Background: Epidemiological evidence which suggests that prolonged breastfeeding protects against breast cancer has accumulated in recent years. Issues with regard to the timing of breastfeeding and effect modification by correlates of breastfeeding and other risk factors of breast cancer remain unresolved.
Methods: A population-based case–control family study of breast cancer among women diagnosed by the age of 50, conducted in two geographic areas in Germany, was used to evaluate the effect of breastfeeding on risk of breast cancer.
Results: Among parous women in this study (553 cases, 1094 age-matched population controls), having ever breastfed a child for at least 1 month did not confer protection (odds ratio of 0.9 and 95% confidence interval (CI) 0.8–1.2). However, risk of breast cancer significantly decreased with increasing duration of breastfeeding (p for trend = 0.01) and the estimated relative risk was 0.6 (95% CI 0.4–0.9) for 13–24 months of cumulative breastfeeding and 0.5 (95% CI 0.3–1.1) for 25 months or more. Risk was less related to number of children breastfed than to increasing average length of breastfeeding per child (p for trend = 0.03).
Conclusions: The reduction in risk associated with duration of breastfeeding was not primarily due to breastfeeding the firstborn and more evident in women who were older ( > 25 years) when they first breastfed and among women who experienced a recent full-term pregnancy. Risks were modified somewhat by a first-degree family history of breast cancer whereby a greater reduction in risk per additional month of breastfeeding was observed among women with a family history than those without (0.9 vs. 1.0). The study results support a protective role of prolonged breastfeeding against the development of breast cancer in predominantly premenopausal women in Germany.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price excludes VAT (USA)
Tax calculation will be finalised during checkout.
Lane-Clayton JE (1926) A further report on cancer of the breast with special reference to its associate antecedent conditions. In: Report on Public Health and Medical Subjects, 39. London: HM Stationery Office.
Ing R, Petrakis NL, Ho JH (1977) Unilateral breast-feeding and breast cancer. Lancet 2: 124–127.
Byers T, Graham S, Rzepka T, Marshall J (1985) Lactation and breast cancer. Evidence for a negative association in premenopausal women. Am J Epidemiol 121: 664–674.
McTiernan A, Thomas DB, Johnson LK, Roseman D (1986) Risk factors for estrogen receptor-rich and estrogen receptor-poor breast cancers. J Natl Cancer Inst 77: 849–854.
Rosero-Bixby L, Oberle MW, Lee NC (1987) Reproductive history and breast cancer population of high fertility, Costa Rica 1984-85. Int J Cancer 40: 745–747.
Layde PM, Webster LA, Baugham AL, Wingo PA, Rubin GL, Ory HW (1989) The independent associations of parity, age at first full term pregnancy, and duration of breastfeeding with the risk of breast cancer. Cancer and Steroid Hormone Study Group. J Clin Epidemiol 42: 963–973.
Newcomb PA, Storer BE, Longnecker MP, et al. (1994) Lactation and a reduced risk of premenopausal breast cancer [see comments]. N Engl J Med 330: 81–87.
United Kingdom National Case-Control Study Group (1993) Breast feeding and risk of breast cancer in young women. BMJ 307: 17–20.
Yang CP, Weiss NS, Band PR, Gallagher RP, White E, Daling JR (1993) History of lactation and breast cancer risk [see comments]. Am J Epidemiol 138: 1050–1056.
Brinton LA, Potischman NA, Swanson CY, et al. (1995) Breastfeeding and breast cancer risk. Cancer Causes Control 6: 199–208.
Katsouyanni K, Lipworth L, Trichopoulou A, Samoli E, Stuver S, Trichopoulos D (1996) A case-control study of lactation and cancer of the breast. Br J Cancer 73: 814–818.
Romieu I, Hernandez-Avila M, Lazcano E, Lopez L, Romero-Jaime R (1996) Breast cancer and lactation history in Mexican women. Am J Epidemiol 143: 543–552.
Enger SM, Ross RK, Henderson B, Bernstein L (1997) Breastfeeding history, pregnancy experience and risk of breast cancer. Br J Cancer 76: 118–123.
Enger SM, Ross RK, Paganini-Hill A, Bernstein L (1998) Breastfeeding experience and breast cancer risk among postmenopausal women. Cancer Epidemiol Biomarkers Prev 7: 365–369.
McCredie M, Paul C, Skegg DC, Williams S (1998) Reproductive factors and breast cancer in New Zealand. Int J Cancer. 76: 182–188.
