Transcript Common Misconceptions about Vitamin D by Bouchra Jandali

Common Misconceptions about Vitamin D
Bouchra Jandali, MD
Noon Conference
April 4, 2016
Outline
o Introduction
o Vitamin D deficiency guidelines
o Vitamin D and musculoskeletal health
o Vitamin D and extra-musculoskeletal diseases
o Vitamin D and pregnancy
Vitamin D has been the focus of attention in the
medical and lay literature in the past few years
In fact, it is the nutrient du jour
Rosen, C. J. & Taylor, C. L. Nat. Rev. Endocrinol. 9, 434–438 (2013)
Misconceptions about Deficiency
What is the definition of vitamin D deficiency?
The blood level of 25(OH)D that is defined as vitamin D
deficiency remains somewhat controversial
< 75 nmol/L (30 ng/ml)
Or
<50 nmol/L (20 ng/ml)
Or
<25 nmol/L (10 ng/ml)
Vitamin D Deficiency Guidelines
 Institute of Medicine (IOM):
– Vit D level < 20 ng/ml or 50 nmol/L
 European Society of Endocrinology (ESE):
– Vit D level < 20 ng/ml (deficiency)
– Vit D level < 30 ng/ml (insufficiency)
 International Osteoporosis Foundation (IOF):
– Vit D level < 30 ng/ml or 75 nmol/L
Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D , 2011
Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, et a.l. J ClinEndocrinol Metab. 2011
Dawson-Hughes B, Mithal A, Bonjour JP, Boonen S, Burckhardt P, Fuleihan GE, Josse RG, Lips P.2010 IOF position statement
Vitamin D Assays and Deficiency
Barake M, Daher RT, Salti I, Cortas NK, Al-Shaar L,Habib RH, et al. J Clin Endocrinol Metab. 2012
El-Hajj Fuleihan G, Rahme M, Bassil D. Nutritional Influences on Bone Health.2013
Should vitamin D screening be a part of
primary care?
• There is no evidence demonstrating benefits
of screening for vitamin D deficiency at a
population level
Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, et a.l. J ClinEndocrinol Metab. 2011
High Risk Group
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Dark skinned
Obese
Institutionalized/ hospitalized
Taking medications that accelerate vit D
metabolism
• Patients with osteoporosis or malabsorption
• Patient with limited sun exposure
Misconceptions about Osteoporosis
 Low serum 25-hydroxyvitamin D levels are associated
with increased risk of osteoporosis
 Serum 25-hydroxyvitamin D level does serve as a
biomarker of Rickets/osteomalacia
 Low serum vit D levels are associated with increased
risk of fractures and falls
Rosen, C. J. & Taylor, C. L. Nat. Rev. Endocrinol .2013
Low Serum Vitamin D Increases
Osteoporosis, Osteomalacia and Rickets Risk
1. The biologically active form of vitamin D can directly
stimulate osteoclastogenesis in vitro and in some
models inhibits osteoblast mineralization in vivo
2. Prevalence of impaired mineralization in osteoporosis
has not been established
3. Many cases of rickets disease have normal vitamin D
levels
4. A lot of subjects with very low vitamin D levels do not
have osteomalacia
Rosen, C. J. & Taylor, C. L. Nat. Rev. Endocrinol .2013
Priemel, M. et al. J. Bone Miner. Res. 25, 305–312 (2010)
Priemel, M. et al. J. Bone Miner. Res. 25, 305–312 (2010)
Priemel, M. et al. J. Bone Miner. Res. 25, 305–312 (2010)
Lips P, van Schoor NM Best Pract Res Clin Endocrinol Metab. 2011.
Kuchuk NO.et al. J Clin Endocrinol Metab.2009
Kuchuk NO.et al. J Clin Endocrinol Metab.2009
Vitamin D and Fractures
In the absence of calcium supplementation,
vitamin D alone does not reduce fracture risk
Rosen, C. J. & Taylor, C. L. Nat. Rev. Endocrinol .2013
Vitamin D and Risk of Falls
Should Older People Receive Vitamin D to Prevent
Falls?
The evidence is inconsistent, inconclusive as to
causality, and insufficient to serve as a basis for DRI
development
Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D , 2011
• In at least two RCTs of elderly individuals at
risk of fractures, when high doses of vitamin D
were administered intermittently the risk of
fracture and falls was actually increased rather
than reduced
Sanders, K. M. et al. J. Am. Med. Assoc. 303, 1815–1822 (2010)
Glendenning, P. et al. A randomized controlled trial. J. Bone Miner. Res
Vitamin D and Risk of Falls
Favorable
Unfavorable
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Pfeifer et al., 2000
Flicker et al., 2005
Broe et al., 2007
Pfeifer et al. (2008)
Bischoff-Ferrari et al, 2006
Prince et al, 2008
Bischoff et al, 2003
Graafmans et al, 1996
Bischoff-Ferrari HA, et al. a meta-analysis of randomised controlled trials. BMJ.2009
Bischoff-Ferrari HA, et al. a meta-analysis of randomised controlled trials. BMJ.2009
Misconceptions about Diseases
Arabi, A. et al. Nat. Rev. Endocrinol. 6, 550–561 (2010)
Misconceptions about Diseases
 For extra-skeletal outcomes, including cancer,
cardiovascular disease, diabetes, and
autoimmune disorders, the evidence was
inconsistent, inconclusive as to causality, and
insufficient to inform nutritional requirements
 Randomized clinical trial evidence for extra
skeletal outcomes was limited and generally
uninformative
Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D , 2011
Misconceptions about Supplements
Vitamin D supplementation is safe at any level
A tendency exists to believe that if some of a
nutrient is good, then more is better
The risk for deficiencies such as rickets and osteomalacia is
expected to decline with increasing intake of vitamin D
However, as intake continues to increase, the risk of excess
intake and adverse effects begins to emerge
Am. J. Clin. Nutr. 88, 578–581 (2008)
Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D , 2011
IOF Recommendations
 The estimated average vitamin D requirement for
older adults to reach a serum 25OHD level of 75
nmol/L (30 ng/ml) is 20 to 25 μg/day (800 to 1,000
IU/day)
 Intake may need to be adjusted upward to as much as
50 μg/day (2,000 IU/day) in individuals who are
obese, and in those with osteoporosis, limited sun
exposure (institutionalized, homebound), and
malabsorption, and in non-European populations
Dawson-Hughes B, Mithal A, Bonjour JP, Boonen S, Burckhardt P, Fuleihan GE, Josse RG, Lips P.2010 IOF position statement
IOF Recommendations
 Each 2.5 μg (100 IU) of added vitamin D will
increase the serum 25OHD level by about 2.5
nmol/L (range 1.75– 2.75 nmol/L) or 1.0 ng/ml
(range 0.7 to 1.1 ng/ml)
 In high-risk individuals, the serum 25OHD levels
should be retested after about 3 months of
supplementation
Dawson-Hughes B, Mithal A, Bonjour JP, Boonen S, Burckhardt P, Fuleihan GE, Josse RG, Lips P.2010 IOF position statement
Misconceptions about Pregnancy
Calcium and vitamin D requirements are not
increased during pregnancy or lactation. Nor
does vitamin D supplementation alter the
development of the fetal, infant, or maternal
skeletal health outcomes
Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D , 2011
However, the
European Society of Endocrinology
advocates
Different Recommendations

