NEW ORLEANS — Inconsistent professional guidelines and variation in individual prescribing habits are barriers to achieving safe and consistent vitamin D dosing recommendations, according to a speaker here. 

“Low vitamin D levels are associated with many chronic illnesses, so by increasing vitamin D levels we may be able to improve the overall health of our communities and the population in general,” said Kathleen McLeod, DNP, MAOM, FNP-BC. 

In an effort to develop an evidence-based guideline for vitamin D supplementation in her practice, McLeod performed an evidence summary and determined that vitamin D 4,000 IU daily is superior to 2,000 IU and is safe and effective to increase and maintain 25OH D levels to 30 mg/mL. 

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McLeod and colleague Katherine Kenny, NDP, RN, ANP-BC, FAANP, then developed an educational intervention adapting principles from the Theory of Planned Behavior (TPB), which focuses on three domains: attitude, subjective norms, and perceived behavioral controls. 

The attitude domain assessed how clinicians felt about vitamin D supplementation. The subjective norm domain measured what providers felt patients and colleagues thought about following the guidelines. The perceived behavior control domain assessed the amount of control providers felt they had over affecting change with vitamin D supplementation.

Surveys were conducted both before and after the intervention to assess providers’ intent to change practice. “When we did a statical analysis of all the data points, it showed that the attitude actually seemed to be the most likely to change after the intervention,” McLeod said during a poster session at the American Association of Nurse Practitioners 2015 meeting

Post-intervention, the researchers observed a significant increase in intent to change behavior (t=-3.068).

“Use of the theoretical framework of TPB suggests positive trending toward provider acceptance of guidelines, which may reduce ambiguity of dosing schemes, and potential patient safety issues may be averted,” McLeod said. 


  1. McLeod K, Kenny K. Poster Session. “Development of an Evidence-Based Practice Guideline for Vitamin D Dosing in Adult Primary Care.” Presented at: AANP 2015. June 10-14; New Orleans.