Abstract
Background:
High substance use among Ethiopian high school students has been reported in localized studies, yet key contributing factors such as parental substance use, school policies, and environmental influences remain under-researched, particularly in Jimma. Identifying the prevalence and contributing factors specific to this setting is essential for developing targeted prevention strategies and guiding school and community-level interventions.
Methods:
This cross-sectional study assessed substance use prevalence and the associated factors among 206 high school students (Grades 9–12) in Jimma Town, Jimma, Ethiopia. Participants were selected using multistage random sampling from two schools. Self-administered questionnaires, including an adapted Brief Screener for Tobacco, Alcohol, and other drugs, were used to screen participants. Data were entered in Epi-Data 3.1 and analyzed using SPSS 27; bivariate and multivariate logistic regression analyses identified associated factors, and statistical significance was determined at a 95% confidence level, P value (.05).
Results:
Among 202 participants, the prevalence of substance use was 27.2% (95% CI: 21.1–33.3). The most common substances used were Khat 48.5% (95% CI: 1.75–1.96), followed by alcohol 26.7% (95%CI: 1.27–1.56), and tobacco products 8.9% (95% CI: 1.23–1.52). Living with parents (AOR = 9.245, 95% CI: 0.96–88.94, P = .045), parents’ neutral opinion on substance use prevention (AOR = 2.762, 95% CI: 1.09, 6.94, P = .031), students’ lack of information on substance use (AOR = 0.343 95% CI: 0.15, 0.77, P = .010), and peer substance use especially chewing Khat (AOR = 16.512, 95% CI: 6.68–40.80, P < .001) significantly increased odds of substance use.
Conclusions:
The high prevalence of substance use among high school students necessitates a collaborative approach involving all stakeholders to foster a safer and more supportive educational environment. Schools should mandate comprehensive substance use prevention programs, establish clear prevention-focused policies, and engage parents and the community to build a cohesive support network.
Introduction
Substance use among high school students is a multifaceted issue with significant implications for individual health, societal well-being, and national development. High school students in the adolescence stage of development are vulnerable to substance experimentation and abuse due to challenges such as peer pressure, societal norms, and economic hardships. 1 Because their brains are not fully developed, they have a strong tendency to seek pleasure and avoid pain, but their judgment and decision-making skills are limited, which hinders their capacity to evaluate risks and make sound decisions, including drug use. 2 Thus, not only is the risk of psychoactive substance use high during adolescence, but also its initiation early in life has been known to contribute to higher levels of use and substance use disorders later in life. 3
In 2021, an estimated 1 in 17 individuals between the ages of 15–64 worldwide reported drug use in the past 12 months. 4 In Ethiopia, where adolescents and youth comprise 33.8% of the population 5 rapid socio-economic development has been accompanied by a rising trend in substance use, particularly among high school students. 6 While comprehensive nationwide data on substance use prevalence among high school students is scarce, localized studies suggest a concerning prevalence rate. A cross-sectional study with 3355 students of Grades 9 and 10, from 36 high schools across four major regions of Ethiopia, found; 2.4% students were current smokers and 4.7% had ever smoked cigarettes. Use of smokeless cigarettes was reported by 3.2%, while 41.8% reported drinking alcohol. 8.7% of students had used Khat (Catha edulis) at least once, compared to 4.8% who chewed it consistently. Significant regional differences in drug usage patterns were observed; the southern regions were inclined to smoke cigarettes and use Khat, while alcohol use was higher in the northern regions. Substances commonly abused included tobacco, alcohol, Khat, and, to a lesser extent, illicit drugs like cannabis and stimulants. 7
Substance use among high school students has far-reaching consequences beyond academic underachievement. It heightens the risk of addiction, mental disorders and physical illnesses like HIV and STDs due to risky behaviors while intoxicated; strains interpersonal relationships, leads to delinquency, and isolates adolescents from constructive social activities. Additionally, it imposes a significant economic burden on healthcare systems and social services. 8
Some factors that are generally linked to substance use include awareness, beliefs and myths about substance use, 9 gender, and area of living. But of particular significance are the family members’ substance use history, peer pressure, school substance use regulation, school substance controlling system, and environmental factors like availability of substance retailing shops. 10
The family and school environments are critical for high school students, as they provide the primary foundations of support, guidance, and learning. A stable family environment promotes emotional well-being and fosters values such as responsibility, empathy, and resilience. Parents play an important role in supporting adolescents as they traverse through changes in growth and development period. Studies point to a strong link between substance use behaviors and attitudes of parents to children’s attitudes toward substance use. 11 The school environment also shapes students’ intellectual growth and social skills, offering structured learning, mentorship, and peer interaction. Schools play a crucial role in shaping attitudes and behaviors toward drug use among students. Also, schools that have liberal norms toward substance use, especially when students come from families with permissive attitudes toward drinking and smoking, tend to have a higher prevalence of substance use among their students. 12
