Alcohol use in patients with non-alcoholic fatty liver: a tangled web of causality

Wine consumption was first associated with a reduced risk of cardiovascular disease in 1979 (1); subsequent studies, including several meta-analyses, showing a J-shaped association with modest alcohol consumption (especially for wine and beer) associated with a lower rate of cardiovascular complications and all-cause mortality, compared with abstention and heavy alcohol use (2). However, controversy persists regarding whether “modest” levels of alcohol consumption (typically defined as ≤2 drinks per day for women and ≤4 drinks per day for men) can achieve health benefits without causing harms (3,4). Differences in patterns of alcohol use and differential levels of confounding across study populations are cited for reasons why benefit versus harm in a given population may vary (4). One such confounder may be the presence of non-alcoholic fatty liver (NAFL), a more prevalent condition among alcohol users now than decades ago