Ethnic differences of cancer incidence in Estonia: two cross-sectional unlinked census based cancer incidence analyses
Estonian and Russian ethnic groups in Estonia differ from one another in several aspects such as historic and socio-economic background, language and culture. The aim of the current study was to examine ethnic differences in cancer incidence in Estonia, and to compare the situation before and after the profound political and economical changes in early 1990s.
Methods: Two cross-sectional unlinked census based cancer incidence analyses were performed.
Cancer incidence data were obtained from the Estonian Cancer Registry. Population denominators came from the population censuses of 1989 and 2000.
Standardised cancer incidence rates were calculated for men and women for the aggregate periods 1988-1990 and 1999-2000. The absolute differences in standardised cancer incidence rates for Estonians and Russians together with standard errors and p-values for SE-s in 1989 and 2000 were evaluated for both sexes.
Differences in cancer incidence between Estonians and Russians in 1989 and 2000 were estimated for both sexes, using standardised rate ratios with 95% confidence intervals.
Results: Between 1988-1990 and 1999-2000, the total cancer incidence in Estonian men increased while in Russian men it decreased. The rates for stomach and lung cancer declined for both ethnic groups, whereas the decline for Russian men was larger compared to Estonian men, especially for lung cancer.
Cancer incidence in women increased for both ethnic groups from 1988-1990 to 1999-2000. Most importantly this change was caused by the increased incidence of breast cancer, which was more pronounced in Estonian women.
Conclusions: The Russians in Estonia have an excess cancer rate for a number of sites, and the differences are more pronounced in men.
A constant finding is the excess of stomach cancer in Russians for both sexes. Some of the differences in cancer rates between the Estonians and Russians in Estonia are likely to be attributable to variation in exposure to specific etiologic factors that are caused by differences in lifestyle, such as diet, smoking and drinking habits.
However some of changes over time may be due to differential migration. Further research to understand these ethnic differences in cancer incidence is warranted.
Published on: 2009-06-28