Hui Wang
Qiaoqin Ma
Lin He
Tingting Jiang
Weiyong Chen- Department of HIV/STD Prevention and Control, Zhejaing Provincial Center for Disease Prevention and Control, Hangzhou, China
Background: Vocational high school students in China exhibit higher rates of sexual activity than their academic counterparts; however, existing studies predominantly focus on college populations, leaving a critical gap in longitudinal data tracking the evolution of sexual knowledge and behavioural patterns among vocational students. This study aimed to evaluate changes over time in sexual safety knowledge, STIs/HIV and reproductive health-related sexual behaviours among boys who have had sex in Chinese vocational high schools.
Methods: In 2015 and 2021, an anonymous survey was conducted separately using the same questionnaire and survey method among students in Years 1–2 of the same vocational high school in a district of Zhejiang Province. The results of the two surveys were compared using univariate analyses, and multivariate analyses.
Results: In 2015 and 2021, 180 and 90 male students, respectively, had ever had sex, representing rates of 17.44% (180/1,032) and 8.49%(90/1,060). The results of the multivariate analysis showed that, in 2021, those who knew that sexual contact was the main mode of HIV transmission(OR = 14.14, 95% CI: 7.16–27.92), knew that contracting an STI increased the likelihood of HIV infection (OR = 7.83, 95% CI: 4.30–14.29), and knew that condom use could reduce both STIs(OR = 33.51, 95% CI: 15.08–74.49) and HIV infection(OR = 16.77, 95% CI: 8.58–32.76) were significantly more prevalent than in 2015. Furthermore, students who had received sex and STI/HIV prevention education and rated it as "good" (OR = 5.62, 95% CI: 2.72–11.64), who believed they could confidently refuse sex without a condom(OR = 1.95, 95% CI: 1.14–3.32), and who reported consistent condom use(OR = 2.27, 95% CI: 1.21–4.25) were also more prevalent in 2021. Use of contraception methods such as condoms(OR = 2.76, 95% CI: 1.50–5.09), the pill(OR = 2.42, 95% CI: 1.35–4.35), extracorporeal ejaculation (OR = 1.77, 95% CI:1.02–3.09), and the safe period(OR = 2.22, 95% CI: 1.22–4.04) also increased significantly. However, the proportion of students who had their first sexual relationship with a non-regular partner decreased(OR = 0.47, 95% CI: 0.24–0.93).
Conclusion: The participants' knowledge of safe sex and sexual behaviour improveed between the two surveys. However, these positive changes have not had a significant enough impact to prevent STIs/HIV transmission and reduce pregnancy. Further efforts are needed to ensure that these changes lead to effective STIs/HIV prevention and reduction among students.
Introduction
Adolescence is a unique period during which young people develop behavioural patterns that can either protect their own and others' health, or expose them to present and future health risks (1). Adolescent sexual health and sexually transmitted infections (STIs) are major global public health concerns. Adolescents' sexual attitudes, behaviours and health risks are evolving, their sexual and reproductive health needs are more pronounced than those of adults because they are more likely to have multiple concurrent sexual partners, and are less likely to use condoms than other age groups. They are also more physiologically vulnerable due to cervical immaturity, and less likely to seek healthcare than adults. In general, STIs are on the rise among adolescents worldwide, although HIV infection and unintended pregnancy among adolescents are declining, they still require great attention (1, 2).
In recent years, the sexual attitudes and behaviours of Chinese adolescents have changed significantly due to the acceleration of socio-economic development and information dissemination (3). China's HIV epidemic surveillance data shows that the HIV epidemic has spread to schools, with an increasing number of cases among high school students (4). The incidence of STIs, including HIV infection, has also increased significantly among adolescents (5). Students at vocational high school (VHS) face higher sexual health risks due to their specific educational background and social environment, and they engage in sexual behaviours at significantly higher rates than regular high school (RHS) students (6–10). For instance, a survey in Zhejiang Province revealed that 10.8% of VHS students had engaged in sexual behaviour, compared to 5.8% of RHS students (8). VHS students are more likely to have non-regular sexual partners, and to have had more sexual partners, which increases their risk of contracting STI and HIV infection (11). In addition, unplanned pregnancies and abortions among VHS students are also worrying, with about 3/4 of abortions among high school students being performed by VHS students (11).
