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Self-Reported Impact of Chlamydia Testing on Subsequent Behavior

Results of an Online Survey of Young Adults in England

Hartney, Thomas (MSc); Baraitser, Paula (MPH); Nardone, Anthony (PhD)

doi: 10.1097/OLQ.0000000000000323
Original Study

Background The National Chlamydia Screening Programme performs 1.7 million tests annually among young adults in England. The effect of chlamydia screening on subsequent behavior is unknown. This study examined the self-reported impact of testing on young adults' subsequent health care–seeking and sexual behavior.

Methods We conducted a cross-sectional Web-based anonymous survey using an online panel to recruit 1521 young adults aged 16 to 24 years and resident in England. Survey questions were developed using the theory of planned behavior. Multivariate log-binomial regression was used to identify the variables associated with an impact on subsequent behavior after testing.

Results Most respondents reported that being tested for chlamydia had a positive effect on their subsequent sexual behavior (68.6%; 422/615) or health care–seeking behavior (80.0%; 492/615). In multivariate analysis, being female and having a high level of engagement at last test were both associated with positive impacts on sexual behavior (72.7% [adjusted prevalence ratio {aPR}, 1.19; 95% confidence interval {CI}, 1.07–1.33] and 82.7% [aPR, 1.55; 95% CI, 1.27–1.89], respectively), and health care–seeking behavior (84.4% [aPR, 1.13; 95% Cl, 1.04–1.24] and 86.3% [aPR, 1.23; 95% CI, 1.07–1.41], respectively). Among respondents with minimum level of engagement, 72.4% (76/105) reported an increase in subsequent health care–seeking behavior.

Conclusions Chlamydia testing had a positive impact on young adults' self-reported health care–seeking and sexual behavior. This suggests that chlamydia screening has a wider effect on young adults' sexual health beyond that of treatment alone.

A cross-sectional online survey of young adults in England found that they report that being tested for chlamydia had a positive impact on their subsequent health care–seeking and sexual behavior.

From the Centre for Infectious Disease Control and Surveillance, Public Health England, London, UK; and Kings Centre for Global Health, Kings College London, London, UK

Acknowledgments: The authors would like to thank the National Chlamydia Screening Programme staff who contributed to this manuscript: Kate Folkard and Kevin Dunbar for comments on the manuscript, and Angie Bone for help with the survey tool. The authors thank the market research agency, Kadence, for their work in coordinating the survey, and the young adults who submitted their responses.

Conflicts of interest and sources of funding: The authors declare no conflicts of interest.

Correspondence: Thomas Hartney, MSc, Centre for Infectious Disease Control and Surveillance, Public Health England, 61 Colindale Ave, London NW9 5EQ, UK. Email:

Received for publication November 19, 2014, and accepted May 29, 2015.

The National Chlamydia Screening Programme in England aims to reduce the prevalence and sequelae of Chlamydia trachomatis infection by opportunistically screening sexually active young people aged 15 to 24 years annually or with every change of partner. The program carried out 1.7 million chlamydia tests in 2012, achieving a national diagnosis rate of 1979 per 100,000 population.1

Being tested for a sexually transmitted infection (STI) can be associated with changes to subsequent sexual risk behavior and sexual health knowledge.2,3 Different behavioral changes may follow either positive or negative test results.4,5 Most studies investigating behavioral change after testing have been among adolescents attending STI clinics in the United States. Limited evidence exists on the effect of testing asymptomatic individuals in community settings.6

A recent UK population–based survey found that 66.4% of individuals with prevalent chlamydia infection had not been screened for chlamydia in the past year.7 Young adults' attitudes toward chlamydia and chlamydia testing are important factors in whether they accept opportunistic testing.8,9 Barriers to testing uptake include feelings of stigma,10 embarrassment,11 lack of knowledge of the consequences or risk of infection,12,13 and preconceived beliefs about the testing process.14

This quantitative cross-sectional study examined the impact of testing on subsequent sexual and health care–seeking behavior and how young adults' attitudes toward chlamydia testing relate to testing uptake. This will help to identify the potential secondary harms (e.g., anxiety and reduced perception of risk) and benefits (e.g., increased knowledge and reduced risk behavior) of chlamydia screening.

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We conducted a cross-sectional Web-based anonymous survey that ran from 30th May to 15th June 2012. Respondents were recruited via a market research company, which accessed existing panels of young adults who had volunteered to complete online surveys. Panel members who met the eligibility criteria (aged between 16 and 24 years and resident in England) were invited to complete a questionnaire about chlamydia and sexual health, in return for a small monetary incentive of less than £1. The questionnaire contained between 25 and 40 questions, depending on responses given, and took on average less than 10 minutes to complete.

