vitamin d3 engl

8/11/2019 Vitamin D3 Engl

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Elecsys Vitamin D3(25-OH)More than a classical bone marker


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25-hydroxyvitamin D

Vitamin D seems to be implicated in the development of several

diseases. Insufcient levels of vitamin D are correlated with an

increased risk of developing non-skeletal pathologies, e.g. car-

diovascular diseases, cancer, autoimmune diseases, diabetes and

pregnancy risks.1,2

Worldwide it is estimated that 1 billion people have vitamin D

deciency or insufciency.2

A vitamin D serum level of at least 30 ng/mL or 75 nmol/L is

desirable.3

The importance of vitamin D

Vitamin D plays a central role in calcium andphosphorus metabolism and skeletal health


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The natural form of vitamin D is cholecalciferol, vitamin D3.

Vitamin D2(ergocalciferol) can be found in some plants and

fungi and can also be synthesized by irradiation of plant sterols.

Vitamin D3is converted in the liver to 25-hydroxyvitamin D3

and is further converted in the kidney into the active hormone

1,25-dihydroxyvitamin D3.

Until very recently, vitamin D2and D3were considered to be

interchangeable and equivalent. It has become clear that vita-

min D2is substantially less potent than vitamin D3.4,5Vitamin

D2and D3seem to be absorbed from the intestine and to be

25-hydroxylated in the liver with equal efficiency, but vitamin

D2leads to an increased metabolic degradation of endogenous

vitamin D3. Although it is certainly possible to treat patients

satisfactorily with vitamin D26it seems to have no advantage

over vitamin D3.

25-hydroxyvitamin D3is the best indicatorto assess the vitamin D status of a patient


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Synthesis of vitamin D


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Cholecalciterol D3 7-dehydrocholesterol pre-Vit.D Vit. D

temp. dependentIsomerization

Increases

Ca2+absorption (small intestine)

Urinary calcium re-absorption (kidney)

Bone mineralisation

(25-OH) Vit. D

low Ca2+, PO43- PTH

24,25 (OH)2D

1,24,25 (OH)3D

+

several other metabolites

UVB radiation

(290 - 315 nm)

Liver

Bloodvessel

Skin

Kidney

Lipoproteins Vitamin D

binding

protein with

bound vitamin D

Albumin

1,25 (OH)2Vit. D

active hormone

Synthesis of vitamin D3in human skin

The sunlight is an essential partto convert the proform of vitamin Dto its biologically active form


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Fortifies bone and muscle strengthand eliminates rickets

Low bone density is common in adults. Currently over 200 million

people worldwide suffer from low bone density and osteoporosis,

80 % of them are women.7

Vitamin D supplementation in combination with calcium can

help to decrease the incidence of low bone density, and in turn,

fractures and osteoporosis especially in the elderly.

Vitamin D also plays an essential role in muscle growth and

development8and in regulating muscle contractility.9

The predominant cause for rickets is vitamin deciency. Rickets,

a softening of the bones in children which can lead to fractures

and deformity, is among the most frequent childhood diseases in

less developed countries.10

The classical role of vitamin D


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Cytokine

regulation

Immunoglobin

synthesis

Activated T lymphocyte

Activated B lymphocyte

1-OHase

1-OHase1-OHase

Decreased

reninDecreasedparathyroid

hormone

Parathyroid hormone regulation Blood pressure regulation

VDR-RXR

VDR-RXR

VDR-RXR

TLR-2/1

24-OHase

25 (OH)D

Calcitroic Acid

1,25 (OH)2D

1,25 (OH)2D

1,25 (OH)2D

1,25 (OH)2D

Immunomodulation

Breast, colon, prostate, etc.

