changes associated with chronic alcohol consumption. One study analyzed AVP and ANP promoter DNA methylation changes in the peripheral blood of 99 AUD patients on days 1, 7, and 14 of alcohol withdrawal,106 and the another study tracked blood DNA methylomic changes in 10 AUD patients (normal in phases 1 and 2 but affected with AUDs in phase 3) and 10 controls (unaffected with AUDs) in three phases (phase 1: 1986; phase 2: 1990–1992; and phase 3: 2003–2009).107 These two longitudinal studies support that alcohol consumption influences DNA methylation, and genome-wide DNA methylation drifts over time. Additionally, multigenerational epigenetic studies could elucidate whether AUD-associated DNA methylation changes are more likely to be inherited from parents. Studies have shown that not only maternal smoking but also grandmaternal smoking is associated with elevated pediatric asthma risk in offspring.108 Using a rat model, it has been demonstrated that in utero nicotine exposure results in alterations to both the somatic and germ cell epigenome.109 Thus, epigenetic mechanisms appear to underlie some part of the multigenerational transmission of a nicotine-induced asthma-like phenotype. Since many women continue to smoke and/or drink during pregnancy, the negative impact of tobacco or alcohol on the epigenome of the fetus
