Informed

Breastfeeding reduces premenopausal breast cancer risk

In a large, prospective cohort study of premenopausal women, breastfeeding was protective against premenopausal breast cancer, especially in women with a first-degree family history of breast cancer [1]. The study, published in the Archives of Internal Medicine, assessed the relationship between breastfeeding and incidence of premenopausal breast cancer among women participating in the large Nurses’ Health Study II.

The researchers analysed detailed information on breastfeeding history and supplemental feeding among 60,075 premenopausal women who reported at least one pregnancy. Questionnaires on demographic, anthropometric and lifestyle factors were also collected, with follow-up questionnaires every two years. After 357,556 person-years of follow-up, 608 incident cases of premenopausal breast cancer were diagnosed, with an average age of diagnosis of 46 years. Women who had ever breastfed had a lower incidence of premenopausal breast cancer compared with women who hadn’t.

Among women with a first-degree relative with breast cancer there was a 59 per cent reduction in incidence of premenopausal breast cancer when comparing those who had ever breastfed with those who hadn’t. The authors concluded that women with a family history of the disease should be particularly encouraged to breastfeed.

This large study confirms the findings of the Second Expert Report [2] that breastfeeding protects against premenopausal breast cancer. The Report also found that exclusive lactation for six months reduces the risk of postmenopausal breast cancer. See A Closer Look at: Breastfeeding leaflet for more information.

To read about UK breastfeeding rates, visit our diet, lifestyle and weight statistics section.

References

1. Stuebe AL et al 2009 Arch Intern Med 169(15):1364-1371
2. WCRF/AICR. Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. Washington DC: AICR, 2007