Response to the letter from Dr Shelton
1990

Response to Dr. Shelton's Letter on Breast Cancer Risks

publication Evidence: moderate

Author Information

Author(s): D.B. Thomas, E.A. Noonan

Primary Institution: Fred Hutchinson Cancer Research Center

Hypothesis

The increased relative risk of breast cancer in developing countries may be due to biases in control selection.

Conclusion

The authors argue that their findings of increased breast cancer risk among oral contraceptive users in developing countries are not due to the biases suggested by Dr. Shelton.

Supporting Evidence

  • The prevalence of oral contraceptive use did not vary significantly across different diagnostic categories of controls.
  • Data collection began over 10 years ago, reducing the likelihood of recent disease status affecting results.
  • Findings from other studies in China and Costa Rica support the increased risk of breast cancer in oral contraceptive users.

Takeaway

The study suggests that using oral contraceptives might increase breast cancer risk, especially in developing countries, but the authors believe their results are valid despite concerns about bias.

Methodology

The authors analyzed data on breast cancer risk and oral contraceptive use, considering various potential confounding factors.

Potential Biases

The authors believe that the biases suggested by Dr. Shelton do not adequately explain their findings.

Limitations

The authors did not provide detailed information on all controls' medical histories due to space constraints.

Participant Demographics

The study involved women from both developed and developing countries with a range of diseases.

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