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Evolving Concepts And Importance In Overall Health Status

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VITAMIN D DEFICIENCY Evolving Concepts And Importance In Overall Health Status * Silent epidemic. Vitamin D deficiency is a highly prevalent condition, present in ... – PowerPoint PPT presentation

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Title: Evolving Concepts And Importance In Overall Health Status


1
VITAMIN D DEFICIENCY
  • Evolving Concepts And Importance In Overall
    Health Status

2
  • Silent epidemic.
  • Vitamin D deficiency is a highly prevalent
    condition, present in approximately 30 to 50 of
    the general population.
  • More prevalent in elderly, women of child bearing
    age and infants.
  • Often unrecognized by clinicians.

3
Case 1
  • An elderly AA obese woman was readmitted to the
    hospital from a nursing home because of
    progressive weakness. She had been discharged two
    weeks earlier following a four-month
    hospitalization for severe chronic obstructive
    pulmonary disease. During her previous hospital
    stay, she required prolonged mechanical
    ventilation through a tracheostomy tube and
    total, or central, parenteral nutrition (CPN).
    She was discharged to the nursing home on
    low-flow oxygen therapy. On readmission, she had
    a weak cough and required vigorous tracheal
    suctioning through her tracheostomy tube. PMH is
    significant for seizure disorder, HTN, CRF.
    Depressed levels of serum calcium and phosphate
    resistant to vigorous oral and intravenous
    replacement were noted on both hospital
    admissions.

4
Question
  • Can you identify risk factors for Vitamin D
    deficiency in this patient?

5
  • Elderly
  • Dark skin
  • No sun exposure
  • Diet
  • Obesity
  • CPN-provides 200 IU/d.
  • Dilantin
  • CRF

6
  • For our patient, before she was to return to the
    nursing home, her 25-hydroxyvitamin D level was 7
    ng per mL (17 nmol per L normal 8 to 38 ng per
    mL 20 to 95 nmol per L), and her PTH level was
    161 pg per mL (17 pmol per L normal 9.5 to 49.4
    pg per mL 1.0 to 5.2 pmol per L). Vitamin D and
    calcium supplementation was to begin in the
    nursing home.

7
Risk Factors
  • Individuals older than 65 years
  • Nursing home residents
  • Individuals with nonvertebral
  • or hip fractures
  • Individuals with kidney disease
  • Individuals with low bone mass
  • or osteoporosis
  • Individuals with a history of falls

8
Causes
  • Inadequate sun exposure
  • Sunscreen use SPFgt8
  • Pigmented skin
  • Aging (older than 65 years)
  • Winter season
  • Northern latitudes above 40
  • Decreased absorption
  • Bowel bypass surgery
  • Crohns disease
  • Celiac disease
  • Fat and cholesterol absorption inhibitors

9
Other Causes
  • Breastfeeding
  • Liver failure
  • Chronic renal disease
  • Medications Steroids decrease half life of
    vitamin D. Dilantin, Phenobarbital, and Rifampin
    can induce hepatic p450 enzymes to accelerate the
    catabolism of vitamin D.

10
Metabolism Of Vitamin D
11
Metabolism
  • Source Skin and diet
  • Stores 25 OH Vitamin D3 (calcidiol)
  • Active form 1,25(OH)2 Vitamin D (calcitriol)
  • MOA Steroid hormone. Binds to VDR in nucleus to
    upregulate gene expression in target cells.
  • Functions
  • Calcium absorption in the intestines and is
    required for the efficient utilization of dietary
    calcium.

12
Metabolism
  • Involved in cellular growth, differentiation and
    apoptosis
  • Simulates insulin secretion
  • Modulates the immune system.
  • Reduces inflammation
  • Muscle development
  • Telomere protective

13
Associated Clinical Conditions
  • Muscle Weakness and Falls
  • Proximal muscle weakness
  • Chronic muscle aches
  • Myopathy
  • Increase in falls
  • Recent studies suggest that vitamin D
    supplementation at doses between 700 and 800 IU/d
    in a vitamin D-deficient elderly population can
    significantly reduce the incidence of falls.

14
  • Bone Density and Fractures
  • Risk of osteoporosis may be reduced with adequate
    intake of vitamin D and calcium.
  • Studies support the concept that vitamin D at
    doses between 700 and 800 IU/d with calcium
    supplementation effectively increase hip bone
    density and reduced fracture risk, whereas lower
    vitamin D doses may have less effect.