VHS students receive relatively little sexual health education (6, 12), and a significantly lower proportion receive sex education from their parents than RHS students (12). VHS students also differ from RHS students in terms of their sexual knowledge and awareness of safe sex practices. Studies have shown that VHS students have lower levels of knowledge regarding HIV transmission (7, 9, 10, 12), reproductive health (10, 12) and STI and HIV prevention (6) than RHS students. VHS students viewed more pornographic material and were more likely to have positive attitudes towards high school students' sexual behaviour than RHS students (7, 10). This knowledge gap may lead VHS students to be less aware of the consequences of sexual behaviour and to take fewer protective measures, thereby increasing their risk of contracting STIs/HIV and unwanted pregnancy.
A through understanding of VHS students' sexual behaviour, knowledge and sex education needs is crucial for developing targeted interventions to prevent the spread of STIs/HIV and unwanted pregnancies. This study aims to identify changes in VHS students' sexual behaviour and knowledge, and to evaluate the effectiveness of sex and STIs/HIV prevention education in recent years. This will be achieved by comparing and analysing data from a study conducted among VHS students in Zhejiang Province in 2015 and 2021.
Methods
Study design, location and participants
A cross-sectional survey was conducted in a VHS school in the central region of Zhejiang Province, China, in 2015 and again in 2021 using the same questionnaire. Zhejiang Province, located in the eastern coastal area of China, is a developed region that has experienced rapid economic growth, with its per capita gross domestic product (GDP) increasing from RMB 68,569 in 2014 to RMB 125,043 in 2023 (13).
The inclusion criteria for the study participants in the 2015 and 2021 surveys were as follows: 1. Students in Years 1 and 2 who were studying at the survey school at the time of the survey; 2. Students and their parents who agreed to participate in the survey; 3. Students who did not have a mental health condition or other health problem that would prevent them from completing the questionnaire independently.
Sample size and sampling
Sample size estimations were based on the proprtions of sexual behaviour reported in the recent literature among VHS students in Zhejiang Province prior to the 2015 and 2021 surveys, using the formual n = Z2α × p(1-p)/d2, where Zα = 1.96, α = 0.05, p = reported proportion of sexual behavior, d = p × 0.15.
In 2013, the proportion of VHS students engaging in sexual behaviour was reported to be 10.81% (8). At least 1,468 subjects had to be recruited for the 2015 survey. In 2018, the proportion was reported to be 13.05% (9); at least 1,185 subjects needed to be surveyed in 2021.
In 2015, 2,196 Years 1–2 students were enrolled in the surveyed school, with 1,839 surveyed (1,032 males). In 2021, 2,051 students in both Years were enrolled, with 1,960 surveyed (1,060 males). Sexual behaviour was reported by 266(180 males) in 2015 and 128 (90 males) in 2021. This paper analyses the male students who have had sex.
Study procedure
Both the 2015 and 2021 surveys employed the same questionnaire and research methods in the same school. Both surveys were conducted in classrooms in April and May of their respective years. The investigators were teachers from the surveyed school and students from a local university. The research team provided the investigators with uniform training, covering the purpose of the survey, its methodology, and its requirements. The survey was aimed at all students in Years 1 and 2 at the school.
Prior to commencing the survey, the investigator explained its purpose, methodology and privacy policy to the students' guardians via the parents' WeChat group. This included information on how the questionnaire data would be used. It was made clear that only aggregated statistical data would be used, not personal data, and that no information from the students' questionnaires would be disclosed to school teachers, administrators or other students. Non-participation would not result in any disadvantages. This information was also provided to the students in class and included at the beginning of the questionnaire. After school, the students took the informed consent form home. After careful reading, it was signed by their guardians. During the formal survey, students sat one seat apart from each other. Having read the informed consent section at the beginning of the questionnaire, students indicated their agreement by ticking a box. Once completed, the questionnaire was collected by the investigator. The survey protocols were reviewed and approved by the Ethical Review Committee of the Zhejiang Provincial Centre for Disease Control and Prevention.
Study variables
In 2015, the research team developed a preliminary questionnaire based on a review of domestic and international literature (8, 14–16). This was continuously revised and improved through in-depth individual and group interviews with students from a VHS outside the study VHS and repeated discussions within the research team. The final questionnaire consisted of six sections covering general demographic characteristics, lifestyle and self-assessment, sexual safety knowledge, sexual attitudes, sexual behaviour and risk awareness, safer sex self-efficacy, exposure to sex education and STIs/HIV prevention education at school and assessment. The number of questions in each section was 9, 13, 13, 6, 16 and 5 respectively.
