3 - 122.0
1998-2000
449839
83
82.8
100.3
78.7 - 121.8
Thyroid cancer (ICD-IX 193), males and females
1990-2000
1660971
107
57.3
186.7
151.4 - 222.1
1990-1993
654501
24
22.4
107.2
68.6 - 154.4
1994-1997
556631
48
19.3
249.1
183.6 - 324.6
1998-2000
449839
35
15.60
224.4
150.1 - 290.8
Breast cancer (ICD-IX 174) females
1993-1997*
389645
162
107.8
150.3
127.1 - 173.4
1998-2000*
240917
97
64.1
151.3
121.2 - 181.4*Because of significant territorial variation of breast cancer incidence in the Ukraine SIR was calculated on a baseof local standard 1980-1992.

the most contaminated districts.
For leukaemia and lymphomas (Figure II) in the population from the contaminated districts there werepronounced annual incidence fluctuations. Such annual figures showed an increase for the period 1987-1991
and 1999-2000. Analysis of aggregated time periods for leukaemia and lymphoma incidence rates showed
higher levels in 1986-1991, 1992-1997 and 1998-2000 in comparison with the pre-accident period (19801985) (Table 2). When individual subtypes of these diseases were evaluated, a comparable increase wasseen for lymphoid leukaemia in 1986-1991 and (non-significantly) for 1992-1997, 1998-2000. For myeloid
leukaemia there was an increase in 1986-1991 and 1998-2000 [21, 24].
A screening (ascertainment) effect could be supposed for the first after-accident period. The overall
regression coefficients for this entire period do not suggest any significant difference among the different
20.00

Age-adjusted incidence rates (10-5)

18.00
16.00
14.00
12.00
10.00
8.00

Ukraine6.00

Kiev region
Zhytomir region

4.00

Most contaminated districts
2.00
0.00
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Fig. II. Incidence rates for leukaemia and lymphoma in various regions of the Ukraine. Males
and females.
193

Table 2. Leukaemia and lymphoma incidence rates in the population (children and adults) of 5 mostcontaminated districts in Zhytomyr and Kiev regions, Ukraine.
Mean annual age-adjusted incidence rate (10-5)
ICD9Diseasecode
1980–1985
1986–1991
1992–1997
1998–2000
200–208 10.12 ± 0.75
15.63 ± 1.06
13.41 ± 1.10
13.82 ± 1.52
Leukaemia and lymphoma
Lympho- and reticulosarcoma
200, 202
1.84 ± 0.33
2.70 ± 0.41
3.70 ± 0.58
3.36 ± 0.90
Hodgkin’s disease201
1.82 ± 0.34
2.47 ± 0.48
2.10 ± 0.48
1.23 ± 0.50
Multiple myeloma
203
0.54 ± 0.16
1.03 ± 0.25
0.78 ± 0.22
1.38 ± 0.40
Lymphoid leukaemia
204
3.08 ± 0.40
4.93 ± 0.59
2.97 ± 0.49
4.11 ± 0.75
Myeloid leukaemia
205
0.49 ± 0.17
1.99 ± 0.41
1.06 ± 0.30
2.32 ± 0.62
Other leukaemias
206–208
2.35 ± 0.36
2.51 ± 0.41
2.81 ± 0.53
1.41 ± 0.53
territories [21]. Because of large-scale out-migration of the people from the contaminated areas, there is aconcern that some members of the group of highest potential risk may have been lost to follow-up.
On the western part of Ukraine there was performed a study of morbidity and mortality rate ofleukaemia and lymphoma in relation to the Chernobyl accident during the period 1981-1994 [25, 26, 27, 28].
There were studied the population in two regions: Rivne and Ivano-Frankivsk, which correspond to thecontaminated and the non-contaminated regions as a result of Chernobyl accident, respectively. The study
has revealed that leukaemia and lymphoma morbidity and mortality rate increased mainly during the period
1987-1994 in both regions, irrespectively of their being or not being contaminated by radionuclides. The
most pronounced increase was observed in older age groups of the population of two regions. Besides,
among different forms of these diseases there were registered increases of non-Hodgkin’s lymphoma,
chronic lymphocytic leukaemia and multiple myeloma.
The radiation-related origin of the dramatic increase of thyroid cancer incidence is not in doubt [29, 30].
In Ukraine, the overall incidence of thyroid cancer was approximately doubled during the post-Chernobyl(Figure III). In the Kiev region and city of Kiev, where some 70% of the population of Pripyat and the 30km zone settled, the increases were significant (Figure IV). A dramatic increase occurred in 1996 and 1999
for the most contaminated areas [21].
In the 5 most contaminated districts, female breast cancer rate remained relatively stable during 19801992 (Figure V), though lower than in Ukraine as a whole or in regions that include contaminated districts.
In 1993-2000, however, an increase in the rate of female breast cancer (Table 1) occurred in the 5 mostcontaminated districts; which now corresponds more closely to the rate typical of Ukraine as a whole [21,22, 23].
A molecular-genetic study at Institute of Urology and Nephrology of AMS of Ukraine in collaboration

