New Breast Cancer Risk Factor: Women Who Smoke
Here’s an important “I told you so” moment for women who smoke. If you smoked early in life… before you got pregnant, your breast cancer risk factor may be modestly higher, this from new research that gives weight to the case against smoking and cancer of the breast.
Cancer of the breast is the most common cancer among all women of the world, and in the United States, it is the second most common cause of death in women. Lung cancer is first.
For this research, the experts examined personal smoking history, plus any exposure to passive smoking when assessing the risk of breast cancer using data from over 100,000 female subjects who were followed from the late 1970’s for 30 years; along with another 36,000 women who gave information for 24 years on exposure to secondhand smoke. Clearly there is a very large study group here.
The analysis found that cancer risk was 18% higher among those women who started smoking before they had their first baby, and 4% greater for women who began smoking after the birth of their first child or sometime before menopause. Unexpectedly, smoking after menopause was associated with a slight decrease in risk.
In the follow up years just shy of 9000 incidents of breast cancer were diagnosed. The risk of this type of cancer was higher for the following:
– Current or past heavy smokers who smoked 25+ cigarettes/day).
– Women who began smoking before their 17th birthday.
– Those who smoked for a minimum of 20 years.
As you might expect, the women who smoked heavily,who started early and kept the habit for a long time had the highest risk of this type of cancer.
The good news for non smokers?
Never smoking and being exposed in childhood to passive smoking were not associated with an increased chance of breast cancer. Having parents who smoked, or secondhand exposures at work or school were also not associated with a higher cancer risk, even after adjusting for other known risk factors.
Experts have known for some time that cigarette smoke contains several cancer causing substances, yet the link between smoking and cancer of the breast has been elusive, some studies offering findings that were inconsistent or controversial. One of the difficulties is that lifetime smoking comes from many places – active and passive (secondhand) smoke – and these aren’t so easy to measure.
Breast cancer is a disease that is expected to strike one in seven American women sometime during their lifetime. This year alone, there will be 207,090 new cases of breast cancer among women in the United States according to the National Cancer Institute numbers.
More work in this area is needed to further clarify the breast cancer risk factor, and what can be done to help women resist smoking at an early age, when they can do damage to their bodies that can’t be undone.