Women's Lifestyle Choices May Affect Clearance of Anal Infection With HPV16

January 27, 2014

By Rob Goodier

NEW YORK (Reuters Health) Jan 27 - Most anal infections with human papillomavirus (HPV) clear within three years, but HPV16, which is linked to 90% of anal cancers, clears more slowly, according to a new long-term study of the virus' natural history in women.

The virus is more likely to persist in women who have a simultaneous cervical infection of the same strain. But lifestyle and sexual choices may also speed or delay clearance, the study has found.

"Anal infections are common but persistence is rare. Persistence inhigh-risk women is likely higher and they should be counselled on ways to decrease anal HPV persistence. This would include avoiding anal intercourse or always use a condom during anal sex and avoid finger anal sex as well," lead author Dr. Anna-Barbara Moscicki of the University of California, San Francisco, told Reuters Health by email.

To study the natural history of anal HPV infection, Dr. Moscicki and her team followed 75 anal-HPV-positive heterosexual women (mean age, 23.5) for an average of seven years (84.5 months).

They noted in their report, published online December 23 in Clinical Infectious Diseases, that anal cancer occurs at a rate of 1.5 per 100,000 people, striking women more often than men. In the U.S., an estimated 2250 men contracted anal cancer in 2012, while 3980 women were diagnosed with the disease. Among women, the rate increased by 2% per year from 1973 to 2009.

Known risk factors include anal sex, multiple lifetime partners and smoking. Factors that put women at high risk include a history of vaginal or cervical cancer or CIN III precancerous cells or immunosuppression through HIV or other causes.

In the current study, three years after contracting the virus, nearly 83% of low- and high-risk types of HPV had cleared, with one exception. HPV16, the type most commonly linked to anal cancer, had cleared in only 76.2% of the women at three years.

Slower clearance of HPV16 was significantly linked to a cervical infection at the same time, weekly drinking, touching of the anus during sex, recent anal sex and a failure to use condoms during anal sex.

The link with cervical infection might suggest "some type of global immune dysregulation," the researchers wrote in their paper.

Faster clearance was linked to condom use during vaginal sex and more new sex partners.

"We speculate that both of these suggest that the 'new partner' reflects a dissociation with the previous partner who was responsible for the constant re-exposure. Condom use is more commonly used with "new" partners than steady partners thereby reflecting the 'new' partner," the authors said.

SOURCE: http://bit.ly/1dJ3f21

Clin Infect Dis 2013.


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