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Breast cancer among young U.S. women in relation to oral contraceptive use.

Abstract

BACKGROUND

While most studies have found no association between oral contraceptive use and breast cancer, several studies of younger women have reported an association with long-term oral contraceptive use. PURPOSE. We studied the relationship of patterns of oral contraceptive use to breast cancer risk among younger women. These women have had oral contraceptives available their entire reproductive lives and are now entering the breast cancer-prone years.

METHODS

A population-based, case-control study of breast cancer was conducted in three counties in western Washington State among women born in 1945 or later, ages 21-45. Case patients were 747 women with breast cancer diagnosed in 1983-1990 and identified through the Seattle-Puget Sound Surveillance, Epidemiology, and End Results cancer registry. Control subjects were 961 women identified by random-digit telephone dialing. Subjects were interviewed in person, using pictures of brands of oral contraceptives and calendars of life events as recall aids.

RESULTS

There was no increased incidence of breast cancer associated with ever having used oral contraceptives. Because only 8% of this cohort had never used oral contraceptives, short-term users (< 1 year) were combined with never users as the reference group for further analyses. A small increased risk of breast cancer was associated with long duration of oral contraceptive use (odds ratio for > or = 10 years = 1.3; 95% confidence interval [CI] = 0.9-1.9; P for trend = .03), particularly among women aged 35 years or younger (odds ratio for > or = 10 years = 1.7; 95% CI = 0.9-3.1). Breast cancer was also modestly related to oral contraceptive use early in reproductive life (odds ratio for use within 5 years of menarche = 1.3; 95% CI = 1.0-1.8; P for trend = .04) and to use of high-progestin-potency oral contraceptives for at least 1 year (odds ratio = 1.5; 95% CI = 1.1-2.1). These associations were adjusted for age, age at menarche, term pregnancy, induced abortion, and family history of breast cancer. The associations were not further confounded by case-control differences in education, religion, breast feeding of offspring, or infertility; in oral contraceptive contraindications, indications, or complications; or in measures of breast cancer detection such as mammography or breast biopsy.

CONCLUSIONS

Long-term oral contraceptive use among young women or use beginning near menarche may be associated with a small excess breast cancer risk, possibly due to susceptibility to genetic damage in breast epithelial cells at ages of high breast cell proliferative activity.

IMPLICATIONS

Future studies should investigate whether the patterns of risk we reported are present as this cohort ages.

Links

  • Publisher Full Text
  • Authors+Show Affiliations

    ,

    Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98104.

    , ,

    Source

    Journal of the National Cancer Institute 86:7 1994 Apr 06 pg 505-14

    MeSH

    Adult
    Breast Neoplasms
    Case-Control Studies
    Contraceptives, Oral, Combined
    Contraceptives, Oral, Hormonal
    Female
    Humans
    Middle Aged
    Multivariate Analysis
    Odds Ratio
    Registries
    Time Factors
    Washington

    Pub Type(s)

    Journal Article
    Research Support, U.S. Gov't, P.H.S.

    Language

    eng

    PubMed ID

    8133534

    Citation

    White, E, et al. "Breast Cancer Among Young U.S. Women in Relation to Oral Contraceptive Use." Journal of the National Cancer Institute, vol. 86, no. 7, 1994, pp. 505-14.
    White E, Malone KE, Weiss NS, et al. Breast cancer among young U.S. women in relation to oral contraceptive use. J Natl Cancer Inst. 1994;86(7):505-14.
    White, E., Malone, K. E., Weiss, N. S., & Daling, J. R. (1994). Breast cancer among young U.S. women in relation to oral contraceptive use. Journal of the National Cancer Institute, 86(7), pp. 505-14.
    White E, et al. Breast Cancer Among Young U.S. Women in Relation to Oral Contraceptive Use. J Natl Cancer Inst. 1994 Apr 6;86(7):505-14. PubMed PMID: 8133534.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Breast cancer among young U.S. women in relation to oral contraceptive use. AU - White,E, AU - Malone,K E, AU - Weiss,N S, AU - Daling,J R, PY - 1994/4/6/pubmed PY - 1994/4/6/medline PY - 1994/4/6/entrez KW - Age Factors KW - Americas KW - Biology KW - Breast Cancer KW - Cancer KW - Case Control Studies KW - Contraception KW - Contraceptive Agents, Female--administraction and dosage KW - Contraceptive Agents, Progestin--administraction and dosage KW - Contraceptive Agents--administraction and dosage KW - Contraceptive Methods KW - Cultural Background KW - Cytology KW - Demographic Factors KW - Developed Countries KW - Diseases KW - Ethnic Groups KW - Family Planning KW - Menarche KW - Menstruation KW - Neoplasms KW - North America KW - Northern America KW - Oral Contraceptives KW - Population KW - Population Characteristics KW - Population Dynamics KW - Reproduction KW - Research Report KW - Studies KW - Time Factors KW - United States KW - Washington KW - Whites--women SP - 505 EP - 14 JF - Journal of the National Cancer Institute JO - J. Natl. Cancer Inst. VL - 86 IS - 7 N2 - BACKGROUND: While most studies have found no association between oral contraceptive use and breast cancer, several studies of younger women have reported an association with long-term oral contraceptive use. PURPOSE. We studied the relationship of patterns of oral contraceptive use to breast cancer risk among younger women. These women have had oral contraceptives available their entire reproductive lives and are now entering the breast cancer-prone years. METHODS: A population-based, case-control study of breast cancer was conducted in three counties in western Washington State among women born in 1945 or later, ages 21-45. Case patients were 747 women with breast cancer diagnosed in 1983-1990 and identified through the Seattle-Puget Sound Surveillance, Epidemiology, and End Results cancer registry. Control subjects were 961 women identified by random-digit telephone dialing. Subjects were interviewed in person, using pictures of brands of oral contraceptives and calendars of life events as recall aids. RESULTS: There was no increased incidence of breast cancer associated with ever having used oral contraceptives. Because only 8% of this cohort had never used oral contraceptives, short-term users (< 1 year) were combined with never users as the reference group for further analyses. A small increased risk of breast cancer was associated with long duration of oral contraceptive use (odds ratio for > or = 10 years = 1.3; 95% confidence interval [CI] = 0.9-1.9; P for trend = .03), particularly among women aged 35 years or younger (odds ratio for > or = 10 years = 1.7; 95% CI = 0.9-3.1). Breast cancer was also modestly related to oral contraceptive use early in reproductive life (odds ratio for use within 5 years of menarche = 1.3; 95% CI = 1.0-1.8; P for trend = .04) and to use of high-progestin-potency oral contraceptives for at least 1 year (odds ratio = 1.5; 95% CI = 1.1-2.1). These associations were adjusted for age, age at menarche, term pregnancy, induced abortion, and family history of breast cancer. The associations were not further confounded by case-control differences in education, religion, breast feeding of offspring, or infertility; in oral contraceptive contraindications, indications, or complications; or in measures of breast cancer detection such as mammography or breast biopsy. CONCLUSIONS: Long-term oral contraceptive use among young women or use beginning near menarche may be associated with a small excess breast cancer risk, possibly due to susceptibility to genetic damage in breast epithelial cells at ages of high breast cell proliferative activity. IMPLICATIONS: Future studies should investigate whether the patterns of risk we reported are present as this cohort ages. SN - 0027-8874 UR - https://www.unboundmedicine.com/medline/citation/8133534/Breast_cancer_among_young_U_S__women_in_relation_to_oral_contraceptive_use_ L2 - https://academic.oup.com/jnci/article-lookup/doi/10.1093/jnci/86.7.505 DB - PRIME DP - Unbound Medicine ER -