Together, the family and school environments can play a vital role in helping students navigate challenges, develop a strong sense of identity, and build the confidence needed to succeed both academically and personally. Hence, positive reinforcement from family and school enables students to make better life choices and stay motivated during this pivotal stage of their lives.11,12
Anecdotal evidence suggests a growing prevalence of substance use and the health risks it poses for this demographic in Ethiopia, with limited comprehensive data available, particularly in Jimma. Jimma town of Ethiopia has six schools offering higher secondary education and two universities. Previous studies conducted in Jimma report varying prevalence rates among high school students: one found that 46.8% were Khat users, 13 another study reported lifetime prevalence of Khat chewing at 16% and the current prevalence at 14.2%, with 22.2% experiencing mental distress. 14 Among street children between 12 and 18 years, 30.8% were substance users, with those over 14 being twice as likely to use substances. 15 Clinical observations indicate adolescents from nearby schools in Jimma often seek psychiatric care for substance use disorders, both as inpatients and outpatients. There is limited published data on how family and educational environments may predispose high school students to substance use. Understanding these factors can support the development of effective school-based prevention strategies and community-level interventions. This study was therefore conducted to assess the prevalence and related factors of substance use in this population.
Materials and Methods
Study Area, Design, and Period
The STROBE cross-sectional reporting guidelines were used to report. 16 School-based cross-sectional survey was conducted among high school students (Grades 9–12) in two co-educational schools in Jimma town, the administrative center of Jimma Zone in the Oromia region of Southwest Ethiopia, located approximately 352 km from Addis Ababa. Grades 9–12 in Jimma typically consist of around eight sections per grade, with about 50 students in each section. The study took place from February 15 to April 15, 2024.
Study Population and Sampling
The study population comprised male and female students from Grades 9–12 in two randomly selected schools in Jimma town during the study period. All students who were available during the school term and willing to participate were eligible. This study was designed as a preparatory phase for a subsequent intervention-focused research project on substance use prevention. To ensure feasibility within the time frame and budgetary limitations, the sampling frame and sample size were restricted to those identified for inclusion in the planned intervention study. The sample size for the main study was calculated using the double population proportion formula in STATCAL, a component of the EPI Info software. The final sample size was determined by adding a 10% non-response rate, resulting in a total of 206 participants.
A multistage sampling technique was employed. Two schools—one private (1912 students: 847 males, 1065 females) and one public (2678 students: 1,864 males, 814 females)—were randomly selected. Students were proportionally allocated across Grades 9–12. A sampling frame was created for each section (A-H) in every grade, and participants were randomly selected until the target sample size was reached.
Data Collection Tools and Procedure
The self-completion survey instrument was developed in English and translated into the Amharic and Afan Oromo languages and then back to English by bilingual experts in order to check consistency. It was face-validated by mental health experts to confirm its relevance and clarity. The questionnaire, adapted from the Brief Screener for Tobacco, Alcohol and other drugs (BSTAD), assesses the frequency of use of addictive substances to identify risky substance use. 17 The BSTAD tool is reliable and valid for screening adolescents for substance use disorders (SUDs). Tools that assess the frequency of substance use (e.g., how often a person uses alcohol, tobacco, or other drugs) have already been shown to be effective in adult populations. Therefore, the consistency of BSTAD’s findings with similar research in adults supports the idea that frequency-based screening is useful across age groups. 16 Its application to older high school students (above 17 years) is thus a practical extension, even if not yet formally validated in that age group. Moreover, using a single tool simplifies screening protocols in school or community settings, enabling early identification and timely intervention for at-risk youth. Peer characteristics had questions on the status of addictive substances and the types of substances used. School norms on substance use: consisted of close-ended questions on students’ awareness about the guidelines and policies pertaining to substance use, presence of school clubs, school-based programs for prevention of substance use, ban on sale of addictive substances in the vicinity of the school. 10 Parents’ substance use characteristics: comprised closed-ended questions pertaining to responses from students regarding parents/family members’ use of addictive substances, type of substances used, and students’ reported opinion of their parents toward substance use. School teachers with prior data collection experience collected the data after receiving a one-day session on the questionnaire, survey purpose, and item explanation. A pre-test was conducted on 5% of the sample size at a nearby school to identify potential issues with the design or wording of the questions. Necessary modifications were made to improve item clarity before the main data collection phase. The questionnaires were administered in both Amharic and Afan Oromo, ensuring linguistic accessibility for the students. It took approximately 25 minutes for the students to complete the survey forms. The principal investigator oversaw and coordinated all aspects of data collection, including the training, pre-testing, and monitoring of data collectors and facilitators. The collected data were checked for coding errors, inconsistencies, and completeness.
