Smokers Look Older -- Butt Why?
WebMD News Archive
March 23, 2001 -- In a finding that could give new meaning to the phrase 'cigarette butt,' researchers have figured out why smokers tend to look older than nonpuffers. And they came to their conclusion by directing ultraviolet light to a place where the sun don't shine.
British researchers recruited 33 volunteers for their study -- none of whom had ever used a tanning bed -- and zapped their bare rear ends with ultraviolet light similar to the sun's rays.
"We wanted skin that had no prior ultraviolet light exposure," says Antony R. Young, MD, a professor of environmental dermatology at Guy's, Kings', and St. Thomas' School of Medicine in London. His study appeared in the journal The Lancet on March 24, 2001.
Both before and after the UV exposure, Young and colleagues measured levels of various genetic components in the buttock skin to determine the effects of the rays. Among the genes they tested was one for the protein MMP-1, known to cause destruction of collagen, which gives skin its structure. They also looked at levels of two genes that protect skin from deterioration, called GAPDH and TIMP-1.
In the pre-exposure part of the test, the scientists were able to determine that some backsides had higher levels of the destructive MMP-1 genetic material than others. Some, however, had little or none of it.
After the UV exposure, the scientists asked the volunteers about their smoking habits and based on the answers learned that the three women and 11 men who smoked had higher levels of MMP-1 than the nine women and 10 men who didn't.
"The difference between smokers and nonsmokers was very significant," Young tells WebMD. The smokers reported a wide range of smoking patterns -- having consumed between 10 and 20 cigarettes a day for three to 25 years.
Levels of the genes that protect the skin were unchanged among all the volunteers, regardless of their smoking history.
Bottom line: Smokers get a double whammy -- once from the sun and again from tobacco, since both trigger this skin-destructive MMP-1 action, says Young.