Cohort Studies EVOS/EPOSHiroshimaCaMos RochesterSheffieldRotterdam KuopioGothenburg IGothenburg II EpidosDubboOFELY N=59,232 Person Years = 249,898 % Female = 74 Any fracture = 5444 Osteoporotic Fractures = 3495 Hip Fractures = 957
Independent Risk Factors To be Used at the WHO Model Age BMD BMI Prior fracture Ever corticosteroid use Family history of fracture Current smoker >2U alcohol/day There is a growing consensus that intervention thresholds should be based on absolute risk (probability) of fracture rather than diagnostic thresholds
Identification of Osteopenic Women at High Risk of Fracture: The OFELY Study Prospective cohort study: 671 median follow-up 9.1 years: BMD, Fracture confirmation postmenopausal women age >62 158 incident fractures in 116 women: 8% in normal, 48% in osteopenic, and 44% in osteoporotic women. Sornay-Rendu et al JBMR Oct 2005
Survival probability without fracture in postmenopausal women according to the WHO criteria of BMD
Identification of Osteopenic Women at High Risk of Fracture: The OFELY Study In postmenopausal women with osteopenia: age low BMD( -2) – (-2.5) HR 2.5 (1.3-4.6). increased bone turnover markers BALP HR 2.2 for 1/4 prior fracture HR (age adjusted) 2.2 (1.2- 4.3) risk of fracture in the subsequent 10 years for one factor present (26% vs 2%). Sornay-Rendu et al JBMR Oct 2005
BMD and Previous Fractures in Hip Fracture Patients 28 (29.5%) Non-osteoporotic BMD at all measurements sites, no previous fractures Osteoporotic BMD at least at one measurement site or previous fracture –Patients 113 –Women 87(78%) –Men 26 (22%) E.Segal et al
Better Lighting to Reduce Falls and Fracture? A Comment on de Boer et al. (2004): Different Aspects of Visual Impairment as Risk Factors for Falls and Fractures in Older Men and Women Investments in the daily living conditions and improving the visibility of the elderly visual environment will presumably reduce their risk of falling and fractures, in turn resulting in savings on medical and care expenses. Aart C Kooijman and Frans W Cornelissen JBMR November 2005, Volume 20, Number 11
Absolute vs. Relative Risk Absolute Risk Absolute Risk Incidence or prevalence rate For example 100 smokers are followed for 1 year. If 6 of them fracture the absolute fracture risk is 6/100 = 6% Relative Risk Relative Risk Ratio of absolute risks for 2 groups For example, if absolute risk of fracture is 6% in smokers and 2% in non smokers the relative risk of fracturing is 6/2 = 3
S Ish-Shalom It Often Takes Time to Reach the Diagnosis
S Ish-Shalom Effects of Treatments on Lumbar-spine Bone Mineral Density Placebo Antiresorptive drug Bone Formation drug -101234 Year 0.9 1.0 1.1 1.2 Lumbar-Spine Bone Mineral Density (g/cm 2 ) Fluoride GH IGF1 Srontium PTH 1-84 PTHrP PTH 1-34
Strontium ranelate Sr++ SN CN Sr ++ CH 2 H 2 C CO - O - O OC - O - O H 2 C Protelos - Les laboratoires Servier Ranelic acid Similar to calcium: absorbed in the gut; incorporated in bone; elimination through the kidneys. 100 g/gr bone
Strontium - Bone Retention In the short term the strontium atoms are adsorbed on to the surface of hydroxyapatite crystals In the longer term some strontium will exchange with calcium in the bone mineral and may remain bound in the skeleton for years The exchange is limited with maximum replacement by strontium, when given in high doses, of one in every ten calcium atoms.
Strontium – Bone Retention ICRP model predicts that at 3 months, 1 year, and 3 years after a single oral dose of strontium, the skeleton retains 20%, 15%, and 11%, respectively, of the strontium absorbed by the gut Three-year treatment with strontium ranelate at 2 g/day total strontium intake of 750 g. 25% absorption by the gut Using the ICRP model to calculate the average long-term retention after a 3-year treatment, there is 30 g of strontium in the skeleton. Expressed as a molar fraction of the total calcium content in bone =1% (i.e., after 3 years of treatment with strontium ranelate, there is 1 strontium atom for every 100 calcium atoms in bone tissue).
In Vitro Studies Marie et al. Calc Tiss Int 2001; 121-129 bone formation, at least in certain pre-osteoblastic cell systems the bone resorption activity of osteoclasts. osteoclast apoptosis at higher concentrations
Effects of Strontium Ranelate on BMD Serum Biochemical Markers of Bone Metabolism Serum Biochemical Markers of Bone Metabolism. Spinal Osteoporosis Therapeutic Intervention (SOTI ) Meunier et al NEJM 2004
Clinical Efficacy Vertebral Fracture Results: Spinal Osteoporosis Therapeutic Intervention (SOTI Meunier et al NEJM 2004
Mean % Changes in Spine BMD From Baseline to 3 Years in Patients Receiving Active Treatment in Four Clinical Trials Blake and Fogelman JBMR Nov 2005 atomic number of strontium (Z = 38) vs. calcium (Z = 20).
hPTH1-34 (crystal structure) Adapted from Proc Natl Acad Sci USA (1974);71:384 Adapted from Jin et al. J Biol Chem (2000);35:27238 Human Parathyroid Hormone 1-34 and 1-84 2004 hPTH/PTHrP Receptor hPTH (1-34)
Cumulative Proportion Of Women Enrolled In The Follow-up Study Who Had One Or More Nonvertebral Fragility Fractures After Baseline By Kaplan-Meier Analysis Prince et al JBMR Sep 2005
Doctors are men who prescribe medicines of which they know little, to cure diseases of which they know less, in human beings of whom they know nothing. Francois-Marie Arouet - Voltaire 1694 - 1778