1 / 32

D-mystifying Vitamin D

D-mystifying Vitamin D. Lucia M. Novak, MSN, ANP-BC, BC-ADM The Diabetes Institute Walter Reed Army Medical Center, Washington, DC Adjunct Assistant Professor, Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, MD. Hormone or Vitamin?. Hormone:

colin
Download Presentation

D-mystifying Vitamin D

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. D-mystifying Vitamin D Lucia M. Novak, MSN, ANP-BC, BC-ADM The Diabetes Institute Walter Reed Army Medical Center, Washington, DC Adjunct Assistant Professor, Graduate School of Nursing, Uniformed Services University of the Health Sciences, Bethesda, MD

  2. Hormone or Vitamin? • Hormone: • from Greek “impetus” • is a chemical released by a cellin one part of an organism, that sends out messages that affect cells in other partsof the organism • Vitamin: • essential organic micronutrient that can only be obtained from an external source, food

  3. Measurement of Vitamin D • 1,25(OH)2D or calcitriol • Active form • 4 hour ½-life • Regulated by serum levels of PTH, Ca, PO4 • Levels normal or elevated in 2’hyperPTH • Does not reflect Vitamin D stores • 25(OH)D or calcidiol • Inactive form • 2-3 week ½-life • Major circulating form of Vitamin D • best indicator of status

  4. Holick MF. (2007). Vitamin d deficiency. NEJM, 357(3), 266–80.

  5. Prevalence of Vitamin D Deficiency in US: • Adults: INSUFFICIENT/DEFICIENT: • 11-50% of healthy adults • Age, season, location • Peds/Adolescents: • INSUFFICIENT: 61% • DEFICIENT: 9% • Tangpricha, V. et al. (2002). Vitamin d insufficiency among free-living healthy young adults. Am J Med., 112(8), 659-62. Kumar, et al. (2009). Prevalence and Associations of 25-Hydroxyvitamin D Deficiency in US Children: NHANES 2001-2004Pediatrics, 124(3), 362-370.

  6. Known Consequences of Vitamin D deficiency • Reduces intestinal absorption of calcium and phosphorus; increases PTH • Secondary Hyperparathyroidism: mineralization defect • Osteopenia/Osteoporosis • Low skeletal calcium • Rickets/Osteomalacia • Low phosphorus • Muscle weakness • Standing/walking/falls

  7. Associated Consequences of Vitamin D deficiency • Cancer • CV disease • Diabetes • Autoimmune disorders • Infectious Diseases • more

  8. Review available data:>1000 studies, 25 different health outcomes • IOM: • At least 14 scientists, broad range expertise • Assisted by experienced IOM staff members • Public input • Endo Soc Task Force: • Dr Michael Holick, MD • 6 additional experts • 1 methodologist • Medical writer • Member review

  9. The general conclusions are: IOM • Prevalence OVERESTIMATED • Potential harm from overtreatment ENDO SOC • Prevalence UNDERESTIMATED, everyone at risk • IOM report is a POPULATION model, not intended to direct treatment Both agree that there is NOT ENOUGH DATA to support beyond BONE HEALTH

  10. Confusing What does this mean? Over-treating?

  11. Vitamin D as a Biomarker • Biomarker of EXPOSURE • Reflection of SUPPLY • use to evaluate INTAKE • Biomarker of EFFECT • Using level as CAUSE and/or PREDICTOR for health outcomes

  12. Problems Identified • Factors Affecting Vitamin D levels: • Diet intake (food/supplements) • Dose size/frequency • Sun exposure • Time of day, season, skin pigment, latitude, sunscreen use, clothing, pollution, cloud cover, altitude • Adiposity • Ancestry, especially African

  13. More Problems Identified • PTH is inconsistent marker • Affected by renal function, exercise level, time of day, diet • No consensus of optimal level to reduce PTH or to prevent rise • The interrelation of Vitamin D & calcium • Can we truly separate/differentiate?

  14. Still more Problems Identified • Assay used • Different types of assays • Radioimmunoassay • high-performance liquid chromatography • liquid chromatography tandem mass spectroscopy • What is being measured? • Results not standardized, different parameters of “normal” • 20-100 ng/mL

  15. The Most Significant Problem Identified: • No systematic, evidenced-based process currently exists for determining 25(OH)D cut points that clearly define Vitamin D DEFICIENCY • Use of higher than appropriate cut points will artificially increase the estimated prevalence of Vitamin D deficiency and increase the risk for harm.

  16. Based on the available data …

  17. Biomarker of effect: • Scientifically proven, cause-effect relationship: • SKELETAL HEALTH

  18. Laboratory ranges for Vitamin D status (ng/mL) INSTITUTE OF MEDICINE 2010 • Sufficient: ~ 20 (97.5%) • Insufficient: 12 - < 20 • Deficient: < 12 • SEs/toxicity/pot harm: > 50 • >30 is NOT consistently associated with increased benefits • U-shaped curve ENDOCRINE SOCIETY 2011 • Sufficient: ≥ 30 • Insufficient: 20-29 • Deficient: <20 • Optimal: 40-60

  19. IOM RDA for normal, healthy people to maintain 20 ng/mL: • 0-12 months: 400 IU • 1 year -70 years: 600 IU • >70 years: 800 IU • Pregnant/breastfeeding: 600 IU

  20. ENDO SOCSUGGESTED DA to maintain >30 ng/mL: • 0-12 months: ≥400 IU • 1-18 yrs: ≥ 600 IU (1000) • ≥19 yrs: ≥ 1000 IU (1500-2000) • Pregnant/breastfeeding: ≥ 1000 IU (≥ 1500)

  21. Sun Exposure • Arms and legs for 5-30 minutes • Depends on time of day, season, pigmentation, latitude • 10 am – 3 pm • Twice a week • 20,000 IU • Tanning beds • SKIN CANCER RISK!

  22. Supplementation • D3 preferred (chemically similar, more effective) • BUT D2 is acceptable • Fat soluble, take with meal/snack containing fat

  23. Treatment for DEFICIENCYEndocrine Society, 2011 • 0-18 yrs • 2000 IU/day or 50K IU/week x 6 weeks • >18 yrs: • 6000 IU/day or 50K IU/week x 8 weeks • Obese, malabsorption, meds • 2-3x MORE • 4000-10,000 IU/day

  24. Only Screen High Risk Populations • Elderly • Reduced sun exposure • Darker Skin • Institutionalized/Homebound • Sunscreeen use • Breastfed infants • Renal & Liver Disease • GBP/malabsorption • Drugs (PTN, phenobarb, glucocorticoids, etc) • Overweight/obese ALMOST EVERYONE SHOULD BE SCREENED!

  25. Both Agree…… Research is needed • Large-scale, RCT • Health outcomes/related conditions • Adverse effects/toxicity/safety • Physiology and molecular pathways • Synthesis of evidence and research methodology • Dose-response relationships • Sun exposure • Intake assessments (assays)

  26. Until then …

  27. Counsel patients • Not to self-treat • Take per your CLEAR instructions • Limited supplies, no automatic refills • Careful with calcium intake • Monitor • Labs periodically • After 6-8 weeks therapy • Seasonal late fall/early winter

More Related