Research Brief A Survey of University Students’ Vitamin D–Related Knowledge Shaunessey Boland, MSc; Jennifer D. Irwin, PhD; Andrew M. Johnson, PhD ABSTRACT Objective: To survey Canadian university students’ vitamin D–related knowledge. Methods: Undergraduate university students (n ¼ 1,088) were surveyed as to their vitamin D–related knowledge, including its sources, health benefits, and recommended intake. Results: Overall, students answered 29% of questions correctly on the knowledge test. In addition, the overall test was subdivided into 3 subtests, and students scored 26% on vitamin D source knowledge, 23% on factors affecting vitamin D levels, and 37% on health effects of vitamin D. Only 8% of participants correctly identified the recommended vitamin D intake; 14% correctly identified the amount of time in the sun required to produce adequate vitamin D. Conclusions and Implications: These results suggest that Canadian university students have poor knowledge concerning vitamin D. Program planners should consider improving vitamin D knowledge as a component of future health promotion programs for university students. Key Words: vitamin D, knowledge assessment, university students, health promotion program development (J Nutr Educ Behav. 2015;47:99-103.) Accepted August 23, 2014. Published online October 12, 2014.

INTRODUCTION Vitamin D deficiency is a worldwide epidemic, yet most individuals are largely unaware of the problem.1 Currently, it is estimated that over 1 million Canadians are vitamin D deficient.2 In addition to its importance for bone health,3 recent evidence suggests that vitamin D is useful in promoting musculoskeletal health3,4 and immune functioning,4-6 as well as preventing and managing cardiovascular disease,7 several types of cancer,4,8 and many other diseases.4,9,10 The Institute of Medicine11 recently increased the Recommended Dietary Allowance of vitamin D from 400 to 600 International Units (IU) for those aged 1-70 years, and approximately 25% to 67% of Canadians are not meeting the new mandate.2 Furthermore, about 13% of Canadians (aged 6-79 years) are not even getting the

400 IU of vitamin D required to maintain proper bone health.2,11 These findings are alarming because vitamin D is relatively easy to access from several food sources, as well as the sun and inexpensive supplements.4,12 Of particular concern is that young adults aged 20-39 years are at highest risk of deficiency.2 The health behaviors of young adults are of primary concern because they are forming behaviors that will contribute to the quality of their lives for many years to come.13 In fact, current evidence indicates that adequate vitamin D early in life has been shown to help prevent osteoporosis,14-16 multiple sclerosis,17 cardiovascular disease,7 rheumatoid arthritis,18 some types of cancer,19 and several other diseases later in life.4 Although knowledge is not the only factor that influences behavior, it has an effect and is therefore impor-

Faculty of Health Sciences, Western University, London, Ontario, Canada Address for correspondence: Jennifer D. Irwin, PhD, Faculty of Health Sciences, School of Health Studies, Rm 338, Arthur and Sonia Labatt Health Sciences Bldg, Western University, London, Ontario N6A 5B9, Canada; Phone: (519) 661-2111; Fax: (519) 850-2432; E-mail: [email protected] Ó2015 SOCIETY FOR NUTRITION EDUCATION AND BEHAVIOR http://dx.doi.org/10.1016/j.jneb.2014.08.013

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tant to consider when developing a health promotion program.20 As von Bothmer and Fridlund21 pointed out, it is crucial to have a thorough understanding of students’ health-related behaviors, motivation, knowledge, and attitudes before creating effective and targeted health promotion programs. Therefore, gaining a baseline understanding of university students’ current vitamin D–related knowledge may be a crucial first step in program development, and was the purpose of this study. To date, no other studies have investigated the level of vitamin D knowledge in a group of Canadians.

METHODS Procedure and Participants Potential participants in this study were sent an e-mail invitation including a link to an online survey on vitamin D–related knowledge, administered via SurveyMonkey (SurveyMonkey.com, LLC, Palo Alto, CA). The sampling frame consisted of the entire undergraduate cohort at a large urban Canadian university. The Health Sciences Research Ethics Board at Western University approved all procedures and consent documentation.

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100 Boland et al

Measures

Data Analysis

The Vitamin D Knowledge Survey (Supplementary Data) included 7 questions that evaluated vitamin D–related knowledge. The survey took approximately 5 minutes to complete and was developed specifically for the current study, based on previous studies of vitamin D–related knowledge.22-24

The researchers conducted data analysis using SPSS version 20 (SPSS, Inc, Chicago, IL, 2012). Descriptive statistics were computed for age, sex, and academic faculty in which students were registered. (In Canadian universities, a student’s major cannot be determined by the faculty of registration; as such, the term ‘‘academic faculty’’ is used in this article, correlating most directly with the term ‘‘major’’ in US colleges.) Vitamin D knowledge was similarly summarized and compared across students’ academic faculty using a 1-way independent-groups ANOVA (a ¼ .05).

