Health Education Research, Vol. 19, No. 3, 272-283,
June 1, 2004
© 2004 Oxford University Press
Developing and testing measures predictive of hepatitis A vaccination in a sample of men who have sex with men
1 Section on Social Sciences and Health Policy, Department of Public Health Sciences, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157-1063 and 2 Student Action with Farmworkers and North Carolina Central University, Durham, NC 27705, USA 3 Correspondence to: S. D. Rhodes; e-mail: SRhodes{at}WFUBMC.EDU
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Studies continue to show that the majority of men who have sex with men (MSM) in the US remain unvaccinated against the hepatitis A virus (HAV). Such limited vaccination coverage is a missed opportunity to prevent disease. This study was designed to develop reliable and valid theory-based quantitative measures to understand beliefs and attitudes regarding HAV vaccination among MSM. A convenience sample of 358 patrons of two gay bars in Birmingham, Alabama, completed a theory-based questionnaire. Data were randomly split into two groups. Exploratory factor analysis (EFA) was performed on the first split-half sample to identify factor structure using standard principal component analysis. Confirmatory factor analysis (CFA) was performed on the remaining half sample using structural equation modeling. EFA revealed five scales measuring beliefs about HAV vaccination, including: perceived barriers and benefits associated with HAV vaccination; perceived severity and susceptibility related to hepatitis A infection; and perceived self- efficacy to complete the two-dose vaccine series. CFA revealed acceptable absolute model fits for four scales and excellent comparative model fits for all five scales. Multivariable analysis further validated the scales. Although the results should be tested further, these findings propose standardized measures that may be useful in assessing the beliefs and attitudes of MSM towards HAV vaccination to guide intervention design and evaluation.
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Hepatitis A (HAV) continues to be one of the most frequently reported vaccine-preventable diseases in the US despite the licensure of a vaccine in 1995 (Centers for Disease Control and Prevention, 1998a
). About a third of the US population has serologic evidence of prior HAV infection. Sequelae of HAV can include jaundice and acute liver failure (Centers for Disease Control and Prevention, 1999). Besides the morbidity associated with HAV, the economic burden is substantial. Adults who become ill lose an average of 27 days of work, and between 11 and 22% of HAV cases are hospitalized (Centers for Disease Control and Prevention, 1999). Average direct and indirect costs associated with hepatitis A infection range from $1817 to $2459 per case for adults (Centers for Disease Control and Prevention, 1999). In one common-source outbreak among 43 persons, the estimated total cost was approximately $800 000 (Dalton et al., 1996). In 1989, the estimated annual direct and indirect costs of HAV infection in the US were more than $200 million, equivalent to over $300 million in 1997 dollars (Hadler, 1991).
Because men who have sex with men (MSM) are considered to be at high-risk for HAV infection (Centers for Disease Control and Prevention, 2002), the US Centers for Disease Control and Prevention recommend universal vaccination against HAV for all MSM (Centers for Disease Control and Prevention, 1999). The vaccine against HAV consists of a two-dose series given 6–12 months apart (Gay and Lesbian Medical Association, 2001). National epidemiologic data and results from community-based HAV vaccination programs indicate that MSM in the US are not vaccinated in sufficient numbers, and outbreaks of HAV infection among MSM are reported frequently (Henning et al., 1995; Katz et al., 1997; Centers for Disease Control and Prevention, 1998b; Friedman et al., 2000). Unfortunately, little is known about HAV vaccination acceptance among MSM that could help guide intervention efforts (Centers for Disease Control and Prevention, 1998b).
This study was designed to develop and test reliable and valid, theory-based measures to assess beliefs and attitudes about HAV vaccination among MSM. Rigorous measurement development methodologies, including exploratory (EFA) and confirmatory factor analysis (CFA) procedures, were used.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Item development
Questionnaire items measured demographics, including age, ethnicity, education and income; sexual and other high-risk behaviors; health care access; and five theory-based latent variable constructs. One embedded item assessed whether the participant had completed the questionnaire previously.
The theories used were the Health Belief Model (Rosenstock, 1974; Janz and Becker, 1984) and Social Cognitive Theory (Bandura, 1982, 1986). These theories have been used successfully to explain factors that contribute to health behavior and the mechanisms by which these factors operate (Kohler et al., 1999).
Among MSM, the Health Belief Model has been used to understand sexual risk behavior (Aspinwall et al., 1991; Simon et al., 1993; Wulfert et al., 1996), HIV testing behavior (Maguen et al., 2000), HIV treatment initiation (DiFranceisco et al., 1998), and risk-reduction intervention participation and completion (Gold and Ridge, 2001). When applied to HAV vaccination behavior, the Health Belief Model postulates that in order for individuals to become vaccinated against HAV, they must believe: (1) getting vaccinated is not discouraged by insurmountable barriers (perceived barriers), (2) getting vaccinated against HAV would be beneficial (perceived benefits), (3) contracting HAV would have a negative impact on their lives (perceived severity) and (4) they are personally susceptible to HAV infection (perceived susceptibility).
