Avtor/Urednik		Dodič-Fikfak, Metoda
Naslov		Kritični pregled epidemioloških raziskav, ki obravnavajo učinke nizkih doz ionizirajočih sevanj
Prevedeni naslov		A critical overview of low-level radiation epidemiological studies
Tip		članek
Vir		Sanitas et labor
Vol. in št.		Letnik 3, št. 1
Leto izdaje		2004
Obseg		str. 31-44
Jezik		eng
Abstrakt		Nearly half a million workers in the U.S. are potentially exposed to ionizing radiation, their average level of occupational exposure to low-level radiation being approximately 50mSv. There are a number of problems in interpreting the results of occupational low-level radiation studies, due mainly to the expected small effects of low radiation doses. False positive results due to chance or study bias are diffcult to distinguish from real effects. The major objective of studies of nuclear workers is to evatuate the consistency of these data and risk estimates derived from populations exposed to high-dose radiation. The principal objective of this work was to review the most important epidemiological studies of low-level radiation exposure which were capable to determine very low risks associated with low-level radiation. In all the studies reviewed, the standardized mortality ratio (SMR) for all causes of death was less than 1, which suggests the influence of healthy worker effect. The risks for certain types of cancer were occasionally increased, but the results obtained were mostly statistically nonsignificant and inconsistent. The Wilkins' meta-analysis, which included eight studies and was conducted in order to overcome the problem of small numbers, showed that the risk of blood cancer among workers exposed to radiation doses of 10mSv was two times higher than among workers exposed to radiation doses below 10mSv. The leukaemia risk was by 80% higher. The results indicate that the risk is increasing with the dose received. The studies done to date have shown that subjects exposed to low- level radiation were at an increased risk of developing leukaemia and lymphatic and haematopoetic tissue cancers, but not solid tumors.
Izvleček		Samo v ZDA je nizkim dozam ionizirajočega sevanja (IS) izpostavljenih skoraj pol miljona ljudi. Srednja vrednost izpostavljenosti nizkim dozam ionizirajočega sevanja za te judi je okrog 50mSv. Ker je pričakovani učinek takega sevanja majhen in ker je učinke pristranosti ali slučajne rezultate težko ločiti od dejanskih učinkov, obstajajo številni problemi, kako vrednotiti tako nizke izpostavljenosti. Bistven cilj velikih epidemioloških študij, ki so preučevale vplive nizkih doz radioaktivnega sevanja na zdravje človeka, je bil ugotoviti konsistentnost dobljenih rezultatov s tveganjem, ki je bilo izračunano na podlagi modelov uporabljenih za visoke izpostavljenosti. Osnovni cilj tega dela je bil pregledati tiste najpomembnejše epidemiološke študije o vplivu nizkih izpostavljenosti IS v svetu, ki so imele zadostno raziskovalno moč, da bi lahko odkrile zelo majhna tveganja. V vseh študijah so bile vrednosti SMR (standardizirano razmerje umrljivosti) za vse vzroke smrti manj kot 1, kar kaže na vpliv učinka zdravega delavca na rezultate. Za nastanek določenih rakov je bilo včasih ugotovljeno povišano tveganje, vendar so bili rezultati v večini primerov statistično nesignifikantni in nekonsistentni. Wilkinsova meta analiza, ki je vključila osem študij in je bila narejena zato, da bi se izognila malemu številu opazovanih delavcev, je odkrila enkrat višje tveganje za razvoj rakov krvi in krvotvornih organov pri tistih delavcih, ki so bili izpostavljeni več kot 10mSv v primerjavi z onimi, ki so bili izpostavljeni manj kot 10rnSv. Za razvoj levkemije je bilo to tveganje višje za 80%. Študija je tudi nakazala, da tveganje narašča s prejeto dozo. Dosedanje študije torej kažejo, da imajo ljudje, ki so izpostavljeni nizkim dozam IS višje tveganje za razvoj levkemije in rakov limfatičnega in hematopoetskega tkiva, vendar višje tveganje ni dokazano za razvoj solidnih tumorjev.
Deskriptorji		RADIATION DOSAGE RADIATION, IONIZING RADIATION EFFECTS RADIATION INJURIES META-ANALYSIS