OSTEOPOROSE LUXEMBOURG

Ostéoporose, maladie de la masse osseuse

La masse osseuse est continuellement renouvelée, d’un côté détruite par les ostéoclastes et de l’autre reconstituée par les ostéoblastes. Cet équilibre peut se rompre avec formation de pores dans le squelette, dont le nom d’ostéoporose. La perte du capital osseux est responsable de fractures et déformations. Les causes sont génétiques, hormonales, nutritionnelles et environnementales.

Ménopause, hyperthyroïdisme, carences de calcium, protéines et vitamine D sont parmi les plus importants facteurs de risque.

samedi, 23 juin 2018

Ressources

20-21 octobre: journée mondiale de l'ostéoporose
Dépistage gratuit au CHL

Well Aging au Luxembourg

Médecins spécialistes au Luxembourg

Densité et solidité osseuse

La formation de pores cause une diminution de la densité osseuse

Ostéoporose - os poreux

La Vitamine D

La vitamine D peut être produite à partir de certains aliments (poissons, foie, huiles, œufs, lait, ..), mais la plus grand part est générée par la peau quand elle est exposée aux rayons ultraviolets. Au Luxembourg il faudrait exposer bras et jambes pendant au moins 15 minutes 4 fois par semaines en été ; et donc beaucoup plus en hiver.

Insolation au Luxembourg (heures/mois)

♦ Insolation théorique ♦ Insolation moyenne

Hormis les faibles opportunités d’être exposé aux rayons ultraviolets dans certains pays comme le Luxembourg, les radiations peuvent causer des effets secondaires très mauvais comme des cancers de la peau. Pour cela les médecins traitants ont la possibilité de prescrire des supplémentations en calcium et vitamine D.
suppléments calcium

Ostéoporose - Causes et remèdes

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Osteoporosis General Epidemiology
Table of content
1. Skeletal system - bone turnover
2. OP: epidemiology and risk factors
3. Definition of OP - diagnosis - BMD
4. Consequences of OP -fractures
Structural Organization
Material Constituents:
1. Calcium carbonate
2. calcium phosphate
3. collagen
4. water
Bone Turnover
1. Bone is renewed by continuous remodeling or turnover
2. Bone is resorbed by osteoclasts
3. Resorption releases calcium and collagen metabolites
4. Bone is formed by osteoblasts
5. Resorption and formation are normally in balance (coupled)
6. Uncoupling of bone turnover leads to bone loss
Osteoblasts
Formation of new bone
Osteoclasts
Resorption of existing bone
Bone Remodeling–Normal
Bone Remodeling–Osteoporotic
Bone Balance
Table of content
1. Skeletal system - bone turnover
2. OP: epidemiology and risk factors
3. Definition of OP - diagnosis - BMD
4. Consequences of OP -fractures
Osteoporosis and epidemiology
1. Osteoporosis
2. Osteoporosis is a skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and an increase in fracture risk.
3. Epidemiology
  1. affects over 26 millions individuals in US
  2. more than 1.5 millions fractures caused by osteoporosis occurred annually.
  3. by the age of 65, 1/3 of women will suffer a vertebral fracture
  4. by the age of 80, 1/3 of women will experience a hip fracture
  5. population of elderly increasing, hip fracture will increase
  6. annual cost of osteoporotic hip fracture is about 10 billion
Age distribution in the U.S
Future age distribution in the U.S
Diseases of the elderly
Annual Costs of Various Chronic Diseases
Risk factors for osteoporosis
1. Age
2. Previous fracture
3. Family history: woman with relatives esp.mother who have history of osteoporosis or fracture
4. Race: Asian and Caucasian
5. Body weight: reversely related to risk of osteoporosis
6. Estrogen level: estrogen deficiency, menopause, surgical oophorectomy, irregular menstruation
7. Calcium and vit. D deficiencies are associated with osteoporosis
8. Concurrent diseases and medications (RA, corticoid therapy,…)
9. Immobility state
Table of content
1. Skeletal system - bone turnover
2. OP: epidemiology and risk factors
3. Definition of OP - diagnosis - BMD
4. Consequences of OP -fractures
Osteoporosis: Diagnosis and Evaluation
1. Central DXA (Dual Energy X-ray Absorptiometry) remains the state-of-the-art diagnostic standard
2. Bone density is the most important predictor offracture risk
Interpretation of BMD tests
1. Bmd expected either in absolute units ( gm/cm2) or in SD units compared to age- matched or young normal controls
  1. Z- Score: the number of SD above ( a + number ) or below ( a – number ) the average value in an individual of the same age and gender
  2. T- Score: the number of SD above or below the average value in young adults of the same gender
Interpretation of BMD tests
Peak Bone Mass vs. Rate of Bone Loss
Relevance of BMD Changesto Fracture Risk Reduction
Weaknesses
1. Impact of changes in BMD on fracture risk is not bidirectional
2. Lack of uniformity exists among current BMD testing standards
3. Many factors other than BMD also have an impact on fracture risk
Table of content
1. Skeletal system - bone turnover
2. OP: epidemiology and risk factors
3. Definition of OP - diagnosis - BMD
4. Consequences of OP -fractures
Osteoporosis and Its Consequences
1. Systemic skeletal disorder characterized by:
  1. low bone mass
  2. microarchitectural deterioration of bone tissue
  3. increased bone fragility and susceptibility to fracture
2. Risk of fracture increases with age
3. Postmenopausal osteoporosis (PMO) results primarily from decline in estrogen levels after menopause
Common osteoporotic fracture sites
Prevalent Vertebral Fracture PredictsRisk of Future Hip Fracture
Recognition of Osteoporosis:Very Few Diagnosed and Treated
Osteoporosis is preventable for most people!
1. Start building healthy bones while young
2. Healthy diet and lifestyle are important for BOTH men & women

