The association between 25-hydroxyvitamin D concentration, physical performance and frailty status in older adults.

PURPOSE: Sufficient 25-hydroxyvitamin D (25(OH)D) concentrations might prevent a decline in physical performance, and are considered important for the prevention of frailty. This study investigates the association of serum 25(OH)D concentration with physical performance and frailty status in Dutch older adults. METHODS: This cross-sectional study included 756 men and women, aged ≥ 65 years. Serum 25(OH)D concentration and frailty status (Fried criteria) were assessed in the total population. Screening for frailty status included functional tests of gait speed and hand grip strength. In a subgroup (n = 494), the Timed Up and Go test (TUG) and knee-extension strength were measured. Associations of serum 25(OH)D status with physical performance were examined by multiple linear regression. Prevalence ratios (PR) were used to quantify associations between serum 25(OH)D deficiency (< 50 nmol/L) and frailty. RESULTS: In total, 45% of the participants were vitamin D deficient. Participants with vitamin D status < 50 and 50-75 nmol/L had significantly lower scores on the TUG and gait speed test, compared to participants with vitamin D status > 75 nmol/L. No significant associations with serum 25(OH)D concentrations were observed for handgrip strength or knee-extension strength. Participants with serum 25(OH)D status < 50 nmol/L were about two times more likely to be frail compared to participants with serum 25(OH)D status ≥ 50 nmol/L. No significant associations were observed between the pre-frail state and serum 25(OH)D status. CONCLUSION: In this study, serum 25(OH)D concentrations were significantly associated with frailty status and measures of physical performance, including gait speed and TUG, but not with strength-related outcomes.

A 4-week exercise and protein program improves muscle mass and physical functioning in older adults - A pilot study.

BACKGROUND: Prehabilitation might attenuate common surgery-induced losses in muscle mass and physical performance. Beneficial effects of physical exercise with protein supplementation have been reported in older adults, but typically after an intervention of at least 12 weeks. The time-window for pre-surgery training is often limited to around 30 days, and it is not known if it is possible to achieve comparable results in such a short time window. OBJECTIVES: The aim of this study was to pilot-test the effectiveness of a controlled four-week combined exercise and protein supplementation program on skeletal muscle-related outcomes in a Dutch older adult population. DESIGN: This study was a one-armed pilot trial. PARTICIPANTS: Seventeen older men and women, aged 55-75y, not scheduled for surgery. INTERVENTION: A 4-week intervention program consisting of a twice-weekly supervised resistance and high-intensity aerobic exercise training of 75 min, combined with daily protein supplementation (2 doses of 15.5 g/day at breakfast and lunch). MEASUREMENT: After two and four weeks, isometric quadriceps maximal voluntary contraction (MVC) was assessed via Biodex and quadriceps cross-sectional area (CSA) via magnetic resonance imaging. Other outcome measures were handgrip strength, chair rise time and maximal aerobic capacity (VO2-max), as assessed from a submaximal exercise test. RESULTS: Compliance to the supervised training sessions (99.3%) and the protein supplementation (97%) was very high. The 4-week exercise and protein program led to an increase in quadriceps CSA of 2.3 ± 0.7 cm2 (P = 0.008) in the dominant leg and 3.2 ± 0.7 cm2 (P < 0.001) in the non-dominant leg. Isometric quadriceps MVC increased in the dominant leg (Δ14 ± 4 Nm, P = 0.001) and in the non-dominant leg (Δ17 ± 5 Nm, P = 0.003). Chair rise test time improved with -3.8 ± 0.5 s (P < 0.0001), and VO2-max improved with 3.3 ± 1.1 ml/min/kg (P = 0.014). We observed no changes in body weight and handgrip strength. CONCLUSION: A 4-week exercise and protein intervention led to improvements in muscle-related outcomes in older adults with low levels of physical activity.

Dose-response effects of supplementation with calcifediol on serum 25-hydroxyvitamin D status and its metabolites: A randomized controlled trial in older adults.

BACKGROUND & AIMS: Oral supplementation with vitamin D is recommended for older adults to maintain a sufficient 25-hydroxyvitamin D (25(OH)D) status throughout the year. While supplementation with vitamin D2 or D3 is most common, alternative treatment regimens exist which require further investigation with respect to increasing 25(OH)D concentration. We investigated the dose-response effects of supplementation with calcifediol compared to vitamin D3 and assessed the dose which results in mean serum 25(OH)D3 concentrations between 75 and 100 nmol/L. METHODS: This randomized, double-blind intervention study included men and women aged ≥65 years (n = 59). Participants received either 5, 10 or 15 µg calcifediol or 20 µg vitamin D3 per day, for a period of 24 weeks. Blood samples were collected every four weeks to assess response profiles of vitamin D related metabolites; serum vitamin D3, 25(OH)D3, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3). Further, serum calcium, plasma parathyroid hormone, and urinary calcium were evaluated. RESULTS: Supplementation with 20 µg vitamin D3 increased 25(OH)D3 concentrations towards 70 nmol/L within 16 weeks. Supplementation with 10 or 15 µg calcifediol increased 25(OH)D3 levels >75 nmol/L in 8 and 4 weeks, respectively. Steady state was achieved from week 12 onwards with serum 25(OH)D3 levels stabilizing between 84 and 89 nmol/L in the 10 µg calcifediol group. A significant association was observed between the changes in 25(OH)D3 and 24,25(OH)2D3 (R2 = 0.83, P < 0.01), but not between 25(OH)D3 and 1,25(OH)2D3 (R2 = 0.04, P = 0.18). No cases of hypercalcemia occurred in any treatment during the study period. CONCLUSIONS: Calcifediol supplementation rapidly and safely elevates serum 25(OH)D3 concentrations to improve vitamin D status in older adults. A daily dose of 10 µg calcifediol allows serum 25(OH)D3 concentrations to be maintained between 75 and 100 nmol/L. TRIAL REGISTRATION NUMBER: NCT01868945.