Perceived self-efficacy is a central concept within the Social Cognitive Theory and is considered to be its most important construct (Bandura, 1982, 1986). Perceived self-efficacy is defined as the conviction that one can successfully execute the behavior required to produce the desired outcome in various situations (Bandura, 1982, 1986). Among MSM, perceived self-efficacy has been used to understand sexual risk behavior (Aspinwall et al., 1991; Wulfert et al., 1996; Dilley et al., 1998). Individuals may have varying degrees of confidence for becoming vaccinated against HAV and adhering to the two-dose vaccine series. In this study, perceived self-efficacy to complete the two-dose series was measured.
Item development for this questionnaire followed Nunnally’s principles for the measurement of constructs where the domain of observables was used (Nunnally, 1970), followed by the rationale scale construction approach described by Comrey (Comrey, 1988) and Jackson (Jackson, 1971). Using the theoretical frameworks, questionnaire items were created based on preliminary studies of vaccination behavior among MSM (Rhodes et al., 2000, 2001a,b; Rhodes and Hergenrather, 2002), and other existing literature pertinent to participation in vaccination, clinical trials and screenings specific to hepatitis (Bodenheimer et al., 1986; Israsena et al., 1992; Dal-Re et al., 1995; Katz, 1996; Kottenhahn et al., 1996; Dufour et al., 1999; Friedman et al., 2000; Savage et al., 2000; Hurley et al., 2001; MacKellar et al., 2001) and not specific to hepatitis (Cummings et al., 1979; Montano, 1986; Israsena et al., 1992; Duclos and Hatcher, 1993; Wood et al., 1995; Buchbinder et al., 1996; Hays et al., 1997; Zimet et al., 1997; Tello et al., 1998; Hays and Kegeles, 1999; Zimet et al., 2000; Strauss et al., 2001).
A panel of experts from School of Public Health at the University of Alabama at Birmingham and the Centers for Disease Control and Prevention reviewed and evaluated the original item pool for content validity and clarity of expression. The Advisory Council and the Community Health Advisors of a Birmingham community-based educational organization, which has long-established ties and broad-based support within the MSM community, also reviewed and evaluated the items for applicability and comprehension.
Measures
Theory-based items utilized Likert scale response options. Response options for perceived barriers to HAV vaccination (26 items), perceived benefits of vaccination (nine items) and perceived susceptibility to HAV infection (12 items) ranged from ‘strongly disagree’ (1) to ‘strongly agree’ (5). Response options for perceived severity of HAV infection (seven items) ranged from ‘not at all serious’ (1) to ‘extremely serious’ (10). Response options for perceived self-efficacy to complete the two-dose series (11 items) ranged from ‘not sure at all’ (1) to ‘very sure’ (5).
Data collection
During two weekends in August and September 2001, data were collected in two, predominately male, ‘gay’ bars in Birmingham, Alabama. Potential participants were assured that data collected would remain anonymous. Each bar patron was asked to participate regardless of gender by one of four trained recruiters who explained the study, determined whether the participant had previously completed the questionnaire and assessed the sobriety of potential participants using established criteria (Sy et al., 1998) to ensure informed consent. Only data from participants who self-reported being male were used in these analyses. Questionnaires were self-administered and completed in secluded areas of the bars. Participants were compensated $10.00. Data collection ended at 11.30 p.m. each night. The data were entered twice into an electronic database and validated for data-entry accuracy.
Data analysis
The total sample (N = 358) was randomly divided into two split-half samples (n = 179). Research has suggested that the sizes of these split-half samples are sufficient to confirm the reliability and ‘goodness of fit’ of theory-based measures using structural equation modeling (SEM) (Boomsma, 1983; Marsh et al., 1988). With the first split-half sample, standard procedures of principle component factor analysis were used to determine a factor structure for each scale (Kaiser, 1958; DeVellis, 1991; Tabachnick and Fidell, 2001) using SPSS 10.1. The scree test (Cattell, 1966), eigenvalues (Kleinbaum et al., 1998), the interpretability of the factors (Tabachnick and Fidell, 2001), theoretical considerations (Bryant and Yarnold, 1997) and Cronbach’s coefficient 
(Cronbach, 1951) were used to define all factor structures. Furthermore, retained items loaded at least 0.60 on their target factor and did not load higher than 0.30 on their non-target factor (Nunnally, 1970; Tabachnick and Fidell, 2001).