Adami HO, Bergstrom R, Lund E, Meirik O(1990) Absence of association between reproductive variables and the risk of breast cancer in young women in Sweden and Norway. Br J Cancer 62: 122–126.
Brignone G, Cusimano R, Dardanoni G, et al. (1987) A case-control study on breast cancer risk factors in a southern European populaiton. Int J Epidemiol 16: 356–361.
Kvale G, Heuch I (1987) Lactation and cancer risk: is there a relation specific to breast cancer? J Epidemiol Community Health 42: 30–37.
Ekbom A, Hsieh CC, Trichopoulos D, Yen YY, Petridou E, Adami HO (1993) Breast-feeding and breast cancer in the offspring. Br J Cancer 67: 842–845.
Thomas DB, Noonan EA (1993) Breast cancer and prolonged lactation. The WHO Collaborative Study of Neoplasia and Steroid Contraceptives. Int J Epidemiol 22: 619–626.
Negri E, Braga C, La Vecchia C, Levi F, Talamini R, Franceschi S (1996) Lactation and the risk of breast cancer in an Italian population. Int J Cancer 67: 161–164.
Michels KB, Willett WC, Rosner BA, et al. (1996) Prospective assessment of breastfeeding and breast cancer incidence among 89,887 women. Lancet 347: 431–436.
Stuver SO, Hsieh CC, Bertone E, Trichopoulos D (1997) The association between lactation and breast cancer in an international case-control study: a re-analysis by menopausal status. Int J Cancer 71: 166–169.
Rothman K, Greenland S (1998) Modern Epidemiology, 2nd edn. Philadelphia, PA, USA: Lippincott-Raven.
Tao SC, Yu MC, Ross RK, Xiu KW (1988) Risk factors for breast cancer in Chinese women of Beijing. Int J Cancer 42: 495–498.
Yuan JM, Yu MC, Ross RK, Gao YT, Henderson BE (1988) Risk factors for breast cancer in Chinese women in Shanghai. Cancer Res 48: 1949–1953.
Wang QS, Ross RK, Yu MC, Ning JP, Henderson BE, Kimm HT (1992) A case-control study of breast cancer in Tianjin, China. Cancer Epidemiol Biomarkers Prev 1: 435–439.
Yoo KY, Tajima K, Kuroishi T, et al. (1992) Independent protective effect of lactation against breast cancer: a case-control study in Japan. Am J Epidemiol 135: 726–733.
Chie W-C, Chen C-F, Lee W-C, Chen CJ (1996) Socioeconomic status, lactation and breast cancer risk of parous women in Taiwan. Oncol Rep 3497–3501.
Ross RK, Yu MC (1994) Breast-feeding and breast cancer [letter; comment]. N Engl J Med 330: 1683.
Freudenheim JS, Marschall JR, Vena JE, et al. (1997) Lactation history and breast cancer risk. Am J Epidemiol 146: 932–938.
Siskind V, Schofield F, Rice D, Bain C (1989) Breast cancer and breastfeeding: results from an Australian case-control study. Am J Epidemiol 130: 229–236.
Egan KM, Stampfer MJ, Rosner BA, et al. (1998) Risk factors for breast cancer in women with a breast cancer family history. Cancer Epidemiol Biomarkers Prev 7: 359–364.
Henderson BE, Ross RK, Pike MC, Casagrande JT (1982) Endogenous hormones as a major factor in human cancer. Cancer Research 42: 3232–3239.
Petrakis NL, Wrensch MR, Ernster, VL, et al. (1987) Influence of pregnancy and lactation on serum and breast fluid estrogen levels: implications for breast cancer risk. Int J Cancer 40: 587–591.
Dewailly E, Ayotte P, Brisson J (1994) Protective effect of breast feeding on breast cancer and body burden of carcinogenic organochlorines [letter]. J Natl Cancer Inst 86: 803.
Moysich KB, Ambrosone CB, Vena JE, et al. (1998) Environmental organochlorine exposure and postmenopausal breast cancer risk. Cancer Epidemiol Biomarkers Prev 7: 181–188.
Drescher K, Becher H (1997) Estimating the generalized impact fraction from case-control data. Biometrics 53: 1170–1176.
About this article
Cite this article
Chang-Claude, J., Eby, N., Kiechle, M. et al. Breastfeeding and breast cancer risk by age 50 among women in Germany. Cancer Causes Control 11, 687–695 (2000). https://doi.org/10.1023/A:1008907901087