Bad news for big people – you might have a shorter lifespan than your smaller counterparts, research suggests.
A new study on wild house sparrows showed how changes in DNA that are linked to ageing and lifespan take place as body size gets bigger.
The research centred on telomeres, a special DNA structure which all animals, including humans, have at the ends of their chromosomes and are said to function like “the protective plastic caps at the end of shoelaces”.
Growing a bigger body means cells divide more and part of our telomeres are eroded, making cells and tissues function less well, researchers say. So, you may be able to reach the milk at the back of the top shelf at the supermarket, tall people, but your DNA isn’t happy about it.
The study, conducted jointly by the University of Glasgow’s Institute of Biodiversity, Animal Health & Comparative Medicine and the Centre of Biodiversity Dynamics at the Norwegian University of Science and Technology, found that skeletally bigger house sparrows had shorter telomeres.
Pat Monaghan, regius professor of zoology at the University of Glasgow, who supervised telomere analysis, said: “The reason why the bigger individuals have shorter telomeres might also be related to increased DNA damage due to growing faster. Being big can have advantages, of course, but this study shows that it can also have costs.”
Thor Harald Ringsby, associate professor in population ecology at the Norwegian University of Science and Technology, said: “The results from this study are very exciting and broad-reaching. It is especially interesting that we obtained these results in a natural population.
“The reduction in telomere size that followed the increase in body size suggests one important mechanism that limits body size evolution in wild animal populations.”
The findings are published in the Proceedings of the Royal Society B journal. The study was funded by the European Research Council and the Research Council of Norway.