Even light alcohol consumption linked to higher cancer risk in Japan

In a study conducted in Japan, even light to moderate alcohol consumption was associated with elevated cancer risks. In the study published early online in Cancer, a peer-reviewed journal of the American Cancer Society, the overall cancer risk appeared to be the lowest at zero alcohol consumption.

Although some studies have linked limited alcohol consumption to lower risks of certain types of cancer, even light to moderate consumption has been associated with a higher risk of cancer overall. To study the issue in Japan, Masayoshi Zaitsu, MD, Ph.D., of The University of Tokyo and the Harvard T.H. Chan School of Public Health, and his colleagues examined 2005-2016 information from 33 general hospitals throughout Japan. The team examined clinical data on 63,232 patients with cancer and 63,232 controls matched for sex, age, hospital admission date, and admitting hospital. All participants reported their average daily amount of standardized alcohol units and the duration of drinking. (One standardized drink containing 23 grams of ethanol was equivalent to one 180-milliliter cup (6 ounces) of Japanese sake, one 500-milliliter bottle (17 ounces) of beer, one 180-milliliter glass (6 ounces) of wine, or one 60-milliliter cup (2 ounces) of whiskey.

Overall cancer risk appeared to be the lowest at zero alcohol consumption, and there was an almost linear association between cancer risk and alcohol consumption. The association suggested that a light level of drinking at a 10-drink-year point (for example, one drink per day for 10 years or two drinks per day for five years) would increase overall cancer risk by five percent. Those who drank two or fewer drinks per day had an elevated cancer risk regardless of how long they had consumed alcohol. Also, analyses classified by sex, drinking/smoking behaviors, and occupational class mostly showed the same patterns.

The elevated risk appeared to be explained by alcohol-related cancer risk across relatively common sites, including the colorectum, stomach, breast, prostate, and esophagus.

"In Japan, the primary cause of death is cancer," said Dr. Zaitsu. "Given the current burden of overall cancer incidence, we should further encourage promoting public education about alcohol-related cancer risk."