Glasgow University study links growth rate to lifespan
Slower growth in childhood may be more conducive to a longer lifespan, a study by scientists in Scotland has found.
The Glasgow University team altered the growth rate of 240 stickleback fish by exposing them to cold or warm spells.
It found slow-growing fish lived for about 30% longer than the two-year average lifespan, while fast-growing fish lived 15% shorter than average.
The scientists said the findings may be "likely to apply to many other species, including humans".
The study looked at how the lifespan of the stickleback is affected by the rate at which their bodies expanded early in life.
By varying temperature for short periods, the researchers were able to put them ahead or behind their normal growth schedule.
They noticed the fish got back on track once their environmental temperature was returned to normal, but the change in growth rate affected their rate of ageing.
Researchers found that bodies which grew quicker accumulated greater tissue damage, with life-shortening results.
Professor Neil Metcalfe, from the university's institute of biodiversity, animal health and comparative medicine, said the "striking" results occurred despite all the fish reaching the same adult size.
"You might well expect a machine built in haste to fail quicker than one put together carefully and methodically, and our study suggests that this may be true for bodies too," he said.
"The results of the study are striking. It appears that bodies which grow quickly accumulate greater tissue damage than those that grow more slowly, and their lifespan is substantially reduced as a result.
"These findings are likely to apply to many other species, including humans, since the manner in which organs and tissues grow and age is similar across very different kinds of animal.
"It has already been documented in humans, for example, that rapid growth in early childhood is associated with a greater risk of developing ailments later in life such as cardiovascular disease in middle or old age, possibly because of the way in which the tissues of a fast-grown heart are laid down."
Earlier attempts to test links between growth rates and lifespan by altering diet proved inconclusive because the results could have been affected by the diet itself rather than its effect on growth.
The Glasgow team avoided the problem by keeping the fish on identical diets. All that changed were the temperatures to which they were exposed.
The paper is published in the latest edition of the journal Proceedings of the Royal Society B.