Engineering disciplines in the text include computer applications, network technology, electrical and electronic engineering, numerical control engineering, mould design and fabrication, electrical equipment maintenance and mechatronics; liberal arts disciplines include foreign trade marketing, finance and accounting, preschool education, and art and decoration.
A nuclear family consists of parents and their unmarried children, whereas an extended family consists of parents and their unmarried children, as well as other related family members. Being sexually active means that one of the sexual acts of vaginal, oral or anal sex has taken place.
Data analysis
Data from the two surveys in 2015 and 2021 were combined and statistically analysed using SPSS 23.0 statistical software. The χ2 test was used to compare statistical differences between the two surveys in the distribution of demographic characteristics, knowledge of safe sex, self-efficacy for safe sex, exposure to school sexual safety education, and sexual behaviour-related variables among students who had already had sex.
Variables with a P value <0.05 in the univariate analyses were used as dependent variables, and demographic variables such as year of survey, Year, major, family type, father's literacy, mother's literacy, family economic status and residence were included as independent variables in the corresponding multivariate logistic regression models. The variable for school stage of sexual initiation was also included in the logistic regression model for sexual behaviour-related variables to adjust for possible confounding. Odds ratios (OR) and 95% confidence intervals (CI) were used to describe the relationship between year of survey and the corresponding variables. A P value of <0.05 was used to indicate a significant difference.
Resluts
Characteristics of demographic change between the two surveys
The proportion of male students who were sexually active decreased from 17.44% (180/1,032) in 2015 to 8.49% (90/1,060) in 2021. Among thosee who were sexually active, approximately 47% were first-year students in both years (Table 1). The proportion of engineering majors dropped from 59.4% to 51.1%, while the proportion of students from nuclear families decreased from 76.1% to 64.4%. The proportion of fathers with a junior high school education or less fell from 64.4% to 48.9%, while the proportion for mother decreased from 74.4% to 58.9%. Most students(84%–87%) came from average or higher economic families, and most (71.1% –73.3%) lived at home.
Table 1. Demographic characteristics of the sexually active boys between two surveys.
The χ² tests indicated significant differences in parents' literacy levels (P = 0.014 for fathers, and P = 0.009 for mothers).
Characteristics of changes in safe sex knowledge, safe sex self-efficacy, and exposure to and evaluation of school-based education between the two surveys
Among sexually active boys, the proportion of students with key HIV/STI-related knowledge and positive attitudes increased significantly in 2021 compared to 2015 (all P < 0.05; Table 2): knowing that the main mode of HIV transmission is sexual contact rose from 27.8% in 2015 to 84.4% in 2021; understanding that contracting an STI increases the likelihood of HIV infection grew from 27.2%–72.2%; knowledge of condom use reducing STIs increased from 21.7%–90.0%; knowledge of condom use reducing HIV infection rose from 21.1%–81.1%; confidence in refusing sex without a condom increased from 43.9%–58.9%; and the percentage having received school-based sex and STI/HIV prevention education and rated it as “good” surged from 19.1%–55.0%.
Table 2. Characteristics of safe sex knowledge, safe sex self-efficacy and exposure to and evaluation of school-based education among sexually active boys between two surveys.
Characteristics of changes in sexual behaviour between the two surveys
Significant changes were observed in the sexual behaviors of the students in 2021 compared to 2015 (all P < 0.05; Table 3): first sexual relationship with a non-regular partner decreased from 29.4% to 17.8%; oral sex engagement rose from 37.8%–58.6%; anal sex prevalance increased from 11.7%–26.1%; consistent condom use improved from 17.8%–35.2%; condoms use for contraception grew from 52.8%–74.7%; the use of other contraceptive methods such as the pill (from 25.0%–45.9%), extracorporeal ejaculation (from 35.6%–52.4%), and the safe period (from 25.0%–40.7%) also showed significant increase.
Table 3. Characteristics of sexual behaviour among sexually active boys between two surveys.
