Smoking Boosts Cervical Cancer Risk
Dangerous Combination: Smoking Plus HPV Virus Infection
Nov. 17, 2006 -- HPV, the human papillomavirus, is vastly more dangerous in
women who smoke, a Swedish study finds.
Some 19 kinds of HPV have been linked to cervical
cancer; HPV-16 is the most deadly.
Now, research suggests that women who smoke are more likely to get cervical
cancer if they become infected with that virus
than are nonsmokers.
While the nonsmokers studied were six times as likely to develop cancer if
infected, smokers were more than 14 times as likely to get cancer within nine
years if they had the virus, according to the study.
Researchers Anthony S. Gunnell and his colleagues at Sweden's Karolinska
Institute suspected smoking and HPV-16 might work together.
So they compared the medical records of 375 women who had the earliest stage
of cervical cancer to the records of 363 women with similar characteristics who
did not have the cancer.
Based on Pap smears taken an average of nine years before the women
developed cervical cancer, the researchers were able to tell whether the women
had had an HPV-16 infection.
They also were able to see whether the women had had high or low levels of
HPV in their blood -- something doctors call high or low viral load.
- Among smokers, those who had tested positive for HPV-16 were 14.4 times
more likely to get cervical cancer than those who did not have the
- Among smokers, those who had had high HPV-16 viral load were 27 times more
likely to get cervical cancer than those who did not have the infection.
- However, among nonsmokers, those who had tested positive for HPV-16 were
only six times more likely to get cervical cancer than nonsmokers who did not
have the infection. Having high vs. low HPV-16 viral load did not affect that
Women who had continued to smoke further multiplied their chances of getting
The researchers suggest smoking may help HPV-16 grow faster -- possibly by
slowing helpful immune responses.
They also suggest smoking may speed the process by which HPV-16 causes
The findings appear in the November issue of Cancer Epidemiology,
Biomarkers & Prevention.