Only a handful of studies examined how broader social influences on drinking may influence the relationship between genetic risk or protection and alcohol use. These studies included the use of variables related to religious involvement and school-level (e.g., high school) drinking37,45,48 to examine the effects of instituational social control and group-level social drinking norms. At this level, we also included several studies that used membership in various social groups34,38–40,42,57, like ethnicity, gender, and level of education as indirect measures indexing group differences in social norms about drinking or vulnerability to environmental stressors. However, these variables can be difficult to assess as cultural indicators in G–E associations. Ethnicity may be confounded by population stratification, as the pattern of association between alleles (linkage disequilibrium) and genotype frequencies can vary across ancestry groups42,45, and gender may indicate other biological features (e.g., sex hormone levels)40. Level of education also has a complex relationship with alcohol-related phenotypes, both as a moderator of genetic effects and through shared genetic influences with alcohol problems58. One study examined acculturation34, which also may gauge changes in social drinking norms tied to exposure to mainstream American culture.
