Background Network position contributes to STI risk because of broad sexual network connectivity. Relationship types (i.e., exclusive dating, hook ups) also influence STI risk. Few studies examine how sexual network position and relationship types jointly influence individuals’ STI risk reduction strategies.

Methods We analyzed data from 2011–2017 National Survey of Family Growth for 5,948 and 5,433 unmarried, non-cohabiting sexually active women and men aged 15–44. To describe sexual network position, we created four dichotomous variables that included both past-year number of opposite-sex sex partners (one, multiple) and perceived partner non-monogamy (PPNM, yes/no). Relationship type was defined as a steady or casual sex partner at last sex. Prevalence ratios were used to assess the relationship between network position and two past-year outcomes: condom use at last sex and STI testing. Results were stratified by relationship type.

Results 54% and 47% of women and men aged 15–44 had one partner with no PPNM. 6% and 4% had one partner with PPNM, 22% and 29% had multiple partners with no PPNM and 17% and 20% had multiple partners with PPNM. Men with multiple partners and PPNM had the lowest prevalence of condom use of all four groups (37.7%, CI: 33.5, 44.1 compared with 52–56%). Moreover, women and men in this group with a steady sex partner had higher prevalence of past-year STI testing if they reported PPNM than if they did not (women: aPR=1.31; CI: 1.11, 1.55, men: aPR=1.47; CI: 1.19, 1.81). This same relationship was not seen for women and men whose last sex was with a casual partner.

Conclusion Individuals’ STI risk reduction strategies depend on sexual network position and relationship type. Those with PPNM and a steady sex partner may seek STI testing more frequently. Proxy sexual network measures from national surveys may help target STI prevention and testing interventions.

Disclosure No significant relationships.