6

Age-adjusted incidence rates (10-5)5

M alesFem ales

4

3

2

1

0

1 96 2 -64

1 96 9 -72

1 97 7 -79

1 98 9 -92

1 99 3 -96

1 99 7 -99

Fig. III. Mean annual age-adjusted thyroid cancer incidence rates in the Ukraine.
194

Age-adjusted incidence rates (10-5)

16
Ukraine14

Kiev region
12

Zhytomir region
Kiev city

10

Most contaminated districts
8
6
4
2
0
1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Fig. IV. Thyroid cancer incidence rates in various regions of the Ukraine.
50

Age-adjusted incidence rates (10 -5)

45
40
35
30
25
20

Ukraine15

Kiev region

10

Zhytomir region

5
0
1980

Most contaminated districts

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Fig. V. Breast cancer incidence rates in various regions of the Ukraine.
with medical experts of University of Osaka (Japan) gave the evidence that, among prostate adenoma
patients who are inhabitants of the contaminated territories, in 53% there happened mutagenic inactivationof tumour-supressional gene, p53 and in 96% - development of pre-cancer changes in urotelii of urinary
bladder [31]. The authors has connected these changes with chronic influence of low level ionising radiation
which leads to genetic instability with possible development to chiefly invasive cancer of urinary bladder.
3.2. Cancer incidence in Chernobyl accident recovery operation workers (CAROW).
Standardised cancer incidence ratios (SIR) of different organs in CAROW of 1986, 1987 are illustrated
in Table 3 for periods 1990-1993 and 1994-1997. Significant excess is observed in CAROW for all cancers
in the first years following the accident, especially for the period 1990-1993 [22, 23].
Leukaemia and lymphoma are diseases that have drawn special attention after the Chernobyl accident.
A study of leukaemia and lymphoma in a cohort of Russian recovery operation workers has shown excess ofleukaemia and elevated radiation risks [32, 33, 34], but the data weren’t confirmed in a case-control study[30].
In Ukraine an international haematological review was performed in relation to diagnosis validation
evaluation of diagnostic material quality. The international experts panel has proved the adequacy of
diagnostic criteria applied in different regions of Ukraine as satisfying the international standards and highquality level of diagnosis of acute and chronic leukaemia [35, 36]. The percentage of confirmed cases of
Hodgkin disease and non-Hodgkin lymphomas for which histological slides were available was high, but theavailability of data from the different sources (oncological or haematological dispensaries) has to be
improved.
195

