calcitriol and Muscle-Weakness

Hypovitaminosis D is a common syndrome with well-established risk factors. Only recently, however, are the expansive implications of vitamin D deficiency becoming recognized, including cardiovascular complications, cancer, and dementia. The increased attention to the role of vitamin D has made its assessment more crucial in comprehensive patient management.

Topics: Dementia; Diet; Dietary Supplements; Humans; Muscle Weakness; Neoplasms; Sunlight; Vitamin D; Vitamin D Deficiency

Poor vitamin D status and frailty are common in older people and associated with adverse health outcomes. The aim of this study was to examine the associations between serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels and frailty and components of frailty in older Australian men.. Cross-sectional analysis of the Concord Health and Ageing in Men Project, a large epidemiological study conducted in Sydney, Australia, between January 2005 and May 2007. Participants included 1,659 community-dwelling men. Main outcome measurements were frailty (assessed using the Cardiovascular Health Study), frailty criteria comprising five core components: weight loss; reduced muscular strength/weakness; slow walking speed; exhaustion; and low activity level, and the separate components of frailty. Covariates included serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels measured by radioimmunoassay, age, country of birth, season of blood collection, sun exposure, body mass index, vitamin D supplement use, income, measures of health, parathyroid hormone, estimated glomerular function.. Frailty was present in 9.2% of the sample. Low serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels were independently associated with frailty and with four of the five components of frailty (except weight loss).. 1,25-dihydroxyvitamin D and 25-hydroxyvitamin D levels were independently associated with frailty in older men. This suggests that there might be a number of different biological mechanisms for how low vitamin D status might contribute to the frailty syndrome. In addition, the possibility that improving vitamin D status may specifically influence the incidence and progression of frailty needs to be explored.

Topics: Aged; Aged, 80 and over; Aging; Cross-Sectional Studies; Fatigue; Frail Elderly; Humans; Logistic Models; Male; Motor Activity; Muscle Weakness; New South Wales; Risk Factors; Vitamin D; Walking; Weight Loss

Fibroblast growth factor 23 (FGF-23) plays causative roles in the development of several hypophosphatemic rickets/osteomalacia such as X-linked hypophosphatemic rickets/osteomalacia (XLH) and tumor-induced rickets/osteomalacia. Patients with hypophosphatemic rickets/osteomalacia often complain of muscle weakness and bone pain that severely affect daily activities of these patients. The purpose of this study was to examine whether anti-FGF-23 antibodies, which have been shown to improve hypophosphatemia and rachitic changes of juvenile Hyp mice in a murine model of XLH, also ameliorate hypophosphatemic osteomalacia and affect muscle force and spontaneous motor activity in adult Hyp mice. Repeated injections of anti-FGF-23 antibodies increased serum phosphate and 1,25-dihydroxyvitmain D levels and enhanced mineralization of osteoid in adult Hyp mice, whereas bone length did not change. We found that grip strength was weaker and that spontaneous movement was less in adult Hyp mice than in wild-type mice. In addition, FGF-23 antibodies increased grip strength and spontaneous movement. These results suggest that the inhibition of excess FGF-23 action not only ameliorates hypophosphatemia and impaired mineralization of bone but also improves muscle weakness and daily activities of patients with FGF-23-related hypophosphatemic rickets/osteomalacia.

Topics: Animals; Antibodies, Monoclonal; Blood; Body Weight; Calcification, Physiologic; Disease Models, Animal; Familial Hypophosphatemic Rickets; Female; Femur; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Genetic Diseases, X-Linked; Hand Strength; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Motor Activity; Muscle Weakness; Phosphates; Quadriceps Muscle; Radiography; Skull; Tibia; Vitamin D

Suboptimal levels of 25-hydroxyvitamin D (25OHD) are common in haemodialysis patients (Chronic Kidney disease-5D: CKD-5D) and may be associated with reduced muscle strength and increased falls risk. We tested the hypothesis that 25OHD levels may be independently associated with falls risk in CKD-5D.. Supplementation with calcium and cholecalciferol reduces hip and other nonvertebral fractures in elderly individuals, and this effect may in part be attributable to reduction in falls frequency. The relationship between 25OHD and falls risk has not been investigated in CKD-5D.. This is a cross-sectional study of 25 CKD-5D patients with predialysis 25OHD, 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and intact parathyroid hormone (iPTH) measurement. Falls risk was assessed by quadriceps muscle strength, FallsScreen((c)) test (FST), Berg Balance Scale (BBS), timed 'up and go' (TUG) test, Modified Barthel Index (MBI) and Falls Efficacy Scale (FES).. Mean age was 69.8 +/- 12.1 years, and median time on dialysis was 3.1 years. Median 25OHD level was 55.3 nmol/l (range 20.8-125.8 nmol/l). Muscle strength was significantly positively correlated with 25OHD (P = 0.024) but not with 1,25(OH)(2)D (P = 0.477) or PTH (P = 0.461). Statistically significant correlation between 25OHD levels and FST (P = 0.028) plus MBI (P = 0.0046) was noted. No significant correlation was detected between falls risk and 1,25(OH)(2)D or PTH.. Suboptimal levels of 25OHD in CKD-5D are associated with reduced quadriceps muscle strength and increased falls risk. 25OHD may be more important than the active renal metabolite 1,25(OH)(2)D for muscle strength with implications for vitamin D choice and goals of supplementation. Further investigation is required to examine effectiveness of calciferol supplementation on the incidence of falls in CKD-5D.

Topics: Accidental Falls; Aged; Aged, 80 and over; Chi-Square Distribution; Cross-Sectional Studies; Female; Humans; Kidney Failure, Chronic; Linear Models; Male; Middle Aged; Muscle Weakness; Parathyroid Hormone; Renal Dialysis; Risk Assessment; Risk Factors; Vitamin D