Pregnant women are at high risk for vitamin D
deficiency, which increases the risk of preeclampsia and
cesarean section

Pregnant and lactating women require at least 600 IU/d
of vitamin D and recognize that at least 1500–2000 IU/d
of vitamin D may be needed to maintain a blood level of
25(OH)D above 30 ng/ml
Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, et a.l. J ClinEndocrinol Metab. 2011

Two observational studies reported an association between
supplementation with vitamin D and a reduced incidence
of pre-eclampsia
Haugen, M. et al. Epidemiology 20, 720–726 (2009)
Hypponen, E. et al. Eur. J. Clin. Nutr. 61, 1136–1139 (2007)
 Two case–control studies, one in the USA and one in
Denmark, found no significant difference in serum 25hydroxyvitamin D concentrations between women with
pre-eclampsia and those without
Frolich, A. et al. Eur. J. Obstet. Gynecol. Reprod. Biol. 47, 25–29 (1992)
Seely, E . et al. J. Clin. Enocrinol. Metab. 74, 1436–1440 (1992)
IOM
IOF
ECE
Vitamin D deficiency
<20 ng/ml
<30 ng/ml
<20 ng/ml deficiency
<30 ng/ml insufficiency
Desirable level
50 nmol/L
75 nmol/L
(elderly)
-
Ca and vitamin D
supp
51-70 male
51-70 female
1000 mg/d- 600 IU/d
1200 mg/d- 600 IU/d
800-1000 IU/d
1500-2000 IU/d
1500-2000 IU/d
UL
4000 IU/d to reach 20 2000 IU/d
ng/ml
Vit D in pregnancy
No increased needs
Pregnant ladies < 18 y Daily supp: 600 IU/d
UL
: 4000 IU/d
Pregnant ladies > 18 y Daily supp: 600 IU/d
UL
: 4000
IU/d
-
10,000 IU/d
Increased needs
600-1000 IU/d
4000 IU/d
1500-2000 IU/d
10,000 IU/d
Serum 25 (OH) Vitamin D level is the preferred
indicator of vitamin D status
Hypovitaminosis D is prevalent worldwide
 Risk factors are: dark skinned, hospitalized/
institutionalized, obese, OP, medications
The beneficial effect of vitamin D on musculoskeletal
heath is unquestionable
The relationship between vitamin D and the risk of
common chronic disorders is a subject of continued
controversy
Primary care is in great need of cut-off points for
vitamin D status that are authoritative and evidencebased
A change in 25-OHD assays has a significant impact on
results, patient classification, and treatment
recommendations