The remaining split-half (‘hold-out’) sample was used for instrument confirmation analyses using AMOS (Arbuckle and Wothke, 1999), a statistical package that is commonly used for SEM. CFA via SEM has become one of the primary methods of choice for measurement development (Maruyama, 1997). CFA recognizes the role of theory for establishing a structural model that organizes scale and subscale development. CFA permits evaluating the adequacy of a proposed factor structure. However, because no single factor index is accepted as sufficient to describe the goodness of fit between an estimated model and a theoretical model (Bollen, 1989; Bentler, 1990), commonly used indices, including the relative 
2 fit index, the root mean square error of approximation (RMSEA), the non-normed fit index (NNFI) and the comparative fit index (CFI), were used to access fit.
The relative 2 fit index is a measure of the absolute fit of the model with the data, indicating how closely the model fits compared to a perfect fit. The relative 2 fit index is the ratio of the 2 statistic and the associated degrees of freedom. An acceptable relative 2 fit index is usually set at a 3:1 ratio, while some researchers consider a relative 2 fit index as high as 5 as adequate model fit (Maruyama, 1997; Kline, 1998).
The RMSEA, NNFI and CFI do not measure absolute model fit as does the relative 2 fit index; rather these measures evaluate model fit in comparison to the independence model. The independence model is a null model that assumes that relationships between the observed variables are zero (Ullman, 2001). Thus, these indices indicate whether the model fit is an improvement over the null model, which assumes that the variables are uncorrelated. The RMSEA is a measure of discrepancy per degree of freedom. An RMSEA above 0.10 is considered a poor fit, an RMSEA of 0.08 is considered an acceptable fit and an RMSEA of 0.06 or below is considered a good fit (Hu and Bentler, 1999; Ullman, 2001; Marshall et al., 2001). Values above 0.90 on the NNFI and CFI indicate good model fits. Recent studies suggest that NNFI and CFI are among the best-performing fit indices under a variety of conditions including small sample sizes (Hu and Bentler, 1999).
Thus, this analysis followed the recommendation of Jöreskog for sequentially developing and testing a confirmatory model (Jöreskog, 1993). First, an initial model based on EFA of the first half-sample was specified and then tested using the second split-half sample. Using the complete sample (N = 358), the created scales were entered into a multivariable logistic regression model to test their ability to predict vaccination status. Because the data were normally distributed at P < 0.05, according to the Kolmogorov–Smirnov one-sample test, scales were dichotomized using median splits in order to calculate adjusted odds ratios (OR) and confidence intervals (CI) to assess the magnitude of association between predictors and self-reported vaccination status.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Participants
Of 415 bar patrons approached to complete the questionnaire, 398 participants completed the questionnaire for a 96% response rate. Of these individuals, 34 were women and six men reported no same-sex sexual behavior within the past 5 years. Thus, 358 MSM participants were used in these analyses. Basic demographics are presented in Table I for each split-half sample. There were no statistical differences between the two split-half samples on a variety of basic demographics including mean age, race/ethnicity, education, income, health insurance coverage and HAV vaccination history.
|
Multi-item scales
EFA and reliability analyses using standard factor analytic procedures were performed to evaluate the psychometric properties of the scales on the first split-half sample (DeVellis, 1991
; Tabachnick and Fidell, 2001). Seven factors were identified including, two barrier factors measuring: (1) perceived practical barriers to vaccination and (2) perceived healthcare provider–patient communication about risk; (3) perceived personal benefits to HAV vaccination; (4) perceived severity of HAV infection; (5) susceptibility to HAV infection; and two self-efficacy scales measuring (6) general medical self-efficacy and (7) personal self-efficacy. The factor loadings based on EFA, coefficient s, score means and SDs for these scales are presented in Table II.
|
CFA
Results of the CFA also are presented in Table II, including factor loadings, coefficient
, score means and SDs based on the second split-half sample. All factor loadings ranged from 0.61 to 0.93. Coefficient of created scales ranged from 0.79 to 0.94.
Excellent absolute model fits were found for two constructs of the Health Belief Model, perceived benefits of HAV vaccination and perceived susceptibility to HAV infection, with relative 2 fit indices of 1.21 and 1.68, respectively. Adequate absolute model fits were found for two other constructs, perceived barriers to vaccination and perceived severity of infection, with relative 2 fit indices of 3.43 and 3.18, respectively. The comparative fit indices, RMSEA, NNFI and CFI, indicated adequate or better model fits for each of these four constructs.
