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Alcohol consumption before first pregnancy increased breast neoplasia risk
Women who consumed alcohol between menarche and first pregnancy carried a 10% increased risk for breast cancer, according to study results.
The researchers aimed to investigate the effect of alcohol consumption on breast cancer or proliferative benign breast disease risk in the interval between menarche and first full-term pregnancy.
The analysis included data from 91,005 parous women from the Nurses’ Health Study II. Eligibility criteria included no previous history of cancer. Women were asked about alcohol consumption in 1989. Follow-up continued through June 2009 to gauge breast cancer risk.
The analysis also included a subset of 60,093 women with no history of benign breast disease or breast cancer in 1991. This cohort was followed through June 30, 2001.
Review of histology results indicated that 1,609 cases of breast cancer and 970 proliferative benign breast disease cases developed. The researchers reported that breast cancer risk was increased among women who consumed alcohol between menarche and first pregnancy (RR=1.11 per 10g/day intake; 95% CI, 1.00-1.23). Proliferative benign breast disease also was increased among women who consumed alcohol in this interval (RR=1.16 per 10g/day intake; 95% CI, 1.02-1.32).
Breast cancer risk was elevated among women who drank after first pregnancy (RR=1.09 per 10g/day intake; 95% CI, 0.96-1.23). No similar risk for benign breast disease was observed among women who drank during this time period.
As the interval between first menstruation and first pregnancy increased, the association between drinking before first pregnancy and breast neoplasia increased.
Disclosure: The work was supported by the NCI and NIH.Perspective
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If these studies are truly significant, I suspect that Mormon and/or Muslim women should be less burdened with breast neoplasia. Are they, really? Recent studies from Malaysia (Farooqui M. Asian Pac J Cancer Prev. 2013;14:3017-3021) suggest no dearth of breast cancer in Muslim folk. Utah Mormon women do have less breast cancer but are less likely to survive it compared with non-Mormon Utah women (Merrill RM. BMC Cancer. 2005;5:49). However, parity and breast-feeding behavior muddy any conclusions in this latter study.
Perspective
Back to TopDrinking alcohol daily is recognized as a dose-dependent risk factor for breast cancer. Based on retrospective data, there was a suggestion that higher risks of developing breast cancer were associated with younger ages (ie, younger than 30 to 35 years) at the onset of regular drinking.
With this background, Liu and colleagues analyzed alcohol consumption and risks of developing both breast cancer and proliferative benign breast disease in the large prospective cohort of the Nurses’ Health Study. Their results, showing that elevated relative risks of both breast cancer and proliferative benign breast disease were statistically significantly higher for higher daily consumption and prolonged durations between menarche and first pregnancy, are consistent with other risk factors in which the risks are higher the younger the age of exposure. A classic example is radiation-associated breast cancer in women treated with mantle irradiation for Hodgkin’s disease in which the highest relative risks are among the youngest women.
Three important points to make: Exposures at young ages, for both alcohol and radiation, can manifest decades later in higher risks of breast cancer; pregnancy induces changes in breast tissues and systemic hormones that result in lesser risks of breast cancer; and finally, the attributable risk of breast cancer and proliferative disease to alcohol was only 4% and 11%, respectively. In effect, this means that developing breast cancer is never just one thing, as newly diagnosed women are apt to imagine when looking back and asking themselves what they did or didn’t do to explain why they developed breast cancer. Rather, it is many things, most of which we do not understand. I am sure that one day we will understand why breast cancer develops.