Newswise — Binge drinking is a common and harmful pattern of alcohol use, often defined as consuming at least four (for women) or five (for men) drinks in one drinking episode. However, some people drink well beyond this, consuming two or even three times the binge threshold, putting them at very high risk of acute harm. Previous research on such ‘high-intensity drinking’, or ‘HID’, has been mostly limited to college-age youth, with less known about HID in the mid-adult age group. A new study published in the journal Alcoholism: Clinical and Experimental Research has evaluated the prevalence, consequences, and influences of HID among Australian adults of working age.
Researchers analyzed interview data from over 3000 adults, with an average age of 32, who reported having consumed alcohol within the past 12 months. Participants were assigned to one of four classes based on the most drinks they had consumed within a single 24-hour period in the previous year: ‘non-binge’ (maximum 3 drinks for women or 4 drinks for men); ‘binge-only’ (4-7 drinks for women or 5-9 for men); twice binge threshold, termed ‘HID-2’ (8-11 drinks for women or 10-14 for men); or three times binge threshold, ‘HID-3’ (12+ drinks for women or 15+ for men). In total, 44% of participants had engaged in HID during the last year, half of them at HID-2 and half at HID-3 level. A third (32%) had drunk at the binge-only level, and just 24% of participants had not binged at all in the previous year. HID was more prevalent in men than women.
Not surprisingly, participants classed as HID-2 and HID-3 reported more frequent and heavier drinking than those classed as binge-only. Those who had engaged in HID were also more likely to have experienced serious drinking-related consequences in the previous year. Alcohol-induced blackout (memory loss) was more than ten times as common among HID-3 than binge-only drinkers, and passing out due to heavy alcohol consumption was six times as common. Almost 29% of HID-3 drinkers met criteria for an alcohol use disorder, compared with only 2% of binge-only drinkers.
The participants included around 1000 pairs of twins (some identical, and some fraternal). Twins are an important research source because they can reveal the importance of genetic and environmental influences on a given trait. Statistical modelling of the twin data from this study suggested that a tendency to engage in HID is significantly heritable—genetic differences were estimated to account for around one-third of the variation in HID in this population, and environmental influences (specific to the individual) for the remainder. A next step will be to identify the high-risk environmental factors that contribute to HID in this age group.
This study highlights the importance of differentiating groups of drinkers who consume above and beyond the binge drinking threshold, in order to identify and evaluate those at the very highest risk of harm. The researchers note that the prevalence of HID in this working-age population was unexpectedly high, perhaps reflecting the Australian drinking culture and the participants’ predominantly northern European ancestry. Approaches to mitigate the harms of this extreme drinking behavior will be needed.
High-Intensity Drinking in Adult Australian Twins. G.F. Dash, C.N. Davis, N.G. Martin, D.J. Statham, M.T. Lynskey, W.S. Slutske (pages xxx).