Table 3 Standardised incidence ratios for various cancers in Chernobyl accident recovery
operation workers of 1986 and 1987.
Observed
Years of
Number of personExpected
numbers of
SIR (%)
95% CI
observation years of observation
numbers of cases
cases
All cancers (ICD-IX 140-208), males
1990-1997
577536
1496
1354
110.5
104.9 - 116.1
1990-1993
263084
538
443
121.5
111.2 - 131.8
1994-1997
314452
958
911
105.1
98.5 - 111.8
Leukaemia and lymphoma (ICD-IX 200-208), males
1990-1997
577536
183
81.6
224.2
191.7 - 256.7
1990-1993
263084
81
31.8
255.0
199.5 - 310.5
1994-1997
314452
102
49.9
204.6
164.9 - 244.3
Thyroid cancer (ICD-IX 193), males
1990-1997
577536378.4
442.7
300.0 - 585.3
1990-1993
26308413
3.3
393.0
179.4 - 606.6
1994-1997
31445224
5.1
475.2
285.1 - 665.4
Breast cancer (ICD-IX 174), females
1990-1997
39188
44
29.1
151.2
106.5 - 195.8
1990-1993
15913
12
10.9
110.2
47.9 - 172.6
1994-1997
23275
32
18.2
175.6
114.8 - 236.5
A study based on the data base from the SRU for CAROW who were exposed in the period 1986-1987,
the leukaemia and lymphoma incidence rate was significantly elevated in the years 1990-1993 and 19941997 [22, 23].
Other group of investigators has followed the incidence of leukaemia in CAROW of 1986 and 1987 up
to the end of 1996 [37, 38]. In a cohort of 74.7 thousand CAROW (aged 20-69) there were registered 48
leukaemia cases during 1987-1996. The results were tabulated for the entire period of follow-up. The SIR
ratio values were relative to the comparable age and period-specific rate for Ukraine as a whole. SIR for all
leukaemia (107,8%, 95% CI 77.3 - 138.3%) were not elevated for the whole period of time. SIR for chronic
lymphoid leukaemia did not indicate changes. However, SIR for chronic myeloid leukaemia suggested aincrease of this malignancy (SIR - 258.7; 95% CI 127.8 - 389.5%). In 1989-1991 there was observed highrisk of leukaemia in CAROW of 1986 in comparison with CAROW of 1987 [39].
Russian CAROW from the same period displayed their increase in all types of leukaemia, chronic
lymphoid leukaemia and chronic myeloid leukaemia [32, 33, 34]. In Belorussian CAROW (again from1986-1987) excess of acute leukaemia was seen for 1990-1991 [40].
Besides, Table 3 demonstrates the most significant increases in thyroid cancer occurred in CAROW of1986, 1987 in the periods 1990-1993 and 1994-1997 [22]. A statistically significant increase in breast cancer
incidence rate was also observed in female CAROW of 1986, 1987 in the period 1994-1997, but not during
1990-1993 (Table 3).
3.3. Cancer incidence rate in evacuees from 30-km zone.
Standardised cancer incidence rates of different organs in evacuees are illustrated in Table 4 for theperiods; 1990-1993, 1994-1997. There is some evidence of increase of this pathology in the abovementioned group of sufferers by the Chernobyl accident. Leukaemia and lymphoma cases are significantly
elevated only for the 1990-1993 sub-period [23]. The most significant increases occurred in thyroid cancer
in both 1990-1993 and 1994-1997 sub-periods. About female breast cancer a small increase is suggested [22,
23].

196

Table 4 Standardised incidence ratios for various cancers in evacuees from 30 km zone.
Number of
Observed
Years of
Expected
person-years
numbers of
SIR (%)
95% CI
observation
numbers of casesof observationcases
All cancers (ICD-IX 140-208), males and females
1990-1997
408882
870
1234
70.5
65.8 - 75.2
1990-1993
208805432
618
69.9
63.3 - 77.8
1994-1997
200077438
616
71.1
64.5 - 77.8
Leukaemia and lymphoma (ICD-IX 200-208), males and females
1990-1997
408882
74
59.6
124.2
95.9 - 152.5
1990-1993
208805
43
30.0
143.4
100.5 - 186.3
1994-1997
200077
31
29.6
104.7
67.9 - 141.6
Thyroid cancer (ICD-IX 193), males and females
1990-1997
408882
66
12.9
513.4
389.6 - 637.3
1990-1993
20880523
6.4
362.0
214.1 - 510.0
1994-1997
20007743
6.5
661.4
463.7 - 859.1
Breast cancer* (ICD-IX 174) females
1990-1997
235072
72
52.3
137.7
105.9 - 169.5
1990-1993
119915
37
25.7
143.9
97.5 - 190.2
1994-1997
115157
35
26.6
131.7
88.1 - 175.3*Because of significant territorial variation of breast cancer incidence in the Ukraine SIR was calculated on abase of local standard 1980-1992.

