London, Oct 13 (PTI) People who are well educated mayhave a longer lifespan, with almost a year added for eachyear spent studying beyond school, according to a majorstudy.
The study of the genes that underpin longevity also foundthat people who are overweight cut their life expectancy bytwo months for every extra kilogramme of weight they carry.
Researchers at the University of Edinburgh in the UKfound that people who give up smoking, study for longer andare open to new experiences might expect to live longer.
"Our study has estimated the causal effect of lifestylechoices," said Peter Joshi, Chancellor's Fellow at theUniversity of Edinburgh's Usher Institute.
"We found that, on average, smoking a pack a day reduceslifespan by seven years, whilst losing one kilogramme ofweight will increase your lifespan by two months," saidJoshi.
Researchers analysed genetic information from more than600,000 people alongside records of their parents' lifespan.
Because people share half of their genetic informationwith each of their parents, the team was able to calculatethe impact of various genes on life expectancy.
Lifestyle choices are influenced to a certain extent byour DNA - genes, for example, have been linked to increasedalcohol consumption and addiction.
The researchers were able to work out which genes havethe greatest influence on lifespan.
Their method was designed to rule out the chances thatany observed associations could be caused by a separate,linked factor.
This enabled them to pinpoint exactly which lifestylefactors cause people to live longer, or shorter, lives.
They found that cigarette smoking and traits associatedwith lung cancer had the greatest impact on shorteninglifespan.
For example, smoking a packet of cigarettes per day overa lifetime knocks an average of seven years off lifeexpectancy, they calculated.
However, smokers who give up can eventually expect tolive as long as somebody who has never smoked, according tothe researchers.
Body fat and other factors linked to diabetes also have anegative influence on life expectancy.
The study, published in the journal NatureCommunications, also identified two new DNA differences thataffect lifespan. The first - in a gene that affects bloodcholesterol levels - reduces lifespan by around eight months.
The second - in a gene linked to the immune system - addsaround half a year to life expectancy.
The research used data from 25 separate populationstudies from Europe, Australia and North America.
"The power of big data and genetics allow us to comparethe effect of different behaviours and diseases in terms ofmonths and years of life lost or gained, and to distinguishbetween mere association and causal effect," said ProfessorJim Wilson, of the University of Edinburgh's Usher Institute.
PTI SARSAR.
This is unedited, unformatted feed from the Press Trust of India wire.