The effect is subtle, but genuine. Smoking also appears to accelerate other natural aging processes, such as skin sagging and wrinkles. By middle age, long-time smokers can appear years older than non-smokers of the same age.
British research found smokers were much more likely to develop grey hair before the age of 50 compared with non-smokers.
As it happens, scientists are at work on a genetic fix for grey hair. The London Sunday Times describes how albino mice have been made to produce pigmented hair. The process works by using pigment-producing genes suspended in fatty globules called liposomes. After being rubbed into the skin, cells in the hair follicles pick up the genes and start making pigment. This won't be coming to a hair salon near you any time soon, however. Ironing out the technical and safety details will take several years.
Tobacco isn't the only cause of premature ageing. The Associated Press reports on research conducted in Canada: Studies in identical twins showed that given the same genetic makeup, smoking, tanning and heavy alcohol use can all make someone look prematurely older.