The study, which has been published by international journal Sexually Transmitted Infections, found having anal sex and more partners were associated with more STIs.
â€śHaving anal sex and more partners were associated with more STIsâ€ť says co-investigator Associate Professor Nigel Dickson, Director of the Otago University based AIDS Epidemiology Group.
â€śCondoms were protectiveâ€ť Dickson says. â€śMen who reported not using condoms about half the time or more when they had anal sex were 70 per cent more likely to report STIs compared to men who used condoms more consistently, regardless of whether their partners were regular or casual.â€ť
The findings are based on the Gay Auckland Periodic Sex Survey (GAPSS) and national internet-based Gay Online Sex Survey (GOSS) led by Dr Peter Saxton of Auckland University, in collaboration with Dickson and Tony Hughes from the New Zealand AIDS Foundation. The surveys were funded by the Ministry of Health.
Dr Saxton, who heads the Gay Menâ€™s Health Research Group at the University of Auckland, says while HIV is the most serious sexually transmitted infection, others can cause unpleasant problems for gay men.
â€śFor example human papilloma virus (HPV), the virus that causes cervical cancer in women, can lead to anal and oral cancer in infected men,â€ť Dr Saxton says.
â€śSeveral STIs can impact on HIV spreadâ€ť he adds. â€śMen with an ulcerative STI like a syphilis sore â€“ that can be painless and unnoticed especially anally - are at greater risk of acquiring HIV if they have unprotected sex with an infected man because it breaches mucosal integrity and concentrates infectable cells. A person with HIV is more infectious if they have another STI because it elevates HIV viral load at that siteâ€ť.
The study found that STI rates among New Zealand gay and bisexual men were comparable or slightly lower than similar populations in Australia and some northern European countries.
It also found about 40 per cent of men who were not specifically seeking STI treatment had been for a sexual health check in the last 12 months. Similar numbers went to a general practitioner as a sexual health clinic to do so.
â€śThis shows that general practitioners need to be aware of appropriate testing for gay and bisexual men,â€ť Dickson says.
â€śHowever, 10 years ago a New Zealand study found that around two thirds of gay men said their healthcare providers always or usually presumed they are heterosexual.
â€śEncouragingly, checks were more common among those at more risk, for example men reporting many partners and anal sex. Unfortunately they were not more common among those who used condoms less. There were also less common among Asian and Pacific MSM, and those identifying themselves as bisexual.â€ť
Study co-author Adrian Ludlam from the Gay Menâ€™s Health Research Group says the findings will likely underestimate the actual incidence since many STIs can be asymptomatic. He recommended that gay and bisexual men should routinely ask for anal, urine and throat screening at least once a year, and more often if having multiple partners, as part of a sexual wellbeing check.
Tony Hughes, Scientific Director at the New Zealand AIDS Foundation adds â€śas we enter the era of antibiotic resistance, community-based STI prevention is going to become a high priority for gay and bisexual men. The more we know about the local spread of these STIs, the better placed we will be to prevent transmission.â€ť