The work concerns the assessment of radiation risks for non-cancer diseases of circulatory system among the Chernobyl liquidators. The medical and dosimetric data from Russian National Medical and Dosimetric Registry were used. The cohort data from 1986 to 2000 years of 61017 liquidators are discussed. Radiation risks are established for the cerebrovascular diseases and for the essential hypertension the significant. ERR =0.45/Gy, with 95% CI = (0.11; 0.80) for the cerebrovascular diseases and ERR = 0.36/Gy, with 95% CI = (0.005; 0.71) for the essential hypertension. It approves the results which were established by authors for the similar cohort in 1986-1996. The cerebrovascular diseases (CVD) are considered in greater details. The significant heterogeneity of the radiation risks by working time in Chernobyl zone is shown for the first time. ERR = 0.89/Gy for the working time less then 6 weeks, and ERR = 0.39/Gy in average for all periods of working in the zone. Among the liquidators entered Chernobyl zone during the first year after the accident (29003 liquidators), the CVD's risk group consists of persons accumulated more then 150 mGy from external sources in less, then 6 weeks (RR = 1.18 with 95% CI = (1.00; 1.40)). The significant CVD's risk from averaged dose rate was defined for external doses greater then 150 mGy (ERR for 100 mGy/day = 2.17, with 95% CI = (0.64; 3.69)).

The paper provides analysis of information about incidence and mortality with respect to malignant neoplasms of the digestive system in the Chernobyl liquidators accumulated in the Russian National Medical and Dosimetric Registry (RNMDR) in the period from 1986 to the beginning of 1998. The study includes male liquidators registered in six regional centers of the RNMDR providing most reliable medical and dosimetric data on an annual basis, namely Northwest, Volgo-Vyatsky, Central-Chernozemny, Povolzhsky, North-Caucasian and Urals. The number of liquidators under study is 96026 persons, which accounts for 57% of all liquidators registered in the RNMDR. The mean dose in the study cohort is 108 mGy, the mean age at the time of entry in the zone is 34.3 years and the total accumulated number of person-years is 1011727. The incidence and mortality rates for cancers of the digestive system were compared for liquidators and the population of Russia in general through calculation of the standardized incidence ratio (SIR) and the standardized mortality ratio (SMR). The values of SIR and SMR with 95% confidence intervals (CI) for malignant neoplasms of the digestive system were estimated to be 0.88 (0.80; 0.97) and 0.72 (0.64; 0.80), respectively. For liquidators who arrived in the zone in 1986 these are 0.97 (0.85; 1.11) and 0.81 (0.70; 0.94), respectively. During the period of 1991-1997, when SIR in liquidators became stable, the values of SIR and SMR with 95% CI for malignant neoplasms of the digestive system were 1.00 (0.90; 1.10) and 0.87 (0.78; 0.98), respectively. For liquidators who arrived in the zone in 1986 these values were 1.15 (1.00; 1.33) and 1.02 (0.86; 1.19), respectively. Estimation of radiation risks for this class of diseases did not reveal any statistically significant increase in cancer incidence or mortality with increase in external radiation dose in liquidators.

Background: In the Netherlands, the influenza vaccination rate increased from 6% in the eighties up to 16% in the late nineties. The Dutch Influenza Council, founded in the early nineties, started a series of activities in a multitargeted intervention strategy. The increase in vaccination rate is related to the activities in this intervention. Methods: In the yearly reports of the Dutch Influenza Council, all data on government policy, vaccination rate, patient and doctor behavior were assembled, together with data from other sources (Dutch Bureau for Statistics, Prevention project of the Dutch College of General Practitioners). Results: In a timetable, all activities are presented. Patient knowledge on high-risk groups improved. The rise in vaccination rate shows two tops: in 1992 at the start of the Dutch Influenza Council, and in 1996 at the start of the national GP-prevention project. In 1999, the vaccination rate in high-risk groups was 76%. Conclusions: This multitargeted system approach was successful in increasing vaccination rates, especially in high-risk groups. This combined effort of government, private enterprise and national GP organizations sets an example for other national preventive actions.

