A study published online in August, 2013 in the Journal of Clinical Nursing found that breastfeeding for six months or longer could delay diagnosis of breast cancer by about 10 years. But the protective benefits were cancelled out if mom was a smoker.
The study, conducted at the University of Granada in Spain, examined medical records of more than 500 women aged 19 to 91, who were diagnosed and treated for breast cancer between 2004 and 2009 at a university hospital in the province of Granada.
Non-smokers who did not have children or who breastfed for less than three months were diagnosed with breast cancer at an average age of 57; non-smokers who breastfed between 3 and 6 months were diagnosed at a similar age of 56. Non-smokers who breastfed longer than six months, on the other hand, were diagnosed at an average age of 68 — more than 10 years later. However, women who breastfed longer than six months but were smokers were diagnosed at an average age of 47, or 21 years earlier. These results held steady, even when family history of breast cancer was factored in.
Previous studies done in the United States and elsewhere had found breastfeeding to be slightly protective against breast cancer. One review of studies on breastfeeding and breast cancer found that breast cancer risk decreased by 4 percent for every 12 months of breastfeeding; the review found that a breastfeeding period of 12 months seemed to offer similar protection, whether the mother had nursed just one baby, or multiple babies adding up to a total of 12 months of breastfeeding.
The fact that smoking outdoes any benefit derived from breastfeeding came as no surprise; smoking is a well-established carcinogen and has been linked specifically to breast cancer in other studies.
The American Cancer Society estimates that more than 234,000 cases of breast cancer will be diagnosed in 2013 in the U.S., with about 40,000 deaths occurring from it this year. Being that the incidence of breast cancer has skyrocketed in recent decades, and that diagnoses are coming at younger and younger ages, it is important for women to do what is in their power to avoid the disease.
The American Academy of Pediatrics recommends for mothers to breastfeed exclusively for the first six months of a baby’s life, continuing to at least 12 months as other foods are added to the baby’s diet. The Centers for Disease Control and Prevention report that three-quarters of all American babies are breastfed as newborns, the highest number in many years. But the most recent CDC analysis, which covers the year 2010, found that only 49 percent of U.S. babies were breastfed to six months, and only 27 percent were breastfed to 12 months. The CDC blames this in part on hospital culture that does not do enough to encourage breastfeeding and highlight its importance.
One health advocate called on nurses to take a more active role in talking to new moms about the importance of breastfeeding, and of avoiding cancer-causing habits such as smoking and excessive alcohol consumption.
By Eirian Hallinan