Elsevier

International Congress Series

Volume 1276, February 2005, Pages 106-109
International Congress Series

Mortality and morbidity from cancer in the population exposed to high level of natural radiation area in Ramsar, Iran

https://doi.org/10.1016/j.ics.2004.11.109Get rights and content

Abstract

The aim of this study was to investigate if a higher incidence or mortality from cancer is seen among the population living in the high-background radiation area of Ramsar. The Ramsar city was divided into areas of high level of natural radiation area (HLNRA) and normal level of natural radiation area (NLNRA). Data regarding morbidity and mortality from cancer were obtained from different sources. Standard incidence ratios (SIR) were used to compare the morbidity experience of HLNRA to those of NLNRA. Standard mortality ratios (SMR) were calculated for two regions of the HLNRA (low exposure and high exposure) using national mortality rates. The incidence ratio for females was 1.5, indicating a slight increase in incidence in the HLNRA compared with that in the NLNRA. The mortality was slightly higher for females living in HLNRA (SMR=1.3 in high exposure area and 1.2 in low exposure area). Neither SMRs nor SIRs showed a statistically significant difference from the unity. No increase in incidence or mortality was seen among the male population. We have concluded that more epidemiologic studies are needed before a solid conclusion can be made.

Introduction

Ramsar, an Iranian city located in Caspian littoral, is one of the few areas in the world where very high levels of natural radiation, as high as 100 ⎧Gy h-1, were recorded in some spots [1]. Studies of the effect of natural radiation on the health of people living in this area have been a special interest to scientists for a long time. Cytogenetics studies of the inhabitants in the area of Ramsar have established a higher frequency of chromosomal aberrations [2], [3]. The aim of this study was to investigate if a higher incidence or mortality from cancer is seen among the population living in the high background radiation area of Ramsar compared to normal radiation area.

Section snippets

Materials and methods

The total area of Ramsar was divided into two regions: high level of natural radiation area (HLNRA) and normal level of natural radiation area (NLNRA). The HLNRA included the following four villages: Chaparcar-Sar, Talesh-Mahaleh, Sadat-Mahaleh (Sadat Rostai and Sadat-Shahr) and Ramak. The NLNRA included all other areas of the Ramsar city. Since the level of radiation differed in villages in HLNRA, the villages were further divided into two categories; Talesh-Mahalleh, Chaparsar, Sadat Rostai

Results

During the calendar year of 2003, a total of 43 incident cases of cancer occurred in the Ramsar area, of which, 36 cases were in the NLNRA and seven cases in the HLNRA. While the distribution of cancer was comparable between sexes in the NLNRA (52% for female and 48% for male), a marked difference was seen in the HLNRA (85% in female and 15% in male). The age adjusted incidence rate of cancer was slightly higher among female population of the HLNRA compared to the NLNRA (incidence ratio,

Discussion

Correlation between natural background radiation and cancer morbidity and mortality has been studied in various countries in the world. Early studies proved a positive association (Italy [5] and Poland [6]), but some studies failed to show any correlation (India [7] and Ireland [8]). Our study showed a slight increase in cancer morbidity among females living in the area with higher levels of natural background radiation and no increase of cancer among males. The discrepancy between male and

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