As breast cancer patients and survivors, we naturally are concerned about the possibility that our daughters might also develop breast cancer. They are at higher risk than the general population even in the absence of harmful BRCA1 or BRCA2 mutations in the family.

There are steps that can be taken during the prenatal period and at each stage of childhood and young adulthood to reduce the subsequent risk of breast cancer. For example, use of birth control pills, exposure to radiation of the chest, and cigarette smoking during the teenage years and young adulthood increase the risk of breast cancer in later years, whereas vigorous exercise during this period reduces it. Now a new study has reported that alcohol consumption between first period and first full-term pregnancy increases the risks of benign proliferative breast disease disease and breast cancer.

Alcohol increases breast cancer risk

Even low levels of alcohol consumption have been associated with increased breast cancer risk in most studies that have examined its effects. The increased risk appears to be greater among postmenopausal women and for estrogen receptor positive (ER+) tumors. However, one study also reported that teenage girls with a family history of breast cancer who consumed seven alcoholic drinks per week doubled their risk of benign breast disease in young adulthood, which in turn increased their subsequent risk of breast cancer.

Alcohol consumption that takes place before diagnosis has also been found to be associated with a modest but significant increase in breast cancer recurrence. One study reported that elevated risk of recurrence was found among wine drinkers who had at least two servings per day compared to no alcohol intake.

Latest research finds drinking at young age increases risk

The study referenced at the beginning of this news story was designed to examine the contribution of alcohol consumption during the interval between first period and first birth to both the risk of benign proliferative breast disease and the risk of breast cancer. Breast tissue is especially susceptible to carcinogens during this period. To conduct that study, the authors analyzed data from 91,005 mothers in the Nurses’ Health Study II who had no cancer history at the time of enrollment, completed a questionnaire concerning early alcohol consumption in 1989, and were followed through June 2009. A subset of 60,093 of the women who had no history of benign proliferative breast disease or cancer in 1991 and were followed through June 2001 were included in the analysis of benign proliferative breast disease.

A total of 1,609 breast cancer cases and 970 benign proliferative breast disease cases were diagnosed during the study periods. Alcohol consumption between first period and first full-term pregnancy was associated with increased risks of breast cancer (11% increase per 10g/day alcohol intake) and benign proliferative breast disease (16% increase), adjusted for drinking after first pregnancy. "If a female averages a drink per day between her first period and her first full-term pregnancy, she increases her risk of breast cancer by 11 percent,” said co-author Graham Colditz in a separate interview. Drinking after first pregnancy produced a similar increased risk of breast cancer but not of benign proliferative breast disease. The association between drinking before first pregnancy and breast cancer appeared to be stronger with longer intervals between first period and first pregnancy. The authors conclude that alcohol consumption before first full-term pregnancy is associated with increased risks of benign proliferative breast disease and breast cancer.

Please see our articles on how to reduce breast cancer risk in our daughters during the prenatal period and infancy, childhood and puberty, and the teenage years and young adulthood for more information.