For perceived self-efficacy to complete the two-dose vaccination series, the relative 2 index, the test of absolute model fit, was 8.44, clearly indicating poor absolute fit of the model with the data. However, the RMSEA indicated acceptable comparative model fit at 0.80; the NNFI and the CFI also indicated that the model fit the data, each well above the 0.90 criterion for good model fit. The absolute model fit was found to be poor using the relative 2 index, but the comparative model fit was found acceptable by the three standard measures of comparative model fit: the RMSEA, the NNFI and the CFI. Thus, for perceived self-efficacy, the data did not compare to a perfect model fit, but the model was an improvement over a null model. See Table III.
|
Multivariable logistic regression analysis was used for further instrument validity analysis to determine the best fitting and most parsimonious model to describe the relationship between HAV vaccination and the theory-based measures, using the complete dataset (N = 358). Results of this analysis are presented in Table IV. When all variables were placed into a multivariable model, perceived practical barriers and perceived benefits of vaccination against HAV, and perceived severity of HAV infection were associated with HAV vaccination. Neither perceived susceptibility nor perceived self-efficacy was a significant predictor of vaccination status when testing the independent contribution of each of the constructs while adjusting for the other constructs in the model. The predictive power of this model was high, correctly classifying 81.9% of participants into their actual vaccination status (
2 = 58.46; P = 0.001).
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
In this study, a relatively short and easy to use questionnaire was developed and tested to assess beliefs and attitudes related to HAV vaccination using a racially/ethnically diverse sample. The scales within the questionnaire were developed using EFA and CFA using split-half samples of MSM bar patrons in Birmingham, Alabama. EFA identified five scales and seven factors with good internal reliability. CFA revealed that four of the five scales had acceptable absolute model fits and that all five scales had excellent comparative model fits. These scales were perceived barriers to HAV vaccination, which had two subscales, one measuring practical barriers and a second subscale measuring healthcare provider–patient communication; perceived benefits to HAV vaccination; perceived severity of HAV infection; perceived susceptibility to HAV infection; and perceived self-efficacy, which had two subscales, one measuring general medical self-efficacy and a second measuring personal self-efficacy.
Study limitations
Potential limitations of this study should be noted. First, the results of this study may not apply to all MSM. However, the degree of fit between a sample and a target population about which generalizations can be made is a common challenge; in fact, nearly all studies of sexual behavior among MSM are based on non-random, self-selected samples (Rhodes et al., 2002). Nevertheless, because these MSM were recruited in bars in Birmingham, Alabama, future studies should explore the factor structure within other population groups who are recommended for HAV vaccination as well as other samples of MSM. Second, although a self-administered format was used to minimize response bias, these results remain based on self-reported data with their potential limitations (Rhodes et al., 2002). However, tested techniques found to increase validity of self-reported behavior were applied (Fishbein and Pequegnat, 2000). Third, although the sample was split into two halves, the split-half samples likely represent the same population and, hence, are much more similar than samples drawn from two separate populations. Thus, future studies are necessary to explore the reliability across samples of MSM. An entirely new sample might represent a different population.
Furthermore, both split-half samples completed the questionnaire in its entire form with all of the items from the original item pool, including the items that were subsequently rejected. If the rejected items exercised any effects on the responses to the scale items, these would be comparable for the two split-half samples, but not comparable in subsequent replications that use only the finalized scale items.
Implications for health education practice
The measures developed and tested may be useful for researchers, health educators and program planners to identify and assess beliefs and attitudes about HAV vaccination that are most salient to specific populations of MSM. To our knowledge, theoretically developed scales measuring psychosocial constructs of HAV vaccination among MSM have not published previously. The development and dissemination of reliable and valid measures provide new insights into the etiology of HAV vaccination among MSM and a set of psychometrically sound measures for use in future vaccination efforts.
As suggested by Ajzen and Fishbein (Ajzen and Fishbein, 1980), the most predictive measures closely link belief and attitudinal measures to behavioral outcomes—in this case HAV vaccination. Because these scales were grounded in a theoretical framework, they can be tested and evaluated further to verify whether the identified beliefs and attitudes about HAV predict actual vaccination behavior among MSM through a prospective cohort design.
Using the total sample of MSM, multivariable logistic regression analysis identified three theory-based variables that correctly predicted over 80% of HAV vaccination status. The analysis revealed that MSM who reported high perceived practical barriers to vaccination were 70% less likely to be vaccinated against HAV. Thus, intervention strategies to increase vaccination among these MSM may focus on educating MSM about insurance coverage for vaccination, identifying locations for vaccination administration, and reducing the out-of-pocket expense of vaccination against HAV.
Furthermore, individuals vaccinated against HAV had higher scores of perceived benefits of vaccination suggesting that intervention strategies may need to focus on increasing the perceived benefits of vaccination among individuals who remain unvaccinated. Successful social marketing efforts may focus on personal responsibility, protecting one’s health and the health of one’s sexual partners.
The higher score of perceived severity of HAV infection among vaccinated individuals within this sample may warrant intervention strategies that increase this perception among unvaccinated individuals. Based on other research indicating that many MSM may be unfamiliar with the health consequences associated with HAV infection (Gay and Lesbian Medical Association, 2001), intervention approaches may need to increase awareness of HAV and the perception of the seriousness of HAV infection. Although research affirms that knowledge does not imply behavior change, an awareness of the health issue and an understanding of the severity of the consequences and the associated preventive actions are necessary antecedents for subsequent intervention messages to be placed in context (Prochaska and DiClemente, 1986). Other research has found that many MSM lack sufficient knowledge of health risks and thus inadequately judge severity of disease (Rhodes and Hergenrather, 2002).
