STI Risk Perception in the British Population and How It Relates to Sexual Behaviour and STI Healthcare Use: Findings From a Cross-sectional Survey (Natsal-3)

Abstract

Background: We investigated how STI risk perception relates to behavioural STI risk and STI healthcare (sexual health clinic attendance/chlamydia testing) in the British population.

Methods: Natsal-3, a national probability-sample survey undertaken 2010-12, included 8397 sexually-active 16-44 year-olds. Participants rated their risk of STIs (excluding HIV) given their current sexual lifestyle. Urine from a randomly-selected sub-sample of participants (n = 4550) was tested for prevalent STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis).

Findings: Most men (64% (95% CI: 62-66)) and women (73% (72-74)) rated themselves as not at all at risk of STIs, 30% (29-32) men and 23% (22-25) women self-rated as not very much, and 5% (5-6) men and 3% (3-4) women as greatly/quite a lot at risk. Although those reporting STI risk behaviours were more likely to perceive themselves as at risk, > 70% men and > 85% women classified as having had unsafe sex in the past year, and similar proportions of those with a prevalent STI, perceived themselves as not at all or not very much at risk. Increased risk perception was associated with greater STI healthcare-use (past year), although not after adjusting for sexual behaviour, indicating in a mediation analysis that risk perception was neither necessary or sufficient for seeking care Furthermore, 58% (48-67) men and 31% (22-41) women who had unsafe sex (past year) and rated themselves as greatly/quite a lot at risk had neither attended nor tested.

Interpretation: Many people at risk of STIs in Britain underestimated their risk, and many who correctly perceived themselves to be at risk had not recently accessed STI healthcare. Health promotion needs to address this mismatch and ensure that people access healthcare appropriate to their needs.

Fig. 1

Age-adjusted relative risk ratios (with 95% confidence interval) for rating oneself as greatly/quite a lot or not very much at risk, compared with not at all at risk, by sexual behaviours and presence of STIs in urine in the past year (sexually-active men and women aged 16–44 years). Notes for this figure: Denominator is those aged 16–44 reporting at least one sexual partner in the past year. Graphs show age-adjusted relative risk ratios (with 95% confidence interval) for each outcome, comparing those rating themselves as not very much at risk or greatly/quite a lot at risk with those rating themselves as not at all at risk. ‘Unsafe sex’ = reported either no condom used at first occasion of sex with a new partner and/or sex with 2 + partners and no condom used with any partner (past year), excluding those who had only oral sex in the past year. Prevalent STI in urine: Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, or Mycoplasma genitalium. Denominators for prevalent STI in urine are smaller than for behavioural variables as urine was only requested from a sub-sample of participants. For full data, including denominators, see Supplementary Table 2.