La vitamine D, hormone protectrice ?

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La Vitamine D, hormone protectrice ?
Vitamin D Production and Metabolism
The Making of an Active Vitamin
Calcitriol
Vitamin D Production Is Disrupted by Various Factors
Vitamin D Winter
A High Prevalence of Vitamin D Inadequacy* Was Seen Across All Geographic Regions
Insolation à Luxembourg (heures/mois)
25 0H Vit D et PTH au cours de l’année à Luxembourg
25-OH vitamine D2-D3
1. Limites de la technique : 4 à 150 ng/mL
2. Valeurs usuelles : 30 – 100 ng/mL
3. Insuffisance : 10 – 30 ng/mL
4. Déficience : <10 ng/mL
5. Du 09/10/08 – au 09/01/09
6. Total dosages 2993
7. Age moyen 54 ans
8. Hommes 26.5%
9. Femmes 73.5%
10. < 10 ng/mL 586 19.6%
11. 10 – 30 ng/mL 1867 62.4%
12. 30 – 100 ng/mL 537 17.9%
13. > 100 ng/mL 3 0.1%
14. Moyenne 20.3 ng/mL
15. Médiane 18.4 ng/mL
16. Centile 5% 5 ng/mL
17. Centile 95% 41 ng/mL
18. Automate Liaison ® - DiaSorin ®
25-OH vitamine D3
1. Limites de la technique : 4 à 100 ng/mL
2. Valeurs usuelles : 30 – 80 ng/mL
3. Insuffisance : 10 – 30 ng/mL
4. Déficience : <10 ng/mL
5. Du 17/10/07 – au 09/10/08
6. Total dosages 6876
7. Age moyen 56 ans
8. Hommes 24.5%
9. Femmes 75.5%
10. < 10 ng/mL 620 9.0%
11. 10 – 30 ng/mL 5237 76.2%
12. 30 – 80 ng/mL 1015 14.8%
13. > 80 ng/mL 4 0.1%
14. Moyenne 21.0 ng/mL
15. Médiane 20.0 ng/mL
16. Centile 5% 8.0 ng/mL
17. Centile 95% 36.5 ng/mL
18. Automate Modular ® - Roche ®
Distribution réelle de la 25OH-Vitamine D
Distribution souhaitable de la 25OH-Vit D
Reasons for High Prevalence of Vitamin D Inadequacy in Postmenopausal Women
1. Lack of sunlight exposure, including the use of sunscreen
2. Vitamin D is not readily available in the diet
3. Ability to synthesize vitamin D in the skin decreases with age
4. Lack of compliance with taking daily supplements
La vitamine D le calcitriol agit
1. au niveau nucléaire
2. par l’intermédiaire de récepteurs VDR (de la famille des récepteurs des hormones stér. et thyr.)
3. sur l’expression de multiples gènes
  (activation ou répression)
4. C’est un régulateur de la transcription
  = action génomique (à côté d’autres actions non génomiques)
Polymorphisme du gène VDR:
dépistage de populations à risque
1. pour l’ostéoporose?
2. pour les fractures?
Le récepteur nucléaire pour le calcitriol = VDR (vitamin D receptor)
son gène présente des polymorphismes
qui font l’objet de recherches intenses
1. Cdx-2
2. Fok1
3. Bsm1
4. Apa1
5. Taq1…
La vitamine D,
sa forme active = le calcitriol = le 1,25 (OH)2 cholécalciférol