Variables
The primary outcome variable was substance use. In this study, the prevalence of substance use refers to the participants’ responses to past one-year use of addictive/psychoactive substances like Khat, alcohol, tobacco, marijuana, prescription drugs, and non-prescription drugs, assessed using the adapted BSTAD scale, with a score of “1” for “Yes” and “0” for “No.”
The independent variables considered in this study were: sociodemographic characteristics of students (sex, age, grade of study, religion, ethnicity, parents’ marital status, living status, education of head of family, occupation of head of family, average monthly income of family, source of information on substance use); parents’ substance use characteristics measured with close-ended questions (use of addictive substance, opinion toward substance use). Responses from participants were scored “1” for “Yes” response and “0” for “No / Not sure”; School norms had close-ended items on guidelines, rules, action against substance users, training, active youth clubs, and sale of illegal substances in the vicinity. Responses from participants were scored “1” for “Yes” response and “0” for “No / Not sure.” The total score was 7. The summed up individual scores were categorized as good awareness >3.5, poor awareness <3.5. Peer characteristics were measured with closed-ended questions. Responses were scored “1” for “Yes” response and “0” for “No / Not sure.” Having information on substance use prevention had dichotomous response options and was scored as “1” for “Yes” and “0” for “No.”
Data Analysis and Presentation
All the complete survey forms were considered were analysis. Data entered into Epi-Data software version 3.1 was transported to SPSS version 27 for analysis. Descriptive statistics were done to describe the study population. Bivariate and multivariate analysis was employed to identify factors associated with the outcome variable. Those variables which were found to be significant in the bivariate analysis (P < .25) were retained for the multivariate analysis. Adjusted odds ratio (AOR) with 95% confidence interval was computed to assess the level of association and statistical significance (P < .05). The results are presented in tables, figures, and charts for comparison with previous study results.
Results
A total of 202 respondents completed the survey forms, giving a response rate of 98%.
Sociodemographic Characteristics
An overview of the sociodemographic characteristics of high school students shows the gender distribution was nearly balanced, with 49% male and 51% female students. The average age of students was 17.37 years (SD = 1.77), 77.7% of them were in the 15–19 age group. Students were relatively evenly distributed across grades, with the largest group in Grade 10, 30.7%. 73.3% lived with their parents, and 81.2% were unmarried. Family income varied, with nearly half (48%) earning between 1501 and 5000 ET Birr monthly. The primary source of information on substance use and its prevention was from the schools (44.6%) or social media (30.2%). The details of the same have been given in Table 1.
Sociodemographic Characteristics of High School Students in Jimma Town, Jimma, Southwest Ethiopia (N = 202). 5
Parent Substance Use Characteristics
A small proportion of students (13.9%) reported that their parents used alcohol or other addictive substances; a significant portion (41.6%) of the students reported their parents had a favorable view of substance use prevention, while 30.2% perceived their parents had unfavorable opinion, and 28.2% were unsure of their parents’ stance. The results are presented in Supplementary Table 1.
