Scientific proof that taller or bigger people and animals live shorter lives may have been found in a new study on DNA.
Research carried out 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 round telomeres, special DNA structures that all animals, including humans, have at the ends of their chromosomes which are said to function like "the protective plastic caps at the end of shoelaces".
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 the telomere analysis, said: "Growing a bigger body means that cells have to divide more. As a result, telomeres become eroded faster and cells and tissues function less well as a result.
"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.
