A study from the University of Colorado investigates why people who abstain completely from alcohol have a higher mortality risk than light drinkers. And after dividing the non-drinkers into categories, researchers unpicked some interesting data.

Recent studies have asserted that drinking some alcohol has a protective effect, reducing mortality.

In a study published in Population Research and Policy Review, researchers from both the University of Colorado Boulder and the University of Colorado Denver analyzed whether varying characteristics among groups of non-drinkers could account for their relatively higher risk of dying.

Professor Richard Rogers from CU Boulder says: “Among non-drinkers, people have all sorts of background reasons for why they don’t drink. We wanted to tease that out because it’s not really informative to just assume that non-drinkers are a unified group.”

After collecting drinking habit data from a 1988 National Health Interview Survey of over 41,000 people in the US, and seeing which of the respondents had died by 2006, Rogers and his team found that three categories of non-drinkers emerged:

  • Abstainers – fewer than 12 drinks in their lives
  • Infrequent drinkers – fewer than 12 drinks a year
  • Former drinkers – people who used to drink more than 12 drinks a year.

Within each group, subgroups also appeared. For example, within the abstainer group, the most common reason for not drinking was due to a “dislike of the taste.” That particular group had a 17% higher mortality risk compared with people who drink occasionally.

According to the study, the infrequent drinkers group had only a slightly higher mortality risk than the light drinkers, but former drinkers had the highest risk among all nondrinker groups, at 38%.

The researchers suggest that reasons for this high rate is that many “former drinkers” were at one time alcoholics and people who previously had problems with alcohol.

Among those who do drink, there are also different groups and mortality risk rates compared with those who are light drinkers:

  • 1-2 drinks a day produced a 9% higher mortality rate
  • 3-4 drinks a day gave a 49% figure
  • And more than 3 drinks a day meant 58% higher risk.

Rogers adds: “I think the idea that drinking could be somewhat beneficial seems like it’s overstated. There may be other factors that lower mortality for light drinkers. It’s not just the act of drinking.”