Parathyroid glands

Innate immunity

Macrophage/monocyte

25 (OH)D

> 30 ng/mL

Blood

Kidneys

Pancreas

Increased insulin

Increased

cathelicidin

Tuber-

culosis

tubercle

Lipopolysaccharide

or tuberculosis

tubercle

Blood sugar control

Enhances p21 and p27

Inhibits angiogenesis

Induces apoptosis

Increased VDR

Increased 1-OHase

Adapted from reference 2

Biologically active 1,25-dihydroxyvitamin Dbinds to the vitamin D receptor and targetsmore than 200 genes


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The importance of vitamin D and potentialhealth consequences of vitamin D deficiency

Increasing evidence from clinical studies linksvitamin D deficiency with a higher riskof developing several diseases

Vitamin D seems to lower cancer risks

A large population-based casecontrol study assessing the rela-

tionship of serum 25(OH)D concentrations and breast cancer

risk in post-menopausal women shows that the concentration of

serum 25(OH)D was inversely associated with the risk of post-menopausal breast cancer.11

An analysis of two studies with more than 800 cases and 800

controls showed that serum 25(OH)D level of 50 ng/mL are asso-

ciated with 50% lower incidence of breast cancer, compared to a

baseline of 40 ng/mL. The inverse relation with multiple sclerosis risk

was particularly strong for 25-hydroxyvitamin D levels measured

before the age of 20.15

In women for every 10 nmol/L increase of serum 25(OH)D level

the odds of MS was reduced by 19%, suggesting a protective

effect of higher 25(OH)D serum levels.16


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Vitamin D deficiency is a risk factor for developing

cardiovascular diseases

Vitamin D is important for blood pressure regulation. Low vitamin D

levels can cause cardiovascular diseases including hypertension17

and hardening of artery walls.18

Low levels of 25(OH)D ( < 15 ng/mL) are associated with higher

risk of myocardial infarction in a graded manner. This was shown

in a study of > 400 men originally free of diagnosed cardiovascular

disease and who developed myocardial infarction or coronary heart

disease during a 10 year follow-up.19

Low 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levelsare independently associated with all-cause and cardiovascular

mortality. Appropriate serum levels of 25-hydroxvitamin D are

associated with a decrease in mortality. This data have been

obtained in a seven year follow-up study of > 3000 patients

referred for angiography.20

Vitamin D deficiency increases the risk for type 1 diabetes

Meta-analysis of data from four case-control studies showed that

the risk of type 1 diabetes was signicantly reduced in infants

who were supplemented with vitamin D compared to those who

were not supplemented.21

In children who received vitamin D supplementation regularly

(daily dose of 2000 IU), the risk for type 1 diabetes was reduced

by about 80% compared with those receiving less.22

Vitamin D and calcium insufciency may negatively inuence

glycemia, whereas combined supplementation with both nutri-

ents may be benecial in optimizing glucose metabolism.23

10 years follow up in the prospective population based Ely-study

showed an inverse association of baseline serum vitamin D con-

centration with future glucose levels and insulin resistance in 524

non-diabetic adults.24

Vitamin D deficiency seems to increase pre-eclampsia risks

and may inhibit fetal growth A nested case-control study of pregnant women followed

from less than 16 week gestation to delivery showed a relation

between serum 25(OH)D concentrations at less than 22 week

and risk of preeclampsia.25

In a longitudinal study involving 198 children, it was found that

children born to mothers with decient levels of vitamin D (< 11

ng/mL) had signicantly lower whole-body and lumbar spine bone

mineral content at age 9 years than those whose mothers were

vitamin D replete ( > 20 ng/mL).26

Vitamin D supplementation of such mothers, especially when the

last trimester of pregnancy occurs during the winter months, could

lead to an enhanced peak bone-mineral accrual and a reduced

risk of fragility fracture in offspring during later life.


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Everybody with insufficient sun exposure 2,10

Due to lifestyle reasons and spending most of the time indoors,

many people with insufcient sun exposure are at risk for vitamin D

deciency.

The elderly 27

The natural process of aging can reduce vitamin D levels as themechanisms for vitamin D synthesis become less efcient over time.

Pregnant women28

Vitamin D plays a vital role in the regulation of cell growth,

immunity and cell metabolism. It is important for the normal

growth of the fetus. Deciencies have been prevalent even in

studies where > 90% of the women took prenatal vitamins.

Who is at risk for vitamin D deficiency?