Chi-square tests reveale no significant differences between the two surveys for the following variables: school stage of sexual initiation, sex of sexual partner, number of sexual partners, experience of pregnancy with a female sexual partner, and experience of an STI diagnosis.
Results of multivariate logistic regression analysis
A multivariate logistic regression model was established for each variable demonstrating a significant difference in distribution in the univariate analysis. After adjusting for demographic variables (year of survey, year, major, family type, father's literacy, mother's literacy, family economic status, and residence), the following factors exhibited markedly elevated odds ratios in 2021 compared to 2015 (Table 4): knowing that sexual contact is the main mode of HIV transmission(OR = 14.14, 95% CI:7.16–27.92), knowing that contracting an STI increases the likelihood of HIV infection (OR = 7.83, 95% CI: 4.30–14.29), knowing that condom use can reduce STIs (OR = 33.51, 95% CI: 15.08–74.49) and HIV infection (OR = 16.77, 95% CI: 8.58–32.76), believing that they would confidently refuse to have sex without a condom(OR = 1.95, 95% CI: 1.14–3.32), and having received and rated school sex education and STI/HIV prevention education as “good” (OR = 5.62, 95% CI: 2.72–11.64).
Table 4. Results of multivariate logistic analysis.
Sexual behaviour variables demonstrating significant differences in the univariate analyses were further adjusted for school stage of sexual initiation in addition to demographic variables. The multivariate logistic regression analysis revealed that the following were significantly more prevalent in 2021 than in 2015: oral sex (OR = 2.60, 95% CI: 1.47–4.60) and anal sex (OR = 2.65, 95% CI: 1.28–5.48), consistent condom use(OR = 2.27, 95% CI: 1.21–4.25), and various contraceptive methods such as condoms use(OR = 2.76, 95% CI: 1.50–5.09), the pill (OR = 2.42, 95% CI: 1.35–4.35), extracorporeal ejaculation (OR = 1.77, 95% CI: 1.02–3.09), and the safe period (OR = 2.22, 95% CI: 1.22–4.04). However, the proportion of students who initiated sexual relationship with non-regular partners decreased (OR = 0.47, 95% CI: 0.24–0.93).
Discussion
The present study was conducted using the same questionnaire and survey methodology among students in Years 1–2 in the same school, six years apart. The study revealed positive changes in the rates of sexual initiation, knowledge, and self-efficacy regarding sexual safety, as well as in various sexual behaviors among boys who had already had sex in VHS.
From 2015–2021, there was a notable increase in the knowledge of the study population regarding the main mode of HIV transmission being sexual contact and the effectiveness of condom use in reducing STIs and HIV infection, with adjusted ORs above 14. Additionally, the understanding that contracting STIs increases the likelihood of HIV infection also improved, with an adjusted OR of 7.8. There was a significant increase in the proportion of students who received and rated sexual health and STIs/HIV prevention education at school as good. Schools are the main place for adolescents to receive sex education and education on the prevention of STIs/HIV (17, 18), and comprehensive school-based education can significantly improve adolescents' knowledge of sexual and reproductive health and STIs/HIV prevention, as well as reducing risky sexual attitudes and behaviours (17–19). National surveillance data for male high school students in the United States showed a decrease in the percentage engaging in sexual intercourse, falling from 47.0% to 32.0% between 2013 and 2023 (20). The 2021 survey results were significantly lower than the aforementioned US surveillance data in 2023 (20), lower than 9.0% (8) and 10.5% (9) of male students in Years 1–3 at VHS in this province, 9.3% of male students in Years 1–3 at RHS in Guangdong province (21), and closer to 8.7% of male students at RHS in Guizhou Province (22). This study reported a significant decrease in the proportion of students engaging in sexual behaviour, suggesting that VHS students are making better choices in this regard. Students with higher levels of knowledge about sexual and reproductive health and disease prevention tend to initiate sexual behaviour later (18, 23). We report a significant improvement in parental literacy among male students in 2021, and higher parental literacy is associated with delayed onset of sexual behaviour in their children (24, 25). However, the overall low level of parental literacy in the study suggests that there is a need to help students' parents to understand the importance of sex education and to master the correct methods, and to encourage them to have open and healthy communication with their children. This finding is encouraging, given that the literature reports that an association between early sexual intercourse and multiple sexual partners, unprotected sex, unwanted pregnancy, STIs and HIV infection (26–28).
