People tend to unwittingly choose a life partner with a comparable life expectancy, research suggests.

A study by researchers at the MRC Human Genetics Unit and Roslin Institute suggests that people tend to unwittingly choose a life partner who is likely to have a comparable life expectancy.

They also unconsciously select mates who share similar risks of illnesses – such as high blood pressure or heart disease – according to a genetic study. The findings help explain why long-term couples often suffer from the same ailments in later life and have similar life expectancies.

UK Biobank

The researchers examined data from the UK Biobank study – a major study of genes and lifestyle factors linked to health – involving more than half a million people.

The team looked at information from the parents of couples and found that even in-laws shared genetic risk factors for diseases and similar longevity.

Why is that?

These similarities are greater than would be expected by chance, the study says, suggesting people inadvertently choose a mate who shares the same disease risks as them.

As many ailments are not visible when most people choose their partners, experts say the surprising finding is most likely a result of choosing a mate with shared lifestyle factors that are genetically linked to disease.

Joint risk behaviours such as smoking or healthy behaviours, like keeping a healthy weight, are most likely to lead to shared diseases in later life and, ultimately, a similar life expectancy.

Our study suggests that humans tend to select partners for behavioural or physical traits that are genetically related to disease and longevity. Understanding what traits these are will require new and long-term studies that follow hundreds of thousands of couples from the moment they meet until later in life when they develop disease. Professor Albert Tenesa, The Roslin Institute and MRC Human Genetics Unit

Studying couples and non-blood relatives is vital to understand why several members of a family can be affected by the same disease. This study demonstrates that both long-term sharing of risk factors and people selecting partners with similar traits contribute to disease burden and ultimately longevity. Dr Konrad Rawlik, The Roslin Institute

The study is published in the journal “Heredity” and was funded by the UK Government’s Biotechnology and Biological Sciences Research Council and the Medical Research Council.

Links

Tenesa Research Group

Original article: https://doi.org/10.1038/s41437-019-0185-3