Increase of regional total cancer incidence in north Sweden due to the Chernobyl accident?
OBJECTIVE
Is there any epidemiologically visible influence on the cancer incidence after the Chernobyl fallout in Sweden?


METHODS
A cohort study was focused on the fallout of caesium-137 in relation to cancer incidence 1988-1996.


METHODS
In northern Sweden, affected by the Chernobyl accident in 1986, 450 parishes were categorised by caesium-137 deposition: < 3 (reference), 3-29, 30-39, 40-59, 60-79, and 80-120 kiloBecquerel/m(2).


METHODS
All people 0-60 years living in these parishes in 1986 to 1987 were identified and enrolled in a cohort of 1 143 182 persons. In the follow up 22 409 incident cancer cases were retrieved in 1988-1996. A further analysis focused on the secular trend.


RESULTS
Taking age and population density as confounding factors, and lung cancer incidence in 1988-1996 and total cancer incidence in 1986-1987 by municipality as proxy confounders for smoking and time trends, respectively, the adjusted relative risks for the deposition categories were 1.00 (reference < 3 kiloBecquerel/m(2)), 1.05, 1.03, 1.08, 1.10, and 1.21. The excess relative risk was 0.11 per 100 kiloBecquerel/m(2) (95% CI 0.03 to 0.20). Considering the secular trend, directly age standardised cancer incidence rate differences per 100 000 person years between 1988 to 1996 and the reference period 1986-1987, were 30.3 (indicating a time trend in the reference category), 36.8, 42.0, 45.8, 50.1, and 56.4. No clear excess occurred for leukaemia or thyroid cancer.


CONCLUSIONS
Unless attributable to chance or remaining uncontrolled confounding, a slight exposure related increase in total cancer incidence has occurred in northern Sweden after the Chernobyl accident.
Tondel
Martin
M
Division of Occupational and Environmental Medicine, Department of Molecular and Clinical Medicine, Faculty of Health Sciences, Linköping University, 581 85 Linköping, Sweden. Martin.Tondel@lio.se
Hjalmarsson
Peter
P
Hardell
Lennart
L
Carlsson
Göran
G
Axelson
Olav
O
D000293:Adolescent; D000328:Adult; D002588:Cesium Radioisotopes / Q000008:administration & dosage / Q000009:adverse effects; D047852:Chernobyl Nuclear Accident; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D011156:Population Density; D011847:Radioactive Fallout / Q000009:adverse effects* / Q000032:analysis; D018788:Radioactive Hazard Release; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology
D002588:Cesium Radioisotopes; D011847:Radioactive Fallout