est une hormone 1, 25-Dihydroxy-Cholécalciférol
La vitamine D agit:
1. sur le métabolisme phosphocalcique
  (intestin, tube rénal proximal et distal, ostéoblastes, ostéoclastes
  parathyroïdes, cellules C de la thyroïde…)
2. sur d’autres glandes endocrines
  (hypophyse, surrénales, ovaires, testicules, pancréas…)
3. sur le système immunitaire
  (monocytes, macrophages, lymphocytes T et B, thymocytes…)
4. et sur de multiples autres tissus
  (muscle strié, coeur, utérus, placenta, sein, prostate, épiderme, fibroblastes
  follicules pileux, mélanocytes, parotide, foie, intestin, vessie, cerveau…)
5. sur la prolif. et la différ. cellulaires
  (psoriasis, lignées tumorales…)
A Higher Dose of Vitamin D Reduces the Risk of Falls in Nursing Home Residents: A Randomized, Multiple-Dose Study
1. Posted 03/28/2007
2. Kerry E. Broe, MPH; Tai C. Chen, PhD; Janice Weinberg, ScD; Heike A. Bischoff-Ferrari, MD, MPH; Michael F. Holick, MD, PhD; Douglas P. Kiel, MD, MPHAuthor Information
Vitamin D Reduced the Risk of Falling
Recommendations for Vitamin D Intake
High Doses of Vitamin D Shown to Be Well Tolerated
1. Studies of up to 5 months’ duration suggest that there were no significant adverse effects in healthy men with the use of vitamin D in doses ≤10,000 IU/d
2. Vitamin D toxicity and hypercalcemia have been shown to be accompanied by 25(OH)D level >88 ng/mL (200 nmol/L)
3. Daily vitamin D intake >40,000 IU required to achieve this level
4. Minimal side effects were observed in 48 of 50 adults with vitamin D deficiency given a single intramuscular dose of 600,000 IU annually
Clinical trials
In clinical trials, the absence of vitamin D toxicity among generally healthy adults using vitamin D at a dose of 250 µg/day (10,000 IU vitamin D3) or higher supports the selection of this dose as the tolerable upper intake level.
Low Patient Compliance With Vitamin D Supplements
1. Fewer than 1 in 5 women with osteoporosis takes vitamin D supplementationa
2. 33% of patients are taking supplements containing vitamin D onlyb
3. According to a survey conducted in Austria, the United Kingdom, and Mexico (n=151), calcium and vitamin D supplementation were taken by
  1. 73% of patients in Austria
  2. 15% of patients in the United Kingdom
  3. 12% of patients in Mexico
4. In Austria, where calcium and vitamin D supplementation are free to patients
  1. 20% of patients take supplementation regularly
National Osteoporosis Foundation: Updated Recommendations
Recommended Intake for Adults ≥50 Years

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