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The present cross-sectional study obtained ethical approval by the ethical committee of China (NCAIDS) and was conducted in Guangzhou and Harbin in September 2015. These particular two cities were selected as study sites because of the yearly increase of HIV-infection rates in college students, and the fact that they are an example of a typical city in Northern and Southern China. Guangzhou, the provincial capital of Guangdong province in south China, has a total of over 100 universities. In 2012, the proportion of new cases among the college student in Guangzhou was five times that of 2002[35]. Similarly, AIDS has rapidly spread among college students in Harbin, the provincial capital of Heilongjiang. In Harbin, the new cases of young students in 2015 were almost three times higher than 2013[36]. In the present survey, a total of 3, 081 students, aged 17-21 years, were recruited from seven universities and the response rate was 96.5%.
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Two-stage cluster sample design was used in the current study. In the first stage, seven universities were randomly sampled from Guangzhou and Harbin. In China, the major subjects of the first-grade students are the public basic courses; thus, the HIV awareness would not be affected by the specialized knowledge among freshmen. We randomly selected three classes in the first grade within each university and obtained informed consent from all students before the survey. All students were informed regarding the voluntary nature of participation, and those who did not complete the questionnaires for various reasons were excluded. Students who were willing to participate in this survey completed an anonymous questionnaire written in Chinese at an appointed classroom.
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On the basis of the construct of the integrated model, we developed a structured self-administered questionnaire. The original items pool was compiled by performing a literature review and consulting experts from health education, psychology, communications, and epidemiology. The final version of the questionnaire was created following numerous rounds of amendments. It consisted of seven aspects, including information on demographics, severity of and susceptibility to HIV, attitude to HIV health education, intent-to-premarital-sex, response efficacy, and condom-use self-efficacy. The levels of perceived severity of and perceived susceptibility to HIV were evaluated by five items according to the Perceived Risk of HIV Scale (PRHS)[37], and their Cronbach's α coefficients were 0.67 and 0.79, respectively. Condom-use self-efficacy was assessed by three items in accordance with the Condom-Use Self-Efficacy Scale (CUSES)[38] and the Cronbach's α coefficient was 0.67. As no maturity scales existed for reference, the items of response efficacy, attitude toward HIV education and intent-to-premarital-sex were formulated according to the related studies and experts' advice. The Cronbach's α coefficients were 0.55, 0.64, and 0.60, respectively. The details of the questionnaire are presented in Table 1. The answers of the questionnaire were in a scoring system: Students were asked to rate their agreement on a scale from 1 (strongly disagree) to 10 (strongly agree).
Characteristic N % Age < 20 2, 249 75.3 ≥20 699 23.5 Gender Male 1, 387 46.7 Female 1, 586 53.3 Survey city Guangzhou 2, 107 70.9 Harbin 866 29.1 Table 1. Demographic Characteristics of Students (n=2, 973)
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SPSS 13.0 (IBM Corp, Armonk, NY, USA) was used for data process and analysis, including interpolation of missing values, description of statistics of demographic characteristics and measurements of variables, internal reliability, construct validity and Mann-Whitney U-test. IBM SPSS AMOS 17.0 (IBM Corp, Armonk, NY, USA) was used for structure equation modeling (SEM). SEM is a multi-statistics method, which fits theoretical models with sample data in two steps, as follows[39]: (ⅰ) confirmatory factor analysis (CFA) tests the fitting degree between the sample data and hypothetical construct, thus determining the structural validity; (ⅱ) path analysis, which follows a reasonable result of CFA, aims to verify the rationality of structure model and illustrate the causal link among the major latent variables. Through SEM, we could estimate coefficients of variables as well as direct, indirect, and total effects among latent variables in the regression model. Indices, including chi-square goodness-of-fit test (χ2/df), the goodness-of-fit index (GFI), the comparative fit index (CFI), and the root mean square error of approximation (RMSEA) were used to evaluate the model fitness. In general, the criteria to assess the model were: χ2/df < 5[40], GFI > 0.9, CFI > 0.9[41], and RMSEA < 0.05[42].
