Trends in Breast Cancer Incidence in Sweden (1958-1988)
Author Information
Author(s): I. Persson, R. Bergström, P. Sparén, M. Thörn, H.-O. Adami
Primary Institution: University Hospital, Uppsala, Sweden
Hypothesis
What factors contribute to the rising incidence of breast cancer in Sweden over the decades?
Conclusion
The increase in breast cancer incidence in Sweden is primarily due to birth cohort effects rather than the use of contraceptives or hormone replacement therapy.
Supporting Evidence
- The average annual increase in age-standardised incidence was 1.3%.
- Incidence rates increased significantly among younger age groups.
- Cohort effects were found to be more important than period effects.
- Women born in the 1950s had a 3-fold higher risk compared to those born in the 1880s.
- Data showed a slowing of incidence increase in the oldest age groups.
Takeaway
Breast cancer rates have been going up in Sweden, especially among younger women, and this is mostly because of changes in lifestyle over generations.
Methodology
Analysis of data from the Swedish National Cancer Registry covering 110,658 cases of invasive breast cancer over 31 years.
Potential Biases
Potential bias due to changes in cancer registration practices and diagnostic activities over time.
Limitations
The study did not include in situ breast cancers and relied on registry data which may have had some under-reporting in earlier years.
Participant Demographics
The study focused on women diagnosed with invasive breast cancer in Sweden.
Statistical Information
P-Value
<0.001
Statistical Significance
p<0.05
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