The purpose was to investigate whether women starting oral contraceptives (OC) use young and before first pregnancy have an increased risk for breast cancer. Breast cancers occurring up until 1997 among 37 153 Helsinki students born between 1946 and 1960 were identified by record linkage from the Finnish Cancer Registry; for each cancer case five age-matched random controls were picked from the same student population. Those who had used the Helsinki Student Health Service (HSHS) at least three times (150 cases and 316 controls), form the final study subjects. Data on OC use and background characteristics were collected from patient records and data on live births were derived from the population register. Odds ratios (OR) were adjusted for number of births, smoking, and activity in sports. Most women had used OCs while using the HSHS and started OC use at the age of 20 or later and before their first pregnancy. OC users had a higher risk of breast cancer: adjusted OR=2.1 (95% confidence intervals 1.1- 4.2). Among OC users, no statistically significant differences in risk of breast cancer were found in regard to starting age or first birth.
Learning Objectives: At the conclusion of the session, the participant in this session will be able to: 1) Recognize the difficulty of studying the health impacts of health care interventions, when outcomes occur much later in the future, most people are exposed, assumed diseases are caused by many factors, the content of the intervention changes over time, and the impact varies in different groups. 2) Recognize that in the preventive health care we have commonly used interventions, all health impacts of which are not known.
Keywords: Breast Cancer, Contraceptives
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: None
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.