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Original article
Self-perceived risk of STIs in a population-based study of Scandinavian women
  1. Sonia Guleria1,
  2. Mette Tuxen Faber1,
  3. Bo T Hansen2,
  4. Lisen Arnheim-Dahlström3,
  5. Kai-Li Liaw4,
  6. Christian Munk1,
  7. Mari Nygård2,
  8. Susanne Krüger Kjær1,5
  1. 1 Unit of Virus, Lifestyle and Genes, Danish Cancer Society Research Center, Copenhagen, Denmark
  2. 2 Department of Research, Cancer Registry of Norway, Oslo, Norway
  3. 3 Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
  4. 4 Epidemiology at Merck, Merck Research Laboratories, Kenilworth, NJ, USA
  5. 5 Department of Gynecology, Rigshospitalet, University of Copehagen, Copenhagen, Denmark
  1. Correspondence to Professor Susanne Krüger Kjær, Unit of Virus, Lifestyle and Genes, Danish Cancer Society Research Center, Copenhagen, 2100, Denmark; susanne{at}cancer.dk

Abstract

Objective This study examined the associations between current behaviours/characteristics and self-perceived risk for STIs, among randomly selected women aged 18–45 years from Denmark, Norway and Sweden.

Method A population-based, cross-sectional, questionnaire study (paper based, web based and telephone based) was conducted during 2011–2012. We compared medium–high STI risk perception with no/low risk perception. The associations were explored for women who had ever had sexual intercourse and for women with a new partner in the last 6 months using multivariable logistic regression.

Result The overall prevalence of medium–high STI risk perception was 7.4%. It was highest among women aged 18–24 years (16.2%) and among the Danish women (8.8%). Number of new sexual partners in the last 6 months (≥3vs 0 partners, OR 14.94, 95% CI 13.20 to 16.94) was strongly associated with medium–high STI risk perception. Among women with a new partner in the last 6 months, lack of condom use increased medium–high STI risk perception (OR 1.73, 95% CI 1.52 to 1.96). Genital warts in the last year, binge drinking and being single were associated with increased risk perception and remained statistically significant after additional adjustments were made for number of new partners and condom use with new partners in the last 6 months.

Conclusion Subjective perception of risk for STI was associated with women’s current risk-taking behaviours, indicating women generally are able to assess their risks for STIs. However, a considerable proportion of women with multiple new partners in the last 6 months and no condom use still considered themselves at no/low risk for STI.

  • sexually transmitted infections
  • risk perception
  • scandinavian women
  • sexual behavior
  • cross-sectional

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Introduction

STIs are common and are considered a substantial global burden.1 2 Chlamydia is the most commonly reported bacterial STI in women worldwide, with a lifetime prevalence of 17% among Nordic women aged 18–46 years.3 Human papillomavirus is the most common viral STI worldwide, with an estimated prevalence of around 10% in Northern Europe.4 STI can persist as asymptomatic infections5 and can lead to severe and potentially fatal complications in women.1 In addition to high prevalence and difficulties in timely diagnosis of STI, other challenges such as high rates of reinfection and increasing resistance to antibiotics, especially for gonorrhoea, increase the economic burden of these infections.2

STIs have previously been associated with number of lifetime sexual partners, lack of condom use and an episode of STI in the past.3 Non-sexual behaviours such as smoking and alcohol consumption are also reported to be associated with STI among the Nordic women.3 Interventions such as compulsory sex education to raise awareness on STI and opportunistic screening programmes to identify asymptomatic individuals are available in Denmark, Norway and Sweden.6 In addition to STI awareness, an individual’s own risk perception may influence attitudes towards effective utilisation of preventive programmes.7 8 Previous studies have reported that individuals who perceived a higher risk of acquiring STI were more likely to have been screened or to have intentions of doing so in the future.7 8 On the contrary, a large proportion of sexually active British individuals at increased risk of STI due to unsafe sexual behaviours, such as a new sexual partners in the previous year and non-use of condoms with new partners, did not attend sexual health clinics or get screened for STI.9 The perception of STI risk is associated with women’s current sexual behaviours and has been studied previously.10 11 In one study, recent risky sexual behaviours were associated with perception of STI risk among Swedish women aged 18–30 years,11 but in another study, no associations were found between the two.10 These studies are limited by a small sample size, low response rate, inclusion of only adolescent/young women or women of a certain ethnic group, and therefore, the results of these studies are less generalisable to the general female population.