The proportion insisting on condom use differed significantly between the two surveys. This may be related to the higher level of knowledge about HIV/STIs among study participants in the second survey and their perception that condom use can prevent STIs/HIV. Chinese literature reports that college students with higher levels of sexual and reproductive health knowledge are less likely to engage in unprotected sex (18), and Thai VHS students with high levels of HIV knowledge exhibit higher rates of condom use (29). The two surveys were conducted 6 years apart. During this time social perceptions and attitudes towards safer sex may have changed. A more open social climate may have made it easier for students to talk about and cope with safer sex, and may have led to a greater willingness to accept knowledge. The present study also reported a significant increase in the proportion of participants who said they could refuse unprotected sex, and a large body of literature has reported that self-efficacy and willingness to use condoms among adolescents is strongly associated with actual condom use (30, 31). To promote the implementation of safer sex behaviours among VHS students, it is necessary to increase levels of knowledge about STIs/HIV prevention and self-efficacy to refuse unprotected sex.
Although condom use increased significantly, the difference in the number of sexual partners between the two surveys was not statistically significant. Considering that the number of 2 or more sexual partners accounted for about 1/3 of the total, only 35% of condom use in the second survey failed to prevent the transmission of STIs/HIV among students. No significant difference was found in self-reported experience of STIs diagnosis among study participants, suggesting that changes in sexual behaviour are not sufficient to reduce the risk of STI and that there is a need for STIs/HIV prevention services for VHS students. Students use condoms mainly for contraception rather than for STIs/HIV prevention (11, 32). Therefore, sex education and STIs/HIV prevention education in schools should help students improve their ability to protect themselves during sex, strengthen the awareness of the role of condoms in disease prevention, and eliminate the stigma against condoms and promote students' initiative to seek access to condoms.
The proportion of students reporting ever using condoms, ever using the pill, extracorporeal ejaculation and the safe period all increased by 15% or more, suggesting that there has been a significant improvement in students' awareness of the use of these types of contraception. While there has been a considerable improvement in contraceptive use among students, the actual use of all types of contraception remains low, indicating the need for enhanced contraceptive education. Given the range of contraceptive methods available to students, the fact that this study only looked at the proportion of students who had ever used contraception, the uncertainty surrounding the effectiveness of ejaculation and the safe period, and the fact that the choice of contraceptive method may be influenced by culture, personal preference and information received, the proportion of students who did not reduce their risk of pregnancies in this study requires further investigation. Future interventions should combine school-based education and community programmes. These interventions should develop gender-sensitive sexual health education modules that consider local social and cultural factors, with the aim of improving condom and other contraceptive uptake.
Our study reports a significantly higher percentage of oral sex among male VHS students, and the percentage in 2021 is significantly higher than the percentage of oral sex among 15–17 year old male adolescents in the United States (33), and even higher than the percentage of male students who have already had sexual intercourse in the 4th year of college in China (34). As society continues to open up, oral sex is gradually becoming more accepted in China. Yingying Huang reported that from 2000–2015, the proportion of Chinese men giving oral sex to women increased from 20.3%–36.8%, while the proportion of women giving oral sex to men increased from 16.2%–36.8% (35). While the risk of disease transmission from oral sex is much lower than from vaginal or anal sex, it can still transmit gonorrhoea, chlamydia, syphilis and HIV (36–38). Local and foreign adolescents rarely use protective measures during oral sex (27, 33, 34, 39), which may increase the risk of disease transmission through oral sex. Chinese studies have found that college students who engage in oral sex are at risk of having multiple sexual partners, non-regular sexual partners, sexual partners from the community or outside of school, less frequent condom use, and more frequent sex (33). The rapid increase in oral sex among VHS students may reflect the changing patterns of sexual behaviour among young people. Schools and health authorities should pay attention to this phenomenon and take targeted publicity and intervention measures.
Anal sex, whether homosexual or heterosexual, is a high-risk sexual behaviour involving a much higher risk of transmitting STIs/HIV than oral or vaginal sex. The significant increase in the rate of anal sex, coupled with the high proportion of multiple sex partners and the low rate of consistent condom use, means that the future risk of disease transmission through anal sex cannot be ignored. Surveillance of anal sex among VHS students should be strengthened in order to monitor the rate of anal sex and the protection level, and to provide data to inform targeted interventions.
