Vitamin D und postmenopausale Knochengesundheit

Fractures contribute significantly to morbidity and mortality of postmenopausal women. Among postmenopausal women aged 60 years and older, the mortality-adjusted residual lifetime risk of fracture has been estimated to be 44–65?%. Thus, effective strategies are urgently needed to prevent fractures among postmenopausal women. This review summarizes the available evidence that supports vitamin D3 supplementation at a dose of 800 IU per day as a strategy to reduce falls and fractures, including hip fractures, among postmenopausal women by about 20–30?%. This recommendation is supported by the Position Statement on Vitamin D of the International Osteoporosis Foundation, the 2011 World Osteoporosis Day Report, and the US Endocrine Society. Further, this recommendation is supported by the high prevalence of vitamin D deficiency among postmenopausal women. The prevalence of vitamin D deficiency (serum levels below 50 nmol/l or 20 ng/ml) among younger and older postmenopausal women has been found to be about 50?% in many countries around the world, with the highest prevalence (80?%) in older women with hip fractures.     

Higher 25-hydroxyvitamin D concentrations are associated with better lower-extremity function in both active and inactive persons aged > or =60 y

BACKGROUND: Vitamin D may improve muscle strength through a highly specific nuclear receptor in muscle tissue. OBJECTIVES: We investigated whether there is an association between 25-hydroxyvitamin D [25(OH)D] concentrations and lower-extremity function in ambulatory older persons, whether that association differs by activity level, and, if so, whether there is an identifiable threshold in the association. DESIGN: The study was a population-based survey of the ambulatory US population aged 60 to > or =90 y (n = 4100). Lower-extremity function according to serum 25(OH)D concentrations was assessed by linear regression analyses and regression plots after control for activity level (inactive or active) and several other potential confounders. Separate analyses were performed for the timed 8-foot (ie, 2.4 m) walk test and a repeated sit-to-stand test. RESULTS: The 8-foot walk test compared subjects in the lowest and highest quintiles of 25(OH)D; the latter group had an average decrease of 0.27 s [95% CI: -0.44, -0.09 s (or 5.6%); P for trend < 0.001]. The sit-to-stand test compared subjects in the lowest and highest quintiles of 25(OH)D; the latter group had an average decrease of 0.67 s [95% CI: -1.11, -0.23 s (or 3.9%); P for trend = 0.017]. In the 25(OH)D reference range of 22.5-94 nmol/L, most of the improvement occurred in subjects with 25(OH)D concentrations between 22.5 and approximately 40 nmol/L, and further improvement was seen in the range of 40-94 nmol/L. Stratification by activity level showed no significant effect modification. CONCLUSION: In both active and inactive ambulatory persons aged > or =60 y, 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.     

Effect of Vitamin D on falls: a meta-analysis

Context  Falls among elderly individuals occur frequently, increase with age, and lead to substantial morbidity and mortality. The role of vitamin D in preventing falls among elderly people has not been well established. Objective  To assess the effectiveness of vitamin D in preventing an older person from falling. Data Sources  MEDLINE and the Cochrane Controlled Trials Register from January 1960 to February 2004, EMBASE from January 1991 to February 2004, clinical experts, bibliographies, and abstracts. Search terms included trial terms: randomized-controlled trial or controlled-clinical trial or random-allocation or double-blind method, or single-blind method or uncontrolled-trials with vitamin D terms: cholecalciferol or hydroxycholecalciferols or calcifediol or dihydroxycholecalciferols or calcitriol or vitamin D/aa[analogs & derivates] or ergocalciferol or vitamin D/bl[blood]; and with accidental falls or falls, and humans. Study Selection  We included only double-blind randomized, controlled trials (RCTs) of vitamin D in elderly populations (mean age, 60 years) that examined falls resulting from low trauma for which the method of fall ascertainment and definition of falls were defined explicitly. Studies including patients in unstable health states were excluded. Five of 38 identified studies were included in the primary analysis and 5 other studies were included in a sensitivity analysis. Data Extraction  Independent extraction by 3 authors using predefined data fields including study quality indicators. Data Synthesis  Based on 5 RCTs involving 1237 participants, vitamin D reduced the corrected odds ratio (OR) of falling by 22% (corrected OR, 0.78; 95% confidence interval [CI], 0.64-0.92) compared with patients receiving calcium or placebo. From the pooled risk difference, the number needed to treat (NNT) was 15 (95% CI, 8-53), or equivalently 15 patients would need to be treated with vitamin D to prevent 1 person from falling. The inclusion of 5 additional studies, involving 10 001 participants, in a sensitivity analysis resulted in a smaller but still significant effect size (corrected RR, 0.87; 95% CI, 0.80-0.96). Subgroup analyses suggested that the effect size was independent of calcium supplementation, type of vitamin D, duration of therapy, and sex, but reduced sample sizes made the results statistically nonsignificant for calcium supplementation, cholecalciferol, and among men. Conclusions  Vitamin D supplementation appears to reduce the risk of falls among ambulatory or institutionalized older individuals with stable health by more than 20%. Further studies examining the effect of alternative types of vitamin D and their doses, the role of calcium supplementation, and effects in men should be considered.      

