Genetic link between obesity and loneliness discovered

A total of 15 genetic loci linked to loneliness have been discovered in a new study, as well as an association between obesity and a person's risk of loneliness. 

Genetics makes a small but significant contribution to someone's predisposition to loneliness, according to the new study published in Nature Communications. Genetic factors were estimated to make up 4.3 percent of someone's risk of experiencing loneliness. 

Data from a total of 487,647 participants from the UK Biobank scheme was used in the study, collected using a self-reporting questionnaire on social interactions and perceived loneliness. The researchers identified a possible causal link between obesity and loneliness. 

Loneliness affects a quarter of UK residents over the age of 65, and is associated with a higher risk of all-cause mortality. However, the genetic factors affecting loneliness have remained unclear. This is the first study identifying specific genetic determinants for social interaction or isolation. 

'We often think that loneliness is driven purely by our surrounding environment and life experiences,' Dr John Perry, from the University of Cambridge and an author of the study, told the Telegraph. 'But this study demonstrates that genes can also play a role.' 

The study also identified six genetic loci linked to sports club or gym attendance, 13 to social club attendance, and 18 to religious group participation. These behavioural traits shared some of their genetic architecture, suggesting a shared predisposition to social interactions. 

However, the study also identified some genetic traits associated with specific activities. For instance, an allele in the alcohol dehydrogenase gene, encoding the enzyme involved in breaking down alcohol, is a genetic variant linked only pub or social club attendance, but not sports or religious group attendance. 

Dr Perry concluded: 'There is always a complex mix of genes and environment, but it does suggest that at a population level, if we could tackle obesity we would be able to bring down loneliness as well.'