1. OSTEOPOROSIS 06/25/12 José L. González, PGY3

2. Definition  Reduction in bone strength  increase risk of fx  T-score: < -2.5 SDs  T-score: 30 yo, matched for sex and race  Osteopenia: <-1 to 2.5 SDs

3. Epidemiology  >10 million  8 million women & 2 million men  Most fractures occur in women w/ osteopenia  Rate of colles fx increases initially, later hip  May be due to the way we fall  Vertebral > Hip > Colles

4. Risk Factors  Age, female sex, cigarette smoking, prior fxs, low body weight, excess etoh  Meds: glucocorticoids, cyclosporine, heparin, levothyroxine, anticonvulsants  Diseases  Vision  Dementia  Chronic inflammatory diseases RA Crohns

5. Bone Remodeling  Bone mass is 50-80% heritable  Peak skeletal mass  early adulthood. Constant mass 30-45 yoa, then increased resorption  Estrogens, androgens, vitamin D, PTH  2 functions  Repair microdamage of the skeleton  Maintain [Ca2+] serum

6. Risk Factors: Parathyroid Hormone  Kidneys  1. ↑ hydroxylation  1,25OH vit D  2. decreased Ca2+ loss  Small Intestine  ↑Ca2+ absorbtion  Bone  Release of Ca2+

7. Risk Factors: vitamin D / Calcium  Calcium: RDI 1000 – 1200  Vitamin D: RDI 800-1000 units daily  RFs for low vit D: High latitude Low intake Chronic liver or renal disease  Estrogen  Physical Activity  ↓risk in rural communities

8. Diagnosis  US, CT scan, single energy absorptiometry, DXA  DXA  Lumbar and hip m.c. used  Z-score: age matched  T-score: 30 yo, race and sex matched

9. Who to test:  All women > 65 yoa  Estrogen deficient women @ risk  Vertebral abnormality of x-ray suggestive  Primary hyper parathyroidism  Steroids > 7.5mg x 3 months  Monitoring response to meds  Repeat @ 2 year intervals

10. Who to treat:  T-score < -2.5 SDs  Post-menopausal women w/ RFs  RFs: age, prior fx, family hx, low weight, smoking, RA, etoh  FRAX calculator

11. Treatment: SERMs, PTH, Calcitonin  Raloxifene:  tx & pv of ER+ breast ca  Tx & pv of osteoporosis  PTH: in small amounts  Calcitonin: (intranasal)  Hormone produced by thyroid  decreases osteoclast activity  Decreases vert. fxs only

12. Treatment: Estrogens  Estrogens (in the form of combined OCPs)  Decrease fracture risk by 50%  Increase risk of MI by 29%  Increase stroke risk by 40%  dementia 2x  Increase risk of breast ca by 26%  Decrease risk of colon ca by 37%  Increase risk of VTE by 100%  10,000 patients:  prevents (5 hip, 6 colles & 44 clinical fxs)  leads to (8 breast cas, 8 MIs, 18 VTEs)

13. Treatment: Bisphosphonates  Alendronate:  5mg x 2 yrs, 10mg x 9 months  90% ↓vert. fx, 50% ↓hip fx  70mg PO dose once weekly  Risedronate:  use in steroid-induced OP  Ibandronate  Zolendronic Acid:  70mg IV q yearly  for hyperCa2+

14. Bisphosphonates: Side Effects  Osteonecrosis of the jaw  hypocalcemia  GI side effects  Esophagitis, ulceration  Contraindicated in strictured esophagus  Drink w/ full glass H20 and remain upright x 30min

15. Sources:  Harrison’s Principles of Internal Medicine. 18th ed. New York, NY: McGraw-Hill; 2005:946.