Early oral contraceptive use and breast cancer among premenopausal women : final report from a study in southern Sweden

In southern Sweden during the 1960s, women began to use oral contraceptives (OCs) extensively at a young age. This case-control study investigates the relationship between the use of OCs and breast cancer development in women in southern Sweden diagnosed in the early 1980s. The risk for breast cancer after OC use among premenopausal women was modeled, after adjustment was made for age, age at menarche, and age at first full-term pregnancy or parity. Both the duration of OC use before 25 years of age and commencement of OC use at a young age were associated with a significant increase in the risk of breast cancer as well as a significant trend. The duration of OC use before the first full-term pregnancy was associated with an increased risk of breast cancer, but it did not show a significant trend. The total duration of OC use was weakly, but not significantly, associated with breast cancer development. The odds ratio for women starting OC use before 20 years of age was 5.8 [95% confidence interval (CI), 2.6-12.8]; for women using OCs for greater than 5 years before age 25, it was 5.3 (95% CI, 2.1-13.2); and for women using OCs for greater than or equal to 8 years before first full-term pregnancy, it was 2.0 (95% CI, 0.8-4.7). In multivariate analyses including the different measurements of OC use, only starting age of OC use was significantly associated with breast cancer. The exposure-response relationship between duration of OC use and risk of breast cancer depended on the age at first use of OCs. Given a fixed duration of OC use, the risk increased with younger starting age of OC use. The findings point to the importance of the early reproductive years as risk determinants for breast cancer after OC use.

Medienart:

Artikel

Erscheinungsjahr:

1989

Erschienen:

1989

Enthalten in:

Zur Gesamtaufnahme - volume:81

Enthalten in:

Journal of the National Cancer Institute - 81(1989), 13 vom: 05. Juli, Seite 1000-4

Sprache:

Englisch

Beteiligte Personen:

Olsson, H [VerfasserIn]
Möller, T R [VerfasserIn]
Ranstam, J [VerfasserIn]

Themen:

Age Factors
Biology
Breast Cancer--determinants
Cancer
Case Studies
Contraception
Contraceptive Methods--side effects
Contraceptives, Oral
Control Groups
Data Analysis
Data Collection
Demographic Factors
Developed Countries
Diseases
Europe
Family Planning
Incidence
Journal Article
Measurement
Neoplasms
Northern Europe
Oral Contraceptives--side effects
Population
Population At Risk
Population Characteristics
Research Methodology
Research Support, Non-U.S. Gov't
Risk Factors
Scandinavia
Studies
Sweden

Anmerkungen:

Date Completed 25.07.1989

Date Revised 10.05.2019

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM027143716