The summer break is over. The days are getting shorter, holidays are receding and daily routines have resumed. For some people, this brings a vague feeling of melancholy, isolation or loneliness.<\/p>\n\n
But is loneliness only an emotion? Or can it also leave a biological imprint<\/strong> ?<\/p>\n\n The experience of loneliness and genetics<\/strong> seem to belong to two different worlds.<\/p>\n\n Our genetic make-up provides a biological foundation<\/strong>. It contributes to the functioning of our nervous, hormonal and immune systems, and to individual differences in how we respond to the environment. However, our genes alone do not determine our behaviour or state of health.<\/p>\n\n This is where we encounter epigenetics<\/strong>.<\/p>\n\n This discipline studies how the environment and lived experiences may be associated with changes in the regulation of gene expression, without changing the DNA sequence. DNA methylation is one of the mechanisms studied.<\/p>\n\n The environment influencing these mechanisms is not only nutritional, physical or climatic. It is also social<\/strong>. Social interactions are therefore among the environmental factors that may interact with certain biological processes.<\/p>\n\n A pioneering study by Cole and colleagues compared gene expression in the white blood cells of people with high or low levels of chronic loneliness. The researchers identified 209 differentially expressed genes<\/strong>, including changes affecting pathways involved in inflammation and antiviral responses.\u00a0<\/p>\n\n These findings helped open new avenues of research into the links between loneliness, the social environment and gene expression.<\/p>\n\n More recent work explores another hypothesis, relating to epigenetic age<\/strong>.<\/p>\n\n A study published in 2024 involving 1,310 people observed a weak association between higher levels of loneliness and several markers of epigenetic age acceleration. The authors emphasise, however, that these results should be interpreted cautiously. They demonstrate an association but do not establish that loneliness directly causes these biological changes.\u00a0<\/p>\n\n Thus, against a given genetic background, the social environment could contribute to modulating certain biological mechanisms.<\/p>\n\n Talking, sharing, meeting others and maintaining social connections may contribute to more than our emotional wellbeing. These interactions also form part of our social environment, which may interact with certain biological mechanisms studied in genetics and epigenetics.<\/p>\n\n MEDICAL REFERENCES<\/strong><\/p>\n\n\nEpigenetics: a link between the environment and gene expression<\/h2>\n\n
Loneliness and gene expression: what does research show?<\/h2>\n\n
Loneliness and epigenetic age: associations that remain exploratory<\/h2>\n\n
Key points<\/h2>\n\n