This study has several limitations. The cross-sectional design of this study limits the ability to make causal inferences. Future research should adopt a prospective cohort study to gain a deeper understanding of the long-term causal effects of specific sex education strategies on students' acquisition of sexual health knowledge and adoption of healthy behaviours. The relatively small number of male students who reported having sex in the 2021 survey may limit the statistical power and generalisability of our findings. In addition, the self-reported nature of sexual behaviour may introduce bias due to social desirability or recall inaccuracies. Finally, the study was conducted in a single VHS, which may not be representative of all VHS students in Zhejiang Province or other regions of China. Therefore, our results should be interpreted with caution and further research with larger and more diverse samples is needed to confirm these findings.
Conclusions
In conclusion, our study found that the proportion of male VHS students engaging in sexual behaviour decreased significantly, while their knowledge of safer sex, belief that they could refuse sex without a condom, consistent use of condoms, and ever use of condoms, the contraceptive pill, the safe period, and extracorporeal ejaculation for contraception increased. However, these positive changes are not significant enough to prevent STIs/HIV transmission and reduce pregnancy. This study reports a significant increase in the rate of oral and anal sex. Education and public health authorities can use these findings to inform prevention policies and create effective messages that respect cultural norms and address existing gaps. Firstly, schools should launch comprehensive sex education and STIs/HIV prevention programmes to raise students' awareness of condom use and contraception. Secondly, given the rising prevalence of non-vaginal sex, dedicated curricula should address misconceptions around STI/HIV transmission through these routes and promote harm reduction strategies. Thirdly, parent-child communication should be strengthened through family-focused initiatives that reinforce safer sex practices outside of schools. Finally, ongoing monitoring of sexual health trends among vocational students is critical in order to refine interventions and align them with evolving behavioural patterns. By adopting a multi-sectoral approach that combines education and community engagement, policymakers can effectively mitigate the transmission of STIs/HIV and unintended pregnancies in this vulnerable population.
Data availability statement
The datasets presented in this article are not readily available because The dataset we used involve sexual behaviour of young students which is sensitive in the context of China. Requests to access the datasets should be directed to Dr. Qiaoqin Ma, email:qqma@cdc.zj.cn.
Ethics statement
The studies involving humans were approved by Zhejiang provincial center for disease prevention and control. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants' legal guardians/next of kin.
Author contributions
HW: Conceptualization, Data curation, Formal analysis, Writing – original draft. QM: Conceptualization, Supervision, Writing – original draft, Writing – review & editing, Methodology. LH: Conceptualization, Investigation, Writing – original draft. TJ: Investigation, Writing – original draft. WC: Investigation, Data curation, Writing – original draft. JZ: Investigation, Writing – review & editing. WC: Investigation, Conceptualization, Writing – original draft.
Funding
The author(s) declare that financial support was received for the research and/or publication of this article. This study was funded by Zhejiang Provincial center for disease prevention and control.
Acknowledgments
Zhejiang provincial center for disease prevention and control(CDC) conducted this study in cooperation with the CDC in the study area and the occupational high school surveyed. We are grateful for their cooperation in this study and for conducting the data collection. We also thank all those students who participated in the surveys.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Generative AI statement
The author(s) declare that no Generative AI was used in the creation of this manuscript.
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Abbreviations
VHS, vocational high school; RHS, regular high school; STI, sexually transmtted infection.
References
1. World Health Organization. Adolescent and Young Adult Health (2024). Available online at: https://www.who.int/news-room/fact-sheets/detail/adolescents-health-risks-and-solutions (Accessed November 11, 2024).
2. Beckwith S, Chandra-Mouli V. Blum RW.trends in adolescent health: successes and challenges from 2010 to the present. J Adolesc Health. (2024) 75(4S):S9–S19. doi: 10.1016/j.jadohealth.2024.04.015
4. Cai C, Tang H, Chen FF, Li D, Lv F. Characteristics and trends of newly reported HIV infection in young students in China, 2010–2019. Chin J Epidemiol. (2020) 41(9):1455–9.