3.4. Cancer incidence rates in children sufferers by the Chernobyl accidentChildren constitute a group vulnerable to radiation. Cancer incidence rates in the children population of
the most contaminated districts in Zhytomyr and Kiev regions are provided in Table 5, including the data forthe period before the accident (1980-1985). When compared to the pre-accident values (1980-1985), theonly significant excess observed in children is for thyroid cancer diagnosed during 1992-1997 and forleukaemia during 1986-1991, though the latter result may have other explanations than radiation.
According to [41] there was observed a steep increase of thyroid cancer incidence rate in children andadolescents of Ukraine. Before the Chernobyl accident (1981-1985) the level of morbidity constituted 0.05
per 100,000 children. In the post-accidental period the dynamics of this pathology was: 0.11 in 1986-1990,
0.41 in 1991-1995, and 0.40 per 100,000 children in 1996-2000.
Status of haemopoetic system due to acute and chronic irradiation has been studied in 42,888 children
inhabiting the four contaminated regions of Ukraine during 15 years after the Chernobyl accident [42, 43].
Data analysis suggested absence of excess leukaemia and lymphoma incidence rate during 1980-1999 incomparison with spontaneous background. But, in a group of 3,840 exposed children with high risks ofoncohematological pathology [42], 11 cases of acute leukaemia were registered during the period of
observation of this cohort.
There was also performed a study of the incidence of acute childhood leukaemia during 1980-1996 in
12 large territories of Ukraine including 4 regions which were contaminated by the Chernobyl accident [44,45, 46]. This study has revealed an increase of acute childhood leukaemia incidence rate in most of theregions excluding Kiev city. Certain specificity of different types of leukaemia in children age groups of 0-4,
5-9, 10-14 was revealed. It should be pointed out that the incidence rate of acute leukaemia in 10-14 years
increased mainly in the contaminated regions. Acute myeloid leukaemia had a tendency to increase in 10-14
years. In the post-accidental period (1986-1996) there was also observed an increase of inherited leukaemia
in most of territories.
With relation to this finding there is a very interesting study of acute leukaemia occurrence among thechildren exposed in utero due to the Chernobyl accident [47]. To ascertain the effect of in utero radiation
exposure and the development of leukaemia a review was undertaken of leukaemia subtypes occurring
197

Table 5 Standardised incidence ratio (SIR) for cancer in children population (0-14) of the mostcontaminated districts in Zhytomyr and Kiev regions.
Site of tumours (codeNumber of
Observed
Expected
ICD-IX)
person-years
numbers
numbers of
SIR (%)
95% CIand years of observation of observationof casescases
All cancers (140-208)
1980-1985
33707644
36.48
120.6284.98 - 156.26
1986-1991
20933744
22.69
193.95
136.64 - 251.26
1992-1997
15017031
16.26
190.62123.51 - 257.72
1998-2000
80656
7
8.70
80.46
20.86 - 140.07
1998-2000 (age 10-29)
10762937
22.61
163.62110.90 - 216.34
Leukaemia and lymphoma (200-208)
1980-1985
33707621
17.28
121.5169.54 - 173.49
1986-1991
20933727
10.75
251.11156.39 - 345.84
1992-1997
15017011
7.72
142.4958.28 - 226.69
1998-2000
80656
2
4.13
48.47
(-18.71) - 115.66
1998-2000 (age 10-29)
10762910
7.58
131.8850.14 - 213.61
Leukaemia (204-208)
1980-1985
33707619
10.88
174.6896.13 - 253.22
1986-1991
20933722
6.78
324.35188.82 - 459.89
1992-1997
1501707
4.87
143.7037.25 - 250.15
1998-2000
80656
0
2.59
0.00
0.00 - 0.00
1998-2000 (age 10-29)
1076295
2.58
193.6323.91 - 363.35
Thyroid cancer (193)
1980-1985
3370760
1.13
0.00
0.00 - 0.00
1986-1991
2093372
0.69
289.84(-111.86) - 691.53
1992-1997
1501709
0.49
1824.77632.59 - 3016.95
1998-2000
80656
1
0.28
362.91(-348.40) - 1074.22
1998-2000 (age 10-29)
1076296
1.14
527.32105.38 - 949.27
All cancers except leukaemia and lymphoma, and thyroid cancer (140-208 less 200-208, 193)
1980-1985
33707623
18.07
127.2975.27 - 179.31
1986-1991
20933715
11.24
133.4065.89 - 200.91
1992-1997
15017011
8.05
136.6555.89 - 217.40
1998-2000
80656
4
4.30
93.06
1.86 - 184.26
1998-2000 (age 10-29)
10762921
13.89
151.1686.51 - 215.81

