Role of vitamin D in the academic performance of health sciences students in Saudi Arabia Vitamin D and academic performance

Purpose – Many researchers have reported that vitamin D can affect brain development as well as brain function. The prevalence of vitamin D deficiency in the Saudi population is 81% and it is more among women than among men. Though many studies have been done to find out the factors influencing the academic performance of Health sciences students, there is not adequate evidence regarding the influence of vitamin D level on academic performance. Therefore, this study aims to find out the association if any, between the vitamin D level and academic performance of health sciences students. Design/methodology/approach – After obtaining the ethical committee approval, the data was collected from 86 female medical students, 70 female applied medical sciences students and 57 nursing students of Northern Border University. The detailed questionnaire contained the aim of the study, demographic characteristics and academic performance predictors such as self-efficacy, academic motivation, academic engagementandsocialengagement.ThevitaminDlevelsweremeasuredbyanenzyme-linkedimmunosorbentassay(ELISA)machine(BioTek)whichisavailableinthelocalhospital.ThemultiplelinearregressionanalysiswasusedtofindouttheassociationbetweenvitaminDlevelsandacademicperformance. Findings – ThisstudyshowedthatvitaminDlevelhada significantassociationwiththe overallperformance of the students as well as their self-efficacy. Research limitations/implications – Since there is a lot of stress among health sciences students due to subject overload and inadequacy of time, the health aspects are often overlooked. This study emphasizes the importance of early screening of vitamin D levels and early intervention in those with low vitamin D levels for better academic performance. Social implications – There is very little awareness of the impact of vitamin D deficiency on academic motivation, academic engagement, social engagement and self-efficacy among medical and health sciences students. This study can increase awareness. Originality/value – There are very few studies done to find out the association between Vitamin D level and academic performance. This study is unique as it has highlighted the association between vitamin D level and grade point average (GPA) and also the association between vitamin D level and academic predictors such as self-efficacy, academic motivation, academic engagement and


Introduction
Improvement in academic performance is considered to be one of the main goals of education (Al Shawwa et al., 2015). There are several studies done to find out the factors influencing the academic performance of university students. But there is a paucity of literature regarding the influence of vitamin D on the academic performance of university students (Burrows, Whatnall, Patterson, & Hutchesson, 2017). The role of vitamin D in improving cognitive function has been a subject of debate. Some studies have pointed out that higher vitamin D level is associated with increased cognitive function (Llewellyn, Langa, & Lang, 2009;Llewellyn et al., 2010;Buell et al., 2009Buell et al., , 2010Annweiler et al., 2010;Lee et al., 2009). On the other hand, another group of researchers in their prospective study found no association between vitamin D levels and cognitive function in elderly men (Slinin et al., 2010). Due to the high prevalence of vitamin D deficiency especially among female university students in Saudi Arabia (Sulaiman, Abukanna, Alenezy, & Balla, 2017;Hasanato et al., 2015), it is important to find out whether vitamin D level has any influence on the academic performance of the female students. This study was, therefore, undertaken among female health sciences students to evaluate the influence of vitamin D level on academic performance.

Materials and methods
After obtaining the approval of the ethical committee, the study was done at Northern Border University. The data was collected from January 2022 to March 2022. The subjects of our study were the female students of colleges of medicine, applied medical sciences and nursing. The students with comorbidities like diabetes, hypertension and renal diseases were excluded from the study. In total, 213 students volunteered to participate in our study of which 86 students were from medicine, 70 students from applied medical sciences and 57 students were from nursing. A detailed questionnaire which had the aim of the study mentioned was used to collect the data. The first part of the questionnaire included the details such as the college in which they were studying and year of study and grade point average (GPA). The vitamin D level was measured using an enzyme-linked immunosorbent assay (ELISA) machine (BioTek) and vitamin D 25-OH ELISA Assay Kit from Calbiotech Incorporation which is available in the local hospital. The vitamin D levels were studied in three groups students with <12, 12-20 and >20 ng/ml, as earlier studies have shown that most of the female students have low levels of vitamin D in Saudi Arabia (Al-Elq, 2012).
Other than the GPA, the academic performance part of the questionnaire had four main components which are non-cognitive predictors of academic performance, namely, Self-Efficacy (SE), Academic Motivation (AM), Academic Engagement (AE) and Social Engagement (S. Eng.) (Feldman & Kubota, 2015;Olivier, Archambault, De Clercq, & Galand, 2019;Huang, 2011). Each of these components had items (questions) that they could answer in the form of a 1 to 5 Likert scale. The average response to all the questions formed a score for each component. The average of the scores of all four components was taken as the overall performance score. So, each participant had four components scores and one overall score that summarized her performance. IBM SPSS v26 software was used for statistical analysis. The demographic variables were analyzed using frequency distribution. The main variables, namely, the academic performance predictors, were summarized as mean and standard deviation (SD). Multiple linear regression analysis was used to find out the association between vitamin D level and academic performance. A p-value < 0.05 was considered statistically significant.

