Healthcare Practitioner Diagnosing and Recommending Vitamin D: a Comparative Survey of Attitudes and Practices

Research Article

J Fam Med. 2021; 8(8): 1273.

Healthcare Practitioner Diagnosing and Recommending Vitamin D: a Comparative Survey of Attitudes and Practices

Alschuler LN¹*, Chiasson AM¹, Brooks A¹, Chen MK¹ and Marshall K²

1Andrew Weil Center for Integrative Medicine, University of Arizona, Tucson, United States

2Pharmavite, LLC, West Hills, United States

*Corresponding author: Alschuler LN, Andrew Weil Center for Integrative Medicine, 655 N Alvernon Way, Ste. 120 University of Arizona, Tucson, 85711-1824, United States

Received: September 11, 2021; Accepted: October 11, 2021; Published: October 18, 2021


Background: It is estimated that over 1/3 of the world’s population and 18% of the US population is deficient in vitamin D. Currently, Healthcare Practitioners’ (HCPs) vitamin D testing and recommending beliefs and behaviors are poorly understood. This study aims to evaluate beliefs and practice regarding vitamin D among U.S. HCPs with an interest in nutrition, specifically assessing impact of Integrative Medicine (IM) fellowship training on these practice beliefs and behaviors.

Methods: An Internet-based 62-item survey was electronically provided to HCPs identified through the Andrew Weil Center for Integrative Medicine database that includes non-Fellows and Fellows of IM.

Results: Of 3,984 recipients of the survey, a total of 361 (9.1%) completed the survey. Of respondents, 221 (61.2%) completed an IM Fellowship. The vast majority of respondents (332, 93.5%) believe that vitamin D deficiency is widespread and affects the majority of the population. Three of four HCPs indicate that vitamin D status can be accurately assessed by measuring serum 25-hydroxyvitamin D (262; 74%), and that vitamin D supplementation improves overall health of patients (277; 77.4%). Most respondents, especially those with fellowship training in integrative medicine, both test and recommend vitamin D3 (cholecalciferol) for various chronic conditions and in at-risk populations.

Conclusions: There is widespread understanding of the role of vitamin D in health maintenance and in specific health conditions. Overall, primary care, physician-level training, length of time in practice, and IM fellowship training are the most significant predictors of beliefs and practices regarding vitamin D.

Keywords: Dietary supplements; Integrative medicine; Risk assessment; Surveys and questionnaires; Vitamin D; Vitamin D deficiency


IM: Integrative Medicine; FIM: Fellowship in Integrative Medicine; HCP: Healthcare Practitioner; 25OHD: 25-Hydroxy- Cholecalciferol


Vitamin D deficiency is a global health issue, designated in the US as a “nutrient of public health concern,” by the 2015 U.S. Dietary Guidelines [1]. In the US, 40% of the population has a blood concentration of 25-hydroxyvitamin D (25(OH)D) less than 30ng/mL indicating Vitamin D insufficiency [2]. Data from the 2014 NHANES report found that 18% of the U.S. population over the age of 1 year of age had 25(OH)D levels less than 20ng/mL and 5% had levels below 12 ng/mL [3]. Widespread use of sunscreens, reduced time spent outdoors, and diets with minimal consumption of vitamin-D rich foods contribute to vitamin D deficiency and insufficiency in the general population. Vitamin D deficiency is more common in individuals with dark skin pigmentation, young children (especially under age 2y), obesity, the elderly (over 70y), and institutionalized individuals [4,5,6]. Trends in vitamin D prescribing have changed significantly since the 2011 Institute of Medicine (IOM) recommendations increased the safe upper limit of vitamin D3 supplementation for people over 9y, from 2000IU (50mcg) to 4000IU (100mcg) daily [7]. This recommendation was largely based on evidence supporting the benefits of vitamin D for bone health and fracture risk reduction [8,9,10]. Vitamin D, a fat-soluble vitamin, has hormone-like pleotropic effects [11], influencing mineral homeostasis and bone metabolism [12], cell proliferation [13], immunity [14], adiposity [15], and inflammatory responses [16]. There appears to be no association between vitamin D status or supplementation and all-cause mortality [17], or cardiovascular events [18,19], Vitamin D supplementation has been associated with a 16% reduced risk of cancer death [20], While a cancer preventive effect is not yet established [21,22]. Vitamin D status may be inversely correlated with depression risk [23], although supplementation does not appear to attenuate the risk of depression [24]. Vitamin D deficiency may be associated with autoimmune disease severity [25]. Vitamin D deficiency is 35% higher in obese individuals, 24% higher in overweight individuals [26], and is implicated in poor glycemic control in people with type 2 diabetes [27] and metabolic syndrome [28]. Major medical societies have issued guidelines regarding testing and supplementation of vitamin D. In 2011, the IOM established a recommended daily allowance of 600IU (15mcg) vitamin D3, needed to sustain serum 25(OH)D above 20ng/mL (50nmol/L) and 4000IU (100mcg) per day as the safe UL for vitamin D intake [29]. This estimate has been criticized as insufficient due to various methodological errors used in the IOM analysis [30]. The American Academy of Family Physicians (AAFP) guidelines recommend against routine screening, citing variability in the sensitivity and reliability of vitamin D testing. The AAFP guidelines recommend against vitamin D supplementation in the general population noting lack of clinical trial evidence documenting that correction of vitamin D deficiency results in a reduced risk of cancer, mortaility diabetes type 2, or fractures in high-risk individuals [31]. The 2021 US Preventive Services Task Force recommendation is that there is insufficient evidence to determine the benefits and harms of screening for vitamin D deficiency in asymptomatic adults [32]. In contrast, the US Endocrine Society recommends vitamin D screening in individuals at risk and supplementation for those deficient in vitamin D (serum 25(OH)D </= 20ng/mL) and those with insufficient vitamin D (serum 25(OH)D between 21-29ng/mL) in order to achieve vitamin D sufficiency at 30ng/mL (75nmol/L). The US Endocrine Society sets the safe UL as 4000IU (100mcg) daily for children and 10,000IU (250mcg) daily for adults [33]. Underlying the divergence of these guidelines are challenges with vitamin D testing and the establishment of vitamin D cutoff values. There is established inaccuracy (10-15% coefficient of variation and bias as high as 30%) in vitamin D assays that rely upon immunoassay methodology [34]. Alternatively, LC-MS/MS testing may provide greater accuracy, but utilizes complex methodology, is also subject to error [35]. There is also concern that the serum 25(OH)D level does not necessarily correlate with tissue stores, is not the most accurate measure of vitamin D in individuals with dark skin pigmentation, nor represents levels sufficient for optimal physiology. Finally, there appears to be a U-shaped curve related to vitamin D with both lower and higher levels associated with increased risks of cardiovascular disease, vascular calcification, falls, frailty, and all-cause mortality [36,37]. Despite the presence of guidelines regarding vitamin D testing and prescribing, and likely due to confusion between guidelines, surveys suggest that vitamin D testing and recommending practices among physicians are inconsistent [38,39], There are limited surveys for vitamin D recommending practices and none exist among physicians with fellowship level training in Integrative Medicine (FIM), presumably a group highly aware of the evidence regarding vitamin D testing and supplementation.