among the children born in the year of Chernobyl accident (1986) and followed 10 years of post-exposure in
the most affected region of the Ukraine (Zhytomir region). A comparison of leukaemia cumulative incidence
rates was made between the children from the exposed and the non-exposed (Poltava region) territories. For
all cell types of leukaemia there was observed a significantly increase of incidence in the exposed region.
The rate of acute lymphoblastic leukaemia was more than three times greater in the exposed region than in
the unexposed region. The results of this study suggest that the increased risk of acute leukaemia among
those children born in 1986 and reside in the radioactively contaminated territories may be associated with
exposure to radiation resulting from the Chernobyl accident.
4. Discussion and conclusion
The established system of follow-up, dispanserisation of sufferers by the Chernobyl accident allow tocollect annually data about health status of different groups of these people. In this context it should be
reminded that the health condition of sufferers by the Chernobyl accident as well as Ukrainian population asa whole are related not only with the consequences of Chernobyl, but with aggravation in the last years of
economic, social and environmental conditions in Ukraine. The Chernobyl accident has caused a heavy
impact on the environment of vast territories of Ukraine, significant worsening of the economic situation instate, disruption of social life in the contaminated areas, growing anxiety and fears among sufferers, as well198

as certain biomedical effects on the people.
From the other side the exposed population undergo much more intensive and active follow-up of theirstatus of health rather than do the general population. Implementation of modern screening procedures (forexample ultrasound devices) have improved the quality of diagnostic procedures. These could in somedegree influence on the registered figures of diseases. Meanwhile, these figures are basis for analysis andconclusions about long-term tendencies in health status of the population affected by the Chernobyl
accident.
Similar trends in incidence rates for cancer were apparent in the different Ukrainian population groups
directly affected by the Chernobyl accident (residents of the most contaminated districts, recovery operation
workers and evacuees). There is excess of thyroid cancer [21, 22, 23, 24, 29, 30, 41]. For female breast
cancer and some other solid cancers there are suggestions of increases. Further studies are required toconfirm these tendencies along with evaluation of the effects of screening and improved registration quality.
The small number of cases for certain types of cancer and the confounding effect due to out-migration meanthat cancer monitoring and surveillance should include not only the contaminated districts but outside
regions where such residents are relocated. The apparent increases at least in part may reflect differences incase ascertainment between the affected groups and the general population of Ukraine, not relating with aradiation-related effect [30, 48]. The existing data on cancer and leukaemia-lymphoma incidence after
Chernobyl are based on the two registries: Chernobyl registry (SRU) and national cancer registry (NCR).
This approach requires more comprehensive linkage between two registries.
References
1.

Fifteen years of Chernobyl catastrophe. Experience of mitigation. National Report of the Ukraine,K.:Chornobylinterinform, 2001, 144 p. (in Ukrainian).
2. Ministry of the Chernobyl Affairs of Ukraine. Ten years after the accident at the Chernobyl nuclear power plant.
Ukrainian National Report, Kiev (1996). (In Ukrainian).
3. Oleg Nasvit. Research and Managing Institution in Ukraine concerning the Radiological Consequences of theChernobyl Accident. In: T. Imanaka (Ed) - Research Activities about Radiological Consequences of the Chernobyl
NPS Accident and Social Activities to Assist the Sufferers by the Accident. Research Reactor Institute, Kyoto
University, March 1998, pp.58-64.
4. Gulak L.O. Cancer register of the Ukraine: Experience of formation and usage in scientific researches and branchadministration. Environment and Health, Kiev, ¹ 2, 1997, pp. 12-13. (In Russian).
5. Winkelmann R., Gulak L., Okeanov A., Remennik I. Cancer registration techniques in the New Independent Statesof Former Soviet Union /IACR, Lyon, 1998, 200 p.
6. 6 Gulak L.O. Methodological aspects of large scale cancer register formation. Oncology, Kiev, Vol. 3, ¹ 2-3,
2001, pp.198-202. (In Russian).
7. Buzunov V.A., Pirogova Ye.A., Tereshtchenko V.M. at al. Dinamic of adult population health living on
contaminated with radionuclieds territories in: Medical Consequences of the Chernobyl Accident, Monograph in 3
books.”MEDECOL” interdisciplinary Scientific and Research Centre BIO-ECOS, Kiev, 1999, Book 1, -pp. 108119. (In Russian).
8. Omelyanets N.I., Kartashova S.S. Medico-demographycal consequences . //Chernobyl catastrophe. - K., 1995. P.414-417. (in Russian).
9. Omelyanets N.I., Kartashova S.S. , Dubova N.F., Savtchenko A.B. Integral estimation of Social - economic anddemographyc condition in contaminated with radionucleads regions of the Ukraine, in: Remote medical
consequences of the Chernobyl Catastrophe: Proceeding 2 international conference, 1-6 June, - K., 1998. - pp.102103. (In Ukrainian).
10. Buzunov V.A., Strapko N.P., Krasnikova L.I. Time trend of health of Chernobyl NPP accident consequences
liquidates. In.: Medical Consequences of the Chernobyl Accident, Monograph in 3 books. “MEDECOL”
Interdisciplinary Scientific and Research Centre BIO-ECOS, Kiev, 1999, Book 1, pp.65-85.
11. Buzunov V.A., Strapko N.P., Pirogova Ye.A. et al. Epidemiology of non-cancer diseases among Chernobyl