School Characteristics
The school characteristics pertaining to substance use prevention are presented in Supplementary Table 2. Only about one fourth of students (25.2%) reported that their schools have clear guidelines on substance use prevention. Nearly half (49%) were aware of specific rules prohibiting substance use by teachers and students, but almost one fourth 26.2% were unaware of it. Less than half (46%) reported that their schools actively addressed alcohol and illegal substance use issues; the rest either reported in the negative or did not know, 28.2% and 25.7%, respectively. Only 39.1% of students had received training on substance use prevention. School clubs, often effective platforms for health promotion, were lacking, with a significant 55.9% reporting the absence of such clubs in their schools. About 40.1% of students had access to health-related information at school, but a similar proportion (43.6%) lacked these resources. While 27.7% of students admitted that illicit drugs and alcohol were sold near their schools, half of them (50.5%) reported that such sales did not take place in the area, and 21.8% were unaware of it.
Factors Associated with Substance Use among High School Students in Jimma Town, Jimma, Southwest Ethiopia.
AOR: Adjusted odds ratio, OR: Odds ratio (P < .25, considered for multiple logistic regression).
Substance Use Characteristics of Peers
Peer use of substances in the Supplementary Table 3 shows that almost one fourth of the students reported having friends with the habit of Khat chewing (24.8%), alcohol use and tobacco users were 7.9% and 6.4%, respectively. Ten percent had friends who took over-the-counter medications and took more than they were supposed to take. Marihuana, cocaine and inhalants were similar in proportion (3%).
Parent-related Factors Associated with Substance Use among High School Students in Jimma Town, Jimma, Southwest Ethiopia.
AOR: Adjusted odds ratio, OR: Odds ratio (P < .25, considered for multiple logistic regression).
Prevalence of Substance Use
From a total of 202 students, 55 students confirmed they had used addictive substances in the recent year; see Figure 1 given in the Supplementary file. The overall prevalence of substance use was more than one fourth, 55 (27.2%, 95% CI: 21.1–33.3). The most commonly used substances are summarized in Figure 2, given in the Supplementary file. Khat (48.5%, 95% CI: 1.75–1.96), followed by alcohol (26.7%, 95% CI: 1.27–1.56). A small proportion of students were using heroin, cannabis, and other substances, 0.5%, 1.5%, and 1%, respectively.
Overall Prevalence of Substance Use Among High School Students in Jimma Town, Jimma Southwest Ethiopia.
Types of Substances Used by High School Students in Jimma Town, Jimma, Southwest Ethiopia.
Factors Associated with Substance Use Among High School Students
The factors associated with substance use, along with their odds ratios (OR) and AOR, confidence intervals (CI), and P values, are presented in Tables 2, 3, and in Supplementary file Table 4. The AORs are derived from multivariable logistic regression models, controlling for potential confounders.
Chi-Square Association of Substance use by Peers and Substance Use among High School Students in Jimma Town, Jimma, Southwest Ethiopia.
Females had slightly higher odds of substance use compared to males (AOR = 1.10, 95% CI: 0.59–2.04), though this difference was not statistically significant (P = .763). Living with parents was associated with significantly higher odds of substance use compared to living alone (AOR = 9.245, 95% CI: 0.96–88.94, P = .045). Students having information on substance use prevention were significantly less likely to report substance use compared to those who did not receive such information. After adjusting for confounding variables, students who received information were approximately 66% less likely to use substances compared to those who did not (AOR = 0.343, 95% CI: 0.15, 0.77, P = .010).
Religion: Orthodox individuals had significantly lower odds of substance use compared to Muslims (AOR = 0.162, 95% CI: 0.04–0.64, P = .010), indicating a protective association. Protestants also showed lower odds (AOR = 0.352, 95% CI: 0.09–1.26), though this was not statistically significant.
Regarding parent characteristics, students with parents who have a favorable view of substance use prevention are approximately 2.8 times more likely to avoid substance use compared to those with neutral parental opinions (AOR = 2.762, 95% CI: 1.09, 6.94, P = .031).
Peer substance use: Use of tobacco and its products, Khat, inhalants, over-the-counter medications, and prolonged use of prescription medications were found to be associated with substance use among the students (P < .05). The analysis is given in Table 4.
