Obesity and smoking accelerate human aging

Researchers are providing one more reason to drop excess weight and quit &to=http:// english.pravda.ru/society/2001/07/12/9893.html ' target=_blank>smoking: a new study finds that both accelerate human aging.

The new study included more than 1,100 British women between 18 and 76 years of age. The women filled out a questionnaire on their smoking history and provided blood samples, which were also tested for concentrations of a body fat regulator called leptin and for telomere length.

Telomeres cap the ends of chromosomes in cells and protect them from damage. However, each time a cell divides -- and as people age -- these caps get shorter, so decreases in telomere length have long been associated with the aging process, tells the Forbes.

Doctors have long warned of the dangers to longevity from smoking and obesity, but analysing the molecular consequences is a far newer science. "Obesity and cigarettes cause oxidative stress to increase and this cumulative damage over time causes the loss of the telomeres, which we believe is a marker of accelerative ageing and accounts for why these people get heart disease, diabetes, osteoarthritis and other age-related disease," said Prof Spector.

The investigators measured concentrations of a body fat regulator, leptin, and telomere length in &to=http:// english.pravda.ru/main/2002/03/21/27116.html ' target=_blank>blood samples from 1,122 women between 18 and 76. Telomere length decreased steadily with age, and telomeres of obese women and smokers were much shorter than those of lean women and those who had never smoked.

Prof Spector said: "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 four years corresponds to 7.4 years of ageing."

But ex-smokers had less shortening of their telomeres than those who still smoked. "Their rate of loss slows down. There is a point in giving up."