Radiation and non-radiation factors impact on development of cerebrovascular diseases in the Chornobyl clean-up workers. The epidemiological study results.

OBJECTIVE

To establish the cerebrovascular disease risks in the Chornobyl clean-up workers with regard to whole-body external dose and non-radiation factors i.e. biological, social-and-hygienic, behavioral ones.

MATERIALS AND METHODS

Risk-analysis was based on the cohort of the Chornobyl male clean-up workers of 1986-1987 period (8625 men including 3623 with known whole-body external radiation dose values). Data from the Clinical-and-epidemiological registry, National Research Centre for Radiation Medicine were used. Observation period was since 1992 till 2010. We have used the approach with the internal control group with radiation doses less than 0.05 or 0.1 Gy.

RESULTS

The statistically significant radiation risks were established for the chronic forms of cerebrovascular disease at doses 0.5 Gy and higher, for some forms of the disease in certain dose-age strata i.e. 0.25 Gy and more. Statistically significant non-radiation risks for cerebrovascular disease were recorded with regard to age, psychoemotional stress, alcohol abuse, malnutrition, smoking, harmful working conditions etc. Role of age as a confounding factor was analyzed under the assessing of radiation risks with Mantel-Haenszel method application to improve the estimates of radiation effects.