Materials and Methods

This study set out to determine most common beliefs and testing and recommending practices regarding vitamin D and among healthcare practitioners with an interest in nutrition. The impact of integrative medicine training will be assessed by comparing respondents who have completed an IM fellowship to respondents who have expressed interest in IM fellowships, but have not enrolled in such. The predictive value of other factors, namely practitioner type, time in practice and the nature of practice on vitamin D beliefs and practices will also be assessed.


This cross-sectional study was based on results from an Internetbased 62-item survey (see Table 2) developed by study investigators and reviewed by Center faculty. The survey included 5 sections: practice beliefs, practice behaviors, testing and recommending practices for specific diseases, and frequency of recommending common vitamin D dosages. Background characteristics (credentials, years in practice, practice type, community setting, and age) were also obtained. The practice belief scale included 8 items regarding the prevalence and criteria of vitamin deficiency, accuracy of testing, impact of vitamin D on bone density, premature mortality, and risks of high vitamin D levels. The practice behaviors scale included 11 items related to general testing, indications for recommending vitamin D, monitoring vitamin D recommendations, and type of vitamin D recommendations. All items were answered with Yes, No or I Don’t Know.


The survey was electronically provided through Qualtrics to non-Fellows and Fellows of Integrative Medicine (FIM) practitioners identified through the University of Arizona Andrew Weil Center for Integrative Medicine (AWCIM) database. Participants were offered $175 towards an AWCIM online educational offering upon completion of the survey. Enrollment goals were 200 FIM alumni and 100 HCPs who had not started the IM fellowship curriculum or had not yet progressed to curriculum containing information about nutrition and dietary supplements. All responses were de identified for analysis.

Statistical analysis

Descriptive statistics are presented for all survey items. Chisquare tests were conducted to examine differences in practice characteristics between the IM-trained vs. non-IM trained groups. To investigate the associations between IM-training and practice belief/behaviors, multinomial logistic regression models were used to predict practice beliefs and behaviors items. The response category ‘yes’ was used as the reference category for each question and the response categories “no” and “don’t know” were analyzed against the reference. The relevant predictors included in the models were MD credential, 15 years in medical practice, primary care, solo practice, and academic as the covariates to be controlled for, in addition to the main predictor of interest-IM trained vs. non-IM trained groups. Age was not included as it was strongly correlated with years in practice. Analyses were conducted using IBM®SPSS® Statistics Desktop V26.0 (Armonk, New York).



Out of 3,984, a total of 361 (9.1%) completed the survey. Survey participant characteristics are presented in Table 1. Practice Characteristics by IM trained vs. non-IM trained. Statistically significant differences indicated FIM trained respondents were more likely to have MD/DO credentials (86% vs. 72%), be in practice over 15 years (62% vs. 44%), be a solo practitioner (28% vs. 13%), be over 50 years old (52% vs. 31%), and less likely to practice in academic settings (19% vs. 26%). There was a trend (p=0.054) for FIM respondents to be in primary care practice (65% vs. 55%).