Additionally, PEth is considered to be more reliable than other indirect alcohol markers like carbohydrate‐deficient transferrin, gamma‐glutamyl transpeptidase or alanine aminotransferase, as it is not affected by factors such as medications or health problems unrelated to alcohol consumption, such as celiac disease, cancer, thyroid disease and metabolic syndromes [13, 19, 37]. This evidence concerns the gene GPT and celiac disease.