A brief compilation of the causes of this vitamin deficiency, how to treat, and current USPSTF recommendations regarding screening.

1. Vitamin D Deficiency
Camille Renee
June 6 2018
Saint James School of Medicine
Clinical Sciences: Family Medicine
Preceptor: Dr. MS

2. Vitamin D
• D2 = ergocalciferol—ingested from plants
• D3 = cholecalciferol—consumed in milk, formed in sun-exposed
skin (stratum basale)
• 25-OH D3 = storage form
• 1,25-(OH)2 D3 (calcitriol) = active form
• ↑ GI absorption & ↓ renal excretion of Ca, ↓ PTH production, &
contributes to normal bone growth/mineralization
Le, Tao. First Aid: USMLE Step 1 2017 McGraw-Hill Education 2017

3. Metabolism
https://www.inlifehealthcare.com/wp-content/uploads/2014/03/vitd.jpg

4. Deficiency
• Serum 25-OH Vit D < 20 ng/mL (insufficiency is 20-29 ng/mL)
• Vitamin D deficiency can occur with ↓ intake (↓ dietary intake, GI
absorption, or UV exposure), impaired hepatic conversion to 25-
OH Vit D (rare), impaired renal conversion to 1,25-OH Vit D
(common, seen in CKD)
Kiefer, M. & Chong, C. Pocket Primary Care. Wolters Kluwer 2014

5. Complications
• 2° hyperparathyroidism
• Inadequate bone mineralization (>
osteomalacia or rickets)
• ↑ fracture risk & ↑ falls in elderly
• has also been assoc w/ myriad
extraskeletal disease, including DM,
cancer, & MS, although these are
controversial & RCTs demonstrating
extraskeletal benefits of
supplementation are lacking
Kiefer, M. & Chong, C. Pocket Primary Care. Wolters Kluwer 2014
Le, Tao. First Aid: USMLE Step 1 2017 McGraw-Hill Education 2017

6. Groups at Increased Risk
• Elderly (↓ skin production)
• Inhabitants of Northern climates
• Obese (Vit D sequestered in adipose tissue)
• Homebound/institutionalized/inadequate sun exposure
• Postmenopausal women
• GI disease (↓ absorption: IBD, celiac, biliary disease)
• Medications (e.g., phenytoin, glucocorticoids, rifampin, cholestyramine,
ketoconazole, 5-FU/leucovorin)
• Genetic (1α-hydroxylase or VDR mutations)
Kiefer, M. & Chong, C. Pocket Primary Care. Wolters Kluwer 2014
Sabatine, M. Pocket Medicine. Wolters Kluwer Lippincott 2011

7. Evaluation
• Screening: Some debate about merits of screening asx individuals;
however, many (including AACE) suggest clinically screening all pts
to find those at ↑ risk, & then to test Vit D in this population
• Labs: Obtaining 25-OH Vit D generally sufficient; in pts w/ ESRD,
would also obtain PTH & 1,25-OH Vit D (due to ↓ renal conversion,
they may have insufficiency despite adequate 25-OH Vit D)
Kiefer, M. & Chong, C. Pocket Primary Care. Wolters Kluwer 2014

8. USPSTF Recommendations
Toy et. al. Case Files: Family Medicine. McGraw Hill Education 2016
USPSTF still holds by its recommendation
for daily vitamin D intake in women
above the age of 65 who are at increased
risk of falls (Level B recommendation).
Calcium carbonate (500 mg three times
daily) and vitamin D (800-1000 IU daily)
reduce the risk of osteoporotic fractures
in both men and women.
www.uspreventiveservicestaskforce.org

9. USPSTF Grades
www.uspreventiveservicestaskforce.org

10. Treatment
• Vitamin D deficiency: Loading dose of ergocalciferol (vit D2) 50,000 IU weekly for 4-8
wks then maintenance dosing of 50,000 IU monthly or cholecalciferol (vit D3) 1000 to
2000 IU daily; may require longer course for repletion in obese patients or extreme
deficiency. The treatment goal serum level of 25-OH vit D is greater than 30 ng/ mL
• Vitamin D insufficiency: 800–2000 IU QD will replete levels in an avg adult by 3 months
• Prevention: The IOM recommends 600 IU of Vit D & 1000 mg Ca daily intake for all
adults, and 800 IU of Vit D & 1200 mg Ca for adults >70 y; upper level of Vit D intake
(above which ↑ risk of harm) set at >4000 IU daily for all adults
• Calcitriol: Use primarily restricted to CKD pts w/ hypocalcemia or parathyroid disease
Kiefer, M. & Chong, C. Pocket Primary Care. Wolters Kluwer 2014
Toy et. al. Case Files: Family Medicine. McGraw Hill Education 2016

11. http://oyle.kalakaari.co/thank-you-sun/