4 Inactive form of vitamin D Active form of vitamin D Vit. D จะอยู่ในกระแสเลือดประมาณ 24 ชั่วโมงD2&D3Vitamin D binding protein (DBP)Inactive form of vitamin DcalcidiolActive form of vitamin D+FGF23CYP27B1+PTHCa, FGF23-
14 According to a recent study, A High Prevalence of Vitamin D Inadequacy* Was Seen Across All Geographic RegionsIn a cross-sectional, international study in postmenopausal women with osteoporosis (N=2589)9081.8%8071.4%63.9%7060.3%57.7%6053.4%50The findings of an international epidemiologic study indicate that vitamin D inadequacy is highly prevalent among postmenopausal women with osteoporosis throughout the world, even in regions with ample sunlight.1 This cross-sectional, single-visit study enrolled 2589 postmenopausal women with osteoporosis between May 2004 and March 2005 in 18 countries in Europe, Latin America, the Middle East, Asia, and Australia. Vitamin D inadequacy was defined by a serum 25(OH)D level <30 ng/mL.1The mean 25(OH)D concentration among the study population as a whole was 26.8 ng/mL. Nearly 64% of the study population demonstrated a serum 25(OH)D concentration <30 ng/mL and approximately 31% had a concentration <20 ng/mL. The prevalence of vitamin D inadequacy (<30 ng/mL) was at least 53% in all 5 regions involved in the study and was highest in the Middle East (81.8%) and Asia (71.4%).1In the study population, risk factors for vitamin D inadequacy included body mass index >30 kg/m2 (odds ratio, 2.4 [95% confidence interval: 1.83, 3.14]), living in a nonequatorial climate (1.91 [1.58, 2.32]), possessing fair to poor health (1.86 [1.49, 2.33]), no recent travel to sunny areas (1.86 [1.54, 2.25]), vitamin D supplementation <400 IU/day (1.78 [1.41, 2.24]), and no vitamin D supplementation (2.36 [1.97, 2.82]).2Nearly 59.8% of the study participants used a medication approved for the treatment of osteoporosis, such as bisphosphonates, selective estrogen-receptor modulators, calcitonin, or parathyroid hormone, and approximately 54.2% used vitamin D supplements.1Prevalence, %40302010AllLatin AmericaEuropeMiddleEastAsiaAustraliaRegions*Vitamin D inadequacy was defined as serum 25(OH)D <30 ng/mL.Study Design: Cross-sectional, international study of 2589 women with osteoporosis from 18 countries to evaluate serum 25(OH)D distributionAdapted from Lips P, et al. J Intern Med. 2006;260:245–254.ReferencesLips P, Hosking D, Lippuner K, et al. The prevalence of vitamin D inadequacy amongst women with osteoporosis: an international epidemiological investigation. J Intern Med. 2006;260:245–254.Rizzoli R, Eisman JA, Norquist J, et al. Risk factors for vitamin D inadequacy among women with osteoporosis: an international epidemiological study. Int J Clin Pract. 2006;60:1013–1019.1414
15 หน้าที่ของวิตามินดี1. ส่งเสริมให้มีการดูดซึมแคลเซียมในลำไส้เข้าสู่กระแสเลือด (โดยเพิ่ม active absorption of calcium ที่ duodenum and upper jejunum)
20 patients 319 cases Female 103 cases, mean age 74.2 yrs
21 Results Muscle strength was lower in older subjects 12% of women and 18% of men had 25(OH)D values below < 12ng/mLMuscle strength was lower in older subjectsCorrelation between muscle strength vs. agefemale: r = -0.35; p = .0005male: r = ; p < .OOO1women had lower muscle strength than men (p < .OOO1).In men both 25(OH)D and 1,25(OH)2D was significantly correlated with LEP (r = 0.24; p = .0004/r = .14; p = .045).In women, only 1,25(OH)2D was significantly correlated with LEP (r = 0.22; p = .034)
23 A population-based survey of the ambulatory US population aged 60 to 90 yr. (n= 4100).
24 Reference range22.594regression plots of lower-extremity function on the 8-foot (ie, 2.4 m) walk test by 25-hydroxyvitamin D concentrations.Plots are adjusted for sex, age, race or ethnicity, BMI, calcium intake, poverty-income ratio, number of medical comorbidities, self-reported arthritis, use of a walking device, month of assessment, activity level (inactive or active), and metabolic equivalents in active elderly.
