Vitamin D plays an important role in bone health and may have protective effects against various diseases. It exists in two main forms, D2 and D3, with D3 being the most common. Vitamin D is obtained through dietary intake, sun exposure, and supplementation. Deficiency is common due to indoor lifestyles and is associated with diseases like rickets. The document discusses challenges in testing vitamin D levels accurately due to matrix effects and differences between assays. A study at a Kuwait hospital found most patients had insufficient vitamin D levels and established a reference range. While testing can provide information, biological activity depends on adequate intake and sun exposure.
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Ebook ini merupakan sebuah tutorial untuk menguasai html dengan cepat, karena membahas semua tag-tag html yang didukung oleh html5, sekaligus akan membuat seseorang lebih mengerti dengan cepat dalam belajar web dasar
Presentation by Karen Hill on Supporting public administration reform in ENP countries at a conference co-organized by SIGMA with the Jordanian Ministry of Planning and International Cooperation and the EU at the Dead Sea, Jordan 10 May 2016.
Agenda of the workshop organised by SIGMA for the Lebanese Court of Accounts on Introducing performance auditing in Supreme Audit Institutions, held in Beirut 28-29 June 2016
Ebook ini merupakan sebuah tutorial untuk menguasai html dengan cepat, karena membahas semua tag-tag html yang didukung oleh html5, sekaligus akan membuat seseorang lebih mengerti dengan cepat dalam belajar web dasar
Presentation by Karen Hill on Supporting public administration reform in ENP countries at a conference co-organized by SIGMA with the Jordanian Ministry of Planning and International Cooperation and the EU at the Dead Sea, Jordan 10 May 2016.
Agenda of the workshop organised by SIGMA for the Lebanese Court of Accounts on Introducing performance auditing in Supreme Audit Institutions, held in Beirut 28-29 June 2016
ABSTRACTBackground Obesity is associated with vitamin D ins.docxransayo
ABSTRACT
Background: Obesity is associated with vitamin D insufficiency
and secondary hyperparathyroidism.
Objective: This study assessed whether obesity alters the cuta-
neous production of vitamin D3 (cholecalciferol) or the intestinal
absorption of vitamin D2 (ergocalciferol).
Design: Healthy, white, obese [body mass index (BMI; in kg/m2)
≥ 30] and matched lean control subjects (BMI ≤ 25) received
either whole-body ultraviolet radiation or a pharmacologic dose
of vitamin D2 orally.
Results: Obese subjects had significantly lower basal 25-
hydroxyvitamin D concentrations and higher parathyroid hor-
mone concentrations than did age-matched control subjects.
Evaluation of blood vitamin D3 concentrations 24 h after
whole-body irradiation showed that the incremental increase
in vitamin D3 was 57% lower in obese than in nonobese sub-
jects. The content of the vitamin D3 precursor 7-dehydrocho-
lesterol in the skin of obese and nonobese subjects did not dif-
fer significantly between groups nor did its conversion to
previtamin D3 after irradiation in vitro. The obese and
nonobese subjects received an oral dose of 50 000 IU (1.25
mg) vitamin D2. BMI was inversely correlated with serum
vitamin D3 concentrations after irradiation (r = �0.55,
P = 0.003) and with peak serum vitamin D2 concentrations
after vitamin D2 intake (r = �0.56, P = 0.007).
Conclusions: Obesity-associated vitamin D insufficiency is
likely due to the decreased bioavailability of vitamin D3 from
cutaneous and dietary sources because of its deposition in body
fat compartments. Am J Clin Nutr 2000;72:690–3.
KEY WORDS Vitamin D, ultraviolet radiation, tanning bed,
obesity, 25-hydroxyvitamin D, parathyroid hormone, obesity,
vitamin D3, sunlight, obesity, 25-hydroxyvitamin D3, bioavailability
INTRODUCTION
Obese individuals, as a group, have low plasma concentra-
tions of 25-hydroxyvitamin D [25(OH)D] (1–5), which are asso-
ciated with increased plasma concentrations of immunoreactive
parathyroid hormone (1, 6, 7). Although the explanation for the
increased risk of vitamin D deficiency in obesity is unknown, it
has been postulated that obese individuals may avoid exposure to
solar ultraviolet (UV) radiation, which is indispensable for the
cutaneous synthesis of vitamin D3 (3). Alternatively, it has been
proposed that production of the active vitamin D metabolite
1,25-dihydroxyvitamin D [1,25(OH)2D] is enhanced and thus, its
higher concentrations exert negative feedback control on the
hepatic synthesis of 25(OH)D (1). It has also been suggested that
the metabolic clearance of vitamin D may increase in obesity,
possibly with enhanced uptake by adipose tissue (2).