The objectives of this study were to present country-specific prevalence of self-perceived risk for STI among women aged 18–45 years, from Denmark, Norway and Sweden, who had ever had sexual intercourse, and to determine whether current behaviours are associated with STI risk perception. The analysis was performed among all women in the study population and among a subgroup of women with at least one new partner in the last 6 months.

Methods

Study population

Details regarding the study population have been described elsewhere.12 Briefly, a cross-sectional study was conducted in Denmark, Norway and Sweden during 2011–2012. Each of these countries have a national register that contains information on all residents of the respective country. Information on each citizen in the registers can be identified by a unique personal identification number (PIN), which is assigned to all residents in these countries. Random samples of women aged 18–45 years were drawn from the national register in each of the three countries using the PIN, resulting in a total sample of 83 720 women (Denmark=26 000, Norway=26 803 and Sweden=30 917). Women who were not able to respond to the questionnaire because they did not speak the local language or because they were mentally or physically challenged and women who had died or emigrated were not included in the study (n=3167), leaving 80 553 women eligible for the study. Overall, 60.6% women participated in the study (Denmark: 75.1%, Norway: 54.5% and Sweden: 53.7%), resulting in a sample of 48 788 women. The present study includes only women who reported to have had sexual intercourse (Denmark=17 925, Norway=13 156, and Sweden=15 585). In addition, we only included women without missing information on explanatory variables (Denmark=16 799 (93.7% of the eligible), Norway=11 959 (90.9% of the eligible) and Sweden=14 216 (91.2% of the eligible)), resulting in a study population of 42 974 women.

Data collection

The women eligible for the study were sent an invitation letter and a self-administered questionnaire, which could be answered by paper or via the internet. Women who did not respond to the initial invitation and a subsequent reminder were offered to answer the questionnaire via a telephone. The questionnaire asked information related to demography, lifestyle and sexual health. Approximately 65% women responded to the questionnaire via paper, 18% via the internet and 17% via phone. The women who answered the questionnaire were considered to have consented to participate in the study.

Statistical analysis

To assess the perception of STI risk, women were asked the following question: ‘What risk do you think you have for contracting a sexually transmitted infection?’ In Norway and Sweden, the women chose from the following response categories: ‘no risk’, ‘low risk’, ‘medium risk’ and ‘high risk’. The questionnaire used in Denmark additionally had a ‘very high risk’ response category. There were only 64 women in the very high-risk response category in Denmark. The responses were categorised as: medium–high risk and no/low risk. We present the prevalence of medium–high STI risk perception among women in three age groups (18–24, 25–34 and 35–45 years) separately for each country. The associations between factors related to current behaviours, selected a priori, and medium–high STI risk perception were analysed using logistic regression. The results are presented as ORs with corresponding 95% CI. Because the effects of the factors associated with STI risk perception were similar among the three countries (online supplementary table 1a) and among the different types of response (paper based, web based and telephone based; online supplementary tables 1b), the data were combined for these characteristics in the logistic regression models. For the total study population of women who had ever had sexual intercourse, we present models adjusted for country, age (continuous), type of response and number of new partners in the last 6 months (ever/never and continuous). Furthermore, we present models restricted to women with complete information on new partners and condom use in the last 6 months adjusted for: (A) country, age, type of response and number of new partner in the last 6 months; and (B) country, age, type of response, number of new partner in the last 6 months and condom use with new partners in the last 6 months. All statistical analyses were carried out using STATA V.14.0.