Recruitment continued until at least 1500 complete responses were received. Quotas were used to ensure that the sample was representative of the age, sex, and geographical distribution of 16- to 24-year-olds in England.

Ethical approval was obtained from the research ethics committee of University College London (Project ID 3875/001).

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Questionnaire Design

The questionnaire covered 3 main areas: the perceived behavioral impact of testing, attitudes toward chlamydia and chlamydia testing, and contextual information such as respondent demographics, testing history, and recent sexual behavior.

The questionnaire was designed by a working group, based on the results of an evidence review and existing survey tools. The market research agency advised on improving dropout rate and consistency of responses. The questionnaire was piloted with 10 young adults and was left unchanged after receiving satisfactory feedback.

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Contextual Information

We included questions to collect contextual data for each respondent, including demographics, testing history, and recent sexual behavior. Where possible we used the same questions used in previous population-based studies, including the National Surveys of Sexual Attitudes and Lifestyles and the 2011 UK census. This allowed us to assess the survey sample for representativeness against the general population and provided a source of questions that had already undergone extensive piloting and validation.

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Perceived Behavioral Impact of a Chlamydia Test

Respondents who had been tested for chlamydia were asked whether this had an impact on 9 behaviors, 5 relating to sexual health service use and 4 to sexual behavior. Responses were given using a 5-point Likert response scale from “much more likely” to “much less likely.” These responses were assigned a score from 1 to 5, with responses of “Don't know” excluded, and combined into a behavioral impact scale score for each respondent. This scale had a Cronbach α score of 0.85, which indicated an acceptable level of internal consistency.15 For subsequent analysis, the responses were split into 2 impact scales, one for service use and one for sexual behavior. A positive outcome on each scale was defined as the respondent having a scale score greater than the midway possible score (>15/25 for service use and >12/20 for sexual behavior).

A comprehensive consultation was defined as one with 7 key components in addition to the chlamydia test: namely, condoms, information on use of condoms, on other types of contraception, on chlamydia, other STIs, safer sex, and advice on relationships. Respondents were asked how many components they were offered when last tested, to measure the level of engagement between the testing service and respondent. This was used to generate an index of the level of engagement, from 0 (an offer of a test with no other components) to 7 (a comprehensive consultation), based on the number of components offered.

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Attitudes to Chlamydia and Chlamydia Testing

We used the theory of planned behavior as a theoretical framework for developing attitudinal questions.16 This provided a way to categorize beliefs and attitudes identified from the evidence review as being related to chlamydia and chlamydia screening, including normalization, stigma, and perceptions of personal risk. Respondents used a 5-point Likert response scale, from “strongly agree” to “strongly disagree,” to indicate their level of agreement with 6 statements representing the 3 aspects of the framework that contribute toward behavioral intention: behavioral attitudes, subjective norms, and perceived behavioral control.

Responses were scored from 1 to 5 according to whether the statement represented a positive or a negative attitude, with responses of “Don't know” scored as neutral (3), and combined into an attitude scale score for each respondent. The scale had a Cronbach α score of 0.6, indicating a borderline level of internal consistency which was deemed to be acceptable in light of the small number of items included. The attitude scale was divided into quarters: very negative attitudes (scores from 6 to 12), negative attitudes (13–18), positive attitudes (19–24), and very positive attitudes (25–30).

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Statistical Analysis

Univariate associations between variables were examined using Mantel-Haenszel matched prevalence ratios (PRs). Log-binomial regression was used to identify which factors were associated with each of the outcomes. Multivariate models used variables identified by univariate analysis as being associated with the outcome (P < 0.10). A backward elimination stepwise selection method was used to determine the variables to include in the final models (P < 0.05), and adjusted PRs (aPRs) were reported. Statistical analyses were carried out in Stata (version 13.1).

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Sample Size and Demographics

Because of the recruitment method, it was not possible to calculate the uptake rate from the eligible population or to apply adjustment weights to the sample. Of the 1588 submitted survey responses, 67 were incomplete and excluded from subsequent analyses, representing a 4.2% dropout rate.

As specified by recruitment quotas, the sample was representative of the age, sex, and geographical distribution of young adults aged between 16 and 24 years in England in 2011 (Table 1). The sociodemographic characteristics of this convenience sample were also representative of this population, based on ethnicity and employment rates from the 2011 census: 19.1% (290/1521) of the sample were of nonwhite ethnicity compared with 19.5% from census data, and 12.9% (196/1521) were unemployed compared with 14.0% from census data who were unemployed or otherwise economically inactive (excluding full-time students).



