A descriptive, cross-sectional, questionnaire-based study was conducted among university students during Jan-Feb 2015. Students were recruited from Ajman University of Science and Technology and identified by the academic staff through students’ records. All students who were registered at Ajman University of Science and Technology – including medical (i.e. dental, pharmacy and health sciences) and non-medical colleges (i.e. engineering, business administration, law, information technology, mass communications and humanities) – were invited to participate. Ajman University of Science and Technology was founded in 1988 and it has two campuses, one in Ajman and the other in Fujairah. It serves around 5,000 students from all over the UAE.

The sample size was measured using the Raosoft online calculator (Raosoft) [20]. Raosoft online calculator is designed specifically for population surveys to calculate the sample size and determine how many responses are needed, to meet the desired confidence level with the margin of error (usually 5%). Therefore, it is highly recommended to be used for such study with the consideration of the population size [21,22]. The total population of students in UAE is approximately 98,000 [23]. Therefore, in order to achieve a confidence level of 95% and a 5% margin of error, a minimum sample size of 383 was required. However, a total of only 280 students agreed to take part and were requested to fill in the questionnaire form after the importance of the study and their contribution to it was explained. They were also asked to sign a consent form if they wished to participate in the study. A sample of 280 students would provide a confidence level of 90% and a 5.85% margin of error which may not fully affect the power of the study.

Regarding questionnaire validity and reliability, a structured questionnaire was developed after a thorough literature review, which was conducted initially by the chief investigator and research papers were shortlisted for further discussion among the research team. All the views, thoughts and concerns on the proposed study were taken into consideration during the design phase. This also involved a face and content validity of the quality assessment tool to ensure that the questionnaire was reflective of the practice in the UAE. An initial draft of the questionnaire was designed after the research team had reviewed all the selected papers comprehensively [19,24,25]. Individual survey items were reviewed by a group of college pharmacy faculty members and consensus was reached regarding the clarity and importance of each item. The validation process was further expanded by piloting the questionnaire with four students who met the eligibility criteria and were not aware of this study. Additional comments were utilised to further refine the instrument. The questionnaire was divided into two sections; it included items related to participants’ characteristics and 11 items assessing consumers’ knowledge, attitudes and practices related to DS:

1. Personal data, including age, gender, nationality, and college.

2. Knowledge, attitudes and practices about DS.

The second section of the survey was trichotomous. The questions were yes/no/I do not know type questions and were divided into 3 points; yes =1, no =2, I do not know =3. The scoring was calculated as the total number of yes, no, I do not know responses and then the percentage of scores was measured in the two groups.

Data were analysed using SPSS version 22.0. A chi-square test for independence was used to detect relationships between group inclusion (medical and non-medical students) and their KAP towards DS; results for categorical variables are presented as N (%). Linear regression was conducted to determine the odds of using supplements, by groups. Odds ratios for using supplements compare those who responded “Yes, we use it” to those who responded either “No, we do not use it” or “Don’t Know”. An alpha level of 0.05 was set to denote statistical significance.

The mean age of the 280 participants was 21 years (SD= ±4). The age categories were also defined with intervals equal to 5 years (e.g. 16-20 years old). An equivalent number of participants from each gender (Male=140 and Female=140) were included (see [Table/Fig-1]). There were almost twice as many non-health sciences students (N=182) as health sciences students (N=98).

More than one-third of participants (N=108; 39%) were found to be using DS. Among 108 supplement users, it was found that most were non-medical students (N=74), female (N=59) and aged under 20 (N=55). There was no significant difference between groups of medical and non-medical students regarding the use of DS (p=0.193). Of these 108, two-thirds (69%) were found to be taking these supplements on a daily basis. However, non-medical students had significantly less information about what these supplements were (p=0.040) and were less likely to attend a health campaign or workshop on DS (p=0.006). In addition, non-medical students were found to be less likely to seek help from healthcare providers when using these supplements (p<0.001). This may be because they were more likely to think that these supplements are safe (p<0.001), and do not cause interactions (p=0.039) [Table/Fig-2].

The most common source of information to which subjects referred for DS information was healthcare providers followed by the internet, TV/journal advertisements, relatives/friends, signs/posters in an educational institute and product information leaflets. Considered together, both groups considered healthcare professionals to be the primary and the most trusted source of information (62%), and there was no significant difference between groups (p=0.475). However, there were marked differences in other sources of DS information consulted between medical and non-medical students (p=0.006). For example, those in medical schools relied more heavily on DS leaflets compared to nonmedical school students (p=0.001), while those in non-medical schools relied more on friends’/relatives’ advice (p=0.100) [Table/Fig-3].

Most participants (N=137) perceived that the best way to obtain nutrients is through food and supplements together. However, some participants (N=45) believed that supplements are the best way to obtain the nutrients they need; these were mostly non-medical students (N=32) compared to 13 medical students. Overall, respondents agreed that the most common reasons for consuming DS were to maintain good health (N=58), ensure adequate nutrition and fill a nutrition gap (N=43). The majority felt that all the factors in [Table/Fig-4] together were important reasons for taking DS (N=98). The reasons for conserving DS are presented in [Table/Fig-4].

