Dr. Tim Spector and researchers at St. Thomas' Hospital in London stumbled upon the fact. They found cells of overweight women and those who smoke are "older" than those who are not fat and those who don't smoke.
Their findings have been published in The Lancet medical journal.
The age of a cell can be measured with the caps or "telomeres" on the ends of chromosomes. With every consecutive division of the cell, the telomeres get shorter and shorter.
Spector says, "The difference in telomere length between being lean and being obese corresponds to 8.8 years of aging; smoking corresponds on average to 4.6 years of aging; and smoking a pack per day for 40 years corresponds to 7.4 years of aging."
Researchers also finds the oxidative stress facilitating telomere erosion. Spector adds, "Our results emphasize the potential wide-ranging effects of the two most important preventable exposures in developed countries -- cigarettes and obesity."
Scientists studied telomere length in 1122 white women between the ages of 18 and 76 years. The obesity and smoking are related to the oxidative stress.