Addressing the Musculoskeletal Components of Fracture Risk with Calcium and Vitamin D: A Review of the Evidence

Osteoporotic fractures are an extremely common and serious health problem in the elderly. This article presents the rationale for calcium and vitamin D supplementation in the prevention and treatment of osteoporotic fractures and reviews the literature evidence on the efficacy of this strategy. Two musculoskeletal risk factors are implicated in osteoporotic fractures in the elderly: the loss of bone mass due to secondary hyperparathyroidism and the increased propensity to falls. Calcium and vitamin D reverse secondary hyperparathyroidism with resultant beneficial effects on bone mineral density (BMD). Additionally, calcium and vitamin D supplementation significantly improves body sway and lower extremity strength, reducing the risk of falls. The effects of combined calcium and vitamin D on parathyroid function and BMD provide a strong rationale for the use of this therapy in the prevention and treatment of osteoporosis and osteoporotic fractures. There is general agreement that, in patients with documented osteoporosis, calcium and vitamin D supplementation should be an integral component of the management strategy, along with antiresorptive or anabolic treatment. Frail elderly individuals constitute another major target population for calcium and vitamin D because evidence from randomized studies in institutionalized elderly subjects demonstrates that these supplements reduce osteoporotic fracture risk, particularly in the presence of dietary deficiencies. However, the results of trials in community-dwelling subjects have been equivocal. Within the primary-care setting, further research is required to establish appropriate target subgroups for calcium and vitamin D supplementation; overall, the data are consistent with a benefit individuals with insufficient calcium and/or vitamin D, although patients with documented osteoporosis will derive further benefit in terms of fracture prevention from the addition of an antiresorptive agent.     

Health effects of vitamin D

Increasing data suggest that many or most adults in the United States and Europe would benefit from vitamin D supplements. This review summarizes the benefits of vitamin D with the strongest evidence today from randomized controlled trials for fall and fracture prevention.
Beyond fall and fracture prevention, vitamin D may also reduce overall morbidity by multiple mechanisms. Prospective epidemiological studies supported by strong mechanistic evidence suggest a reduction of cardiovascular disease (incident hypertension and cardiovascular mortality) and colorectal cancer, extending to weaker evidence on immune-modulatory and anti-inflammatory benefits of vitamin D.     

The Role of Falls in Fracture Prediction

Close to 75% of hip and non-hip fractures occur among seniors age 65 years and older. Notably, the primary risk factor for a hip fracture is a fall, and over 90% of all fractures occur after a fall. Thus, critical for the understanding and prevention of fractures at later age is their close relationship with muscle weakness and falling. In fact, antiresorptive treatment alone may not reduce fractures among individuals 80 years and older in the presence of nonskeletal risk factors for fractures despite an improvement in bone metabolism. This article will review the epidemiology of falls, and their importance in regard to fracture risk. Finally, fall prevention strategies and how these translate into fracture reduction are evaluated based on data from randomized controlled trials.     

Effect of cholecalciferol plus calcium on falling in ambulatory older men and women: a 3-year randomized controlled trial

BACKGROUND: A recent meta-analysis found that cholecalciferol (vitamin D) should reduce falls by more than 20%. However, little is known about whether supplemental cholecalciferol plus calcium citrate malate will lower the long-term risk of falling in men, active older individuals, and older individuals with higher 25-hydroxyvitamin D levels. METHODS: We studied the effect of 3-year supplementation with cholecalciferol-calcium on the risk of falling at least once in 199 men and 246 women 65 years or older and living at home. Individuals received 700 IU of cholecalciferol plus 500 mg of calcium citrate malate per day or placebo in a randomized double-blind manner. Subjects were classified as less physically active if physical activity was below the median level. Low 25-hydroxyvitamin D levels were classified as those below 32 ng/mL (<80 nmol/L). RESULTS: In 3 years, 55% of women and 45% of men reported at least 1 fall. Mean +/- SD baseline 25-hydroxyvitamin D levels were 26.6 +/- 12.7 ng/mL (66.4 +/- 31.7 nmol/L) in women and 33.2 +/- 14.2 ng/mL (82.9 +/- 34.9) in men. Cholecalciferol-calcium significantly reduced the odds of falling in women (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.30-0.97), but not in men (OR, 0.93; 95% CI, 0.50-1.72). Fall reduction was most pronounced in less active women (OR, 0.35; 95% CI, 0.15-0.81). Baseline 25-hydroxyvitamin D level did not modulate the treatment effect. CONCLUSIONS: Long-term dietary cholecalciferol-calcium supplementation reduces the odds of falling in ambulatory older women by 46%, and especially in less active women by 65%. Supplementation had a neutral effect in men independent of their physical activity level.     

Quality of Life in Sarcopenia and Frailty

The reduced muscle mass and impaired muscle performance that define sarcopenia in older individuals are associated with increased risk of physical limitation and a variety of chronic diseases. They may also contribute to clinical frailty. A gradual erosion of quality of life (QoL) has been evidenced in these individuals, although much of this research has been done using generic QoL instruments, particularly the SF-36, which may not be ideal in older populations with significant comorbidities. This review and report of an expert meeting presents the current definitions of these geriatric syndromes (sarcopenia and frailty). It then briefly summarizes QoL concepts and specificities in older populations and examines the relevant domains of QoL and what is known concerning QoL decline with these conditions. It calls for a clearer definition of the construct of disability, argues that a disease-specific QoL instrument for sarcopenia/frailty would be an asset for future research, and discusses whether there are available and validated components that could be used to this end and whether the psychometric properties of these instruments are sufficiently tested. It calls also for an approach using utility weighting to provide some cost estimates and suggests that a time trade-off study could be appropriate.