Discussion
Substance use was prevalent among over a quarter (27.2%, 95% CI: 21.1–33.3) of high school students, raising concerns about adolescent health. This aligns with similar rates reported in some parts of Ethiopia, Kolfe-Keraniyo, 26.5% students, 10 and 28.6% in Wolaita Sodo University, 18 30.8%, Jimma, 15 and in other Sub-Saharan regions like 26.3%, Oyo State, Nigeria. 19 However, the prevalence was lower than in Northwest Ethiopia, 52.5% students, 20 72.7% in Abuja, Nigeria 21 and 70.1% in Uganda. 22 In contrast, it was higher than the reported 13.7% from North China, 23 16% in Ambo, Ethiopia, 24 17.3% in parts of Nigeria, 25 as well as 6% in Nepal. 26 These differences likely reflect geographic, cultural, and methodological variations. Overall, the findings highlight substance use as a widespread and pressing public health issue among youth.
Khat chewing was most common, 48.5% (95% CI: 1.75–1.96), followed by alcohol, 26.7% (95% CI: 1.27–1.56); tobacco products, 8.9% (95% CI: 1.23–1.52) and other addictive substances were heroin, cannabis, and other substances 0.5%, 1.5%, and 1%, respectively. Other studies confirm that Khat, alcohol, and tobacco are the substances of choice among the youth in Ethiopia, although there are variations in the proportions within this study.10,13,14,20,27 The variations among studies on the prevalence of different substances used could be because of the differences in socio-cultural environment and ease of accessibility. Khat use is socio-culturally embedded in Jimma, Ethiopia. Integrating interactive lessons on Khat, alcohol, and other substances in the school curriculum is essential, strengthening community-based awareness campaigns, peer-led interventions, and school counseling services for a more holistic approach toward substance use prevention.
Female students showed slightly higher odds of substance use than males (AOR = 1.10, 95% CI: 0.59–2.04); the wide confidence interval and non-significant P value (P = .763) indicate no strong evidence of a gender association. Corroborates the study reported in Abuja, Nigeria. 21 Other research in Ethiopia reported higher rates of substance use among males.20,24,28 Cultural norms affect access and disclosure, with males possibly underreporting and females becoming more open. Motivations also differ—males often use substances for thrill or social reasons, while females may use them to cope with emotional stress or trauma. This highlights the need to explore underlying drivers for substance use in both genders. Gender- responsive prevention strategies, such as life skill training, gender sensitive counseling services, targeted peer support groups, are suggested for specific vulnerabilities. Further, extracurricular activities like sports, arts can be integrated to provide healthy outlets to reduce risk behaviors.
Religious affiliation was significantly associated with substance use. Orthodox students had 88% lower odds of substance use compared to Muslim students (AOR = 0.162, 95% CI: 0.04–0.64, P = .010), similar to the study among university students in North-eastern Ethiopia. 29 While Protestants showed reduced odds in the unadjusted model, this was not statistically significant after adjustment (AOR = 0.352, 95% CI: 0.09–1.26). Religious affiliations have been found to protect adolescents against substance use by offering supportive networks, stress-buffering practices, and a faith-based lifestyle. Peer influence within religious settings and the proactive roles of religious leaders can discourage substance use among youth.
Students with information on substance use prevention were significantly less likely to use substances, 66% lower odds (AOR = 0.343, 95% CI: 0.15–0.77, P = .010), suggesting a protective effect of awareness. However, a study in India found substance users had better knowledge than non-users 30 ; another research warns that factual information alone may unintentionally increase use. 31 While education is important, it is insufficient by itself; effective prevention requires a holistic approach addressing social, psychological, and environmental factors.
Interestingly, living with parents was linked to higher odds of substance use (AOR = 9.245, 95% CI: 0.96–88.94, P = .045), indicating that factors like parental substance use, poor supervision, or family stress play a crucial role. Living with parents does not always provide protection if the environment supports or tolerates substance use. The wide confidence interval suggests a lack of precision in the estimate, likely due to a small number of students in this subgroup. Further research with larger samples is needed to clarify this association.
Students with a history of parental substance use had slightly higher odds of using substances, though the association was not significant (OR = 1.318; P = .529). Parental attitudes were more influential in this study; students whose parents supported substance use prevention were 2.8 times more likely to avoid substance use than those who perceived their parents had a neutral stance on substance use (AOR = 2.762, 95% CI: 0.09–6.94, P = .031). Neutral stance referred to students’ perception of parents’ opinion as neither supportive nor opposing substance use prevention. It may reflect a lack of communication in the family regarding substance use, indifference or uncertainty regarding substance use issues. This may contribute to a higher risk for substance use among the students. Studies in Ethiopia and India have reported that many students perceive their parents as indifferent or permissive.10,11,25 In this study, 41.6% believed their parents were “okay” with substance use, and nearly a third were unsure of their parents’ views. Research shows that permissive parental attitudes and lack of care can increase adolescent substance use and psychological distress.10,20,25,32 While parental presence can offer surveillance, indifference contributes to normalization of substance use, reflecting broader community norms, underscoring the importance of parenting education and counseling and involving parents in school-based prevention efforts.