Supplementary file 1

Results

The majority of the 42 974 women in our study were <34 years old (53.5%), had more than high school education (70.0%), were married or cohabiting (71.0%) and had reported to be alcohol drinkers at the time of the study (89.1%; table 1). Approximately 13% women reported to have had one or more new partners in the last 6 months. The age distribution was similar in the three countries. In addition, the distributions of number of new partners and condom use with a new partner in the last 6 months were similar between the countries. Table 1 displays the prevalence of medium–high STI risk perception for current behaviours/characteristics, among all women who had ever had sexual intercourse (n=42 974) and among women with a new partner in the last 6 months (n=5620). In the total study population, the largest variation in prevalence of medium–high STI risk perception was seen for number of new partners in the last 6 months: ranging from 4.2% among women with no new partners in the last 6 months to 48.2% among women with ≥3 new partners in the last 6 months. On combining the information on number of new partners in the last 6 months and condom use with new partners, among women with ≥3 partners and never/rare condom use with new partners in the last 6 months, the prevalence of medium–high STI risk perception was 56.3% (data not shown), that is, 43.7% still perceived themselves to be at no/low risk of STI.

Table 1

Characteristics and prevalence of medium–high STI risk perception among all women who had ever had sexual intercourse (n=42 974) and among women with a new partner in the last 6 months (n=5620)

The overall prevalence of medium–high STI risk perception was 7.4%, covering 8.8% in Denmark, 6.4% in Norway and 6.4% in Sweden. Figure 1 displays the prevalence of medium–high STI risk perception among women in three age groups in the three countries. The prevalence was higher among Danish women in all the three age groups. Among the three age groups, the prevalence was highest among the youngest women (18–24 years) in all the three countries: 19.5% for Danish, 14.7% for Norwegian and 13.3% for Swedish women. For 25–34 year-old women, the prevalence varied from 6.6% (Norway) to 8.8% (Denmark), while for 35–45 year-old women it varied from 2.9% (Norway) to 4.0% (Denmark).

Figure 1

Country-specific prevalence of self-perceived medium–high risk of STIs by age group. DK, Denmark; NO, Norway; SW, Sweden.

Figure 2 displays age-specific and country-specific prevalence of self-perceived medium–high STI risk by number of new partners in the last 6 months. For women in each age group, the prevalence of medium–high STI risk perception increased as number of new partners in the last 6 months increased; this pattern was observed for women in each country. The Danish women had higher prevalence in each age group.

Figure 2

Age-specific and country-specific prevalence of self-perceived medium–high risk of STIs by number of new sexual partners in the last 6 months. DK, Denmark; NO, Norway; SW, Sweden.

Table 2 presents ORs for perceiving medium–high compared with no/low STI risk adjusted for country, age, type of response and number of new partners in the last 6 months for the total study population. Having a large number of new partners in the last 6 months was associated with a higher likelihood of perceiving medium–high risk for STIs (≥3 partners vs 0 partners, OR 15.20, 95% CI 13.34 to 17.33). Women with genital warts in the last year were also more likely to perceive their risk for STI to be medium–high compared with women with no genital warts in the last year (OR 2.61, 95% CI 2.07 to 3.30). Single, divorced or widowed women were more likely to consider their risk of STI acquisition to be medium–high than women who were either married or cohabiting (OR 3.45, 95% CI 3.12 to 3.81). Women who were binge drinkers (more than six alcoholic drinks at one occasion) were also more likely to perceive medium–high risk for STIs, with the likelihood being highest among those who were frequent (>once/month) binge drinkers (OR 1.94, 95% CI 1.65 to 2.28). Women’s educational level at the time of the study was not associated with perception of STI risk.