The paper provides analysis of information about solid cancer incidence among liquidators of the Chernobyl accident accumulated in the Russian National Medical and Dosimetric Registry (RNMDR) from 1986 to the beginning of 1997. The RNMDR contains individual dosimetric data and results of annual medical examinations of liquidators living in the territory of the Russian Federation (174916 persons by the beginning of 1999). Consideration is given to male liquidators who had no cancer before entering the 30-km zone around the Chernobyl NPP and for whom information was available about date of birth, date of arrival to the zone, duration of stay in the zone and data of medical examinations. The number of liquidators meeting these requirements is 160564, which accounts for about 90% of all liquidators registered in the RNMDR. For most of liquidators (70%) the Registry database contains information on external radiation dose received during their stay in the 30-km zone. The mean dose in this study cohort is 0.1 Gy, the mean age at the time of the first arrival in the zone is 34 years and the total number of accumulated person-years is 1353935. The cohort of liquidators is briefly described and the cancer incidence rates are compared in liquidators and the population of Russia as a whole through calculation of the standardized incidence ratio (SIR). The excess relative risk per unit dose is also estimated (ERR/Gy). The risk values with 95% confidence intervals for all solid malignant neoplasms and cancers of respiratory organs and digestive system are estimated to be 0.91 (0.25; 1.57), 1.13 (-0.24; 2.40) and 0.85 (-0.3; 2.04), respectively.

The RNMDR is a multi-level information system. Primarily it is integrated in the existing health care system. In principle primary health care is provided at the levels of uchastoks (local), rayon's (district) and oblasts (province). Regional centers have been established for compiling and processing data from the oblast level. Thereby, four hierarchical levels exist federal, regional, oblast and rayon. Regional centers have been set up for each of the 11 administrative, so-called economical regions of Russia. They have to be regarded as decentralized units of the central registry as their main task is to channel the information flow from the local to the federal level. According to the normal Russian administration these regions are further subdivided into republics, oblasts and krays. At present there are altogether 89 units at this level. These units are further subdivided into rayon's, altogether more than 2,000 in the Russian Federation. Four of the oblast units (Bryansk, Kaluga, Orel and Tula oblasts) have at the same time the logistical status of a regional center. These oblasts represent the most contaminated geographical areas in Russia. The software for all levels of surveillance is used for computerization of primary information collection, uniform data base support and statistical and radio-epidemiological analysis. Thus the software employs advanced computer techniques to collect, store, process, transfer and analyze demographic, medical, dosimetric and epidemiological data and ensures the reliability of software products at all levels of surveillance, as well as their lack of complexity and ease of use for medical personnel. The software falls into two functional parts - database support and analysis of information collected. Databases of large-scale and local registries store information in different ways, i.e. these bases are of different physical structure. In order to make the analytical part of the software flexible and multipurpose, i.e. independent of the specific features of particular bases, access to them should be uniform. The system of statistical and radio-epidemiological data analysis (SDA) enables the basic epidemiological indexes to be calculated in the interactive mode. It also provides thorough statistical and radio-epidemiological analysis of data from the RNMDR primary documents. Standard and specialized software in use are integrated into a unified information system of storage and epidemiological, medical and statistical analysis of data.

We present a detailed description of dosimetric data entered in the Russian National Medical and Dosimetric Registry (RNMDR) for emergency workers (liquidators) involved in recovery operations (RO) after the Chernobyl accident. The data on the absorbed doses from external exposure are based on the documents given to liquidators by organizations that performed dosimetric monitoring in the zones of operation. Using the data on external doses currently available in the RNMDR for 119,416 liquidators (78.4% of the total number of 152,325 persons), different statistical characteristics were derived to assess the reliability of the information. The paper also discusses dose distributions according to the date of beginning work in the RO zone [up to 250 km from the Chernobyl nuclear power plant (NPP)], on the distance of the settlement where the liquidators were accommodated or worked from the NPP, and on the duration of their stay in the RO zone. To analyse the reliability of the dosimetric data, the notion of an effective exposure dose rate (EEDR), i.e. the ratio of the dose registered in RNMDR and the duration of stay in the RO zone, was introduced for each liquidator, and corresponding statistical characteristics for the distribution of EEDR depending on the date of entry into the RO zone and distance from the place of residence or work to the NPP were obtained. The analysis for different groups of liquidators shows that the dosimetric information of the RNMDR is, as a statistical aggregate, generally consistent with the data on the radiation situation in the RO zones.

