Habitual moderate–heavy drinking ups AF risk even in young Asians

At moderate-to-heavy levels, drinking confers increased atrial fibrillation (AF) risk even in young people, as shown in a large Korean cohort study.

Specifically, young adults with sustained moderate-to-heavy alcohol consumption for 4 years had a 25-percent higher risk of AF compared with those who consistently abstained or did mild drinking (adjusted hazard ratio [HR], 1.25, 95 percent confidence interval [CI], 1.12–1.40). [JAMA Netw Open 2022;5:e2229799]

Meanwhile, sustained heavy drinking for 4 consecutive years was associated with a greater risk increase compared with abstinence (adjusted HR, 1.47, 95 percent CI, 1.18–1.83).

The analysis used data from the Korean National Health Information Database (NHID) and included 1,537,836 young adults (mean age 29.5 years, 71.5 percent men), of which 3,066 developed AF over a median follow-up of 5.6 years.

“A positive correlation between high cumulative alcohol consumption and higher risk of AF was consistently observed in apparently healthy young adults. These findings do not come as a surprise, since no clear interaction between alcohol and age has been reported from previous studies,” according to the investigators Dr Minju Han and colleagues from the Seoul National University Hospital, Seoul, Republic of Korea.

Even among young people, alcohol use is one of the risk factors of AF, the investigators pointed out. Alcohol may trigger AF via stimulation of the sympathetic nervous system that promotes adrenaline secretion, parasympathetic modulation of autonomic tone, and slowing of interatrial electrical conduction concomitant with a shorter atrial refractory period resulting in re-entry. [J Am Coll Cardiol 2014;64:281-289; Europace 2020;22:216-224; Eur J Prev Cardiol 2021;28:666-676; J Am Coll Cardiol 2016;68:2567-2576]

Other experts have also proposed structural changes in atria, such as left atrial enlargement and atrial tissue fibrosis, as possible pathophysiology. [J Am Heart Assoc 2016;5:e004060; J Am Coll Cardiol 2016;68:2567-2576]

However, “there has been no consensus on how much alcohol should be considered low- or high-risk drinking,” the investigators said.

“By analysing the association between alcohol burdens that were defined by the two different methods and risk of AF, we confirmed that both persistent moderate-to-heavy drinking for 4 years and semiquantitative cumulative alcohol consumption burden higher than 10 points was significantly associated with a higher risk of AF,” they added.

Based on the current data, annual alcohol intake of 105 to ≥210 g per year on average might represent a new threshold for average alcohol content over a 4-year period that increases AF risk and could be used as a reference in subsequent longitudinal studies, according to the investigators.

In a linked editorial, Drs Lars Frost from Silkeborg Regional Hospital, Silkeborg, Denmark, and Renate Schnabel from University Heart and Vascular Center Hamburg, Hamburg, Germany, commended Han and colleagues for extending knowledge on the unfavourable association between alcohol intake and AF among young adults, an age group usually not at high risk of AF. [JAMA Netw Open 2022;5:e2229808]

“The public health implications in relation to our current knowledge of alcohol and AF are clear and based on firm evidence. To prevent AF, drink less than two standard drinks of alcohol per day. To reduce AF burden, abstain from alcohol. A recommendation to start alcohol consumption to prevent AF can certainly not be given,” Frost and Schnabel wrote.