Furthermore, the general methodology used to develop these measures provides a useful model for health educators and researchers to employ in constructing and testing new measures of other important constructs. As this research was driven by key constructs from health behavior theory and relationships from the vaccination literature, a deductive or construct-oriented approach to scale development was employed. Compared with a inductive approach, scales developed using a deductive approach are more economical to build and tend to be more parsimonious, communicate information more directly, and generally have equivalent levels of validity and predictive effectiveness.
|
Conclusions |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Although both the Centers for Disease Control and Prevention and the Gay and Lesbian Medical Association have called for the universal vaccination of MSM (Centers for Disease Control and Prevention, 1999
; Gay and Lesbian Medical Association, 2001), studies continue to find that MSM are not vaccinated against HAV infection. Furthermore, little is understood about the beliefs and attitudes that influence HAV vaccination behavior of MSM. These measures, which have been found to discern salient beliefs and attitudes surrounding issues of HAV vaccination, may be useful to identify salient factors related to HAV vaccination within groups of MSM, and individual- and community-level interventions can be designed and evaluated using findings from these measures. This study provides preliminary insight into HAV vaccination among a sample of MSM, but further research must be initiated to increase opportunities to prevent HAV infection, disease and their related sequelae as well as inform future efforts as vaccines against HIV and hepatitis C become available.
|
Acknowledgments |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Human subject review and oversight were provided by the Institutional Review Board of the University of Alabama at Birmingham. This study was supported in part under a cooperative agreement from the Centers for Disease Control and Prevention through the Association of Teachers of Preventive Medicine. Manuscript preparation also was supported in part by the Community Health Scholars Program funded by the W. K. Kellogg Foundation. The authors also would like the bar owners and managers, as well as Jason Avery, MPH, Department of Epidemiology and International Health, and Sasha Divekea and Shardul Shah, Department of Health Behavior, School of Public Health, University of Alabama at Birmingham.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgmentsReferences |
|---|
Ajzen, I. and Fishbein, M. (1980) Understanding Attitudes and Predicting Social Behavior. Prentice-Hall, Englewood Cliffs, NJ.
Arbuckle, J.L. and Wothke, W. (1999) AMOS 4.0: User’s Guide. Small Waters, Chicago, IL.
Aspinwall, L.G., Kemeny, M.E., Taylor, S.E., Schneider, S.G. and Dudley, J.P. (1991) Psychosocial predictors of gay men’s AIDS risk-reduction behavior. Health Psychology, 10, 432–444.[CrossRef][Web of Science][Medline]
Bandura, A. (1982) Self-efficacy mechanism in human agency. American Psychologist, 37, 122–147.[CrossRef]
Bandura, A. (1986) Social Foundations of Thought and Action: A Social Cognitive Theory. Prentice-Hall, Englewood Cliffs, NJ.
Bentler, P.M. (1990) Comparative fit indexes in structural models. Psychological Bulletin, 107, 238–246.[CrossRef][Web of Science][Medline]
Bodenheimer, H.C., Jr, Fulton, J.P. and Kramer, P.D. (1986) Acceptance of hepatitis B vaccine among hospital workers. American Journal of Public Health, 76, 252–255.
Bollen, K.A. (1989) A new incremental fit index for general structural equation models. Sociological Methods and Research, 17, 303–316.[CrossRef]
Boomsma, A. (1983) The robustness of LISREL against small sample sizes in factor analysis models. In Jöreskog, K.G. and Wold, H. (eds), Systems under Indirect Observations: Causality, Structure, Predictions (Part I). North Holland, Amsterdam.
Bryant, F.B. and Yarnold, P.R. (1997) Principle components analysis and exploratory and confirmatory factor analysis. In Grimm, L.G. and Yarnold, P.R. (eds), Reading and Understanding Multivariate Statistics. American Psychological Association, Washington, DC, pp. 99–136.
Buchbinder, S.P., Douglas, J.M., Jr, McKirnan, D.J., Judson, F.N., Katz, M.H. and MacQueen, K.M. (1996) Feasibility of human immunodeficiency virus vaccine trials in homosexual men in the United States: risk behavior, seroincidence and willingness to participate. Journal of Infectious Disease, 174, 954–961.[Web of Science][Medline]
Cattell, R. (1966) The meaning and strategic use of factor analysis. In Cattell, R.B. (ed.), Handbook of Multivariate Experimental Psychology. Rand McNally, Chicago, IL, pp. 174–233.
