Cancer incidence in northern Sweden before and after the Chernobyl nuclear power plant accident

• Published in: Radiation and Environmental Biophysics
• Main Authors: Alinaghizadeh, Hassan, Tondel, Martin, Wålinder, Robert
• Format: Article in Journal/Newspaper
• Language: English
• Published: Uppsala universitet, Arbets- och miljömedicin 2014
• Subjects: Cancer; Cesium-137; Chernobyl; Ecological study; Environment; Epidemiology; Ionizing radiation; Nuclear accident; Radiation; Sweden; Occupational Health and Environmental Health; Arbetsmedicin och miljömedicin; Northern Sweden
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231289; https://doi.org/10.1007/s00411-014-0545-6

Sweden received about 5 % of the total release of Cs-137 from the Chernobyl nuclear power plant accident in 1986. The distribution of the fallout mainly affected northern Sweden, where some parts of the population could have received an estimated annual effective dose of 1-2 mSv per year. It is disputed whether an increased incidence of cancer can be detected in epidemiological studies after the Chernobyl nuclear power plant accident outside the former Union of Soviet Socialist Republics. In the present paper, a possible exposure-response pattern between deposition of Cs-137 and cancer incidence after the Chernobyl nuclear power plant accident was investigated in the nine northernmost counties of Sweden (2.2 million inhabitants in 1986). The activity of Cs-137 from the fallout maps at 1986 was used as a proxy for the received dose of ionizing radiation. Diagnoses of cancer (ICD-7 code 140-209) from 1980 to 2009 were received from the Swedish Cancer Registry (273,222 cases). Age-adjusted incidence rate ratios, stratified by gender, were calculated with Poisson regression in two closed cohorts of the population in the nine counties 1980 and 1986, respectively. The follow-up periods were 1980-1985 and 1986-2009, respectively. The average surface-weighted deposition of Cs-137 at three geographical levels; county (n = 9), municipality (n = 95) and parish level (n = 612) was applied for the two cohorts to study the pre- and the post-Chernobyl periods separately. To analyze time trends, the age-standardized total cancer incidence was calculated for the general Swedish population and the population in the nine counties. Joinpoint regression was used to compare the average annual percent change in the general population and the study population within each gender. No obvious exposure-response pattern was seen in the age-adjusted total cancer incidence rate ratios. A spurious association between fallout and cancer incidence was present, where areas with the lowest incidence of cancer before the accident coincidentally had ...