Gay men who don't have anal sex still at high risk of bacterial STIs

Gay men may still have a significant risk of syphilis and urethral gonorrhoea even if they do not have anal sex, results of a study published in Sexually Transmitted Infections suggest. The study was conducted in Melbourne, Australia, and involved gay and other men who have sex with men (MSM) undergoing sexual health screens between 2002 and 2012.

“We found a substantial and significant risk of PS [primary syphilis] and UGC [urethral gonorrhoea] for men who had not had anal sex,” comment the authors. “This risk was not different to the risk of these infections in men reporting anal sex.”

Rates of syphilis, chlamydia and gonorrhoea are increasing among gay men in many countries, driven by a combination of risky sexual behaviour, improved diagnostic tests and increased testing of samples from the throat and rectum (rather than just the penis).

Most health promotion campaigns targeted at gay men have sought to reinforce messages regarding the importance of condom use for anal sex.

However, anal sex forms only part of the repertoire of sexual activities for the majority of gay men. For instance, oral sex is much more frequently practised than anal sex and condoms are very rarely used. It is known that sexually transmitted infections (STIs) can be transmitted via activities other than anal sex.

Investigators in Melbourne therefore analysed the records of gay men attending the Melbourne Sexual Health Centre between 2002 and 2012. They wished to establish the proportion of cases of primary syphilis, urethral chlamydia and urethral gonorrhoea diagnosed in men who reported no recent anal sex.

There were 37,533 consultations over the period of the study; 2374 (6%) reported no anal sex.

A total of 204 cases of primary syphilis were diagnosed. Of these, twelve (6%; 0.5 cases per 1000 consultations) involved men who reported no anal sex; 51 cases (25%, 0.4 per 1000 consultations) were in men who said they always used condoms for anal sex; and 132 cases (65%, 0.6 cases per 1000 consultations) involved men who reported not always using condoms for anal sex.

The risk of syphilis was not significantly greater for men reporting anal sex. Men who reported consistent condom use (AOR = 0.80; 95% CI, 0.43-1.51) or not always using condoms (AOR = 1.26; 95% CI, 0.7-2.28) did not have a higher risk, compared to men not reporting anal sex.

A total of 673 cases of urethral chlamydia were detected; of these 16 (2.5%, 1.5 cases per 1000 consultations) were in men who did not report anal sex. Just under a third of cases (194, 29%, 2.4 cases per 1000 consultations) involved men who reported consistent condom use for insertive anal sex and 455 diagnoses involved men who did not always use condoms for insertive anal intercourse (68%, 3.8 cases per 1000 consultations).

Men who reported insertive anal sex had an increased risk of urethral chlamydia compared to men who reported no anal sex. The risk was approximately 75% greater for men who reported “always” using condoms (OR = 1.72; 95% CI, 1.03-2.88, p = 0.04) and was more than doubled for individuals who used condoms inconsistently (OR = 2.76; 95% CI, 1.67-4.55, p < 0.001).

Of the 618 cases of urethral gonorrhoea diagnosed, 44 (7.1%, 14 cases per 1000 consultations) were in men who did not report anal sex. Over a quarter of cases involved men who said they always used condoms for insertive anal sex (169 cases, 27%, 15 cases per 1000 consultations) and the remaining 402 (65%, 18.4 cases per 1000 consultations) were in men who did not always use condoms for insertive anal sex.

The risk of urethral gonorrhoea was not significantly greater for men reporting insertive anal sex. Men who reported consistent condom use (AOR = 0.98; 95% CI, 0.68-1.42) or not always using condoms (AOR = 1.39; 95% CI, 0.97-1.98) did not have a higher risk, compared to men not reporting anal sex.

 “It is important than MSM are aware that sexual practices other than anal sex pose a risk of infection,” comment the investigators. They suggest that as well as oral sex, practices such as 'nudging' (external contact between the penis and anus) and 'dipping' (insertion of the penis without ejaculation) may contribute to the spread of infection. However their study did not collect detailed information on these practices.

In addition, the authors argue that public health strategies need to highlight the importance of shortening the duration of infection through frequent testing. Otherwise infection rates are unlikely to be reduced in gay men, they say.