The evidence

Alcohol and breast cancer risk, with and without drinking

By GyroscopeUpdated November 15, 20265 sources

Alcohol raises breast cancer risk from the first drink a day, and it’s the cancer women are most likely to get from drinking. NIAAA says even one drink a day can raise a woman’s risk by 5% to 15%. In a pooled analysis of 53 studies, each 10 g a day, about two thirds of a US drink, added about 0.7 cases per 100 women by age 80.

Breast cancer is the part of the alcohol story that surprises women most. Wine has a healthy image, and a glass in the evening can feel like self-care. But breast tissue responds to the estrogen that alcohol raises. Even the National Academies, which found a possible benefit from moderate drinking for death rates overall, rated the higher breast cancer risk with “moderate certainty.”

What the chart shows

In 2002 researchers pooled the individual data of 58,515 women with breast cancer and 95,067 without, from 53 studies, and worked out risk by grams of alcohol a day. Risk rose 7.1% for each extra 10 g a day, the same in smokers and non-smokers.

They then turned it into absolute numbers using the breast cancer rates in rich countries around 1990: 8.8 of 100 non-drinking women by age 80, rising to 9.4 at 10 g a day, 10.1 at 20 g and 11.6 at 40 g. A US drink is 14 g, so a glass of wine a day is a bit over the 10 g row, and two glasses is near the 30 g row. Breast cancer is more common today than in 1990, so the counts on every row would be higher now, but the steps between them are what drinking adds.

NCI puts it in relative terms: light drinkers are about 1.04 times as likely as non-drinkers to get breast cancer, moderate drinkers 1.23 times, and heavy drinkers 1.6 times.

Why alcohol affects the breast

Two reasons stand out. Alcohol raises estrogen in the blood, and NCI says high estrogen levels can cause breast cancer. And the body turns alcohol into acetaldehyde, which damages DNA. How alcohol causes cancer has the full chain.

Is it only heavy drinking?

No. The pooled analysis found the risk rising in a straight line from low amounts, and NCI says women who have just one drink a day have a higher risk than women who drink less than one a week. The World Health Organization’s office for Europe found in 2023 that about half of the region’s alcohol-caused cancers happen in people who don’t drink heavily.

What cutting back does

NCI lists breast cancer among those where stopping is “possibly” linked to lower risk. The evidence is thinner than for mouth and esophageal cancers, partly because the risk builds over years and takes years to fall. Nobody knows yet exactly how fast it comes down. What’s clear is that every drink a day you take away removes one step on the chart.

What we’d do

If breast cancer runs in your family, or you’ve had it, treat alcohol as something to cut to zero or close. If you drink, the daily drink is the one that adds up: a glass every night adds up to more than a few glasses at a party once a month. Smaller pours, more dry nights and a good non-alcoholic option all lower it.