Centers for Disease Control and Prevention (1998a) Hepatitis A vaccination of men who have sex with men—Atlanta, Georgia, 1996–1997. MMWR Morbidity and Mortality Weekly Report, 47, 708–711.[Medline]
Centers for Disease Control and Prevention (1998b) Summary of notifiable diseases, United States, 1997. MMWR Morbidity and Mortality Weekly Report, 46, 3–87.
Centers for Disease Control and Prevention (1999) Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morbidity and Mortality Weekly Report, 48, 1–37.
Centers for Disease Control and Prevention (2002) Sexually transmitted diseases treatment guidelines—2002. MMWR Morbidity and Mortality Weekly Report, 51, 1–80.[Medline]
Comrey, A.L. (1988) Factor-analytic methods of scale development in personality and clinical psychology. Journal of Consulting and Clinical Psychology, 56, 754–761.[CrossRef][Web of Science][Medline]
Cronbach, L.J. (1951) Coefficient alpha and the internal structure of tests. Psychometrika, 16, 297–334.[CrossRef][Web of Science]
Cummings, K.M., Jette, A.M., Brock, B.M. and Haefner, D.P. (1979) Psychosocial determinants of immunization behavior in a swine influenza campaign. Medical Care, 17, 639.
Dal-Re, R., Gonzalez, A., Ramirez, V., Ballesteros, J., del Romero, J. and Bru, F. (1995) Compliance with immunization against hepatitis B. A pragmatic study in sexually transmitted disease clinics. Vaccine, 13, 163–167.[CrossRef][Web of Science][Medline]
Dalton, C.B., Haddix, A., Hoffman, R.E. and Mast, E.E. (1996) The cost of a food-borne outbreak of hepatitis A in Denver, Colo. Archives of Internal Medicine, 156, 1013–1016.
DeVellis, R.F. (1991) Scale Development: Theory and Applications. Sage, Newbury Park, CA.
DiFranceisco, W., Kelly, J.A., Sikkema, K.J., Somlai, A.M., Murphy, D.A. and Stevenson, L.Y. (1998) Differences between completers and early dropouts from 2 HIV intervention trials: a health belief approach to understanding prevention program attrition. American Journal of Public Health, 88, 1068–1073.
Dilley, J.W., McFarland, W., Sullivan, P. and Discepola, M. (1998) Psychosocial correlates of unprotected anal sex in a cohort of gay men attending an HIV-negative support group. AIDS Education and Prevention, 10, 317–326.
Duclos, P. and Hatcher, J. (1993) Epidemiology of influenza vaccination in Canada. Canadian Journal of Public Health, 84, 311–315.[Web of Science][Medline]
Dufour, A., Remis, R.S., Alary, M., Otis, J., Masse, B., Turmel, B., Vincelette, J., Lavoie, R., LeClerc, R. and Parent, R. (1999) Factors associated with hepatitis B vaccination among men having sexual relations with men in Montreal, Quebec, Canada. Omega Study Group. Sexually Transmitted Diseases, 26, 317–324.[Web of Science][Medline]
Fishbein, M. and Pequegnat, W. (2000) Evaluating AIDS prevention interventions using behavioral and biological outcome measures. Sexually Transmitted Diseases, 27, 101–110.[Web of Science][Medline]
Friedman, M.S., Blake, P.A., Koehler, J.E., Hutwagner, L.C. and Toomey, K.E. (2000) Factors influencing a community-wide campaign to administer hepatitis A vaccine to men who have sex with men. American Journal of Public Health, 90, 1942–1946.
Gay and Lesbian Medical Association (2001) Healthy People 2010 Companion Document for Lesbian, Gay, Bisexual and Transgender (LGBT) Health. Gay and Lesbian Medical Association, San Francisco, CA.
Gold, R.S. and Ridge, D.T. (2001) ‘I will start treatment when I think the time is right’: HIV-positive gay men talk about their decision not to access antiretroviral therapy. AIDS Care, 13, 693–708.[CrossRef][Web of Science][Medline]
Hadler, S.C. (1991) Global impact of hepatitis A virus infection: changing patterns. In Hollinger, F.B., Lemon, S.M. and Margolis, H.S. (eds), Viral Hepatitis and Liver Disease. Williams & Wilkins, Baltimore, MD, pp. 14–20.
Hays, R.B. and Kegeles, S.M. (1999) Factors related to the willingness of young gay men to participate in preventive HIV vaccine trials. Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 20, 164–171.[Web of Science][Medline]
Hays, R.B., Kegeles, S.M. and Coates, T.J. (1997) Unprotected sex and HIV risk taking among young gay men within boyfriend relationships. AIDS Education and Prevention, 9, 314–329.[Web of Science][Medline]
Henning, K.J., Bell, E., Braun, J. and Barker, N.D. (1995) A community-wide outbreak of hepatitis A: risk factors for infection among homosexual and bisexual men. American Journal of Medicine, 99, 132–136.[CrossRef][Web of Science][Medline]
Hu, R. and Bentler, P.M. (1999) Cutoff criteria for fit indexes in covariance structure analysis: conventional criteria versus new alternatives. Structural Equation Modeling, 6, 1–55.