There is a notable gap in school-based substance use prevention. Only 25.2% of students were aware of clear guidelines, and just 46% observed active school measures. Prevention training reached only 39.1%, while 55.9% lacked access to health clubs, underscoring the need for stronger school-level interventions. Active control measures and school mini-media have been suggested in previous studies.6,10 Additionally, 27.7% of students reported drug and alcohol sales near their schools, and 21.8% were unsure. Perceived availability and visibility of substances are often linked to higher usage, as they can normalize or facilitate access. However, uncertainty may reflect limited exposure or lack of involvement in substance-using peer groups. Prior studies have highlighted the importance of perceived access7,28 and peer exposure20,29,32,33 as key predictors of substance use. School-based interventions should be interactive, age-appropriate, with clear prevention policies. Enforcing zoning laws to ban Khat and alcohol sales around school areas is imperative, as revealed in the study. Coordinated preventive strategies involving students, teachers, parents, and communities are vital for a protective school environment.
Peer use of substances such as Khat (P < .001), tobacco (P = .026), inhalants (P = .028), over-the-counter drugs (P = .002), and prolonged prescription medication use (P = .027) was significantly associated with student substance use. Conforming to earlier studies in Ethiopia, where peer influence, particularly from close friends, was a strong predictor of use as revealed in the study across four main cities and peri-urban areas in Ethiopia 7 and in areas like Northwest Ethiopia, 20 Ambo Town, 24 and Harari region. 28 Adolescents are easily influenced by peers; peer-led programs should complement educational interventions that enhance knowledge, attitude, and the self-efficacy to resist substance use.
Strengths and Limitations: Unlike previous studies done in Ethiopia, this study offers evidence regarding school policy, family influence that contribute to substance use among high school students. An adaptation of standard adolescent screening tool with simple, straightforward questions was used to capture students’ responses. Two different types of schools were used, yet the small sample size may limit the generalizability of the findings. Despite measures to address potential limitations—such as ensuring anonymity and providing a private room for participation—responses may still have been influenced by social desirability bias. The cross-sectional design used limits the capacity to draw any causal implications.
Conclusion
Over a quarter of high school students were active substance users, with Khat followed by alcohol being the most commonly used. This reflects a wider regional trend and underscores the need for robust prevention strategies. Significant factors linked to substance use included living arrangements, parental attitudes, and peer influence, suggesting the influence of social and family networks.
Recommendations
A comprehensive approach to substance use prevention in schools with structured, age-appropriate, and interactive education programs to improve knowledge, attitude and self-efficacy to avoid substance use is recommended. Clarity, consistency in enforcing school policies on drug use, revitalizing health clubs, and counseling centers; zoning laws to restrict the sale of Khat, alcohol, and tobacco products near schools are fundamental. Involve religious leaders and parents in prevention programs. Large-scale and comparative studies are recommended; evaluate intervention effectiveness across school types.
Supplemental Material
Supplemental material for this article available online.
Footnotes
Acknowledgements
The authors are thankful to the school directors and teachers, and data collectors, for meticulously facilitating and conducting the data collection. We acknowledge our study participants for providing their genuine responses.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The fund to undertake this study was given to us by the Jimma University Institute of Health Research and Innovation director’s office. But the fund they gave us was only for data collection and for the logistics required for providing the training intervention. Otherwise, the funder has no contribution to any aspect of this research.
Patient Consent
No patients were involved in this study.
Statement of Informed Consent and Ethical Approval
The study was accorded Ethical Committee Approval vide Ethics Committee Jimma University Institute of Health Institutional Review Board (JUIH/IRB/360/23 dated 4/03/2023). Written informed and signed voluntary consent was obtained from one of the parents or guardians for participants below 18 years. Informed consent was obtained from each study participant. The study was carried out in accordance with the principles as enunciated in the Declaration of Helsinki.
References
Supplementary Material
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