Responses to the question “Do you use any dietary supplement?” were not significantly different between the two groups of participants (adjusted: 0.077 (-0.048, 0.228) for medical to non-medical students; p = 0.200) [Table/Fig-5].

The majority of respondents (N=249; 89%) reported purchasing DS from pharmacies, whereas 15 participants (5%) purchased them from health club stores, followed by supermarkets (3%) and other stores (3%).

To the best of our knowledge, this is the only study till date in the Middle East, reporting DS use in individuals among the medical & non-medical students. Additionally, this study sought to better quantify frequency of concomitant use of supplements, an important area of ongoing clinical concern. This study also assessed consumers’ preferences related to information sources consulted, as well as consumers’ KAP regarding DS.

This study revealed that the prevalence of DS consumption among university students in the UAE is 39%. As a result, it shows that DS use by university students is a common practice. This relatively high prevalence of DS consumption may be because, the beliefs about the need for supplement use are widespread. The DS use is expected to continue growing in the UAE, as reported by the Nationally Country report data in 2015 [3]. This study’s findings were consistent with three previous studies conducted in developing countries among university students (i.e. Jordan, Malaysia and India) [26–28], in which almost half of the sample population were DS users (≤50%). However, this is lower prevalence among students in a developed country such as the United States, with the rate varying from 55-65% [29,30]. This 39% can be justified by the fact that UAE residents still commonly maintain a diet that is low in nutrients and high in starch and fat, which results in health problems [31]. As a result of the increasing number of DS consumers in the UAE, it is suggested that the criteria used to evaluate DS for inclusion in health-system formularies should be as rigorous as those established for non-prescription drugs, as the self-administered use of DS may increase patients’ risk of developing an adverse reaction. In addition, awareness of dietary supplement use should be integrated into everyday practice. For example, in this study almost two-thirds of participants (65%) perceived that the best way to obtain nutrients is through food and DS together, or DS alone. Participants thought that the use of DS was important to maintain good health (58,21%) and ensure adequate nutrition (43,15%). Similar findings were reported in studies by Al-Naggar et al., Suleiman et al., and Sharma et al., [26–28]. It is important that users get the message that DS are intended to supplement food but are not substitutes for a healthy diet and lifestyle to maintain good health and ensure adequate nutrition. Moreover, supplements cannot replace medication or therapy to treat a medical condition. A supplement alone will not necessarily cure or treat a medical condition. It is also worth mentioning that not all supplements are beneficial, especially when taken in combination with other medications or in case of overdosage.

This study revealed that the most common sources of obtaining information on DS were healthcare professionals, followed by the internet and TV/journal advertisements, which was in concordance with the findings of other studies [26,28]. Being the most trusted source of information, healthcare professionals’ awareness of and ability to pose relevant questions and provide information to users about the use of DS should be enhanced. In addition, DS users should be directed by healthcare professionals to credible sources of information, and instructed on how to evaluate DS use and report an adverse event. Moreover, DS users should start with a little education on DS from a trusted, reliable, evidence-based information source such as physicians or pharmacists rather than seeking information from less reliable and easily accessible source such as TV adverts or the internet.

As for the type of faculty, there were no significant differences between the mean of those from a medical/health sciences background versus those from a non-medical background in terms of DS usage (p =0.139). However, other findings suggest that there are significant differences in the knowledge of health sciences and non-health sciences students pertaining to the health benefits and safety of these supplements, what they are and the source of information and help which should be sought when using them. This difference may be because students from health sciences faculties have better knowledge regarding nutrition and DS than those who are not from health sciences faculties. Similar findings have been reported in other studies [26,32]. Therefore, there is an urgent need to provide university students, especially those from a non-medical background, with education and access to scientific and unbiased information to avoid risks.

This survey has some limitations. First, it was a cross-sectional study and therefore it gave only a snapshot of participants’ KAP relating to DS at the time of the survey. Another limitation of this study is the study population, which was not equally distributed, as there were a large number of non-medical students as compared to medical ones. Finally, careful attention is required before coming to a conclusion due to achieving a smaller sample than what it was estimated which may yield imprecise outcomes.

There is a relatively high prevalence of DS consumption among students, which they use to maintain good health and ensure adequate nutrition. However, findings suggest that there are significant differences in the knowledge of health sciences and non-health sciences students pertaining to the health benefits and safety of these supplements, what they are and the source of information and help which should be sought when using them. Therefore, awareness of dietary supplement use and information should be integrated into everyday practice. There is a continuing need for DS consumers to be educated to better determine the appropriate use of dietary supplements. The UAE government and the local media should make attempts to draw attention to these issues, taking steps to boost public awareness of the potential for adverse effects and supplement-drug interactions and the importance of maintaining a healthy diet.