5. Dong Y, Wang L, Burgner DP, Miller JE, Song Y, Ren X, et al. Infectious diseases in children and adolescents in China: analysis of national surveillance data from 2008 to 2017. Br Med J. (2020) 369:m1043. doi: 10.1136/bmj.m1043
6. Xu F, Bu K, Zhang D, Zhang Y, Zhang H, Jing H, et al. A cross-sectional study on AIDS-related knowledge and demands for health education among first-grade students of senior high schools in Tianjin. Zhonghua Liu Xing Bing Xue Za Zhi. (2019) 40(12):1618–23.32062926
7. Sun J, Li F, He J, Yang B, Wang X. Survey on the source of sexual knowledge, sexual behaviors and AIDS-related knowledge and attitude of henan high school students. Chin Prim Health Care. (2017) 31(11):54–6.
8. Chen YH, Wang F. AIDS knowledge, sexual behaviour among school students in Xinchang county. Chin Rural Health Serv Adm. (2013) 33(11):1252–5.
9. Shou B, Li H, liu D, Lu X, Li J, Lei M. Attitude, orientation and behavior on sexuality among senior high school students of Fuyang district, Hangzhou. Chin J AIDS STD. (2018) 24(1):90–4.
10. Nie Y, Zheng Z, Luo X, Xu Y. Investigation and analysis of sexual development situation and knowledge, attitude and behaviour about sexual and reproductive health of 15415 adolescents in China. Chin J Women Child Health Res. (2022) 33(4):68–74.
11. Zhao WJ, Miao QY, Shi YY. Awareness of AIDS and use of condom among middle school students who have induced abortion in Yuyao city, 2016–2020. Chin J School Health. (2022) 43(6):860–3.
12. Zhao D, Zhu T, Guo X, Song W, Wang X. Attitudes,current status and related factors towards sex education among middle school, high school and vocational high school freshmen in Jiading district, Shanghai municipality. Pract Prev Med. (2024) 31(11):1300–5.
13. Zhejiang Provincial Bureau of Statistics. 2024 Zhejiang Provincial Statistical Yearbook-Comprehensive-National Economic and Social Development Aggregate and Speed (2024). Available online at: https://tjj.zj.gov.cn/art/2024/12/2/art_1525563_58962725.html (Accessed September 25, 2024).
14. Kann L, Kinchen S, Shanklin SL, Flint KH, Kawkins J, Harris WA, et al. Youth risk behavior surveillance–United States, 2013. MMWR Surveill Summ. (2014) 63(4):1–168.
15. Häggström-Nordin E, Borneskog C, Eriksson M, Tydén T. Sexual behaviour and contraceptive use among Swedish high school students in two cities: comparisons between genders, study programmes, and over time. Eur J Contracept Reprod Health Care. (2011) 16(1):36–46. doi: 10.3109/13625187.2010.536922
16. Zhejiang Provincial Centre for Disease Control and Prevention. Implementation of HIV Sentinel Surveillance for Young Students in Zhejiang Province. Hangzhou (China): Zhejiang Provincial Centre for Disease Control and Prevention (2015).
17. Fonner VA, Armstrong KS, Kennedy CE, O'Reilly KR, Sweat MD. School based sex education and HIV prevention in low- and middle-income countries: a systematic review and meta-analysis. PLoS One. (2014) 9(3):e89692. doi: 10.1371/journal.pone.0089692
18. Li C, Cheng Z, Wu T, Liang X, Gaoshan J, Li L, et al. The relationships of school-based sexuality education, sexual knowledge and sexual behaviors-a study of 18,000 Chinese college students. Reprod Health. (2017) 14(1):103. doi: 10.1186/s12978-017-0368-4
19. Guo Y, Diao J, Liu T, Luo L, Zhang X, Li Q, et al. Effects of a school-based sexuality curriculum on sexual and reproductive health in freshmen at Shandong university in China. Adv Physiol Educ. (2023) 47(3):530–7. doi: 10.1152/advan.00165.2022
20. Center for disease prevention and control. Youth Risk Behavior Surveillance Data Summary & Trends Report: 2013–2023 (2024). Available online at: https://www.chconline.org/resourcelibrary/youth-risk-behavior-survey-data-summary-trends-report-2013-2023-downloadable/ (Accessed November 12, 2024).
21. Huang X. Investigation and research on the status quo of students’ attitudes towards love, sex and sexual behavior in senior high schools in Foshan. Chin J Hum Sex. (2018) 27(12):157–60.