The proportions who reported having tested in the previous year—41% of young women and 34% of young men—were either lower or within the confidence intervals (CIs) of the proportions seen in a recent UK population–based survey (National Surveys of Sexual Attitudes and Lifestyles: 51%–57% and 32%–37%, respectively). The proportion who reported not ever having had sex (22%; 338/1521) was also similar to that seen among 16- to 24-year-olds in the population-based survey (20%)—these were excluded from subsequent analyses. The final sample consisted of 1183 complete survey responses from sexually active young adults.

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Previous History of Chlamydia Testing

More than a third of respondents (41.3%; 488/1183) reported never testing for chlamydia, of whom the majority (75.6%; 369/488) reported having 1 or more sexual partners in the past year.

Among respondents who reported testing for chlamydia, 63.4% (441/695) were tested in the previous year. More than half had been tested more than once (57.2%; 398/695): with 50.2% (349/695) tested 2 to 4 times, and 7.1% (49/695) tested 5 or more times. Among those tested, 13.5% (94/695) had received a positive test result for chlamydia, 6.0% (42/695) on their most recent test.

Young women were more likely to report testing (65.9%; 389/590) than young men (51.6%; 306/593), and were more likely to have tested in the previous year (40.8% [241/590] compared with 33.7% [200/593] of young men). Those aged 22 to 24 years were more likely to have tested (61.5%; 276/449) than those aged 16 to 18 years (48.4%; 135/279).

More than half the respondents (57.4%; 399/695) reported being offered free condoms at their last test, 50.9% (354/695) reported being offered information on chlamydia, 37.3% (259/695) on other STIs, 36.5% (254/695) on contraception, 36.0% (250/615) on safe sex, 31.5% (219/695) on use of condoms, and 14.0% (97/615) advice on relationships. These were used to generate the respondents' level of engagement at their last chlamydia test: 17.6% (122/695) had an engagement score of 0, meaning that they were tested without any accompanying sexual health information or condoms; 37.4% (260/695), score of 1 or 2; 23.7% (165/695), score of 3 or 4; and 21.3% (148/695), score of 5 to 7.

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Self-Reported Behavioral Impact of a Chlamydia Test

Among respondents who had tested for chlamydia, 88% (615/695) provided responses on all items which formed the behavioral impact scales. Most reported that testing had a positive impact on their subsequent sexual behavior (68.6%; 422/615) or service use (80% 492/615). The behaviors that respondents most frequently reported they were more likely to engage in were to “Test for chlamydia again in future” (32% much more likely, 38% more likely, 24% unchanged) and to “Recommend a chlamydia test to a friend” (28% much more likely, 40% more likely, 25% unchanged). The behaviors that respondents least frequently reported they were more likely to engage in were “Have fewer partners in future” (13% much more likely, 16% more likely, 58% unchanged) and to “Use condoms every time I have sex” (18% much more likely, 23% more likely, 50% unchanged).

In multivariate log-binomial regression, the variables associated with a positive impact of testing on service use were gender (female to male: aPR, 1.13; 95% CI, 1.04–1.24) and the level of engagement at last test (comparing lowest to highest categories: aPR, 1.23; 95% CI, 1.07–1.41). The variables associated with a positive impact of testing on sexual behavior were gender (female to male: aPR, 1.19; 95% CI, 1.07–1.33) and level of engagement at last test (comparing lowest to highest categories: aPR, 1.55; 95% CI, 1.27–1.89; Table 2).



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Attitudes to Chlamydia and Chlamydia Testing

There was strong evidence of an association between attitudinal scale score quartile and having been tested, which remained after adjusting for other variables associated with testing (comparing lower to upper quartile: aPR, 3.44; 95% CI, 1.12–10.55; Table 3). The positive attitude statement that remained associated after adjustment—including for attitudinal scale score quartile and each other individual attitude—was “My friends get tested for chlamydia” (aPR, 1.29; 95% CI, 1.06–1.56). Agreement with negative attitude statements (i.e., those which were scored negatively when constructing the overall attitude scale) was associated with decreased likelihood of being tested: after adjustment, the negative attitude that remained associated was “I would be too embarrassed to ask for a chlamydia test” (aPR, 0.68; 95% CI, 0.59–0.78).



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Most respondents reported that being tested for chlamydia affected their subsequent health care–seeking and sexual behavior, including recommending a chlamydia test to a friend. Young women were more likely to report a positive impact on subsequent behaviors, as were respondents who had a higher level of engagement with their last testing service, in terms of information and condoms provided to accompany the test. These behaviors included health care–seeking behaviors and safer sex behaviors. More than half of those tested without any other components of a comprehensive consultation reported a positive impact on their subsequent health care–seeking behavior.