Knowledge

score

calculation.

Because each question was intended to investigate different aspects of vitamin D knowledge, all 7 questions were weighted equally in the calculation. Each question was worth 1 point, producing a maximum score of 7 points. Questions that demanded only 1 response were simply marked as correct (1 point) or incorrect (0 points), but for questions that included multiple correct responses, each correct response was worth a fraction of the overall question. For example, if a question included 4 correct answers, each correct answer was worth 0.25 points. In addition, equally weighted points were deducted for incorrect answers. This penalty for guessing was implemented to prevent participants from scoring 100% on multiple response questions by selecting all possible responses to that question. For this reason, the response ‘‘I don’t know’’ was not penalized within the knowledge score. The final knowledge score was recorded as a percentage (of the total score of 7).

Survey validity. To ensure face validity, the researchers reviewed each question in the survey, and a knowledgeable individual in the field of vitamin D25 conducted an expert review to assess the appropriateness of the survey questions and response options. In addition, a pilot-test of the tool was completed with a sample of 12 undergraduate university students to ensure that the target audience understood what each question was asking, as well as what each response meant. In groups of 3, the students were asked to also discuss their ideas on how to make the survey easier to read and understand. The student feedback and the expert review feedback were used to edit the survey accordingly.

RESULTS The researchers sent e-mail invitations to 30,051 undergraduate students; approximately 4% of this sampling frame participated in the survey. Of the 1,088 students who participated, 217 were male and 777 were female. Most (74%) were white, 17% were Asian or Indian (17%), and 9% were of 5 other ethnicities. The remaining 94 students did not specify gender. Although participants were between the ages of 17 and 66 years (mean, 21.6; SD, 6.4), the vast majority were aged 17-21 years (74.9%). Of the 943 participants who identified their academic faculty, 89% were from the social sciences (n ¼ 315), health sciences (n ¼ 221), sciences (n ¼ 166), arts (n ¼ 95), and medical sciences (n ¼ 42). Approximately 99% of the sample (n ¼ 1,078) had heard of vitamin D before taking part in this survey. Most respondents (n ¼ 659) reported not taking any form of vitamin D supplement, but 155 subjects reported taking a multivitamin that contained vitamin D and 91 participants took vitamin D supplements. The primary outcome measure for this study was vitamin D knowledge, as measured by a knowledge test that was created for this study (Supplementary Data). Internal consistency reliability was calculated on the dichotomized (ie, correct vs incorrect) variables on this test, using Kuder–Richardson Formula 20. The reliability of the entire measure was thus calculated to be 0.77, which suggested

that the test demonstrated adequate reliability. Overall, scores on the knowledge test ranged from 0.49% to 88.95% (mean, 29.38%; SD, 15.54%). In addition, the overall test was subdivided into 3 subtests: vitamin D source knowledge (mean, 25.69%; SD, 20.32%), factors affecting vitamin D levels (mean, 23.42%; SD, 20.89%), and health effects of vitamin D (mean, 36.66%; SD, 22.14%). Only 8% of participants identified the recommended vitamin D intake and 14% correctly identified the amount of time in the sun required to produce adequate vitamin D. The authors assesses differences in vitamin D knowledge among the 5 faculties with the most responses (ie, social sciences, health sciences, sciences, arts, and medical sciences) using 1-way independent-groups ANOVA. There was a significant difference among the academic faculties on the knowledge score (F[4,833] ¼ 8.19; h2 ¼ 0.038; P < .001). Table lists multiple comparisons (using Tukey honestly significant difference test). Results suggested that students in the medical sciences were not statistically different from those in the health sciences, and there were no differences among students within the faculties of science, arts, and social sciences. Students in the medical sciences demonstrated significantly more vitamin D knowledge than those in the faculties of science, arts, and social sciences. Students in the health sciences demonstrated significantly more vitamin D knowledge than those in the faculties of arts and social sciences.

DISCUSSION The overall low knowledge found in the current study is particularly concerning because Kolodinsky and colleagues26 found that nutritionrelated knowledge of US college students in a 2007 survey correlated with healthy food choices; as such, low knowledge may point to a lack of purposeful vitamin D–related choices. Furthermore, although generalizations cannot be made beyond Canadian undergraduate students at a large urban university, findings from Georgiou and colleagues25 indicating that non-students/non-graduates

