Male identical twins live longer

According to new University of Washington research twins have lower mortality rates for both sexes throughout their lifetimes.

“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,” said lead author David Sharrow, a UW postdoctoral researcher in aquatic and fishery sciences.

The data comes from the Danish Twin Registry, one of the oldest repositories of information about twins. The authors looked at 2,932 pairs of same-sex twins who survived past the age of 10 who were born in Denmark between 1870 and 1900 and then compared their ages at death with overall Danish population.

For men, they found that the peak benefit of having a twin came in the subjects’ mid-40s. That difference is about 6 per cent, meaning that if out of 100 boys in the general population, 84 were still alive at age 45, then for twins that number was 90. For women, the peak mortality advantage came in their early 60s, and the difference was about 10 per cent.

The lifespan was also extended more for identical rather than fraternal twins

“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.”