Study Sample
Data Collection
Data Measurement
Data Analysis
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Table 1 describes the participants' demographic characteristics. Among 2, 973 valid participants, 46.7% were male and 53.3% were female. An approximate of 75.3% students were aged < 20 years, and the average age was 18.6 years (s=0.8). Finally, an approximate of seven out of 10 students were surveyed from Guangzhou.
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Results of confirmatory factor analysis are demonstrated in Figure 2. The goodness-of-fit statistics suggested that the structural equation model could be accepted and was appropriate for the data. The standardized regression weights (factor loading) and median scores for all items are listed in Table 2. All factor loadings were above 0.45 (0.47-0.81) and statistically significant (P < 0.05), except for the response efficacy. Because the internal consistency of response efficacy was also below the conservative limitation, this variable was excluded from the subsequent analysis.
Figure 2. Confirmatory factor analysis on the integrated model (n=2, 973). Coefficients are shown above and the goodness-of-fit statistics is: χ2/df=335.4/85=3.95, P < 0.001; CFI=0.91; GFI=0.98; RMSEA=0.03. **P < 0.001, *P < 0.05.
Item Factor Loading M Perceived severity 8 If you encounter a HIV-infection-risk event, you will feel fear 0.71 9 If HIV cases was detected in your school, you will feel fear 0.55 6 You regard AIDS as a terrible disease 0.70 8 Perceived susceptibility 2 Your friends may be infected with the HIV virus 0.74 3 Your friend may be a HIV carrier 0.81 2 Response efficacy 6 Using condom properly will decrease the HIV-infection risk 0.72 6 Having one sexual partner is an effective way to prevent HIV 0.53 9 Avoiding premarital sex is an effective way to prevent HIV 0.37 9 Attitude of HIV health education 8 HIV education is an effective way to prevent HIV 0.50 8 You would like to study HIV knowledge for HIV prevention 0.57 8 HIV health education is necessary for college students 0.78 10 Intent-to-premarital-sex 6 The possibility of you have sex during university 0.70 2 You approve of premarital sex 0.65 5 Condom-use self-efficacy 7 You have confidence to use a condom during sex 0.65 9 If you didn't use condom during sex, you would regret 0.70 7 If you didn't use condom during sex, you feel fear 0.47 8 Table 2. Factor Loadings and Median Scores
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To generate a parsimonious model, the statistically insignificant paths were removed and the final model is depicted in Figure 3. The fit indices suggested that the model was satisfied with the conservative criteria, explaining 50.6% of the variance of condom-use self-efficacy.
Figure 3. The final integrated model. The fit indexes were: χ2/df=243.3/53=4.59, P < 0.001; CFI=0.91; GFI=0.98; RMSEA=0.04. **P < 0.001, *P < 0.05.
Table 3 displays the direct, indirect, and total effect of variables on self-efficacy. Apart from the direct effect (r=0.23), perceived severity had two indirect effects on condom-use self-efficacy; i.e., through the attitude to HIV education (r=0.40) and premarital sex (r=-0.16), respectively. Consequently, the total effect of perceived severity on self-efficacy was positive and strong (0.47). However, perceived susceptibility mediated by intent-to-premarital-sex (r=0.29) had an indirect and weak impact on self-efficacy (-0.06). Furthermore, the attitude toward HIV education (r=0.49) and intent-to-premarital-sex (r=-0.31) had a strong direct effect on condom-use self-efficacy.
Variable Direct Effects Indirect Effects Total Effects Perceived severity 0.23 0.24 0.47 Perceived susceptibility 0 -0.06 -0.06 Attitude to HIV education 0.49 0 0.49 Intent-to-premarital-sex -0.31 0 -0.31 Table 3. Effects on Condom-use Self-efficacy
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The results of the rank-sum test demonstrated that male students perceived higher susceptibility, stronger intent-to-premarital-sex and lower condom-use self-efficacy compared with the female students. The mean ranks, median and P values are presented in Table 4.
Variable Mean Rank Median P Male Female Male Female Perceived susceptibility 1562.6 1420.9 3 2 < 0.001 Intent-to-premarital-sex 1854.8 1165.4 6 6 < 0.001 Condom-use self-efficacy 1122.6 1805.7 7 8 < 0.001 Table 4. The Mann-Whitney U-test between Male and Female Students