In reviewing the literature for studies assessing methylation changes associated with alcohol that have potential to translate into clinical biomarkers, several trends emerge. First, fewer studies have used array-based technologies in alcohol as opposed to smoking (10 found for this review). Second, fewer significant associations have been reported and effect sizes are generally more modest in alcohol as opposed to smoking, with top delta beta values frequently under 10%, leaving fewer loci as potential biomarker candidates. Third, the results of candidate gene studies, as listed above, have generally not replicated in later array-based studies. Fourth, many studies have been done using in vitro models, animal models, and post-mortem tissues. These have focused on the relationship between histone modifications and chronic alcohol exposure; findings which are likely further from clinical translation but suggest future avenues for research.