Table 2

Adjusted ORs with 95% CIs comparing medium–high versus no/low risk perception for STIs among all women who had ever had sexual intercourse (n=42 974) and among women with a new partner in the last 6 months (n=5620)

We also assessed ORs for perceiving medium–high STI risk among women who reported to have had at least one new partner in the last 6 months and complete information on condom use with new partners (table 2). In a model adjusted for country, age, type of response and number of new partners in the last 6 months, the likelihood of perceiving medium–high STI risk increased by 28% (OR 1.28, 95% CI 1.23 to 1.33) for each new partner in the last 6 months. When we examined the effect of condom use with new partners in the last 6 months, we found that women who never or occasionally used condoms with a new partner in the last 6 months were more likely to perceive medium–high STI risk compared with women who always or almost always used condoms with a new partner (OR 1.73, 95% CI 1.52 to 1.96). Women who were frequent binge drinkers, or were single/divorced/widowed, were also more likely to perceive medium–high STI risk. Finally, medium–high STI risk perception was lower in less educated (up to high school) women compared with women with an educational level of more than high school. All associations remained statistically significant and were only slightly attenuated when further adjustments for condom use with new partners were made. Furthermore, when mutually adjusted the associations for new partners in the last 6 months and for condom use with new partners in the last 6 months both remained statistically significant.

Discussion

In this large, population-based study, nearly 8% of women aged 18–45 years from Denmark, Norway and Sweden perceived themselves as being at a medium–high risk for acquiring STI. The younger (18–24 years) and the Danish women had a higher prevalence of perceiving medium–high STI risk. Having a new partner in the last 6 months was strongly associated with medium–high STI risk perception. In the total study population as well as among women with at least one new partner in the last 6 months, additional factors associated with medium–high STI risk perception were: genital warts in the last year, binge drinking and being single, divorced or widowed. Among women with new partners in the last 6 months, lack of condom use was also associated with medium–high risk perception, even after adjustment were made for number of new partners. Furthermore, the association with number of new partners in the last 6 months did not change after adjustment were made for condom use with new partners.

In previous studies, 10%–12% of women aged 14–31 years reported a high STI risk perception.10 11 13 Although direct comparisons with these studies may not be possible due to inherent differences in population and study characteristics, the prevalence reported in our study is in close proximity to that observed in the past. In our study, the prevalence of medium–high STI risk perception decreased with increasing age. The younger (18–24 years) women had the highest risk perception: reaching one in every five Danish women. The younger women were also more likely to have one or more new partners in the last 6 months and not to use condoms always or regularly with the new partners (data not shown). These high-risk behaviours could partly explain the perception of higher risk for STIs among the younger women and therefore indicate an adequate risk perception.

The prevalence of medium–high risk perception was higher among Danish women than women from the other two countries in our study. Diverse risk-taking behaviours across the three countries could be a possible explanation. We have previously reported women from Denmark, Iceland, Norway and Sweden to have similar sexual behaviours with respect to age at first intercourse and number of lifetime sexual partners.14 In contrast, we have found contraceptive use at first sexual intercourse to vary among women in the three countries.15 Thus, whether the difference in the country-specific prevalence reported in this study is due to differences in current contraceptive choices of women across the three countries or other unknown factors is not known. Finally, even though the same study design was applied in all three countries, the participation rates differed slightly between the countries, which may have influenced the prevalence of STI risk perception observed in our study.

Women in our study were generally able to make reasonable risk assessments indicating that STI risk perception was associated with women’s actual risk of exposure to STI. Having a new partner in the last 6 months increased women’s risk perception. In addition, among those with a new partner in the last 6 months, lack of condom use also increased women’s STI risk perception, which is in line with previous studies.11 13 When these variables were mutually adjusted, the associations remained statistically significant, indicating that both new partners in the last 6 months and condom use with new partners are significant predictors of women’s perception of STI risk. However, neither having a new partner in the last 6 months, nor recent condom use could fully explain the associations between other current behaviours and STI risk perception. This was evident in the whole study population and in the subgroup of women with new partners in the last 6 months. This indicates that even though a number of new partners in the last 6 months and condom use with new partners are strong predictors, other factors related to women’s current behaviours have an independent effect on STI risk perception. Thus, occurrence of genital warts in the last year increased the likelihood of higher STI risk perception among women in our study. Furthermore, binge drinking was associated with women perceiving medium–high risk for STI. Previous studies have reported that risk-taking behaviours are inter-related.16–19 Therefore, young adults involved in binge drinking, smoking and illicit drug use are also more likely to have first sexual intercourse at an early age, to have high number of sexual partners and to use contraceptives less frequently.16 17 19 Alcohol can impair an individual’s capacity to assess and avoid behaviours that increase the risk for STI.20 Additionally, personality traits such as impulsivity and sensation-seeking can increase risky sexual behaviours after alcohol consumption.21 We observed that being single, divorced or widowed was associated with perception of increased risk for STI, which is in line with other studies.11 22 Although single, divorced or widowed women in our study were more likely to have a higher number of new partners, they were also more likely to use condoms regularly with a new partner (data not shown). Even after these differences were taken into account, perceived risk for STI remained higher among single, divorced or widowed women. This may be explained by residual confounding due to specific sexual habits that we have no information on.