15
  • Role in Cancer Prevention
  • Low intake of vitamin D and calcium has been
    associated with an increased risk of non-Hodgkin
    lymphomas, colon, ovarian, breast, prostate, and
    other cancers.
  • The anti-cancer activity of vitamin D is thought
    to result from its role as a nuclear
    transcription factor that regulates cell growth,
    differentiation, apoptosis and a wide range of
    cellular mechanisms central to the development of
    cancer. These effects may be mediated through
    vitamin D receptors expressed in cancer cells.
  • Vitamin D is not currently recommended for
    reducing cancer risk

16
  • Autoimmune Disease
  • Vitamin D supplementation is associated with a
    lower risk of autoimmune diseases.
  • In a Finnish birth cohort study of 10,821
    children, supplementation with vitamin D at 2000
    IU/d reduced the risk of type 1 diabetes by
    approximately 78, whereas children who were at
    risk for rickets had a 3-fold higher risk for
    type 1 diabetes.
  • In a case-control study of 7 million US military
    personnel, high circulating levels of vitamin D
    were associated with a lower risk of multiple
    sclerosis.
  • Similar associations have also been described for
    vitamin D levels and rheumatoid arthritis.

17
  • Role in Cardiovascular Diseases
  • Vitamin D deficiency activates the
    renin-angiotensin-aldosterone system and can
    predispose to hypertension and left ventricular
    hypertrophy.
  • Additionally, vitamin D deficiency causes an
    increase in parathyroid hormone, which increases
    insulin resistance secondary to down regulation
    of insulin receptors and is associated with
    diabetes, hypertension, inflammation, and
    increased cardiovascular risk.

18
  • Role in Reproductive Health
  • Vitamin D deficiency early in pregnancy is
    associated with a five-fold increased risk of
    preeclampsia.
  • Role in All Cause Mortality
  • Researchers concluded that having low levels of
    vitamin D (lt17.8 ng/mL) was independently
    associated with an increase in all-cause
    mortality in the general population.

19
Diagnostic Tests
  • Measurement of 25(OH) vitamin D serum levels best
    reflects the vitamin D status of an individual.
  • Normal levels 25 (OH) vitamin D are in the range
    of 30 to 80 ng/mL (75 to 200 nmol/L).
  • Concentrations lt 12 to 20 ng/mL (30 to 50 nmol/L)
    are considered deficient.
  • Levels gt 150 ng/mL (374 nmol/L) are considered
    toxic.

20
Dietary Reference Intakes Vitamin DEstablished
in 1997
21
Dietary Sources
  • Natural sources of vitamin D include
  • Fish liver oils, such as cod liver oil, 1 Tbs
    (15 mL) provides 1,360 IU
  • Fatty fish species, such as
  • Herring, 85 g (3 ounces) provides 1383 IU
  • Catfish, 85 g (3 oz) provides 425 IU
  • Salmon, cooked, 100 g (3.5 oz) provides 360 IU
  • Mackerel, cooked, 100 g (3.5 oz), 345 IU
  • Sardines, canned in oil, drained, 50 g (1.75 oz),
    250 IU
  • Tuna, canned in oil, 85 g (3 oz), 200 IU
  • Eel, cooked, 100 g (3.5 oz), 200 IU
  • A whole egg, provides 20 IU
  • Beef liver, cooked, 100 g (3.5 oz), provides
    15 IU

22
Fortified Sources
  • Some of the dietary sources
  • Fortified milk (100 IU/8 oz)
  • Cheeses and yogurt
  • Fortified cereals

23
Updated Recommendations In Process
  • Studies suggest that the daily vitamin D intakes
    should be much higher than 400 IU/d.
  • Daily intakes in the range of 800 to 1000 IU/d
    should be strongly considered.
  • Although there are concerns regarding vitamin D
    toxicity, side effects at intakes exceeding the
    current upper limit of 2000 IU/d have not been
    reported to date.
  • Assessment of vitamin D status with serum
    measurements of 25(OH) vitamin D levels for a
    broader range of patients should be encouraged.

