What factors influence how much alcohol you drink? A new study finds that a genetic disposition or environment does not exert the exact same effects on everyone. Instead, these influences may be stronger or weaker, depending on social context. Specifically, low socioeconomic environments trigger genetic vulnerabilities to alcohol, while high status environments seem to moderate any natural susceptibility.

“We found that genetic differences between individuals explained more variation in the amount of alcohol use in low socioeconomic (SES) environments compared to high SES environments,” Nayla Hamdi, a doctoral student at the University of Minnesota, stated in a press release.

The alcohol beverage industry is an economic powerhouse, contributing over $400 billion in jobs, wages, activity, and taxes to the nation, according to the Distilled Spirits Council of the United States. However, public health officials tell a very different story about liquor. They describe alcohol as one of the top 10 risk factors for death, disease, and disability booze, they say, costs middle- and high-income countries anywhere from 1.3 to 3.3 percent of total GDP.

Meanwhile, scientific researchers continue to explore the intersection of genetics, environment, and drinking. Their conclusions suggest environment plays a significant role in alcohol abuse. One recent study, for instance, found adopted children with a genetic predisposition for alcoholism were at greater risk only if their adoptive fathers had an unskilled occupation. Other studies show genetically influenced alcoholic tendencies are amplified in girls who aren’t very close to their parents; in urban areas; in teens who run with a drinking crowd; and in unmarried women.

Wanting more information on how context might influence natural disposition, the researchers of the current study decided to focus on twins.

High Class Restraint?

Drawing on data from the MacArthur Foundation Survey of Midlife Development in the United States, the research team focused on a sample of 672 twin pairs (aged 25 to 74), including 350 identical twins who share the same genes. Initiated in 1995-1996, the MacArthur Foundation Survey, which examined health, psychological well-being, and social responsibility, reassessed all participants during 2004-2006 via phone interviews and questionnaires. In particular, the team studied participants’ socioeconomic status, measured by household income and educational attainment, and compared this to amount of alcohol, frequency of drinking, and problem use.

What did they discover? Differences in how much people drank were much greater in the lower status group than in the high status group.

“There is greater heterogeneity in the drinking patterns for those with lower as compared to higher SES,” said Dr. Matt McGue, Regents Professor in the department of psychology at the University of Minnesota. “The low SES group includes more light or abstemious drinkers and more heavy drinkers than the high SES group.” At the same time, though, genetic differences explained more of the variation in low status environments compared to high status environments.

Meanwhile, for the high status group, genetic influences were smaller and shared environmental influences were stronger. This pattern suggests the group norm encourages drinking but only in moderation, the researchers explained. It would seem conforming to a higher-status lifestyle is more likely to keep someone who is vulnerable to alcohol in check.

Source: Hamdi NR, Krueger RF, South SC. Socioeconomic Status Moderates Genetic and Environmental Effects on the Amount of Alcohol Use. Alcoholism: Clinical & Experimental Research. 2015.