Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli (IS), Italy A recent study by Xi et al. (1) published last month in the Journal of the American College of Cardiology (JACC), investigated the relationship between the amount of alcohol intake and risk of all-cause, cardiovascular and cancer deaths in more than 330,000 US adults, followed for an average of about eight years.
Their paper helps clarify the debate over the existence and the relevance of the so-called J-shaped curve, an issue frequently discussed as a problem of beliefs rather than the result of scientific data.
The number of people involved in this study is impressive, the methodology is sound, the statistical approach is correct and implemented by important ancillary analyses. Additionally, the Authors have pointed out relevant drawbacks from some of the previous studies such as “abstainer bias” or inappropriate adjustment for confounders or different patterns of alcohol drinking.
Their results support the conclusion that the J-shaped relationship between alcohol consumption and mortality risk cannot be dismissed and should guide the formulation of public policies on alcohol consumption (2).
During the study period, 34,754 people died, including 8,947 deaths from cardiovascular disease and 8,427 from cancer. Compared with lifetime abstainers, light-to-moderate alcohol consumers (≤14 drinks/week for men, ≤7 drinks/ week for women) were at significantly reduced risk of all-cause (light: -21%; moderate: -22%) and cardiovascular mortality (light: -26%; moderate: -29%), respectively. On the other hand, significantly increased risks of all-cause (11%) was found in adults with heavy alcohol consumption (>14 drinks/week for men, >7 drinks/ week for women) compared with those who never consumed (1). In just few words: Alcohol in moderation may lengthen your life, while too much may shorten it.
Another important result presented by Xi et al (1) is that light alcohol consumption appeared to be protective against cancer mortality, while among heavy drinkers the risk of cancer was particularly pronounced, with an increased cancer death risk of 27% as compared to abstainers (1).
Nowadays, while there is general agreement that heavy alcohol is associated with increased cancer risk, some Organisations insist on considering alcohol to be harmful even when it is consumed in light or moderate amounts. The important issue of a possible cancer risk of light-to-moderate alcohol intake remains clouded by uncertainty about whether the findings are confounded by underreporting and other traits (2).
However, the multiple effects of alcohol on health not only depend on quantities but also on patterns of alcohol use (whether intakes are concentrated on short times, such as the weekends, or are regularly dispersed during meals). In this study, it was reported that binge drinking too was associated with a significant increased risk of all-cause (13%) and cancer mortality (22%).
At this time, taking into account the recent findings of the Xi’s study and previous epidemiological evidence, one can reiterate that regular and moderate alcohol consumption (up to 1 drink per day in women, up to 2 in men) protects against fatal and non-fatal cardiovascular disease and all-cause mortality. For light-to-moderate levels of alcohol consumption, the risk of some cancers (breast, colon-rectal, oral) are relatively small and should be considered in the context of each individual global risk. Excessive alcohol use is definitely detrimental to human health and the hazards of even occasional binge drinking should be highlighted and reinforced.
References Xi B, Veeranki SP, Zhao M, Ma C, Yan Y, Mi J. Relationship of Alcohol Consumption to All-Cause, Cardiovascular, and Cancer-Related Mortality in U.S. Adults. J Am Coll Cardiol. 2017;70:913-922. de Gaetano G, Costanzo S. Alcohol and Health: Praise of the J Curves. J Am Coll Cardiol. 2017;70:923-925.
* Visiting Scientist at the Department of Nutrition, Harvard TH Chan School of Public Health, Boston, Massachusetts and recipient of a Fondazione Umberto Veronesi Travel Grant 2017.