All three variants were associated with AUD across allelic and genotypic models: ALDH2, ORs = 0.25, P < 0.001; ADH1B, ORs = 0.22-0.49, P < 0.001; ADH1C, ORs = 0.26-0.46, P < 0.001.
Use of aldehyde-induced adducts to monitor AUD may also be important when considering that approximately 540 million people bear a genetic variant of aldehyde dehydrogenase 2 (ALDH2) predisposing this population to aldehyde-induced toxicity with alcohol use.
However, the suppressive effects of inactive ALDH2 and highly active ADH1B for AUDs are only partial and interact with other factors, such as personality traits, psychiatric comorbidities, and environmental factors.
We evaluated the presence of SNPs in the ADH (ADH1B, ADH1C, and ADH4) and ALDH (ALDH2) genes in alcohol users of Goiânia, State of Goiás - Brazil, and then we established a possible relationship with AUD by allelic and genotypic study.
Being Chinese and possessing an ALDH2*2 allele within Koreans both buffered against the risk for AUD symptoms associated with earlier ADI, indicating that this relationship can be attenuated by protective factors.
Our previous case-control study in a Tibetan population noted that the positive association between c2 allele of cytochrome P4502E1 (CYP2E1) gene and AUD might only exist in males who are homozygotes for 1 alleles of aldehyde dehydrogenase-2 (ALDH2) and alcohol dehydrogenase-1B (ADH1B) genes, but this interaction did not reach statistical significance.
This study examined additive and interactive effects of ALDH2 and ADH1B genotypes on drinking behavior in a mixed-gender sample of Asian young adults, focusing on continuous phenotypes (e.g., heavy episodic and hazardous drinking, alcohol sensitivity, drinking consequences) whose expression is expected to precede the onset of alcohol use disorders.
Despite great advances in understanding of genetic vulnerability in alcohol use disorders, only two gene complexes, ADH and ALDH2, have been identified as having defined effects on alcohol use and liability to dependence in humans.
However, multivariate analyses under a hierarchically well-formulated model strategy with interaction and confounding assessment indicated that (i) heavy alcohol intake was a significant risk factor (odds ratio per 1.0 g of daily ethanol intake; 1.096, 95% confidence interval; 1.026-1.171) for developing AUD after adjusting for other confounders; and (ii) ADH2*1/1 genotype and ALDH2*1/1 genotype were not risk factors after adjusting for daily ethanol intake and other confounders.
Multivariate analysis based on a conditional logistic regression model and a hierarchically well-formulated model strategy revealed that: (i) the OR of developing probable AUD due to 1 g increment of daily ethanol drinking was 1.110* among farmers (95%CI = 1.054-1.170); (ii) OR due to 1 g increment of daily ethanol drinking was 1.329* among non-farmers (95%CI = 1.109-1.593); (iii) OR due to either ADH2*1/1 or ALDH2*1/1 was insignificant; and (iv) the daily amount of smoking is independently associated with probable AUD.
Multivariate analysis based on the conditional logistic regression model showed no significant association of AUD with ALDH2 genotype, marital status, education history, or past history of injury, however, occupation and daily amount of alcohol intake were found to be significantly associated with AUD (OR = 10.72, 95% CI = 1.15-99.99, P = 0.037, and OR = 1.12, 95% CI = 1.06-1.18, P = 0.000, respectively).
On a group level, the rare frequencies of ALDH2*2, the inactive allele of ALDH2, among these aborigines may account partially for their vulnerability to alcohol use disorders.
The Atayal with alcohol use disorders also had a lower frequency of ALDH2*2 than the controls; this allele is known to be responsible for the alcohol-flush reaction among Asians, and thereby deters drinking.