Some people may be genetically programmed to age at a faster rate, according to new research. Scientists have identified a genetic variant linked to the length of telomeres--a region of repetitive DNA that caps the chromosomes. Previous research has shown that telomeres shorten with age and are considered a marker of biological aging. The research was published this week in the journal Nature Genetics.

Other scientists have identified genetic variants that appear linked to healthy aging and longevity, including a variation that causes people to produce less of a protein called cholesterol ester transfer protein (CETP). These people have higher levels of so-called good cholesterol or high-density lipoprotein (HDL), as well as better cognitive function in old age and lower risk of Alzheimer's.

In the new study,

"what we found was that those individuals carrying a particular genetic variant had shorter telomeres i.e. looked biologically older," said Nilesh Samani, of the University of Leicester of the Department of Cardiovascular Sciences, who co-led the project, in a statement. "Given the association of shorter telomeres with age-associated diseases, the finding raises the question whether individuals carrying the variant are at greater risk of developing such diseases."

"The variants identified lies near a gene called TERC which is already known to play an important role in maintaining telomere length," added Tim Spector from King's College London and director of the TwinsUK study, and co-leader of the project. "What our study suggests is that some people are genetically programmed to age at a faster rate. The effect was quite considerable in those with the variant, equivalent to between 3-4 years of 'biological aging" as measured by telomere length loss. Alternatively genetically susceptible people may age even faster when exposed to proven 'bad' environments for telomeres like smoking, obesity or lack of exercise - and end up several years biologically older or succumbing to more age-related diseases. "