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Standardization to the reference method LC-MS/MSand good comparability with HPLC deliversa realistic situation on vitamin D levels

Reference method LCTMS [ng/mL]

0

20

40

60

80

100

0 20 40 60 80 100

Passing/Bablok 16-18

Linear regressiony = 0.27 + 1.00xy = 0.31 + 0.90x

= 0.719r = 0.903

ElecsysVitaminD

3(

25-OH

)assay[ng/mL]

HPLC Vitamin D 25 OH [ng/mL]

0

20

40

60

80

100

0 20 40 60 80 100

Passing/Bablok 16-18

Linear regressiony = 2.69 + 1.03xy = 4.73 + 0.96x

SD (md 95) = 8.14Sy.x = 5.85

= 0.771r = 0.936

ElecsysVitaminD

3(

25-OH)[ng/mL]

Reference standardization vitamin D3(25-OH) pooled data from

4 external labs show the method comparison Elecsys Vitamin D3

(25-OH) vs reference method LC-MS/MS.

Method comparison between the Elecsys Vitamin D3(25-OH) assay

(y) and the HPLC method (x) on the MODULARANALYTICSE170

analyzer in 291 patient samples.


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0 10 403020 50 60

25-OH vitamin D [ng/mL]

70 80 90 100

40

35

30

25

20

15

10

5

0

CV[%]

Roche Competitor

Roche specification

Interassay precision

Interassay precision: Data combined from 3 studies, 3 Roche

controls, 3 human serum sample pools and one additional low

concentrated native human serum in different concentration

ranges (measured at 15 sites on the Elecsys 2010 and MODULAR

ANALYTICSE170 analyzer and four competitor systems as single

determination on 10 days).


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+

+

+

1

9 min.

Ru

AbS-lgGRu

Bi

Bi-vit.D (25-OH)

3

Detection

2

9 min.Sample [35L]

Vit D binding protein is

inactivated during the incubation

Sandwich-complex

between ruthenylated antibody and

biotinylated vit. D (25-OH) bound to a SA-microparticle

AbS-IgG-Ru = ruthenylated antibody against vit.D3(25-OH)Bi-vit.D (25-OH) = biotinylated vit.D (25-OH)SA = Streptavidin

SA-Microparticle

Bi

Ru

The Elecsys Vitamin D3(25-OH) assay principle

Inactivation of the vitamin D binding proteinis the key for correct analyte recovery


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Total assay duration 18 minutes

Assay principle Competitive principle

Sample volume 35 L

Analytical sensitivity 4 ng/ml (10 nmol/L)

Measuring range 4 100 ng/mL (10 250 nmol/L)

Traceability Candidate Reference Method LC-MS-MS

Total precision E2010: CV% 6.6 9.9E170: CV% 3.7 7.8

Sample material Serum, K3-EDTA plasma, Li-heparin

Reagent stability 8 weeks after first opening

Onboard stability 1 week on E2010, 2 weeks on E170

Dilution Manual 1:2 dilution of samples above the measuring range

Expected values 5 95% percentile: 11 43 ng/mL (27.7 107 nmol/L)

Health based reference values are recommended to replace population

based reference values

Consensus expert opinion: minimal vitamin D3(25-OH) level for bone

health: 20 - 32 ng/mL (50 - 80 nmol/L)

more recent consensus of experts: > 30 ng/mL ( > 75 nmol/L) is desirable 3

Key performance overview31


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Why does the Elecsys test specif ically measure vitamin D3

(25-OH) and not vitamin D2(25-OH)?

Vitamin D3(25-OH) is the main metabolite in human serum or plasmafor assessing the overall vitamin D status> 95 % of vitamin D (25-OH) in serum is metabolized to vitamin D3(25-OH), not as vitamin D2(25-OH)

Is a vitamin D3measurement equivalent to or better than a total

vitamin D assay?

The vitamin D3assay is not subject to interference from the non-physio-logic and less potent vitamin D2that may also be present in a specimen.Therefore, a vitamin D3assay is preferred to a total vitamin D assay.

