Why Do Twins Live Longer?

Twins appear to have a slight longevity advantage, and the reason is likely close social bonds

Research at the University of Washington has revealed in both sexes twins have lower mortality rates. The data was taken from the Danish Twin Registry which includes 2,932 pairs of twins born between 1870 and 1900, and compared with the rest of the population. 

"We find that at nearly every age, identical twins survive at higher proportions than fraternal twins, and fraternal twins are a little higher than the general population"

For male identical twins, a 6% longevity advantage came into play in their mid-40s in comparison to the average middle aged man. Female identical twins experienced a 10% advantage from their early 60s. 

What's going on?

When the researchers dived further into the data they found that there was a difference between the sexes in acute causes of death (accidents or lifestyle related) and 'natural' causes of death such as age-related disease. Female twins avoided acute causes but not these 'natural' causes of mortality after the age of 65, whereas male twins seemed to avoid both acute causes earlier on and natural causes after 65. 

"Males may partake in more risky behaviors, so men may have more room to benefit from having a protective other—in this case a twin—who can pull them away for those behaviors. There is some evidence that identical twins are actually closer than fraternal twins," Sharrow said. "If they're even more similar, they may be better able to predict the needs of their twin and care for them"

Credit: 62denTavsan/Flickr

Why? We undervalue the importance of friendship

Recent data has shown a striking proportion of the elderly in developed countries in particular are lonely and have very few people they can rely on in times of need. The researchers postulated that twins, especially identical twins, are frequently very close and supportive of one another. Men experienced a specific benefit because statistically they are more likely to engage in risky behaviour earlier in life, and appeared to benefit from the social support that typically comes from having a twin. 

"Research shows that these kinds of social interactions, or social bonds, are important in lots of settings. Most people may not have a twin, but as a society we may choose to invest in social bonds as a way to promote health and longevity"

The results need to be repeated in more datasets, but we already know the value of social bonds and support - particular in old age. So called 'Blue Zones' in which people generally live longer tend to have close knit communities and excellent support networks. Now we may not be talking about a sizeable longevity benefit here, but this data adds to the point that many people suffer from a lack of company and that this likely has considerable health consequences - both mentally and physically. 

Read more at MedicalXpress