199

accident recovery operation workers. / International Journal of Radiation Medicine , 2001, 3(3-4): 9-25.
12. Nyagu A.I., Loganovsky K.N., Chuprovsky N.U. et all. Neuropsychiatric effects in: V.G.Bebeshko,
A.N.Kovalenko (Eds). - Book 2. Clinical aspects of the Chernobyl catastrophe. - K.: “MEDECOL”
interdisciplinary Scientific and Research Centre BIO-ECOS, Kiev 1999, pp.154-186. (In Russian).
13. Medical Consequences of Chernobyl nuclear power station accident. Book 2. Clinical aspects of the Chernobyl
catastrophe. V.G.Bebeshko, A.N.Kovalenko (Eds).- K.: “MEDECOL” interdisciplinary Scientific and ResearchCentre BIO-ECOS, pp. 399. (In Russian).
14. Medical Consequences of the Chernobyl Nuclear Power Plant Accident. Book 1. Epidemiology of Medical
consequences of the Chernobyl NPP Accident. V.A .Buzunov, L.A.Likhtarev (Eds). “MEDECOL”
interdisciplinary Scientific and Research Centre BIO-ECOS, Kiev 1999, pp.315. (In Russian).
15. Buzunov V.A., Pirogova Ye.A., Prikashtchikova Ye.Ye., Strapko N.P. Dinamic health status adult population
evacuated from 30 km zone and Pripyat city in Medical consequences of the Chernobyl Accident Monograph in 3
books.”MEDECOL” interdisciplinary Scientific and Research Centre BIO-ECOS, Kiev, 1999, V. 1, -pp. 86-107.
(In Russian).
16. Buzunov V.A., Pirogova Ye.A., Repin V.S. at all. Epidemiologic studies of non-cancer incidence of adult
population evacuated from Pripyat and 30-km zone surround the Chernobyl NPP. / International Journal of
Radiation Medicine , 2001, Vol. 3(3-4).- pp.26-45.
17. Korol N.A., Treskunova T.V., Duchota T.A. Children health status affected by accident on CNPP in: Medical
consequences of the Chernobyl Accident, Monograph in 3 books.”MEDECOL” interdisciplinary Scientific andResearch Centre BIO-ECOS, Kiev, 1999, Book 1, -p. 120-134. (In Russian).
18. Romanenko A.E., Bomko E.I., Bomko A.A. Estimation of health effects of long-term chronic exposure of the low
lively radiation among children exposed in consequence of the disaster at the Chernobyl nuclear power plant //Low
doses of ionizing radiation: biological effects and regulatory control: Proceeding of 1st int. conf., Seville, Spain,
17-21 November, 1997. - Vienna, 1997. - P. 326-329.
19. Romanenko A.E., Bomko E.I., Kostenko A.I.,Bomko A.A. Incidence of children resident on radioactively