2

How should the results of the vitamin D 3assay be used

by physicians?

The results should be interpreted in an identical manner to the interpre-tation and use of a total vitamin D assay.

Vitamin D2is not endogenously found in humans. In almost all patients,the results will be similar, except in very rare patients whose majorsource of vitamin D is supplementation by vitamin D2.

4,5

What is the therapeutic relevance of vitamin D3vs. D2? According to its molecular structure, vitamin D2has a lower half-lifethan vitamin D3, which reduces its biological activity. This is due to aformation of vitamin D2(24-OH) which has a lower affinity for thevitamin D receptor.Vitamin D2hampers the hydroxylation of vitamin D3, which leads to adepletion of vitamin D3 (25-OH).

4,5

Vitamin D3and its metabolites have a higher affinity for the vitamin Dreceptor and the vitamin D binding protein than vitamin D2.Therefore supplementation with vitamin D3is more desirable, since someyears the majority of patients are supplemented with vitamin D3.

Why is it possible that different assays may deliver different test

results?

Due to the lack of an accepted international reference preparation for

a vitamin D test every manufacturer uses different ways of traceability

and standardization.

The Elecsys Vitamin D3(25-OH) assay is standardized against liquid

chromatography tandem mass spectrometry (LC-MS/ MS) which nowa-

days is an accepted reference method in clinical chemistry. 29

Our reference method uses a specific mass transition for vitamin D3

(25-OH) in combination with two dimensional HPLC which leads to an

accurate and precise determination of vitamin D3(25-OH).

What is an optimal vitamin D status? Currently there is no standard definition of the optimal vitamin D status.

It is widely accepted that e specially in winter times but also during

summer a high number of normal, apparently healthy individuals have

suboptimal levels of vitamin D.

It should be t aken into consideration that differences in vitamin D3

levels may exist with respect to gender, age, season, geographical lati-

tude and ethnic groups, but these population based reference ranges

should not be taken as clinical cutoff to recommend or dissuade from

vitamin D supplementation. Guidance for supplementation should be

taken from recent literature.30

Health-based reference values are recommended to replace population

based reference values. There is a consensus opinion that the minimal

vitamin D3(25-OH) level for bone health is between 20-32 ng/mL (50-80

nmol/L). A more recent consensus of experts leads to the conclusion

that for general health a desirable concentration of vitamin D3(25-OH)

is > 30 ng/mL ( > 75 nmol/L).

The frequently asked questionsof vitamin D testing


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COBAS, LIFE NEEDS ANSWERS and ELECSYS

are trademarks of Roche.

2010 Roche

Roche Diagnostics Ltd.

CH-6343 Rotkreuz

Switzerland

www.roche.com

References

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Nephrol 3: 15351541.

Holick, M.F. (2007). Vitamin D deciency.2. N Engl J Med; 357: 266-81.

Vieth, R. et al. (2007). The urgent need to recommend an intake of3.

Vitamin D that is effective.Am. J. Clin. Nutr. 357: 266-281.

Trang, H.M. et al. (1998). Evidence that vitamin D3 increases serum4.

25-hydroxyvitamin D more efciently than does vitamin D2.Am J Clin

Nutr. 68: 854858.

Armas, L.A.G. et al. (2004). Vitamin D2 is much less effective than5.

vitamin D3 in humans.J Clin Endocrinol Metab 89:53875391.

Holick, M.F. et al. (2008). Vitamin D2 is as effective as vitamin D3 in6.

maintaining circulating concentrations of 25-hydroxyvitamin D.

J Clin Endocrinol Metab 93: 677681.

Khosla, S. et al. (2007). Osteopenia.7. New Engl. J. Med. 356: 2293-2300.

Endo, I. et al. (2003). Deletion of vitamin D receptor gene in mice8.

results in abnormal skeletal muscle development with deregulated

expression of myoregulatory transcription factors. Endocrinology; 144:

5138-5144.

Vasquez, G. et al. (1997). Stimulation of Ca29. + release-activated

Ca2+channels as a potential mechanism involved in non-genomic

1,25(OH)2-vitamin D3-induced CA2+entry in skeletal muscle cells.

