Abstract Body (Do not enter title and authors here): Background:
Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is responsible for acetaldehyde metabolism with alcohol consumption. ALDH2 deficiency is a common enzymopathy – afflicting ~540 million East Asians. The ALDH2*2 variant, a missense mutation, significantly decreases enzyme activity. Recent studies suggest a potential link between ALDH2 deficiency and increased cardiovascular disease (CVD) risk. High-Density Lipoprotein cholesterol (HDL-C) is inversely associated with CVD and is known to increase with alcohol consumption. However, the impact of ALDH2*2 on HDL-C levels in East Asians remain unclear.

Methods:
Using the NIH All of Us cohort, we assessed HDL-C levels and reported alcohol consumption habits (never, < once/week, > once/week) at enrollment, as well as ALDH2 variant status among East Asian participants. Differences in HDL-C values were analyzed with Mann-Whitney U-tests.

Results:
Among 3,289 US Asian adults (age 46.8 ± 16.1 years; 58.8% female), median HDL-C was 54mg/dL [IQR 45, 67]. Of these, 2809 (85.4%) had wildtype ALDH2, and 480 (14.6%) had ALDH2*2. Individuals with ALDH2*2 reported lower alcohol consumption (Figure A) but exhibited higher HDL-C levels (p=0.0002). The association was similar regardless of sex (Figure B).

Conclusion:
The ALDH2*2 variant is associated with higher HDL-C levels, despite lower alcohol consumption, indicating a possible independent influence on HDL-C levels. In the context of previous studies linking ALDH2 deficiency to adverse CVD outcomes, this suggests that ALDH2 may have a role independent of HDL-C levels, or it could affect HDL function rather than the HDL-C level itself.