Results
The participants of this study were students from 3 colleges, namely, medicine (86), applied medical sciences (70) and nursing (57) who were in their 2nd to 5th year of study at the university. Overall, 291% of these students has their vitamin D level between 12 and 20 ng/ ml, 23.9% had <12 ng/ml and 46.94% had >20 ng/ml. The descriptive statistics of the participants are shown in Table 1. Their median GPA was from 4 to 4.4. Their average SE score was 3.36. Average score of the response of each item under SE was similar except for the first item, namely, "can you manage your time well," which had a lower average score (3.04). The average of AM score was 3.48. For two items, namely, "perform better" and "taking up challenges to reach goals" the average score was high (4.11 and 3.93, respectively). The average AE score was 3.04. But the item, "reading up topics before attending class" had a lower score (2.77). The average of S. Eng. score was 3.32. But the item, "how is your relationship with fellow students" had a high score (3.77) and "It's normal thing to ask others for help" had a low average score of 3.06 (Table 2).
When the data was analyzed using multiple linear regression (Table 3), there was a significant association between vitamin D level and overall academic performance (p-value 5 0.017) and also between vitamin D level and self-efficacy (p-value 5 0.003). If the sample size was larger, small deviations from significance as in the case of AM and AE could have been cured. The medical students had a high overall academic performance when compared to the applied medical sciences students. When the GPA was analysed separately to find out its association with vitamin D level, in the 2nd-year and 3rd-year students, vitamin D levels had a significant association with GPA (p-values were 0.001 and 0.043, respectively) - Table 4.

Discussion
Several important roles including brain health, maintenance of bone health and prevention of fatigue and stress have been attributed to vitamin D by researchers (Holick, 2009;Anjum, Jaffery, Fayyaz, Samoo, & Anjum, 2018;Nowak et al., 2016;Quraishi & CamargoCA, 2012;Kusmiyati, Suryani, Heravati, & Firdausi, 2020). Studies done in the USA and UK have revealed that unhealthy dietary habits add to the health risk of university students (El Ansari et al., 2011;Lowry et al., 2000). Studies done on school children to find out the effect of dietary habits on school performance showed that there is a strong association between eating a healthy breakfast (containing milk and fruits), regularity of meals and school performance. The researchers were of the opinion that the beneficial effect they found may be partially due Vitamin D and academic performance to the skipping of fast food or any unhealthy food which they would otherwise consume during the day (Kim et al., 2016;Mahoney, Taylor, Kanarek, & Samuel, 2005;Widenhorn-Muller, Hille, Klenk, & Weiland, 2008). A systematic review to examine the beneficial effect of breakfast on the academic performance of children and adolescents concluded that most of the studies were targeted at the memory and attention of students rather than cognitive tasks like problem-solving skills (Hoyland, Dye, & Lawton, 2009). Although these studies examine the role of a healthy diet in the performance of school students and university students, there are relatively few studies specifically examining the role of vitamin D level on academic performance.
The tendency of university students is to consume fast food during break hours as they do not have adequate time to enjoy regular meals and most of them are found to have vitamin D deficiency. In a study done in UAE, the researcher highlighted the fact that 44% of female college students from different Arab countries had vitamin D deficiency (Nimri, 2018). Some researchers who studied the vitamin D levels of young women between 25 and 30 years of age in Saudi Arabia, reported that vitamin D level of <20 ng/ml was found in 30% of women (Al-Turki, Sadat-Ali, Al-Elq, Al-Mulhim, & Al-Ali, 2008). Another study done among college students in Saudi Arabia found that 67.8% of female college students had vitamin D level <20 ng/ml (Alzaheb & Al-Amer, 2017). In our study, we found that 23.9% of female health sciences students had <12 ng/ml, whereas 53% of them had <20 ng/ml.
To find out the association between vitamin D level and academic performance, we used academic performance predictors such as self-efficacy, academic motivation, academic engagement and social engagement along with GPA (Brown, Lent, & Larkin, 1989;Dogan, Mai, Yusuf, & Saleh, 2015). Self-efficacy is defined as a personal belief in one's own ability to manage things in life (Walker & Greene, 2009). Self-efficacy helps in facing challenges, forming strategies to overcome challenges and also solving problems (Bandura, 1994). Researchers have found a positive correlation between self-efficacy and academic performance (Yazici, Seyis, & Altun, 2011). In our study, we found a significant association between vitamin D level and self-efficacy. Researchers have put forward the theory that selfefficacy is a direct predictor of academic achievement (Schunk & Mullen, 2012). The significant association between vitamin D level and self-efficacy observed in our study Academic motivation and Academic engagement had some relationship with vitamin D level but there was no statistically significant association (p-value > 0.05). There are no studies found in the available literature to compare our results. However, a study done to find out the impact of vitamin D deficiency on depression among university students revealed that there is a significant relationship between low vitamin D level and prevalence of depression among university students (Tashtoush et al., 2018). Social engagement had no association with vitamin D level. The overall score of the predictors had a significant association with vitamin D level. This further strengthens the evidence that vitamin D level can influence academic performance.
The GPA had a significant association with vitamin D level only in 2nd-and 3rd-year students. As the students experience maximum stress during the initial years of study in medicine as well as allied health sciences, low vitamin D level can aggravate the stress affecting their academic performance adversely.

Conclusion
Our study highlights the importance of early screening of vitamin D level and early intervention for those with low vitamin D level along with adequate diet advice, to improve the academic performance of medical and health science students. Further studies with a larger number of students are needed to establish the role of vitamin D in academic performance.

Limitations of the study
The sample size was small as the students had to get the vitamin D test done and many students were reluctant to do it due to the fear of contracting COVID-19 infection when they visit the hospital laboratory.