Clarification of the mechanism for the subnormal concentra-
tions of 25(OH)D in obesity is nevertheless relevant for the man-
agement of this highly prevalent condition. If, for example, the
increased risk of vitamin D deficiency were the expression of a
lack of exposure to sunlight, it would perhaps be only of acade-
mic in.
How to Optimize Vitamin D Supplementation to Prevent Cancer, Based on Cellul...Edward Hutchinson
In this non copyright prepublication version Reinhold Vieth explains why it may be better to have a high and stable vitamin d status rather than one that swings from high to low either seasonally or as a result of large supplement/UVB exposure variations in 25(OH)D levels.
How to Optimize Vitamin D Supplementation to Prevent Cancer, Based on Cellul...guestb71a04
In this non copyright prepublication version Reinhold Vieth explains why it may be better to have a high and stable vitamin d status rather than one that swings from high to low either seasonally or as a result of large supplement/UVB exposure variations in 25(OH)D levels.
Vitamin D deficiency is recognized as a global public health problem, with deficiency states reported from various countries. Acting as a Pro- Hormone; this is a unique endogenously synthesized vitamin. Besides its pivotal role in calcium homeostasis and bone mineral metabolism, the vitamin-D endocrine system is now recognized to sub-serve a wide range of fundamental biological functions in cell differentiation, inhibition of cell growth, and immunomodulation. Vitamin-D deficiency affects not only musculoskeletal health but also a wide range of acute and chronic disease. The metabolic product of vitamin-D is a potent, pleiotropic, repair and maintenance; secosteroid hormone that targets more than 200 human genes in a wide variety of tissues, meaning it has as many mechanisms of action on genes it targets. Two related sterol compounds viz. Cholecalciferol [Vitamin-D3] and Ergocalciferol [Vitamin-D2] are grouped as ‘Vitamin-D’. Cholecalciferol is of animal origin and the other Ergocalciferol [Vitamin-D2] is plant based. Interestingly, antirachitic properties of Vitamin-D2 and D3 are identical. After oral administration; Vitamin-D3 is absorbed better than D2 in small intestine; and bile is essential for absorption.
1. By
Dr salwa .E. Al-Ansari
Clinical Biochemistry department
j.a. armed forces hospital
Ministry of defense
Kuwait.
2. vitamin D
Fat soluble vitamin
Major two forms :
1. D3
- 25 (OH) D3 (liver)
- 1,25 (OH) D3 (kidney) , active form
- 1.25(OH) T1/2 < 25 (OH)
2. D2 synthesized in plants.
3. Vitamin D roles
1. Bone health
Osteoporosis
Rickets
Muscle weakness
2. Protective role (New!)
Cancers
CVD
Renal diseases
Autoimmune
DM
MS
4. Sources:
1. Diet:
- D2 Plant
- D3 Animal
2. Sun :
e.g. : In Boston, from April
to October at 12 PM EST an
individual with type III
skin, with 25.5% of the body
surface area exposed, would
need to spend 3 to 8 minutes
in the sun to synthesize 400
IU of vitamin D.
5.
6. Skin synthesis varies
Latitude
Season
Clothing
Age
Sunscreen use
Local weather conditions.
8. Frank Vt.D deficiency
Serum levels < 10 ng/ml or 25 nmol/l
Vt.D insufficiency
Serum levels 10-30 ng/ml or < 25-75 nmol/l
Previous laws
9. WHO
Below 10 ng /ml : deficiency
Below 20 ng /ml : insufficiency
Research:
Depending on the range : 30 -76 ng/ml ↑
prevalence of vt.D insufficiency
10. New Laws
2007 International workshop on vt.D :
min. range 20 ng/ml.
2010 International osteoporosis
federation :< 30 ng /ml insufficiency.
Endocrine society: vt.D deficiency < 50
nmol/l .
11. US institute of medicine normal range ≥
50 nmol/l
Reference Laboratories raised lower
boundaries. 75-250 nmol/l.
12. Certain studies ; 30 ng / ml optimum :
below↑ PTH : active Ca resorption.
Criticism:
PTH & vt. D not curve linear .
