Eye Color and Alcohol Dependence

There is a highly statistically significant correlation between blue eye color relative to brown eye color, and alcohol dependence (P = 0.0005 and odds ratio = 1.83 (1.31–2.57)), based upon a study of a sample of 1,263 European-Americans.

More importantly, given the numerous potential correlation-causation confounds between eye color and cultural ethnic differences among various subsets of European-Americans, there are established biological interactions between eye color genes and genes associated with alcohol dependence.

Network-based analyses revealed a statistically significant (P = 0.02) number of genetic interactions between eye color genes and AD-associated genes. We found evidence of linkage disequilibrium between an AD-associated GABA receptor gene cluster, GABRB3/GABRG3, and eye color genes, OCA2/HERC2, as well as between AD-associated GRM5 and pigmentation-associated TYR.

Ideally, the research could be corroborated, or alternatively dismissed as a confound or fluke, with the excellent comprehensive health record data sets of Scandinavian countries comparing blue eyed and brown eyed Scandinavians v. alcohol dependence.