Smoking and Drinking: Breast Cancer Risks You Can Control

Young woman smoking cigarette outside office building
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There are breast cancer risks we can do nothing about, such as getting older or having a family history of breast cancer. Then there are those, such as drinking and smoking, that we can control.

Smoking and Breast Cancer Risk

Smoking has long been recognized as a risk factor for many cancers. In the past few years, research studies have studied smoking as a risk for breast cancer.

Recently, American Cancer Society researchers studying the impact of smoking on breast cancer discovered an increased breast cancer risk in women who smoked. They went on to find that the risk was highest in women that began smoking before given birth to their first child.

Earlier studies that examined the potential relationship between smoking and breast cancer did not satisfy the scientific community. While these studies found a slightly increased risk of breast cancer from smoking, studies did not determine if smoking more each day, or over many years increased the risk of breast cancer.

The Journal of the National Cancer Institute, published the results of the American Cancer Society study. They reported that when researchers analyzed data from 73,388 women, and conducted a 13+ year follow-up they identified 3,721 cases of invasive breast cancer. Smokers had a 24% higher rate of breast cancers than non-smokers. Former smokers had a 13% higher rate than nonsmokers.

The report went on to say that researchers also found a 12% increase in breast cancer risk among women who started smoking at a young age, and a 21% increase in risk among women who started before the birth of their first child.

Women, who are smokers at the time of diagnosis, are strongly encouraged to stop smoking. In addition to all the known health problems related to smoking, if a woman smokes during treatment she runs the risk of adding to her complications. Smoking can causes problems during radiation therapy. It may also impact on the healing process following surgery and reconstruction. Chemotherapy may cause mouth sores; smoking will irritate the sores and add to their discomfort. Smoking also increases a woman’s chance of a blood clot while on hormone therapy.

The Guardian recently reported on a study indicating that smoking increases the risk of breast cancer in older women by almost a fifth.

Drinking and Breast Cancer Risk

The International Agency for Research on Cancer has declared that there is sufficient scientific evidence to classify alcoholic beverages a Group 1 carcinogen that causes breast cancer in women.​ Group 1 carcinogens are the substances with scientific evidence that they cause cancer, such as smoking tobacco.

According to The National Cancer Institute, over 100 studies examined the association between drinking alcohol and women’s risk for breast cancer. Findings identified an increased risk with increased drinking. A review of 53 of these studies (which included a total of 58,000 women with breast cancer) showed that women who drank more than 45 grams of alcohol per day (approximately three drinks) had 1.5 times the risk of developing breast cancer as nondrinkers.

The Million Women Study, which involved 1.3 million women in the UK, demonstrated that the risk of breast cancer increases by 7.1% every time you drink 10 grams of alcohol which is slightly over one drink per day.

The American Cancer Society shares that even a few drinks a week is linked with an increased risk of breast cancer in women. Alcohol can raise estrogen levels in the body, and since many invasive breast cancers are estrogen fed, this may explain the increased risk.

The American Cancer Society suggests that by not smoking, and by limiting alcohol consumption to one drink a day, a woman can reduce her risk for breast cancer.


American Cancer Society: Active Smoking and Breast Cancer Risk: Original Cohort Data and Meta-analysis. Published early online February 28, 2013 in the Journal of the National Cancer Institute. First author: Mia Gaudet, PhD, American Cancer Society, Atlanta, Ga.

National Cancer Institute, Million Woman Study, The Guardian, The International Agency for Research on Cancer.

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