Smokers Look Older -- Butt Why?
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,
"It's a significant finding," says Wright Caughman, MD,
chairman of dermatology at Emory University School of Medicine in Atlanta.
"We've made the observation for years that smokers not only look older but
sound different -- the husky voice. We knew all these things were happening,
but how smoking exacerbated this was not clear.
"We've seen UV rays induce [changes in proteins] in vitro
-- in Petri dish laboratory experiments -- but I suspect this is the first
study of these changes in people," he adds.
Could smoking also increase risk of skin cancer? Possibly, says
"The study clearly shows that ultraviolet light leads to
premature aging of skin. We also know it increases risk of melanoma and
nonmelanoma skin cancer. We have now strong evidence that smoking exacerbates
and increases those changes -- and perhaps increases those skin cancer risks as