News Release

Smoking and obesity accelerate human ageing

EMBARGO: 00:01H (London time) Tuesday June 14, 2005. In North America the embargo lifts at 6:30pm ET Monday June 13, 2005.

Peer-Reviewed Publication

The Lancet_DELETED

People who smoke or are obese are biologically older than slim individuals and non-smokers, suggests a study published online today (Tuesday June 14, 2005) by THE LANCET.

Obesity and smoking are important risk factors for many age-related diseases. Tim Spector (St. Thomas' Hospital, UK) and colleagues in the USA looked for evidence of ageing at a molecular level in smokers and obese individuals. They analysed telomeres, which cap the ends of the chromosomes in our cells and protect them from damage. Every time a cell divides, and as people age, their telomeres get shorter.

The investigators recruited 1122 women from the UK aged 18-76 years onto the study. 119 of the women were obese, with a body mass index (BMI) greater than 30, and 85 women had a BMI under 20. 531 women had never smoked, 369 were ex-smokers, and 203 were current smokers. The participants were asked to complete a questionnaire on smoking history. Their exposure to smoking was measured as pack-years (number of cigarette packs smoked per day x number of years smoking). The investigators measured the concentrations of a body fat regulator called leptin and telomere length in blood samples from the women. They found that telomere length decreased steadily with age and the telomeres of obese women and smokers were much shorter that those of lean women and never-smokers. Lean individuals had significantly longer telomeres than women with midrange BMIs, who, in turn, had longer telomeres than obese individuals. Each pack-year smoked was equivalent to a loss of an additional 18% on top of the average annual shortening of telomeres.

Professor Spector states: "Our findings suggest that obesity and cigarette smoking accelerate human ageing…the difference in telomere length between being lean and being obese corresponds to 8•8 years of ageing; smoking (previous or current) corresponds on average to 4•6 years of ageing; and smoking a pack per day for 40 years corresponds to 7•4 years of ageing. Our results emphasise the potential wide-ranging effects of the two most important preventable exposures in developed countries--cigarettes and obesity."

###

Contact: Professor Tim D Spector, Twin Research Unit, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK. T)+44 (0) 20 7188 6765 victoria.vazquez@gstt.sthames.nhs.uk


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.