contaminated territories of Ukraine and chronically exposed to low doses of ionising radiation. / International
Journal of Radiation Medicine , 2001, Vol. 3(3-4).- pp.61-70.
20. Stepanova Ye. I. Medico-biological consequences of Chernobyl catastrophe in affected children
population. ”MEDECOL” interdisciplinary Scientific and Research Centre BIO-ECOS, Kiev, 1999, Book 2, -p. 532. (In Russian).
21. Prysyazhnyuk A. et al. Results of long-term monitoring of solid cancers and leukaemia in population still living in
the most contaminated with radionuclides territories of the Ukraine after the Chernobyl accident (preliminary
report). In: International Conference “Fifteen Years after the Chornobyl Accident. Lessons Learned”. Kiev, 2001.
Chornobylinterinform. P. 3-118.
22. Prisyazhniuk, A. et al. Epidemiological study of cancer in the Ukraine with reference to the Chernobyl accident. p.
199-228 in: Seventh Symposium on Chernobyl-Related Health Effects, Tokyo, 25-16 November 1998.
23. Prysyazhnyuk A. Ye. et al. Malignant neoplasms in different groups of population affected by the Chernobyl
accident. In: International Journal of Radiation Medicine, 2001, Vol. 1, No 1-2, P. 110.
24. Prisyazhniuk, A., V. Gristchenko, V. Zakordonets et al. The time trends of cancer incidence in the mostcontaminated regions of the Ukraine before and after the Chernobyl accident. Radiat. Environ. Biophys. 34: 3-6(1995).
25. Wyhowska J., Lukawecki L., Mazurok A., Ciapka O., Fabryka A. The multiple myeloma morbidity before andafter nuclear catastrophe in Chernobyl. A study of two administrative districts of the Ukraine: Rivnensk and IvanoFrankovsk //Applied Biology Communications. - 1997. - 7, Suppl. 1. - P. 175.
26. Lukawecki L., Vygovska Y., Prysyaznyuk A., Mazurok A., Tsiapka O., Masliak Z., Fabryka A. The chronic
lymphocytic leukaemia morbidity before and after nuclear catastrophe in Chernobyl //Acta Haematologica
Polonica. - 1998. -29, Suppl. - P. 119. (In Polish).
27. Y.I.Vygovska, L.M.Lukavetsky, A.A.Mazurok, O.M.Tsiapka, A.V.Fabryka. Mortality rate caused by leukemia andlymphoma in Ukraine before and after Chernobyl catastrofe //Brit.J. of Haematology. - 1998.-102.-P.36.
28. Y.I.Vygovska, L.M.Lukavetsky, A.Ye.Prysyaznyuk, A.A.Mazurok, O.M.Tsiapka, Z.V.Masliak, A.V.Fabryka,
L.O.Karlyuk, A.S.Kalis. Haemablastosis incidence rate in representative terrytories of the Ukraine before and after