The strengths of the study include the population-based design with relatively high participation rates, which makes our results highly generalisable. Women included in this study were selected at random from the general populations, which reduces the likelihood of selection bias. Lastly, while most previous studies focus on risk perception among the highly vulnerable group of young women, our study includes a broader age range. The study also has some limitations. First, as we collected self-reported information on current behaviours, a certain degree of under-reporting or over-reporting of the information was likely due to social desirability bias, affecting the validity of the data. Second, we were not able to investigate other potential confounders such as duration of relationship, sexual orientation and practices, which can influence risk perception as well as current behaviours. In addition, we did not examine sexual behaviours and the prevalence of STI among sexual partners of the women, which could also influence STI risk perception among women included in the study.

In conclusion, STI risk perception was highest among the youngest women and among the Danish women in this study. The important factors associated with perception of medium–high STI risk were related to current risk-taking behaviours, including number of new partners in the last 6 months, lack of condom use with new partners in the last 6 months, binge drinking and a history of genital warts in the last year. Therefore, to some extent, there was concordance between the women’s current risk-taking behaviours and the subjective perception of risk for STI. However, a relatively high proportion of women in some high risk-groups still perceived no/low risk for STI.

Key messages

  • The overall prevalence of medium–high STI risk perception was 7.4%.

  • Prevalence of medium–high STI risk perception was higher among younger women and among Danish women.

  • STI risk perception was associated with having new sexual partners and lack of condom use.

  • Genital warts, binge drinking and being single were also associated with women’s risk perception.

Acknowledgments

We wish to thank Kirsten Frederiksen for statistical advice, Cecilia Olofsson and Jessica Pege for data collection and Pouran Almstedt and Suzanne Campbell for database administration.

References

View Abstract

Footnotes

  • Handling editor Catherine H Mercer

  • Contributors CM, BTH, MN, LA-D, K-LL and SKK designed the questionnaire and conceived the study. CM, BTH, MN, LA-D and SKK collected data. SG and MTF conducted analyses and drafted the paper. All authors contributed to the writing of this paper by data interpretation and critical revision of drafts. All authors approved the final draft.

  • Funding Merck & Co., Inc. sponsored the data collection of the study (grant numbers EPO 8014.016 and EPO 8014.033). SG is supported by internal funding from Danish Cancer Research Center, Unit of Virus, Lifestyle and Genes.

  • Competing interests CM received lecture fees and support for conference participation from Sanofi Pasteur MSD. MN has received research grants from MSD/Merck through the affiliating institute. LA-D has received grant support from Merck, Sanofi Pasteur MSD and GlaxoSmithKline. K-LL is an employee at Merck Sharp & Dome Corp, a subsidiary of Merck & Co, Inc, Whitehouse Station, New Jersey, and may own stock or stock options in Merck. SKK has received lecture fees, scientific advisory board fees from Merck and Sanofi Pasteur MSD and unrestricted research grants through the affiliating institute from Merck.

  • Ethics approval In Denmark, approval was obtained from the Data Protection Agency. Approval from the Scientific Ethical Committee is not required in Denmark for questionnaire studies that do not include collection of biological samples. In Norway and Sweden the studies were approved by respective Research Ethics Committee/Data Protection Agency (Norway: 2011/1376 A, 8 September 2011 and Sweden: 04-795/4, 24 November 2004).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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