Smoking and HPV deadly cervical cancer combination says study
Women who carry certain strains of the human papillomavirus (HPV) and who also smoke could be increasing their risk of cervical cancer by as much as 27 times compared with smokers who do not carry the virus, Swedish researchers have said.
By comparison, non-smokers who carried the virus ha just a six-fold increase in risk compared to non-smokers without the virus.
Certain strains of HPV cause cervical cancer in a minority of women who carry them. Smoking has long been known to increase the risk of the disease, but the Karolinska Institute study is the first to estimate the combined effect of the two factors.
Using information from 105,670 cervical smears, the researchers found 499 cases with detectable cervical cancer and compared them against 499 cancer-free samples.
"We were surprised to see this dramatically increased risk among women with high viral loads who smoked," said lead-researcher Anthony Gunnell.
"Our study would imply a synergistic action between HPV and smoking that would greatly increase the likelihood of women developing cervical cancer if they are HPV-positive smokers."
The researchers also reported a relationship between HPV "loads" and the length of time that a woman had been a smoker.
The study could provide some explanation of why most women are able to live with the virus without developing cancer, the researchers said, and merits further research.
The study is published in the journal Cancer Epidemiology, Biomarkers & Prevention.