HIGH PREVALENCE OF HPV INFECTION IN MEN

High prevalence rates of oral human papillomavirus (HPV) of any type, as well as high-risk, oncogenic HPV types, are being reported among all ethnic groups of men in the United States, according to a comprehensive analysis of the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014.

Among a sample of 4493 men and 4641 women, the prevalence of any type of oral HPV infection was 11.5% among men and 3.2% among women.

This means that 11 million men and 3.2 million women in the United States are infected with some type of oral HPV, the study authors point out.

Disturbingly, however, the prevalence of high-risk oral HPV infection was 7.3% among men and 1.4% among women.

This translates into 7 million men and 1.4 million women who have high-risk oral HPV infection. By far the most common type is HPV 16, which is commonly associated with oropharyngeal cancer.

Such risk factors as having more than 16 lifetime sexual partners, smoking, and marijuana use significantly increased the risk of men and women having any as well as high-risk oral HPV infection.

Just as dramatically, men with concurrent genital as well as any or high-risk oral HPV infection had among the highest prevalence rates of oral HPV infection of any subgroup analyzed.

The study was published online October 16 in Annals of Internal Medicine. 

"Overall prevalence of oral HPV infection was high among U.S. men," the authors comment.

"We previously used the latest NHANES data to study the prevalence of genital HPV among US men, and we found that one out of two US men have genital HPV and one out of three US men have high-risk genital HPV — findings which were shocking to us — so we wanted to look at the prevalence of oral HPV among these men because we thought they might be at high risk for having oral HPV infection as well," senior author, Ashish Deshmukh, PhD, MPH,  University of Florida, Gainesville, told Medscape Medical News.

"In this study, we found that the prevalence of overall oral HPV among men who have genital HPV was close to 20%, while the prevalence of high-risk HPV infection was close to 14%, whereas the prevalence of oral HPV infection was less than 5% in men without genital infection," he added.

"To me, this is important because this helps us understand HPV transmission dynamics and it also might help us stratify individuals with a higher prevalence of oral HPV and if we develop potential screening tools [for oral HPV] in the future, these are the men we need to target," Dr Deshmukh said.

NHANES involved US citizens aged 18 to 69 years who underwent a physical exam at a mobile examination center (MEC).

A dental hygienist collected oral rinse specimens, which were transferred to a MEC laboratory.

Each oral rinse sample was analyzed by polymerase chain reaction assay for the presence of any of 37 HPV types.

"Notably, the prevalence of HPV 16, the most common [high-risk] type, was sixfold higher among men (1.8%)…than women (0.3%) (P < 0.001)," the investigators report.

Indeed, men were consistently more likely than women to be infected with all high-risk as well as all low-risk HPV types, they add.

Non-Hispanic black men had the highest prevalence rates of overall oral HPV infection, at 15.8%, as well as high-risk oral HPV infection, at 8.8%.

Respective prevalence rates in white men were 11.7% for overall oral HPV infection and 7.8% for high-risk oral HPV infection.
Rates were lowest among Hispanic men, at a prevalence of 9.9% for overall oral HPV infection and 5.5% for high-risk oral HPV infection. 

However, the prevalence of overall and high-risk HPV oral infection was significantly influenced by behavioral factors, such as smoking and marijuana use.

Among men who smoked more than 20 cigarettes a day, the prevalence of overall oral HPV infection was 23.6% while the prevalence of high-risk oral HPV infection was 15% in the same group of men.

In comparison, among men who had never smoked or who had quit smoking, the prevalence of any oral HPV type infection was 8.3% while the prevalence of high-risk oral HPV infection was 5.4%.

Moreover, the prevalence of high-risk oral HPV infection was 4 to 10 times higher in men who reported having more than 16 lifetime sexual partners compared with men who reported only one or no lifetime sexual partners.

Prevalence rates of oral HPV infection were slightly lower but similar among women who reported the same number of lifetime sexual partners.

Men in particular, but women as well, who reported same-sex partners were also at fairly substantial risk for infection with high-risk oral HPV types: 12.7% and 3.6%, respectively.

"The prevalence of high-risk HPV infection was highest (22.2%)…among men who reported having 2 or more lifetime same-sex oral sex partners," the investigators note.

The overall prevalence of oral HPV infection in men who reported having sex with men was 18.2%.

Persistent Infection

Asked by Medscape Medical News whether most HPV infections aren't relatively rapidly cleared by the body, Dr Deshmukh acknowledged that most of the common HPV types are not harmful and are likely to be cleared after infection, but HPV16 in particular is much more likely to persist than even other high-risk HPV types.

In a study analyzing the persistence of HPV 16,  investigators found that most prevalent infections, though not newly acquired infections, persisted for at least 24 months.

"If a person has more than 16 lifetime sexual partners, then they have a high risk of acquiring HPV 16 but we also have some evidence that these individuals may not clear HPV 16 as fast, so that they are at risk for it to persist," Dr Deshmukh explained.

Dr Deshmukh also pointed out that HPV 16 was most prevalent in men aged 50 to 69 years, none of whom — and most likely, their sexual partners — would have been vaccinated against HPV infection.

This is again an important observation as a subanalysis of the current cohort indicated that men who reported being vaccinated against HPV had the lowest prevalence of oral HPV infection of any of the subgroups analyzed.

Interestingly, study authors also found that rates of oropharyngeal cancer appear to be declining among women, mirroring rates of decline in the incidence of cervical cancer among US women.

Between 2008 and 2012, an average of almost 40,000 HPV-related cancers were diagnosed in the United States each year, the most common being oropharyngeal squamous cell carcinoma: Over 12,000 cases occurred in men and 3100 cases were diagnosed in women.

The study was supported by the National Cancer Institute. Dr Deshmukh has disclosed no relevant financial relationships, but some co-investigators have disclosed relationships, stated in the published paper. 

Ann Intern Med. Published online October 16, 2017. Abstract

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