Smoking and obesity make you old

Reported by Susan Aldridge, PhD, medical journalist

Experiments show that smoking and obesity age the cells of the body.
The telomeres, which are the 'caps' at the end of the chromosomes, get shorter and shorter as we age. In research, telomere length can be used as a useful 'marker' for aging. A team at St Thomas' Hospital, London, now reports on what smoking and being overweight do to the telomeres.

A group of 1122 women aged 18 to 76 years was recruited, of whom 119 were obese, 369 were ex-smokers and 203 current smokers. Telomere length was measured in blood samples. As expected, length decreased with age. But the telomeres of obese women and smokers were also shorter than expected. Each pack year (number of packs smoked per day times number of years smoked) was linked to a loss of 18 per cent of telomere length on top of the expected age-related shortening, In short, obesity and smoking accelerate human aging. Obesity adds nearly nine years to your age, when measured in this way, and smoking a pack of cigarettes a day adds on seven and a half years.

Source
The Lancet online 14th June 2005