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Boland et al 101

Table. Interfaculty Differences (and SEs) on Knowledge Score

Medical science (mean, 37.25; SD, 16.38) P

Health Science 4.01 (2.61) .54

Health science (mean, 33.24; SD, 15.24) P

Science 7.89 (2.67) .08

Arts 9.71 (2.87) .007

Social Science 10.21 (2.54) .001

3.88 (1.59) .11

5.70 (1.90) .03

6.20 (1.36) < .001

1.82 (1.99) .89

2.32 (1.49) .52

Science (mean, 29.37; SD, 16.29) P

3.88 (1.59) .11

Arts (mean, 27.54; SD, 13.13) P

5.70 (1.90) .03

1.82 (1.99) .89

6.20 (1.36) < .001

2.32 (1.49) .52

Social science (mean, 27.04; SD, 15.73) P

0.50 (1.81) .99 0.50 (1.81) .99

Note: Data are presented with P associated with Tukey honestly significant difference post hoc test. The ANOVA associated with this test was statistically significant (F[4,833] ¼ 8.191, P < .001. are less health-focused than students/ graduates indicate that the Canadian population in general is even less aware of vitamin D than the students in the current study. It was especially concerning that so few subjects took supplements or were able to identify food sources of vitamin D accurately because the sources of vitamin D that were least identified or used are the sources on which most Canadians must rely (ie, ingested vitamin D), because the high latitude of Canada makes adequate vitamin D inaccessible via the sun for about half the year.4,27-29 In fact, contrary to the low supplementation found in this study, some researchers advocate that all adults (including those universityaged) should take vitamin D supplements, especially in the winter.4,30,31 The lack of ingested vitamin D that was found coincides with other related research: Canadians of all ages assessed (over 1 year) have high rates of inadequacy ranging from the best rates in youth (aged 14-18 years), of whom 75% have inadequate rates, to the worst rates among adults ($ 19 years) and young children (aged 4-8 years), of whom 90% and 93%, respectively, have inadequate levels. In general, Canadians receive only about 250 IU of vitamin D a day (about 42% of the recommended amount) through their diet.32 From a theoretical perspective, the Health Belief Model33,34 and Expanded Health Belief Model35 assume that people will perform a health-promoting behavior (such as vitamin intake) if they perceive a serious health threat, believe that the

health behavior will reduce the health threat, perceive minimal barriers, and believe they can effectively execute the health behavior (ie, have high self-efficacy to engage in the behavior). Accordingly, if Canadians are aware of the importance of taking vitamin D to improve their health but do not know where to get vitamin D (a barrier that reduces feelings of selfefficacy), they are less likely to seek out these sources and engage in the desired health behavior. Perhaps the noted lack of vitamin D knowledge inclusive of the health effects associated with vitamin D (in)sufficiency, as found in the current study, contributes to the high rates of vitamin D insufficiency that Canadians have demonstrated to date. Indeed, researchers investigating factors associated with the intention to use vitamin D found that knowledge and awareness of its health benefits and increased self-efficacy were tied to the intention to use vitamin D.36 Although a study by Marietta and colleagues37 was different with regard to the focus on the knowledge area studied, because nutrition labeling-related knowledge scores were related to attitudes toward labels and use of labels, it is important to consider that efforts to address the relatively poor vitamin D–related knowledge of participants in the current study may lead to changes in knowledge, attitudes, and behaviors toward healthier vitamin D intake. There are several limitations to the current study. The survey used was developed primarily for the purpose of the study and therefore has not

been used and validated beyond the context of this study. In addition, although the sample was relatively large in numbers, it was derived from only 1 urban Canadian university and therefore may not be generalizable to all Canadian student populations. Furthermore, the sample was homogeneous in terms of age and ethnicity; therefore, generalizations cannot be made. In addition, possible response bias may have influenced the results by potentially increasing the baseline knowledge of students owing to the high response rate of students in the faculties of health sciences and medical sciences. Despite these limitations, the authors found important information about vitamin D knowledge among university students.

IMPLICATIONS FOR RESEARCH AND PRACTICE As a whole, this study added to the research on vitamin D knowledge by assessing the knowledge rates of a sample of Canadian undergraduate university students, and included criteria not previously been tested, such as knowledge of daily requirements for vitamin D intake. Despite recent attention regarding increases to recommended intake of vitamin D, and vitamin D inadequacy throughout the Canadian population, poor knowledge of vitamin D and its sources, required intake, factors affecting vitamin D levels, and its associated health benefits remain high among this study’s

102 Boland et al sample of university students. Certainly, there is a strong need for health promotion programming aimed at increasing vitamin D knowledge rates and providing key information that will help inform and encourage people to adopt health-related behaviors that will decrease rates of insufficiency, particularly among at-risk groups of Canadians.2 Future programs must take into consideration the evidenced gaps in knowledge, among other important variables not considered in this study. Consequently, health promoters need to design effective campaigns targeted to specific populations as a first step to increasing awareness and, eventually, personal responsibility, adequate intake, and overall health.

SUPPLEMENTARY DATA Supplementary data related to this article can be found at http://dx.doi. org/10.1016/j.jneb.2014.08.013.

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A survey of university students' vitamin D-related knowledge.

To survey Canadian university students' vitamin D-related knowledge...
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