Hurley, J.L., Turner, H.S. and Butler, K.M. (2001) Planning and execution of a successful hepatitis B immunization program. Journal of American College Health, 49, 189–191.[Web of Science][Medline]
Israsena, S., Kamolratanakul, P. and Sakulramrung, R. (1992) Factors influencing acceptance of hepatitis B vaccination by hospital personnel in an area hyperendemic for hepatitis B. American Journal of Gastroenterology, 87, 1807–1809.[Web of Science][Medline]
Jackson, D.N. (1971) The dynamics of structures and personality tests. Psychological Review, 78, 229–248.[CrossRef][Web of Science]
Janz, N.K. and Becker, M.H. (1984) The health belief model: a decade later. Health Education Quarterly, 11, 1–47.[Web of Science][Medline]
Jöreskog, K.G. (1993) Testing structural equation models. In Bollen, K.A. and Long, J.S. (eds), Testing Structural Equation Models. Sage, Newbury Park, CA, pp. 294–316.
Kaiser, H.F. (1958) The varimax criterion for analytic rotation in factor analysis. Psychometrika, 23, 187–200.[CrossRef][Web of Science]
Katz, M. (1996) Undervaccination for hepatitis B among young men who have sex with men: San Francisco and Berkeley, California. MMWR Morbidity and Mortality Weekly Report, 45, 215–217.[Medline]
Katz, M.H., Hsu, L., Wong, E., Liska, S. anderson, L. and Janssen, R.S. (1997) Seroprevalence of and risk factors for hepatitis A infection among young homosexual and bisexual men. Journal of Infectious Diseases, 175, 1225–1229.[Web of Science][Medline]
Kleinbaum, D.G., Kupper, L.L., Muller, K.E. and Nizam, A. (1998) Applied Regression Analysis and Other Multivariate Methods, 3rd edn. Duxbury Press, Pacific Grove, CA.
Kline, R.B. (1998) Principles and Practice of Structural Equation Modeling. Guilford Press, New York.
Kohler, C.L., Grimley, D. and Reynolds, K. (1999) Theoretical approaches guiding the development and implementation of health promotion programs. In Raczynski, J.M. and DiClemente, R.J. (eds), Handbook of Health Promotion and Disease Prevention. Kluwer Academic/Plenum, New York, pp. 23–49.
Kottenhahn, R.K., Rosenthal, S.L. and Biro, F.M. (1996) Hepatitis B vaccine completion among adolescents. Delaware Medical Journal, 68, 309–311.[Medline]
MacKellar, D.A., Valleroy, L.A., Secura, G.M., McFarland, W., Shehan, D., Ford, W., LaLota, M., Celentano, D.D., Koblin, B.A., Torian, L.V., Thiede, H. and Janssen, R.S. (2001) Two decades after vaccine license: hepatitis B immunization and infection among young men who have sex with men. American Journal of Public Health, 91, 965–971.[Abstract]
Maguen, S., Armistead, L.P. and Kalichman, S. (2000) Predictors of HIV antibody testing among gay, lesbian and bisexual youth. Journal of Adolescent Health, 26, 252–257.[CrossRef][Web of Science][Medline]
Marsh, H.W., Balla, J.R. and McDonald, R.P. (1988) Goodness-of-fit indexes in confirmatory factor analysis: the effect of sample size. Psychological Bulletin, 103, 391–410.[CrossRef][Web of Science]
Marshall, G.N., Morales, L.S., Elliott, M., Spritzer, K. and Hays, R.D. (2001) Confirmatory factor analysis of the Consumer Assessment of Health Plans Study (CAHPS) 1.0 Core Survey. Psychological Assessment, 13, 216–229.[CrossRef][Web of Science][Medline]
Maruyama, G.M. (1997) Basics of Structural Equation Modeling. Sage, Thousand Oaks, CA.
Montano, D.E. (1986) Predicting and understanding influenza vaccination behavior. Alternatives to the health belief model. Medical Care, 24, 438–453.[CrossRef][Web of Science][Medline]
Nunnally, J.C. (1970) Introduction to Psychological Measurement. McGraw-Hill, New York.
Prochaska, J.O. and DiClemente, C.C. (1986) Toward a comprehensive model of change. In Miller, W. and Heather, N. (eds), Treating Addictive Behaviors. Plenum, New York, pp. 3–27.