Biochem Biophys Res Commun 239: 562565.

Matsuoka, L.Y. et al. (1987). Sunscreens suppress cutaneous vitamin10.

D3 synthesis.J Clin Endocrinol Metab;64: 1165-8.

Abbas, S. et al. (2008). Serum 25-hydroxyvitamin D and risk of post-11.

menopausal breast cancerresults of a large casecontrol study.Carcinogenesis; 29: 9399.

Garland, C.F. et al. (2007). Vitamin D and prevention of breast cancer:12.

Pooled analysis.J. Steroid. Biochem. & Mol. Biol. 103: 708711.

Lappe, J.M. et al. (2007). Vitamin D and calcium supplementation reduces13.

cancer risk: results of a randomized trial.Am J Clin Nutr 85: 15861591.

Adorini, et al. (2008). Control of autoimmune diseases by the vitamin14.

D endocrine system. Nature Clin. Practice Rheumatol. 4: 404-412.

Munger, K.L. et al. (2006). Serum 25-hydroxyvitamin D levels and Risk15.

of Multiple Sclerosis.J. Am. Med. Assoc. 296: 2832-2838.

Kragt, J. et al. (2009). Higher levels of 25-hydroxy-vitamin D are asso-16.

ciated with a lower incidence of multiple sclerosis only in women.

Mult. Scler. 15: 9-15.

Rostand, S.G. (1997). Ultraviolet light may contribute to geographic17.

and racial blood pressure differences. Hypertension 30: 150-156.

Simpson, R.U. et.al. (1988). Involvement of 1,25-dihydroxyvitamin D318.

in regulating myocardial metabolism: physiological and pathological

actions. Cell Calcium 9: 285-292.

Giovanucci, E. et al. (2008). 25-hydroxyvitamin D and risk of myocar-19.

dial infarction in men.Arch Intern Med. 168: 1174-1180.

Dobnig, H. et al. (2008). Independent association of low serum20.

25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels with all-

cause and cardiovascular mortality.Arch Intern Med. 168: 1340-1349.

Zipitis, et al. (2008). Vitamin D supplementation in early childhood and21.

risk of type 1 diabetes: a systematic review and meta-analysis.Arch.

Dis. Child 93:512-517.

Hypponen, et al. (2001). Intake of vitamin D and risk of type 1 diabetes:22.

a birth-cohort study. Lancet 358,1500-1503.

De Boer, et al. (2008). Calcium plus Vitamin D supplementation and23.

the risk of incident diabtetes in the women`s health initiative. Diabetes

Care 31: 701-707.

Forouhi, et al. (2008). Baseline serum 25-hydroxyvitamin D is predic-24.

tive of future glycemic status and insulin resistance. Diabetes 57:

2619-2625.

Bodnar, L.M. et al. (2007). Maternal vitamin D deciency increases the25.

risk of pre-eclampsia.J Clin Endocrinol Metab. 92: 3517-3522.

Javaid, M.K. et al. (2006). Maternal vitamin D status during pregnancy26.

and childhood bone mass at age 9 years: a longi-tudinal study. Lancet.

367: 36-43.Viljakainen, et al. (2006). How much Vitamin D do the elderly need?27.

J. Am. Coll. Nutr. 25: 429435.

Bodnar, L.M. et al. (2007). High prevalence of vitamin D insufciency28.

in black and white pregnant women residing in the northern United

States and their neonates.J Nutr 137: 447-452.

Vogeser, et al. (2004). Candidate reference method for the quantica-29.

tion of circulating 25-hydroxyvitamin D3 by liquid chromatography

tandem mass spectrometry. Clin. Chem. 50: 14151417.

Bischoff-Ferrari, H.A., et al. (2006). Estimation of optimal serum con-30.

centrations of 25-hydroxy vitamin D for multiple health outcomes.

Am J Clin Nutr 84:1828.

See package insert of Roche Elecsys Vitamin D3 (25-OH) assay.31.

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vitamin d3 engl

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