PTH variation when vt. D 20-30 ng / ml
No absolute threshold level.
13. One study (old women): risk of hip
fracture not ↑ by high dose vt.D
Switzerland study: women vt.D <20 ng/
ml not related to ↑ risk fracture (5 years
follow up).
14. No large randomized controlled trials :
vt D supplements → ↓ chronic diseases
other than osteoporosis.
Storage & re-entry into circulation is
poorly understood.
Optimum dosage of vt.D :↑100IU → ↑ 3
nmol/l
15. Observational studies:↑vt.D levels < 150
nmol/l associated with pancreatic cancer.
Vt.D supplements studies : protective
role depends on dose and stage of life to
be given .
16. Vitamin D assay
Most assays for 25(OH)D cannot
differentiate the two distinct forms, 25(OH)
D2 from 25(OH) D3, so the abbreviation
25(OH)D is used.
Types of assays:
HPLC-Chromatography
RIA
Immunoassay
17. Main Issue:
Reference laboratories ↑ demands for test
by 50 % in 2009 than 2008 ???
Problems:
- Laboratories raised lower boundaries.
- Several assay : accuracy & precision
problems.
18. -[vt. D] changes / seasons, exposure, to sun
light & dietary intake
-Vt. D molecule lipophilic in nature →↑
Matrix factors effect → ↓ validity of the
assay.
19. J . A. Armed Forces Hospital
2006-2007 : Cobas 25(OH) vit.D assay
Most samples Low results
lowest levels : 0 ng/ml
Unstable readings for patients on tablets.
Good results ~ 100 ng/ml for patients on
injections.
20. New generation of the assay : total Vt.D
Total vitamin D results from randomly
selected 243 patients attending J.A. armed
forces hospital using method LIAISON,
diaSorin.
We compared vt.D assay for samples at our
hospital (LIAISON, diaSorin:
chemiluminescent immunoassay technology)
and ROCHE, COBAS 6000 from Ministry of
Health hospital).
21. Both instruments are using chemileuscence
technology.
We studied the link between total vt. D,
serum calcium, parathyroid hormone,
glucose and hba1c
22. A 39 healthy volunteers to establish
laboratory reference range.
Patients' age 26-50 years old. Samples
withdrawn in foil covered plain tube. Results
analyzed using SPSS .
Results:
Vt.D
nmol/l
Calcium
mmol/l
PTH
pmol/l
glucose
mmol/l
Hba1c %
median 22.3 2.3 26.4 5.4 7.1
25 % I.Q.R 19.03 2.2 17.8 5 6.2
75% I.Q.R 58.1 2.4 60.8 6.5 9.1
23. Calculated volunteers reference range
(26.7- 90 nmol/l).
No relation was found between vt.D & ca
(P = 0.9), PTH (P = 0.4), Glucose (P = 0.6)
or hba1c (P = 0.2) Spearman’s correlation.
Conclusion
Measurement of total vt.D provides crude
assessment of its status but may give
inaccurate indication of its biological
activity.
25. Most people have Vt.D levels < 75 nmol/l
as consequence of sedentary and largely
indoor life style.
Notes
26. Although it may be tempting to recommend
intentional sun exposure based on our
findings, it is difficult, if not impossible to
titrate one’s exposure. There are well-known
detrimental side effects of ultraviolet
irradiation. Therefore, oral supplementation
remains the safest way for increasing vitamin
D status.
( J Am Acad Dermatol 2010;62:929.e1-e9.)
27. Low vitamin D levels
Dark Skin
Obese
Poor Dietary intake
Malabsorbtion
Poor Exposure to sunlight
Drugs… Phynetoin, steroids
28. Clues:
Cancer risk reduced by vitamin D and
sunbathing.
Multiple sclerosis linked to long winters.
Sunshine vitamin prevents early diabetes.
Heart disease epidemic in sun-starved
Britons.
29. Vt.D dose
Adults over 50 years of age who are at moderate
risk for vitamin D deficiency. Supplementation
with at least 20–25 μg (800–1000 IU) of vitamin
D3 daily is recommended. To achieve optimal
vitamin D status (> 75 nmol/L), many individuals
may require supplementation at greater than 25
μg (1000 IU) daily
30. Treatment of severe deficiency (rickets or
osteomalacia) requires higher doses, e.g.,
1250 μg (50 000 IU) daily for two to four
weeks, then weekly or biweekly, with
monitoring of serum 25-hydroxyvitamin D at
one and three months.