From an article by Miryam Naddaf published in the Nature web site:
More than 3,500 genetic variations that potentially affect smoking and drinking behaviour have been identified in a study involving almost 3.4 million people with African, American, East Asian and European ancestry.
The findings, published in Nature on 7 December1, highlight how increasing the sample size and ethnic diversity improves the power of such genome-screening analyses — called genome-wide association studies (GWASs) — to reveal how various traits are linked to genes, combinations of genes or mutations.
Smoking and drinking are important risk factors for several physical and mental illnesses, including cardiovascular diseases and psychiatric disorders. Although both behaviours are influenced by environmental and social factors, there is evidence that genetics can affect tobacco and alcohol consumption. “We’re at a stage where genetic discoveries are being translated into clinical [applications],” says study co-author Dajiang Liu, a statistical geneticist at Penn State College of Medicine in Hershey, Pennsylvania. “If we can forecast someone's risk of developing nicotine or alcohol dependence using this information, we can intervene early and potentially prevent a lot of deaths.”
Scientists use GWASs to find genetic ties to diseases or behaviours by comparing genetic sequences in large numbers of people. But so far, most of these studies have focused on European populations. Liu and his colleagues constructed a model that incorporated the genomic data of 3,383,199 people, 21% of whom had non-European ancestry.
They identified 3,823 genetic variants that were associated with smoking or drinking behaviours. Thirty-nine of these were linked with the age at which individuals started smoking, 243 with the number of cigarettes smoked per day and 849 with the number of alcoholic drinks consumed per week.
Of the total number of associated variants, 721 were identified only by the multi-ancestry GWAS, and not by an ancestry-naive model that the authors used for comparison. This suggests that large and diverse population samples significantly increase the power of such studies.
The researchers found that the majority of genetic associations for drinking and smoking have similar effects across the different ancestries. “We also find similar heritability estimates [for the traits] across the ancestries … suggesting that generally, the genetic architecture of these behaviours is similar across ancestries,” says Gretchen Saunders, a psychologist at the University of Minnesota, Minneapolis, and co-author of the paper.
You can read more at: https://www.nature.com/articles/d41586-022-04378-w.