77.98% 60% 65.4% 15.4% Pre-men. women Early post-menUrbanized elderly Rural elderly
Slide 14 *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 distribution Adapted from Lips P, et al. J Intern Med. 2006;260:245–254. Prevalence, % 0 10 30 40 60 80 90 Regions 50 70 20 81.8% Middle East 53.4% 71.4% Asia AllLatin America 63.9% Australia 60.3% Europe 57.7% In a cross-sectional, international study in postmenopausal women with osteoporosis (N=2589) A High Prevalence of Vitamin D Inadequacy* Was Seen Across All Geographic Regions According to a recent study,
1. ส่งเสริมให้มีการดูดซึมแคลเซียมใน ลำไส้เข้าสู่กระแสเลือด ( โดยเพิ่ม active absorption of calcium ที่ duodenum and upper jejunum) หน้าที่ของวิตามินดี
หน้าที่ของวิตามินดี 3. รักษาระดับแคลเซียมในกระแสเลือด ไม่ให้ต่ำกว่าปกติ เมื่อแคลเซียมในกระแสเลือดลดลงจะกระตุ้น ให้ active vitamin D เพิ่มขึ้น และเพิ่ม active absorption of calcium ใน GI tract 4. ยับยั้งการหลั่งของ PTH พบว่า ต่อม parathyroid มี receptor ต่อ วิตามินดี เมื่อ จับกันแล้วจะยับยั้งการหลั่งของ PTH 5. ทำให้กล้ามเนื้อมีความแข็งแรงขึ้น
Vitamin D & Muscle Strength
patients 319 cases – Female 103 cases, mean age 74.2 yrs – Male 216 cases, mean age 76.7 yrs
Results 12% of women and 18% of men had 25(OH)D values below < 12ng/mL Muscle strength was lower in older subjects – Correlation between muscle strength vs. age female: r = -0.35; p =.0005 male: r = -0.48; p <.OOO1 women had lower muscle strength than men (p <.OOO1). In men both 25(OH)D and 1,25(OH) 2 D 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)
A population-based survey of the ambulatory US population aged 60 to 90 yr. (n= 4100).
regression 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. 22.594 Reference range
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.
Conclusion In 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.
Objective To examine the different levels of CrCl in relation to falls.
Results The elderly with CrCl 60 ml/min (OR=1.6, 95% CI:1.1–2.2, p=0.012)
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
Discussion & Conclusion there is decreased conversion of 25OHD to 1,25(OH) 2 D by the aging kidney It is postulated that the decrease in falls on calcitriol therapy is related to an increase in serum 1,25 (OH) 2 D, and improvement in muscle strength
Dukas L et al. Osteoporos Int 2005;16:198-203
Risk of Falls and Reduction of Falls by Calcitriol in Elderly Women (CrCl of < 60 ml/min vs CrCl ≥ 60 ml/min) Falls OR 1.6 (95% CI 1.1 – 2.3) Reduction of falls by treatment with Calcitriol OR 0.5 (95% CI 0.3 – 0.9) p = 0.01 Subanalysis of the STOPIT-Study Gallagher JC et al. J Clin Endocrin Metab 2007;92:51-58
Many observational studies, mainly in older populations, indicate that vitamin D status is positively associated with muscle strength The 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.
Additional evidence comes from VDR knockout mouse models with abnormal muscle morphology and physical function Recent identification of CYP27B1 (1- hydroxylase enzyme) bioactivity in skeletal muscle cells support to the direct action of both 25-hydroxyvitamin D and 1,25(OH) 2 D in muscle
(Endocrinology 152: 354–363, 2011)
It is well known that vitamin D deficiency causes rachitic/osteomalacic myopathy and cardiac disorder and the provision of vitamin D can reverse the symptoms However the underlying mechanisms remain unclear. The question of whether the vitamin D receptor is found in muscle has been debated but not settled The 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
Results Of 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.
Results Meta-analysis showed no significant effect of vitamin D supplementation on – grip 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)
Conclusion Based 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
Conclusion Vitamin 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