This population-based study revealed that condom use with temporary partners was not associated with STI risk perception for men whereas it was for women, despite a higher percentage of men reporting consistently having used condoms with temporary partners than women. It is particularly notable that correlates to STI risk perception differ substantially between men and women. Awareness and severity perceptions of HPV and HPV-related cancer were not associated with either condom use or risk perception, whereas education level was positively associated with condom use. Women who were youngest at sexual debut also had two-fold increased odds of reporting non-condom use with temporary partners compared to women with later sexual debuts. Also, women with immigrant mothers were almost twice as likely to report using condoms consistently with temporary partners compared to women with Swedish-born mothers. Number of reported temporary partners was the only common factor associated for both men and women with condom use and STI risk perception.
Based on an underlying KAP assumption, we expected to find those with higher levels of HPV awareness or disease severity perceptions also reporting more consistent condom use with temporary partners. The fact that these variables were not at all associated was surprising, as was the finding that they were not associated with STI risk perception either. This may point to an ineffectiveness of KAP assumptions in explaining this area of risk and prevention practice. This also points to education level's correlation to condom use as an effect of socio-economic status rather than an effect of disease knowledge. High socio-economic status often reduces barriers to prevention for both chronic and infectious diseases 
Our findings regarding men's STI risk perception and condom use correlates are particularly disconcerting considering the prioritized and liberal views of sexual education in Swedish schools 
. The Health Belief Model (HBM) is similar to KAP in that it linearly associates perceived threat of a disease with the likelihood of taking preventive health action 
. Even though KAP and HBM assumptions are supported by public education policy on sexual health, they do not appear predictive of the practice of condom use in both sexes. This calls for a rethinking of educational and public policy in efforts to promote condom use to reduce STI burden. This study reveals that efforts primarily aimed to increase STI awareness and/or perceptions of risk will not suffice in influencing prevention behavior. A deeper understanding into the actual barriers individuals experience in engaging in prevention behavior, with subsequent strategizing to alleviate these barriers, is necessary in the sphere of public health epidemiology.
In societies where health risk exposure information is abundant, as is the case today in countries with high GDP per capita such as Sweden or the U.S., few epidemiological studies aim to measure how individuals interpret their risk exposure and whether or how this is in turn associated with prevention behavior. Our study shows vast gender differences in how risk is perceived and correlated to prevention behavior. Future attempts to measure possible causes and effects of risk perceptions should also aim to measure gender differences.
Other studies have indicated differences in prevalence of male and female condom use but no other large-scale population-based studies using similar variables have evaluated men and women with separate models 
. The measure of condom use itself is often dubious in terms of partner type, frequency and duration of use and analysis of data is often descriptive only or, if analytic, adjusted only for a limited number of factors 
. It is possible that condom use is primarily associated with pregnancy, and not STI, prevention 
. Lazarus et al. noted high oral contraception use amongst Swedish women, which could partially explain the lower condom use among women found in our study 
. They also noted that low HIV prevalence in Sweden could explain low condom use; however our study shows that men do not correlate condom use to STI risk, so our data does not necessarily support this theory. However, the association of heterosexual men reporting anal sex perceiving themselves to be at higher STI risk perhaps indicates that men do not find vaginal sex as ‘risky’ due to a belief that sexual risk means HIV which is seen as a homosexual and hence anal sex, risk. This could be an example of how risk education messages are internalized in a manner different from those who broadcast them intended.
It should be recognized however that as data were collected cross-sectionally we cannot make any inference about cause and effect. This makes it difficult to interpret the significance shown here of reported relationship status in the models as concurrency is unknown. Another potential limitation to our study is respondents self-define ‘temporary’ when asked about condom use with temporary partners in the past year. To avoid recall bias we limited our questions to only asking about sexual relationships in the past year.
Women with mothers born outside the Nordic countries reported more frequent condom use with temporary partners than those with Swedish or Nordic-born mothers. We have not found adequate explanation in the literature for this unexpected finding. One interpretation might be that these women are raised with different values and hence develop different practices than their peers, but it could also be due to differences in reported versus practiced behavior. In light of our findings, maternal and cultural influences on STI prevention behavior merit further investigation.
Specific to HPV, early sexual debut is a well-known risk factor for developing cervical cancer. This is thought to be due to exposing the cervical transformation zone to HPV infection for a longer time-period and/or an average increased number of lifetime sexual partners 
. We found that young sexual debut age correlated to a nearly two-fold odds ratio for non-condom use with temporary partners, which highlights that other risk-related behaviors than age at sexual debut may contribute to the risk of developing cervical cancer. Factors interacting with age at first intercourse on cervical cancer risk warrant further investigation.
Other studies have shown low condom use to be related to a wide variety of factors, including decreased sensation, partner disapproval, non-communication, low levels of emotional intimacy and alcohol use 
. Höglund et. al's study suggests that attitudes to using condoms with new partners were overwhelmingly positive among high school students, though again our study suggests that these attitudes do not necessarily translate into actual behavior 
This study's population-based sampling frame enhances its generalizability in Sweden and also its relevance in other contexts with similar demographics and social climates. The majority of studies on STI risk and condom use rely on convenience-sampling amongst a selected group, e.g. university students or sex workers. To our knowledge, few national population-based studies of this nature have been conducted outside the Nordic region. With consideration given to the sensitive character of the questions and healthy young population targeted, our ~50% participation rate can be seen as acceptable 
. We did have a slight underrepresentation of men, immigrants, those receiving social welfare, and those with lower education (), but we found no gender-specific interaction effects amongst non-respondents. There is no indication that only a specific group responded, augmenting the study's generalizability to young Swedish adults.
Because the survey was based on a random selection of the population, this minimizes the problem of selection bias. However there is always the potential for a non-response bias, in which those who chose not to participate deviated in regard to the outcome variables under investigation. The possibility of non-response bias in the sexual habits questions cannot be ruled out completely, although the distribution of sexual habits and number of survey respondents whom had not made their sexual debut appeared to be reasonable, reflecting the relative heterogeneity expected in the population. Furthermore, both men and women proportionally indicated similar risk perception levels (), so no non-response bias based on gender specifically can be ascertained with that outcome variable. The proportionality of condom use responses did differ based on gender, with men more apt to report consistent use. Therefore, we cannot rule out the potential for non-response bias for that variable. However, as seen in there is still a clear within-gender response variation for condom use, minimizing the likelihood that non-response bias would be particularly problematic based on this outcome.
Having had multiple sexual partners, or having a partner who has had multiple sexual partners, puts one at risk for a variety of infections such as HIV, Chlamydia, HPV and gonorrhea 
. Even with treatments available today in high resource countries against many of these diseases, contracting one can lead to a plethora of undesirable effects such as significant loss in quality of life, social stigma, antibiotic resistance, impaired fertility and preterm births 
. Early death is related not only to AIDS and cervical cancer but also to other HPV-related cancers – e.g. penile, anal, oral and oropharyngeal malignancies. With these detrimental health effects, proper condom use as a primary prevention measure should remain a top priority for health officials 
. This study concludes however, that campaigns with a primary aim to increase STI knowledge and awareness with the intention of influencing risk perceptions amongst those sexually active, may not effectively translate into an increase in prevention behaviors. To reach the public health goal of reducing STI prevalence, barriers to engaging in STI prevention need to be addressed, including gender barriers as this study highlights.