Background-Low 25-hydroxyvitamin D levels, commonly found in older patients with heart failure, may contribute to the chronic inflammation and skeletal myopathy that lead to poor exercise tolerance. We tested whether vitamin D supplementation of patients with heart failure and vitamin D insufficiency can improve physical function and quality of life. Methods and Results-In a randomized, parallel group, double-blind, placebo-controlled trial, patients with systolic heart failure aged Ն70 years with 25-hydroxyvitamin D levels Ͻ50 nmol/L (20 ng/mL) received 100 000 U of oral vitamin D2 or placebo at baseline and 10 weeks. Outcomes measured at baseline, 10 weeks, and 20 weeks were 6-minute walk distance, quality of life (Minnesota score), daily activity measured by accelerometry, Functional Limitations Profile, B-type natriuretic peptide, and tumor necrosis factor-␣. Participants in the vitamin D group had an increase in their 25-hydroxyvitamin D levels compared with placebo at 10 weeks (22.9 versus 2.3 nmol/L [9.2 versus 0.9 ng/mL]; PϽ0.001) and maintained this increase at 20 weeks. The 6-minute walk did not improve in the treatment group relative to placebo. No significant benefit was seen on timed up and go testing, subjective measures of function, daily activity, or tumor necrosis factor. Quality of life worsened by a small, but significant amount in the treatment group relative to placebo. B-type natriuretic peptide decreased in the treatment group relative to placebo (Ϫ22 versus ϩ78 pg/mL at 10 weeks; Pϭ0.04). Conclusions-Vitamin D supplementation did not improve functional capacity or quality of life in older patients with heart failure with vitamin D insufficiency.
BackgroundStudying physical activity (PA) trends in older populations and potential interventions for increasing PA is important, as PA is a factor in many age-related health outcomes such as chronic disease, premature mortality, physical function and injuries from falls. Objective measures of PA provide valuable information regarding the functional impact that ageing and chronic disease states may have on a patient’s life.AimsThe purpose of this study was to test the validity of the AX3 PA monitor in an older population and to investigate whether the AX3 is a valid measure of distinct types or levels of activity in older people with a spectrum of mobility.MethodsValidity of the AX3 PA monitor was tested using the RT3 as a means of cross-validating the AX3. Study participants wore both the AX3 and the RT3 accelerometers, positioned on their non-dominant side, whilst completing a series of standardised everyday activities.ResultsAlthough overall correlation was high (r > 0.8) between the RT3 and lower-limb-mounted AX3 counts, the correlation between the two devices was much stronger for walking activity than for any of the non-walking activities.DiscussionActivity counts at all lower limb positions for the AX3 and RT3 were highly correlated. Correlation between wrist-mounted AX3 counts and lower limb AX3 counts was only moderate, and worsened when walking aids were in use.ConclusionsThe results of this study indicate that the AX3 monitor is a valid tool, which might be used to objectively measure walking activity in older functionally impaired adults, a welcome finding for this under-researched area.
We thank Begg, Cleland, and Witte for their interest in our article and for their comments that further the debate on the role of vitamin D in vascular disease. As they correctly point out, we deliberately took a pragmatic approach to patient selection in this trial. Our patients are typical of most patients with heart failure 1 -they are old, have comorbid disease, and despite the relatively low frusemide doses used, they have severe functional impairment as evidenced by their low baseline 6-minute walk distances. Their heart failure treatment is not optimal; we deliberately enrolled typical older patients with heart failure, and such patients often cannot tolerate optimal therapy because of problems such as falls and drug interactions. It is for these reasons that exploring new treatments in this patient group is so important.It is certainly true that higher doses of vitamin D, taken for longer, may be required to provide optimum health outcomes. However, at the time at which this study was initiated, the dose that we used was considered relatively high, and a slightly larger dose of 2000 U/d of vitamin D3 given for 9 months also failed to provide benefit in another trial. 2 Suppression of parathyroid hormone is a possible mechanism by which vitamin D supplementation might affect cardiovascular health; however, we have demonstrated improvements in endothelial function and blood pressure in a different patient group with vasculopathy using the same dose of vitamin D2, again without parathyroid hormone suppression. 3 Furthermore, brain natriuretic peptide levels fell in the intervention group relative to placebo in the current study despite parathyroid hormone not being suppressed.There is much still to learn about the effects of vitamin D on vascular health, and it is certainly possible that supplementation in patients with heart failure could still reduce death and symptoms in the longer term. Such improvements do not always mean that physical function and quality of life will improve, and these key outcomes for older, frail people were not affected in our study despite a doubling of 25-hydroxyvitamin D levels from baseline. We saw no evidence of a greater increase in walking distance in those patients with the greatest increases in 25 hydroxyvitamin D levels, and we therefore doubt that further increases in dose are likely to provide additional improvement in physical function. DisclosuresDr Witham has received grant funding for vitamin D research from the Scottish Government, Diabetes UK, Chest Heart and Stroke Scotland, Heart Research UK, and the ME Society. Professor Struthers has received grant funding for vitamin D research from the Scottish Government, Diabetes UK, and Chest Heart and Stroke Scotland. Professor McMurdo has received grant funding for vitamin D research from the Scottish Government. Miles
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