Oral contraceptives and breast cancer in Northern Italy. Final report from a case-control study
1993

Oral Contraceptives and Breast Cancer in Northern Italy

Sample size: 4237 publication Evidence: moderate

Author Information

Author(s): A. Tavanil, E. Negri, S. Franceschi, F. Parazzini, C. La Vecchia

Primary Institution: Istituto di Ricerche Farmacologiche 'Mario Negri'

Hypothesis

What is the relationship between oral contraceptive use and breast cancer risk?

Conclusion

The study found no significant relationship between the duration of oral contraceptive use and breast cancer risk, with some evidence suggesting a decrease in risk with longer use.

Supporting Evidence

  • 16% of breast cancer cases reported using oral contraceptives compared to 14% of controls.
  • The relative risk for ever use of combination oral contraceptives was 1.2.
  • Short-term users had the highest risk, while long-term users had a lower risk.

Takeaway

This study looked at women in Northern Italy to see if using birth control pills increases the chance of getting breast cancer, and it found that using them for a long time might actually lower the risk.

Methodology

Data were collected from a case-control study involving interviews with women diagnosed with breast cancer and matched controls, focusing on their contraceptive use and other risk factors.

Potential Biases

Potential recall bias may have affected the reporting of past contraceptive use, particularly among cases.

Limitations

The low prevalence of oral contraceptive use in the population limited the analysis of subgroups and specific time factors.

Participant Demographics

Women below age 60, with a median age of 48 years.

Statistical Information

P-Value

0.0024

Confidence Interval

1.0-1.4

Statistical Significance

borderline

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