25 regression plots of lower-extremity function sit to stand test by 25-hydroxyvitamin D concentrations.Plots are adjusted for sex, age, race or ethnicity, BMI, calcium intake, poverty-income ratio, number of medical comorbidities, self-reported arthritis, use of a walking device, month of assessment, activity level (inactive or active), and metabolic equivalents in active elderly.
26 ConclusionIn both active and inactive ambulatory persons aged > 60 yr.25(OH)D concentrations between 40 and 94 nmol/L are associated with better musculoskeletal function in the lower extremities than are concentrations <40 nmol/L.
28 ObjectiveTo examine the different levels of CrCl in relation to falls.
29 ResultsThe elderly with CrCl <60 ml/min had higher risk of falls than the elderly with CrCl>60 ml/min (OR=1.6, 95% CI:1.1–2.2, p=0.012)
30 Results In women with CrCl<60 ml/min, calcitriol treatment significantly reduced the cumulative number of falls by 50 percent (p<0.01)calcitriol + estrogen reduced falls by 40 percent (p<0.01)estrogen was not effective.The effect of calcitriol treatment was evident by 12 months of treatment and statistically significant at 36 months of treatment
31 Discussion & Conclusion there is decreased conversion of 25OHD to 1,25(OH)2D by the aging kidneyIt is postulated that the decrease in falls on calcitriol therapy is related to an increase in serum 1,25 (OH)2D, and improvement in muscle strength
33 Reduction of falls by treatment with Calcitriol Risk of Falls and Reduction of Falls by Calcitriol in Elderly Women (CrCl of < 60 ml/min vs CrCl ≥ 60 ml/min)Subanalysis of the STOPIT-StudyFallsOR 1.6 (95% CI 1.1 – 2.3)Reduction of falls by treatment with CalcitriolOR 0.5 (95% CI 0.3 – 0.9)p = 0.01Gallagher JC et al. J Clin Endocrin Metab 2007;92:51-58
35 Many observational studies, mainly in older populations, indicate that vitamin D status is positively associated with muscle strengthThe underlying mechanisms are probably both indirect via calcium and phosphate and direct via activation of the vitamin D receptor (VDR) on muscle cells by 1,25-dihydroxyvitamin D [1,25(OH)2D]VDR activation at the genomic level regulates transcription of genes involved in calcium handling and muscle cell differentiation and proliferation.
36 Additional evidence comes from VDR knockout mouse models with abnormal muscle morphology and physical functionRecent identification of CYP27B1 (1-a hydroxylase enzyme) bioactivity in skeletal muscle cells support to the direct action of both 25-hydroxyvitamin D and 1,25(OH)2D in muscle
38 It is well known that vitamin D deficiency causes rachitic/osteomalacic myopathy and cardiac disorder and the provision of vitamin D can reverse the symptomsHowever the underlying mechanisms remain unclear.The question of whether the vitamin D receptor is found in muscle has been debated but not settledThe results from this investigation show that the vitamin D receptor is undetectable in skeletal, cardiac, and smooth muscle, suggesting that the function of vitamin D on muscle is either of an indirect nature or does not involve the known receptor
40 ResultsOf 52 identified studies, 17 RCTs involving 5,072 participants met the inclusion criteria.Inclusion criteria included randomised controlled trials (RCTs) involving adult human participants.All forms and doses of vitamin D supplementation with or without calcium supplementation were included compared with placebo or standard care.
41 ResultsMeta-analysis showed no significant effect of vitamin D supplementation ongrip strength (SMD −0.02, 95%CI −0.15,0.11)proximal lower limb strength (SMD 0.1, 95%CI −0.01,0.22) in adults with 25(OH)D levels >25 nmol/L (10 ng/mL)Pooled data from two studies in vitamin D deficient participants (25(OH)D <25 nmol/L) demonstrated a large effect of vitamin D supplementation on hip muscle strength (SMD 3.52, 95%CI 2.18, 4.85)
44 ConclusionBased on studies included in this systematic review, vitamin D supplementation does not have a significant effect on muscle strength in adults with baseline 25(OH)D >25 nmol/L (10 ng/mL).However, a limited number of studies demonstrate an increase in proximal muscle strength in adults with vitamin D deficiency
45 ConclusionVitamin D had positive effect on muscle function especially in vitamin D deficiency patients (25(OH)D < 10 ng/mL)further research is needed to fully characterize the exact underlying mechanisms of vitamin D action on muscle tissue