Respondents' attitudes toward chlamydia and chlamydia testing were strongly associated with whether they had been tested. Those who reported that their friends get tested for chlamydia had an increased likelihood of being tested themselves, whereas respondents who reported feelings of embarrassment around asking for a chlamydia test had a decreased likelihood of testing. These associations remained after controlling for other variables, including age, sex, and sexual behavior.

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Strengths and Weaknesses

Rates of testing and other behaviors were self-reported and therefore subject to the respondent's ability to accurately recall events that may have taken place over several years. Furthermore, changes to behavior may reflect intentions for future behavior rather than behavior that has previously taken place. The cross-sectional nature of the study meant that it was not possible to compare sexual and health care–seeking behaviors of participants before and after testing, or to determine the causal relationship between attitudes toward chlamydia testing and testing history. Further longitudinal studies would be needed to validate prospectively this self-reported impact of chlamydia screening on attitudes, sexual behavior, and health care–seeking behavior, before and after testing.

Results of nonprobability Web surveys using volunteer panels are biased when compared with a national probability survey, even when complex recruitment quotas were used,17 and often overestimate sexual risk behaviors.18 It is plausible that young adults recruited via online panels differ from the general population in ways which would reduce the generalizability of the findings. However, when we compared our sample with that of a national probability survey undertaken at a similar time, we observed similar levels of self-reported sexual activity and rates of chlamydia testing.

One of the strengths of using an existing online panel is that this allowed the study to recruit from the general population of young adults, rather than just those attending for screening who are already engaged with sexual health services. This method of recruitment proved to be an effective and timely way to undertake research into the attitudes and behaviors of this population.

Surveys conducted online and where the responses are perceived to be anonymous are less subject to social desirability bias.19 The approach we used would be expected to minimize the underreporting of stigmatized behaviors and overreporting of behaviors that fit social and sex norms.

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Our findings—that young adults report that screening results in behavioral change—have implications for the impact and cost-effectiveness of the program. Previous modeling and systematic reviews of the cost effectiveness of chlamydia screening programs have largely focused on direct cost savings resulting from reduced consequences of infection, such as pelvic inflammatory disease, rather than wider effects on sexual risk behavior and future testing uptake.20,21 Given that 1 in 4 young adults in England are tested for chlamydia each year,1 even modest influences on subsequent behavior could have potentially major health promotion implications.

Different types of brief intervention in medical settings have been shown to result in behavior change: these range from structured behavioral interventions in specialist sexual health settings22,23 to opportunistic smoking cessation advice in UK health care settings.24 More research has been called for to identify the key characteristics of behavioral interventions that make them effective.25 Our results showed a strong association between the level of engagement with testing services and behavioral impact. However, we observed that testing alone, with no additional information provided, has a positive impact on self-reported behavior.

These findings suggest that a chlamydia test in itself can be an effective, even if minimal, driver of health behavior change. This is consistent with studies that have shown that being tested for STIs can lead to increased condom use and safe sex knowledge among adolescents.10,12,13,26,27 Unlike several other studies, we did not observe an increased effect on behavior among those who had received a positive result.2,5 This may have been due to the small sample size of those with a positive result, or a chlamydia diagnosis may lead to less serious psychosocial consequences than other STIs.28

The theory of planned behavior has been shown to explain chlamydia screening intentions among young adults.29 Qualitative work that used the theory as a framework identified that negative emotions and concerns about social implications prevent young adults from getting tested.30 We found that individual attitudes relating to social norms and embarrassment were most strongly associated with chlamydia testing. This aligns with other studies that have found that young adults report feelings of self-consciousness and stigma as barriers to testing uptake.12,31

The findings of this study suggest that chlamydia screening may have indirect benefits on sexual behavior and attitudes. These could include encouraging young adults to get tested regularly for chlamydia and to discuss testing with others, which will in turn encourage nontesting individuals to test. This would be of particular importance for young adults who are not otherwise engaged with sexual health services.

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Further Questions

Chlamydia screening provides an opportunity to engage with the target populations about issues relating to their future sexual health, and the respondent's level of engagement with the testing service was one of the main predictors of a positive impact on subsequent behavior. Sexual health interventions that are appropriate to one setting (e.g., sexual health clinics) may not be appropriate for other settings, and it will be necessary to consider how to tailor approaches to maximize the benefits of testing, depending on the time and resources available. The experience of being tested seems to particularly reduce the barriers to subsequent health care service use, suggesting an additional, and as yet unreported, benefit to screening for chlamydia.

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