Rhodes, S.D. and Hergenrather, K.C. (2002) Exploring hepatitis B vaccination acceptance among young men who have sex with men: facilitators and barriers. Preventive Medicine, 35, 128–134.[CrossRef][Web of Science][Medline]
Rhodes, S.D., DiClemente, R.J., Yee, L.J. and Hergenrather, K.C. (2000) Hepatitis B vaccination in a high-risk MSM population: the need for vaccine education. Sexually Transmitted Infections, 76, 408–409.
Rhodes, S.D., DiClemente, R.J., Yee, L.J. and Hergenrather, K.C. (2001a) Correlates of hepatitis B vaccination in a high-risk population: an Internet sample. American Journal of Medicine, 110, 628–632.[CrossRef][Web of Science][Medline]
Rhodes, S.D., DiClemente, R.J., Yee, L.J. and Hergenrather, K.C. (2001b) Factors associated with testing for hepatitis C in an Internet-recruited sample of men who have sex with men. Sexually Transmitted Diseases, 28, 515–520.[Web of Science][Medline]
Rhodes, S.D., DiClemente, R.J., Cecil, H., Hergenrather, K.C. and Yee, L.J. (2002) Risk among men who have sex with men in the United States: a comparison of an Internet sample and a conventional outreach sample. AIDS Education and Prevention, 14, 41–50.[CrossRef][Web of Science][Medline]
Rosenstock, I.M. (1974) The health belief model and preventive health behavior. In Becker, M.H. (ed.), The Health Belief Model and Personal Health Behavior. Charles B. Slack, Thorofare, NJ, pp. 27–59.
Savage, R.B., Hussey, M.J. and Hurie, M.B. (2000) A successful approach to immunizing men who have sex with men against hepatitis B. Public Health Nursing, 17, 202–206.[CrossRef][Web of Science][Medline]
Simon, P.M., Morse, E.V., Balson, P.M., Osofsky, H.J. and Gaumer, H.R. (1993) Barriers to human immunodeficiency virus related risk reduction among male street prostitutes. Health Education Quarterly, 20, 261–273.[Web of Science][Medline]
Strauss, R.P., Sengupta, S., Kegeles, S., McLellan, E., Metzger, D., Eyre, S., Khanani, F., Emrick, C.B. and MacQueen, K.M. (2001) Willingness to volunteer in future preventive HIV vaccine trials: issues and perspectives from three US communities. Journal of Acquired Immune Deficiency Syndromes, 26, 63–71.
Sy, F.S., Rhodes, S.D., Choi, S.T., Drociuk, D., Laurent, A.A., Naccash, R.M. and Kettinger, L.D. (1998) The acceptability of oral fluid testing for HIV antibodies. A pilot study in gay bars in a predominantly rural state. Sexually Transmitted Diseases, 25, 211–215.[Web of Science][Medline]
Tabachnick, B.G. and Fidell, L.S. (2001) Using Multivariate Statistics, 4th edn. Allyn & Bacon, Needham Heights, MA.
Tello, J., Soong, S.J., Hunter, B., Meriwether, R., Hook, E.W. and Mulligan, M.J. (1998) HIV vaccine acceptance among heterosexual clients of a sexually transmitted diseases clinic. American Journal of the Medical Sciences, 315, 11–16.[CrossRef][Web of Science][Medline]
Ullman, J.B. (2001) Structural equation modeling. In Tabachnick, B.G. and Fidell, L.S. (eds), Using Multivariate Statistics, 4th edn. Allyn & Bacon, Needham Heights, MA, pp. 653–771.
Wood, D., Donald-Sherbourne, C., Halfon, N., Tucker, M.B., Ortiz, V., Hamlin, J.S., Duan, N., Mazel, R.M., Grabowsky, M., Brunell, P. and Freeman, H. (1995) Factors related to immunization status among inner-city Latino and African-American preschoolers. Pediatrics, 96, 295–301.
Wulfert, E., Wan, C.K. and Backus, C.A. (1996) Gay men’s safer sex behavior: an integration of three models. Journal of Behavioral Medicine, 19, 345–66.[CrossRef][Web of Science][Medline]
Zimet, G.D., Fortenberry, J.D., Fife, K.H., Tyring, S.K., Herne, K. and Douglas, J.M. (1997) Acceptability of genital herpes immunization. The role of health beliefs and health behaviors. Sexually Transmitted Diseases, 24, 555–560.[Web of Science][Medline]
Zimet, G.D., Blythe, M.J. and Fortenberry, J.D. (2000) Vaccine characteristics and acceptability of HIV immunization among adolescents. International Journal of STD and AIDS, 11, 143–149.
Received on July 30, 2002; accepted on March 4, 2003
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  D. E. Siconolfi, P. N. Halkitis, and M. E. Rogers Hepatitis Vaccination and Infection Among Gay, Bisexual, and Other Men Who Have Sex with Men who Attend Gyms in New York City American Journal of Men's Health, June 1, 2009; 3(2): 141 - 149. [Abstract] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||