Scientists have found consistent genetic correlations between coffee consumption and drug use and obesity in US and UK adults of European descent. The study is published in the journal Neuropsychopharmacology.
Study: Genome-wide association study of coffee consumption in UK/US participants of European descent reveals cohort-specific genetic associations. Image credit: Farknot Architect/Shutterstock.com
background
Coffee is one of the most popular beverages worldwide, with 60–85% of European and American adults consuming 0.6–5.5 cups of coffee daily. Caffeine is the main psychoactive compound in coffee.
Bioactive compounds found in coffee are known to enhance cognitive function and reduce the risk of several health complications, including liver disease, neurodegenerative diseases, cardiovascular disease, type 2 diabetes, and certain cancers.
In contrast, excessive coffee consumption has been linked to an increased risk of substance use and abuse, abnormal lipid profiles, pregnancy loss, gastrointestinal complications, and cardiovascular disorders.
Previous genetic studies have found that coffee intake is 36-56% heritable, making it amenable to genetic analysis. Several genome-wide association studies of coffee intake have found associations with single nucleotide polymorphisms (SNPs) in or near genes that metabolize caffeine.
In this study, scientists conducted a genome-wide association study of coffee consumption in 10,156 American participants of European descent. They used genetic correlations, as well as phenotypic and laboratory-wide association studies, to investigate the relationship between coffee consumption and multiple biomarkers, health traits, and lifestyle traits.
Additionally, the researchers compared their findings with the largest genome-wide association study of coffee consumption from the UK Biobank. They used these datasets to explore cohort-specific associations with coffee consumption in two distinct populations.
Important Observations
A genome-wide association study of coffee consumption in US participants identified seven significant loci (the location of specific genes on chromosomes), mainly in genes related to metabolic processes.
A significant increase in coffee-related genes was observed in the central nervous system. The majority of genetic associations observed for coffee consumption were associated with adverse outcomes in both the US and UK cohorts, particularly with regard to substance use and obesity-related traits.
Gene-based analysis identified 165 candidate genes, including four previously identified coffee intake-related genes and six novel candidate genes.
The consistent positive genetic associations observed between coffee consumption and substance use highlight the widely accepted fact that there are common genetic factors to all substance use. Existing literature clearly indicates that use of one substance can increase use of other substances.
We also observed consistent positive genetic associations between coffee consumption and obesity-related traits in both the US and UK cohorts.This finding contradicts previous meta-analyses of randomized controlled trials and epidemiological studies that found a small inverse association between coffee consumption and body mass index (BMI) and nonspecific effects of coffee consumption on waist circumference and obesity.
These discrepancies in results may be due to differences in coffee intake across studies, as higher coffee intake is likely associated with lower genetic associations with BMI and obesity. The scientists believe that future subgroup analyses may explain the inconsistent associations between genetics, the prevalence of coffee intake, and obesity-related traits.
Regarding other health outcomes, genetic associations were found between coffee consumption and psychiatric disorders, pain, and gastrointestinal traits in the US cohort, but these associations were not or were not observed in the UK cohort.
Similarly, positive and negative genetic associations were observed between coffee intake and cognitive function in the UK and US cohorts, respectively. Overall, the number of positive genetic associations between coffee intake and various health outcomes was higher and more robust in the US cohort compared to the UK cohort.
As the scientists stated, cultural differences in coffee drinking habits in the US and the UK could be due to discrepancies in genetic associations. Moreover, relatively high levels of coffee intake and caffeine intake from high-calorie beverages have been recorded in the US. This could explain the observed adverse effects of coffee consumption on health outcomes in the US cohort.
Significance of the study
The study revealed that coffee consumption is genetically associated with risk of other substance use and obesity-related traits, and these associations were observed in two large cohorts of European ancestry.
These findings provide a cautionary perspective on combining large datasets from different geo-cultural groups.
As the scientists noted, the study used self-reported coffee consumption data and captured a broad range of phenotypes: individual differences in coffee growing and brewing methods, diet and other lifestyle habits, and environmental and social norms related to coffee consumption may act as potential confounding factors and contribute to the differences observed between cohorts.
The coffee intake phenotype in the US cohort was a 5-ounce cup of caffeinated coffee, whereas in the UK cohort it was primarily decaffeinated coffee, with a less clearly defined cup volume. These factors may also have contributed to the discrepant genetic associations.
Journal References:
Thorpe HHA. 2024. Genome-wide association study of coffee consumption in UK/US participants of European descent reveals cohort-specific genetic associations. Neuropsychopharmacology. doi: https://doi.org/10.1038/s41386-024-01870-x https://www.nature.com/articles/s41386-024-01870-x
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