24
Causes and Management of Vitamin D Deficiency
  • Lack of adequate sunlight or chronic sunscreen
    use Ultraviolet lamp or increased sun exposure.
    In a Boston study, exposure of hands, face, and
    arms to sunlight for five to 15 minutes daily
    between 11 a.m. to 2 p.m. provided adequate
    vitamin D.
  • Total (central) parenteral nutrition 400 to 800
    IU of vitamin D orally per day, or 20 to 25 IU of
    vitamin D per kg intravenously per day.

25
Causes and Management of Vitamin D Deficiency
  • Vitamin D-deficient diet Usually 1,500 to 5,000
    IU of vitamin D2 orally per day, or 50,000 IU of
    vitamin D2 orally per week or 10,000 to 50,000 IU
    of vitamin D2 intramuscularly per month
  • Fat malabsorption 25-hydroxyvitamin D, 20 to 30
    mcg per day
  • Cirrhosis, nephrotic syndrome, renal failure,
    gastric or small bowel resection, rifampin,
    chronic corticosteroids, anticonvulsants
    1,25-dihydroxyvitamin D, 0.15 to 0.5 mcg daily.

26
Key clinical recommendation
  • Daily vitamin D supplementation of 800 to 1,000
    IU is a reasonable dose for adults. Levels of
    25-OH vitamin D should be maintained gt 32 ng per
    mL (80 nmol per L) to maximize bone health.
  • The (AAP) has doubled the recommended intake of
    vitamin D to 400 IU per day for infants,
    children, and adolescents.
  • In patients with severe vitamin D deficiency,
    50,000 IU of vitamin D should be given daily for
    one to three weeks, followed by weekly doses of
    50,000 IU.

27
  • After repletion of body stores, 800 IU of vitamin
    D daily or 50,000 IU of vitamin D once or twice
    monthly is adequate maintenance therapy.
  • Patients with no sun exposure, malabsorption, or
    those taking antiepileptic drugs may require
    larger maintenance doses of vitamin D (i.e., up
    to 50,000 IU one to three times week.
  • In critically ill patients, albumin-adjusted
    calcium levels underestimate true or ionized
    hypocalcemia. Therefore, measured ionized calcium
    levels are recommended, particularly in patients
    who are being treated in an intensive care unit.
  • If calcium supplementation alone fails to
    maintain normal serum levels, the patient is
    vitamin D deficient or resistant and may benefit
    from a trial of calcitriol (Rocatrol).
  • Vitamin D toxicity is very uncommon, and there is
    a wide safety margin at these higher supplement
    doses.

28
References
  • Grant WB. An estimate of premature cancer
    mortality in the US due to inadequate doses of
    solar ultraviolet-B radiation. Cancer.2002941867
    -1875.
  • 2. Holick MF. Calcium plus vitamin D and the risk
    of colorectal cancer. N
  • Engl J Med. 20063542287-2288.
  • 3. Giovannucci E, Liu Y, Rimm EB, et al.
    Prospective study of predictors
  • of vitamin D status and cancer incidence
    and mortality in men. J Natl
  • Cancer Inst. 200698451-459.
  • 4. Garland CF, Garland FC, Gorham ED, et al. The
    role of vitamin D in
  • cancer prevention. Am J Public Health.
    200696252-261.
  • 5. Bodnar LM, Simhan HN, Powers RW, Frank MP,
    Cooperstein E, Roberts
  • JM. High prevalence of vitamin D
    insufficiency in black and white
  • pregnant women residing in the northern
    United States and their
  • neonates. J Nutr. 2007137447-452.
  • 6. Nesby-ODell S, Scanlon KS, Cogswell ME, et
    al. Hypovitaminosis D

29
  • prevalence and determinants among African
    American and white
  • women of reproductive age third National
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    1988-1994. Am J Clin Nutr. 200276187-192.
  • 7. Lips P, Chapuy MC, Dawson-Hughes B, Pols HA,
    Holick MF. An international comparison of serum
    25-hydroxyvitamin D measurements.Osteoporos Int.
    19999394-397.
  • 8. Chen TC, Shao A, Heath H III, Holick MF. An
    update on the vitamin Dcontent of fortified milk
    from the United States and Canada. N EnglJ Med.
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  • 9. Holick MF. Vitamin D deficiency. N Engl J Med.
    2007357266-281
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