22. Peng C, Wang W, Du E, Xing Y, Jia Z. Research on the current situation and influencing factors of sexual behavior among ordinary senior high school students in a second—tier city. Chin J Drug Depend. (2020) 29(2):129–35.
23. United Nations Fund for Population Activities. State of World Population (2014). Available online at: http://www.unfpa.org/sites/default/files/resource-pdf/EN-SWOP14-Report_FINAL-web_2.pdf (Accessed October 11, 2024).
24. Guo W, Wu Z, Qiu Y, Chen G, Zheng X. The timing of sexual debut among Chinese youth. Int Perspect Sex Reprod Health. (2012) 38(4):196–204. doi: 10.1363/3819612
25. Shi Y, Liu R, Yu H, Fu Z, Guo W. Sexual debut among college students in China: effects of family context. J Biosoc Sci. (2022) 54(6):1004–23. doi: 10.1017/S0021932021000523
26. Shrestha R, Karki P, Copenhaver M. Early sexual debut: a risk factor for STIs/ HIV acquisition among a nationally representative sample of adults in Nepal. J Community Health. (2016) 41:70–7. doi: 10.1007/s10900-015-0065-6
27. Ruan F, Fu G, Yan Y, Li Y, Shi Y, Luo L, et al. Inequities in consistent condom use among sexually experienced undergraduates in mainland China: implications for planning interventions. BMC Public Health. (2019) 19(1):1195. doi: 10.1186/s12889-019-7435-4
28. Ma Q, Ono-Kihara M, Cong L, Xu G, Pan X, Zamani S, et al. Early initiation of sexual activity: a risk factor for sexually transmitted diseases, HIV infection, and unwanted pregnancy among university students in China. BMC Public Health. (2009) 9:111.19383171
29. Thato S, Charron-Prochownik D, Dorn LD, Albrecht SA, Stone CA. Predictors of condom use among adolescent Thai vocational students. J Nurs Scholarsh. (2003) 35(2):157–63.12854297
30. Khumsaen N, Gary FA. Determinants of actual condom use among adolescents in Thailand. J Assoc Nurses AIDS Care. (2009) 20(3):218–29.19427599
31. Yu B, Wang Y, Chen XG. Perception of peer condom use buffers the associations between HIV knowledge, self-efficacy, and condom-use intention among adolescents: a moderated mediation mode. Prev Sci. (2022) 23(6):879–88.34962622
32. Ye Q, Jiang W, Zhou J. Impact of health promotion on the current status of abortion and contraceptive methods among students. Pract Prev Med. (2019) 26(1):96–8.
33. Holway GV, Hernandez SM. Oral sex and condom use in a U.S. national sample of adolescents and young adults. J Adolesc Health. (2018) 62(4):402–10.29174873
34. Chen W, Pan X, Guo Z, Zhou X, Wang H, Ma Q. Analysis of oral sexual behavior and related factors among male students from college graduation in Hangzhou. Chin J Prev Med. (2019) 53(3):289–92.
35. Huang Y, Pan S. Sexual techniques changes of China in the 21st century–based on four population-based surveys. Chin J Hum Sex. (2016) 25(11):150–4.
36. Edwards S, Carne C. Oral sex and the transmission of viral STIs. Sex Transm Infect. (1998) 74(1):6–10.9634307
37. Edwards S, Carne C. Oral sex and transmission of non-viral STIs. Sex Transm Infect. (1998) 74(2):95–100.9634339
Keywords: vocational high school, male students, safe sex knowledge, sexual behaviour, change
Citation: Wang H, Ma Q, He L, Jiang T, Chen W, Zhen J and Chen W (2025) Changes in knowledge of safe sex and sexual behaviour among male vocational high school students in Zhejiang Province, China: a 6-year cross-sectional comparison (2015–2021). Front. Reprod. Health 7:1653622. doi: 10.3389/frph.2025.1653622
Received: 9 July 2025; Accepted: 8 September 2025;
Published: 24 September 2025.
Edited by:
Morenike Oluwatoyin Folayan, Nigerian Institute of Medical Research (NIMR), NigeriaReviewed by:
Aldemir Branco de Oliveira Filho, Federal University of Pará, BrazilHari Ram Prajapati, Banaras Hindu University, India
Copyright: © 2025 Wang, Ma, He, Jiang, Chen, Zhen and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Qiaoqin Ma, cXFtYUBjZGMuemouY24=