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

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.