Combined oral contraceptives containing chlormadinone acetate and breast cancer: results of a case-control study
1991

Oral Contraceptives and Breast Cancer

Sample size: 1713 publication Evidence: moderate

Author Information

Author(s): K. Ebeling, R. Ray, P. Nischan, D.B. Thomas, D. Kunde, H. Stalsberg

Primary Institution: Humboldt University

Hypothesis

Does the use of combined oral contraceptives containing chlormadinone acetate influence breast cancer risk?

Conclusion

The study found that chlormadinone as a constituent of combined oral contraceptives does not influence breast cancer risk.

Supporting Evidence

  • The study included 490 cases of newly diagnosed breast cancer and 1,223 controls.
  • Relative risks for breast cancer were not elevated in ever users of combined OCs.
  • Current users showed a relative risk of 1.72 for combined OCs with chlormadinone, but this was attributed to a screening effect.

Takeaway

This study looked at whether a specific type of birth control pill causes breast cancer, and it found that it doesn't.

Methodology

A case-control study comparing 490 breast cancer cases with 1,223 controls, using standardized questionnaires and medical record reviews.

Potential Biases

Selection bias was minimized, but recall bias could still be a concern.

Limitations

The study may have limitations related to recall bias and the generalizability of findings to other populations.

Participant Demographics

Women diagnosed with breast cancer and controls matched by age, with specific exclusion criteria.

Statistical Information

P-Value

p<0.05

Confidence Interval

(0.88, 3.36) for current users of combined OCs with chlormadinone; (1.01, 2.00) for current users without chlormadinone.

Statistical Significance

p<0.05

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