This article presents description of systematized experience accumulated by a large group of specialists in medical and organizational maintenance of RNMDR. The basic tasks of the medical service of the Registry include organizational activities to collection of the primary medical information, quality control of this data at various stages, and also verification of cases of diseases or deaths among the persons registered in RNMDR. The experience accumulated during Registry functioning allows making a conclusion that development and introduction of the managing concept of medical and organizational activities in the RNMDR system provides better registration, and permits improvement of medical examinations and a higher quality of data in the Registry.

The automated quality control system for personal data of Russian National Medical and Dosimetric Registry is a powerful software package including a series of subsystems: syntactical control, logic control, control of migration of contingent under monitoring, compatibility of Registry data. The subsystems to control execution of protocols and epidemiologic control are being developed. The automated quality control system allows having a master database at the national level of the Registry, in which information is subjected to diverse checking and verification.

The work focuses on direct epidemiological assessment of radiation risks in induction of leukemia and thyroid cancer in emergency workers after the Chernobyl accident. The Russian National Medical Dosimetric Registry compiles data for 168 thousand emergency workers as of 01.01.1996. Analysis is performed of 48 leukemias and 47 thyroid cancers diagnosed and verified in emergency workers. The estimated radiation risks are: for leukemia excess relative risk per Gy (ERR/Gy) is 4,30 (95% CI = 0,83; 7,75), excess absolute risk per 104 PY Gy (EAR/104 PY Gy) is 1,31 (95% CI = 0,23; 2,39); and for thyroid cancer ERR/Gy is 5,31 (95% CI = 0,04; 10,58), EAR/104 PY Gy is 1,15 (95% CI = 0,08; 2,22).

This issue presents first a detailed description of dosimetric data registered in the All-Russia Medical and Dosimetric State Registry (ARMDSR) for emergency workers at the Chernobyl NPP. In do-simetric fields of the ARMDSR for emergency workers the data on absorbed doses of external radiation of persons are received from oficial documents given to emergency workers by organizations after carrying out dosimetric monitoring in the zone of emergency works. On the basis of ARMDSR data on radiation doses for 125771 emergency workers (79,1 % from the total number 159027 men) all possible statistic characteristics are developed which allow to estimate degree of reliability of obtained information. In this issue the distribution of absorbed doses depending on the date of beginning of works in the emergency zone (0-250 km from the Unit 4 of the ChNPP), distance from the settlement (where emergency worker lives or nearby which his working place is located) up to the ChNPP, time of being in the emergency zone are given. For analyzing the reliability of dosimetric data the definition of effective exposure dose rate (EEDR) of radiation field for each emergency worker is introduced and corresponding statistic characteristics of distribution of EEDR depending on the data of arrival to the emergency zone as well as distance from residence or working zone up to the ChNPP are listed. Analysis of obtained results for different categories of emergency workers is conducted. It demonstrates that dosimetric data of the ARMDSR as a statistic whole complex doesn't be contrary to radiation situation in emergency zones. Reliability of each individual dose value is at present the subject of studies of corresponding department of the ARMDSR and for specialists of other institutions and organizations.

In presented paper the problem of thyroid cancer following the ChNPP accident is considered for the first time on the basis of system approach. The three main tasks are solved: prognostication of immediate and later effects of radiation action comments with the induction of malignant thyroid tumors; determination of radiation risks of non-cancer thyroid diseases; estimation of radiation risks of cancer thyroid diseases. As a result of conducted prognostication estimates it is shown, in particular, that the attributive life time risk for children from the territories of Bryansk oblast contaminated by radionuclides will constitute 44% (i.e., nearly each second cancer will be conditioned by radiation), for children of Kaluga oblast this coefficient will amount to 26%. In the cohort of children and adolescents of Kaluga oblast (5694 people) with individual radiation dose of thyroid gland based on direct radiometry carried out in 1986 the radiation risk estimates of non-cancer thyroid diseases were obtained. In particular, estimation of excess relative risk coefficient at the dose of 1 Gy equal to 0,2 (0,06; 0,34) is in a good agreement with the data published on the basis of AHS-cohort (Japan). The technology case-control is realized first for determination of radiation risks of thyroid cancer diseases by children and adolescent (at the moment of the accident) living in Bryansk oblast. The relative risk coefficient of thyroid cancer diseases in the western rayons of Bryansk oblast contaminated by radionuclides at the dose of 1 Gy is equal 7,15 (1,52; 33,8). The principal radiation epidemiological data obtained evidence the necessity of conducting the long-term monitoring the persons exposed to radiation action due to the ChNNP accident.