Another reason second-hand smoke is bad: there's a chance it can increase the risk of cervical neoplasia, a new study suggests.
The results, from a study of 4,400 women undergoing Pap tests, show that "women who report exposure to second-hand smoke are more likely to have an abnormal Pap test than women who do not report exposure to second-hand smoke," said lead researcher Dr Kristy K. Ward, of the University of California San Diego.
It's possible that second-hand smoke makes a woman more vulnerable to developing abnormalities in cervical tissue, according to Dr Ward.
Active smoking has already been linked to an increased risk of cervical cancer, and studies have shown that toxins from both first-hand and second-hand cigarette smoke can be found in cervical tissue.
Genes in cells change
"In general," Dr Ward said, carcinogens "cause the genetic material in the cell to change, so it doesn't function normally. This can lead to abnormalities in the cell that show up on a Pap test and have the potential for progressing to cancer."
Past studies have found a link between second-hand smoke and abnormal Pap results, but other studies have failed to confirm the connection. This latest study, reported online in the American Journal of Obstetrics& Gynaecology, is different in that most of the women involved were Hispanic American.
Hispanic women in the US develop cervical cancer at a rate of 11.5 per 100,000 women -- versus 8 per 100,000 among US women in general.
Of the 4,400 women in this study, 7% had an abnormal Pap test result.
70% likely to have abnormal pap test
Overall, the researchers found, women who said they were exposed to "some" second-hand smoke were 70% more likely to have an abnormal Pap result than women with no such exposure, even after other factors, like a woman's own smoking and sexual history, were taken into account.
The results do not specify what the risk of an abnormal Pap smear would be with and without exposure to second-hand smoke. But Dr Ward said any actual increase in risk would be small.
Still, the study shows "once again shows that second-hand smoke exposure is dangerous to a person's health," Dr Ward said.
She also noted that even though most cervical abnormalities on Pap tests will not lead to cancer, at a minimum they lead to extra stress and expenses.
"Personally," Dr Ward said, "a woman with an abnormal Pap test experiences anxiety about the potential of a pre-cancerous or cancerous disease, and it requires extra time, effort and money to continue to return to the health care provider's office for follow-up and treatment."
(Reuters Health, Amy Norton, February 2011)