200

Chernobyl accident /Ukrainian medical newes. - 1998. -2, ¹1-2. pp.252-253. (in Ukrainian).
29. Prisyazhniuk, A., O.A. Pjatak, V.A. Buzanov et al. Cancer in the Ukraine, post-Chernobyl. Lancet: 338(8778):
1334-1335 (1991)
30. .United Nations. Sources and Effects of Ionizing Radiation. Volume I: Sources; Volume II: Effects. United Nations
Scientific Committee on the Effects of Atomic Radiation, 2000 Report to the General Assembly, with scientificannexes. United Nations sales publication E.00.IX.3 and E.00.IX.4. United Nations, New York, 2000.
31. Romanenko A., C.Lee, S.Yamamoto et al., Urinary bladder lesions after the Chernobyl accident:
immunhistochemical assessment of p. 53, proliferation cell nuclear antigen, cycling D 1 and p 21 WAF1/Cip 1.
Jpn. J. Cancer Res. -1999. - ¹ 90. -p.144-153.
32. Ivanov, V.K., E.V. Nilova, A.I. Gorsky et al. Leukaemia incidence in the population of the contaminated districtsof the Bryansk region after the Chernobyl accident (1991-1996 data). in: Fifteen Years after the Chernobyl
Accident. Lessons Learned. International Conference, Kiev, 18-20 April 2001, PP. 3-66.
33. Ivanov, V.K., A.F. Tsyb, A.I. Gorsky et al. Leukaemia and thyroid cancer in emergency workers of the Chernobyl
accident: estimation of radiation risks (1986-1995). Radiat. Environ. Biophys. 36(1): 9-16 (1997).
34. Ivanov, V.K., A.I. Gorski, A.F. Tsyb et al. Radiation risks of leukemia among Russian emergency workers, 19861997. in: International Symposium on Radiation and Homeostasis, Kyoto, Japan, 13-16 July 2001. (In press).
35. Romanenko A.Ye. et al. Main results of pilot study of leukaemia and related diseases in participants of mitigationconsequences of Chernobyl catastrophe in Ukraine. In: International Conference “Fifteen Years after the
Chornobyl Accident. Lessons Learned”. Kiev, 2001. Chornobylinterinform. P. 3-69. (In Russian).
36. Dyagil I.S. et al. Experience of international haematological review in Ukraine. In: Ukrainian journal of
haematology and transfusiology, 2001, N1, PP. 15-18 (in Russian).
37. Ledoshchuk B.A. et al. Results of the 10-years study of leukemia in Chernobyl accident clean-up workers in
Ukraine. In: Risk Analysis: Facing the New Millenium. Proceedings of SRA-Europe 9th Annual Conference/
Rotterdam, the Netherlands. October 10-13, 1999. P.833-836.
38. Ledoshchuk B.A., Gudzenko N.A. Leukemia, lymphoma and related disorders in clean-up workers of theChernobyl catastrophe consequences: developing of our understanding. In: Foresight and Precaution. Proceedingsof ESREL 2000, SARS and SRA-Europe Annual Conference. Edinburgh, Scotland, UK. May 14-17, 2000. P. 765767.
39. Ledoshchuk B.A., Gudzenko N.A. Haemoblastosis in liquidators: 15 years after Chernobyl catastrophe. Main
results and perspective. In: International Conference “Fifteen Years after the Chornobyl Accident. Lessons
Learned”. Kiev, 2001. Chornobylinterinform. P. 3-10.
40. Ivanov, E.P. et al. Chernobyl registry and hematological surveillance of Belarus liquidators. p. 171-192 in: Sixth
Symposium on Chernobyl-Related Health Effects, Tokyo, 10-11 December 1997.
41. Tronko N.D., Bogdanova T.I. Thyroid cancer in children of the Ukraine (consequences of Chernobyl catastrophe).
Kiev: Chornobylinterinform, 1997. 198 p. (in Russian).
42. Bebeshko V.G. et al. Evaluation of blood performing system in Children, evacuated from Prypyat city andinhabited on contaminated with radionuclides territories after Chernobyl accident. In: International Journal of
Radiation Medicine, special issue, 2001, Vol. 3, N2, P. 159.
43. Bebeshko V.G. et al. Influence of negative factors of environment on development of leukaemia and lymphoma inchildren inhabited in Kiev region before and after Chernobyl accident. In: Ukrainian Journal of haematology andtransfusiology, 2001, N2, PP. 17-25 (in Russian).
44. G.Moroz. Childhood leukaemia in Kyiv city and Kyiv region after Chernobyl -17 year follow up // British Journalof Haematology. - 1998. -Vol.102, ¹1. - P.19.
45. Moroz G., Drozdova V., Kireyeva S. Analysis of prognostic factors of acute leukemia after Chernobyl in childrenof Kyiv //Annals of Hematology. - 1999.- Suppl. II to Vol. 78. - P.40.
46. Moroz G., Drozdova V. Risk of acute childhood leukaemia in Ukraine after the Chernobyl reactor accident // The
Hematology Journal. - 2000.- Vol. 1, Suppl. 1. - P. 3.
47. Andrey G Noshchenko, Kirsten B Moysich, Alexandra Bondar, Pavlo V Zamostyan, Vera D Drosdova and Arthur
M Michalek. Patterns of acute leukaemia occurrence among children in the Chernobyl region. / International
Journal of Epidemiology 2001; 30: 125-129.
48. Boice, J.D. Jr. and L.E. Holm. Radiation risk estimates for leukaemia and thyroid cancer among Russian

201

emergency workers at Chernobyl. Letter to the editor. Radiat. Environ. Biophys. 36: 213-214 (1997).

202