Could Being Active Reduce Cancer Death-Risk From Alcohol?

Moderate Drinking Not a Problem

Nick Mulcahy

July 08, 2020

Among adults who drink alcohol at relatively high amounts, regular weekly physical activity may reduce the mortality risk posed by alcohol-related cancers, concludes a new observational study involving 50,000-plus British adults.

Being physically active — for example, by walking, house cleaning, or playing a sport — could be promoted as a risk-minimization measure for alcohol-related cancers, say the authors, led by Emmanuel Stamatakis, PhD, professor of Physical Activity, Lifestyle, and Population Health, University of Sydney, Australia.

The researchers found a "strong direct association between alcohol consumption and mortality risk of [10] alcohol-related cancers."

Specifically, when compared with never drinkers, there was a significantly higher risk of dying from such cancers among drinkers who consumed "hazardous" and "harmful" amounts of alcohol, and also for ex-drinkers.

Notably, occasional drinkers and drinkers within guidelines did not have statistically significantly higher risks for alcohol-related cancer mortality.

But the analysis also found that among the bigger drinkers, the risks were "substantially attenuated" in physically active participants who met at least the lower recommended limit of activity (> 7.5 metabolic equivalent task [MET]-hours/week).

That's not a taxing amount of activity because, for example, general household cleaning results in 3 METs/hour and walking slowly translates into 2 METs/hour. However, nearly a quarter of survey participants reported no physical activity.

The study was published online May 14 in the International Journal of Cancer.

The new results require confirmation because the findings "are limited in their statistical power," with small numbers of cases in several categories, said Alpa Patel, PhD, an epidemiologist at the American Cancer Society (ACS), who was not involved in the study. For example, there were only 55 alcohol-related cancer deaths among the 1540 harmful drinkers.

Patel stressed that, "based on the collective evidence to date, it is best to both avoid alcohol consumption and engage in sufficient amounts of physical activity." That amount is 150-300 minutes of moderate or 75-150 minutes of vigorous activity per week for cancer prevention.

Her message about abstinence is in-line with new ACS guidelines issued last month, as reported by Medscape Medical News. The ACS's guidance was criticized by many readers in the comments section, who repeatedly encouraged "moderation."

However, the ACS also recommended moderation, saying, for those adults who do drink, intake should be no more than 1 drink/day for women or 2 drinks/day for men. 

Study author Stamatakis commented on the alcohol debate.

"Any advice for complete abstinence is bound to alienate many people," he told Medscape Medical News in an email. "Alcohol drinking has been an integral part of many societies for thousands of years."

Stamatakis, who is an occasional beer drinker, also said, "there is no healthy level of alcohol drinking."

This was also the conclusion of a 2018 study published in the Lancet, which stated that there is "no safe limit," as even one drink a day increases the risk of cancer. A few years earlier, the 2014 World Cancer Report found a dose–response relationship between alcohol consumption and certain cancers.

However, epidemiological findings are not necessarily "clinically relevant," commented Jennifer Ligibel, MD, a medical oncologist at the Dana-Farber Cancer Institute, Boston, Massachusetts, in a 2018 interview with Medscape Medical News.

Ligibel explained that there are 50 years of studies linking alcohol and cancers. "With the huge amount of data we have, even small differences [in consumption] are statistically significant," she said.

Ligibel cited an often-repeated statistic: for the average woman, there is a 12% lifetime risk of breast cancer. "If a woman consumes a drink a day, which is considered a low-level intake, that risk may become about 13% — which is statistically significant," Ligibel explained.

But that risk increase is not clinically relevant, she added.

Mean 10 Years of Follow-Up

The new study is the first to examine physical activity, drinking, and the 10 cancers that have been linked to alcohol consumption (oral cavity, throat, larynx, esophagus, liver, colorectal, stomach, breast, pancreas, and lung).

The authors used data from 10 British population-based health surveys from 1994-2008 and looked at adults aged 30 years and older. The mean follow-up period was 9.9 years.

Among 54,686 participants, there were 2039 alcohol-related site-specific cancer deaths.

Alcohol consumption categories were based on UK guidelines, with 1 unit equal to 8 grams (about 2 ounces) of pure alcohol. The categories were as follows: drinking within guidelines (< 14 units/week for women, < 21 units/week for men), hazardous level (14-35 units/week for women, 21-49 units/week for men), and harmful level (> 35 units/week for women, > 49 units/week for men). The survey also queried participants about being ex-drinkers, occasional drinkers, and never drinkers.

Physical activity was assessed using self-reported accounts of the 4 weeks preceding the health survey and intensity of activity (light, moderate, or vigorous) was queried. Physical activity was categorized using the upper (15 MET-hours/week) and lower (the aforementioned < 7 MET-hours/week) recommended limits.

The median age of participants was 51 years; 7.9% were never drinkers and 14.7% exceeded guideline amounts. For physical activity, 23% reported none. The median level of activity was 9 MET-hours/week.

The authors say that the "increased risks [among the harmful, hazardous, and ex-drinker categories] were eliminated" among the individuals who reported physical activity > 7.5 MET-hours/week. That meant the hazard ratios for cancer mortality for each category were reduced to the point that they were no longer statistically significant.

For example, for all drinkers in the "hazardous" category, the risk of cancer-related mortality was significantly higher than for nondrinkers (with a hazard ratio of 1.39), but in the subgroup of these participants who were physically active at the lower recommended limit, the hazard ratio dropped to 1.21.  

These "broad patterns of effect modification by physical activity persisted when the upper physical activity limit [15 MET-hours/week] was used," write the authors.

The new study adds to the literature on cancer mortality and alcohol consumption. In another recent study, researchers looked at eight British cohorts and reported overall cancer mortality associated with alcohol consumption was eliminated among those meeting physical activity recommendations (Br J Sports Med. 2017;51:651-657). The new study added two more cohorts to this base of eight and only focused on cancers that have been linked to alcohol consumption. The earlier study included deaths from all types of cancer.

The refinement of focus in the current study is important, say Stamatakis and colleagues.

"This specificity adds biological plausibility and permits a more immediate translation of our findings into policy and practice," they write. 

Stamatakis practices what he advocates, but is not a teetotaler.

"I exercise (eg, dynamic yoga, HIIT cardio workouts, run, cycle, lift weights) for 45-60 minutes a day and I walk 8000 to 14,000 steps daily. That would categorize me perhaps in the top 3%-5% for my age/sex group. And I enjoy 1-2 cans of craft beer a couple of times a week," he said in an email.

Stamatakis and Patel have reported no relevant financial relationships.

Int J Cancer. Published online May 14, 2020. Abstract

Nick Mulcahy is an award-winning senior journalist for Medscape. He previously freelanced for HealthDay and MedPageToday, and had bylines in the WashingtonPost.com, MSNBC, and Yahoo. Reach him by email and follow him on Twitter.

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