Epidemiological Study of Thyroid Cancer in Cluj County after Chernobyl: 10 Years Follow-Up

Stefania S. Salagean, Rita Burkhardt, Ildikó Mocsy, Nicoleta Muntean

Institute for Public Health, Cluj-Napoca, Romania
 
Corresponding author:Dr. Stefania S. Salagean, Dipl. Biol.
Institute of Public Health Cluj
6 Pasteur Str., 3400 Cluj-Napoca, Romania
Tel.: +40 64-194-252, Fax: +40 64-199-891
e-mail: root@jeffmcm.soroscj.ro

CEJOEM 1998, Vol.4. No.2.:155-160



Key words:
Health impact, Chernobyl accident, thyroid cancer, incidence-rate, pre- and post Chernobyl. 

Abstract:
This study investigates trends in the incidence rates of thyroid cancer in Cluj county in relation to the population exposure to radiation resulted from Chernobyl accident.
The whole population of Cluj county was under study, representing 12.5 million persons/year, that is about 740,000 persons over a period of 17 years, between 1980–1996.
We have calculated the incidence rate of thyroid cancer per 100,000 inhabitants and its distribution per sexes, age groups (nurseling, child, teenager, adult) and per environment (urban – rural). We have also calculated the dynamics indices, which can show the dynamics of this malignant disease over the investigated period of time (1980–1996) and the percentage of thyroid cancer compared to other malignant disease new cases registered annually in Cluj county.
Thyroid cancer represents a very small proportion – about 1% of the total number of new cancer cases recorded annually, with an incidence rate between 0.68 and 3.29%, the maximum value being registered in 1996. We have observed differences in the distribution of the disease in the two sexes, the incidence rate being all the time higher in women than in men. The incidence rate is also higher in the urban environment than in the rural one.
By monitoring the thyroid cancer morbidity over age we have discovered only three cases in young ages (in 1983, 1991 and 1994) all the other cases only affected adults.
In order to establish if there is a change as regards the incidence of thyroid cancer in the population of Cluj county the observed number of cases and the incidence rate for the period 1987–1996 (8 months – 10 years post-accident) were compared with the expected value based on the average incidence rate over a 6 year period before the accident (1980–1985).


Received: 25 November 1997
Accepted: 04 April 1998 
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Posted: 15 November 1998