Article - Additive Effects of Exercise and Vitamin D Supplementation (with and without Calcium) on Bone Mineral Density in Older Adults: A Systematic Review and Meta-Analysis.

Plain Language Summary

Exercise and vitamin D supplementation is thought to improve bone health and a combination of the two may enhance the effect. This systematic review and meta-analysis aimed to determine the effects of a combination of vitamin D and exercise on the health of the spine and leg bone. The results showed that the addition of vitamin D to exercise had no additional benefits on the bone health of the spine or leg compared to exercise alone. It was concluded that the addition of vitamin D to exercise had no additional benefits to bone health than exercise alone. However, this may be due to the use of non-bone specific exercises employed in the study. This study could be used by healthcare professionals to understand that exercise is key to bone health and supplementation of vitamin D may have no further benefits.

Expert Review

Reviewer: Chloe Steele

10th Apr 2024

Conflict of interest

None

Take home message

Whilst this study failed to show additive benefits of exercise and vitamin D, dual therapy may still have some validity especially in individuals with vitamin D deficiency.
Given the high safety and low cost of vitamin D supplementation, it might be worth recommending dual therapy to patients, especially if they are vitamin D deficient, or at high risk of osteoporosis.

Evidence category

A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)

Summary review

Introduction

Exercise and vitamin D supplementation are thought to have positive effects on bone mineral density (BMD) and when in combination, benefits may be enhanced. This systematic review and meta-analysis aimed to determine the effects of vitamin D and exercise combination therapy on the BMD of the lumbar spine and proximal femur.

Methods

The study looked at comparative ≥6 month vitamin D exercise trials in adults aged ≥50 years from 6 electronic databases.
Outcome measures were BMD at lumbar spine, total hip, or femoral neck as determined by dual X-ray absorptiometry, dual photon absorptiometry, and quantitative computed tomography.

Results

Five studies with 360 participants were found to fit the entry criteria. Three were randomised control trials and two were nonrandomised.
One study was in Caucasian men, whilst the remaining four were in postmenopausal Caucasian women.
Two studies were for 24 months, whilst three were 12-month durations.
Exercise regimes varied amongst studies and focused on weight-bearing and non-weight-bearing exercises.
Vitamin D supplementation ranged from 284-2000 IU/d.
The addition of vitamin D to exercise did not affect the BMD of the lumbar spine, femoral neck, or hip compared to exercise alone (P=0.912, P=0.675, and P=0.976 respectively), even when a trial with low vitamin D doses was excluded.

Conclusion

The addition of vitamin D to exercise had no additive benefits on BMD at the lumbar spine or femoral neck. However, this may be due to the trials not employing bone specific exercises and the inclusion of studies which were not performed in individuals with vitamin D deficiency.

Clinical practice applications

Exercise in combination with vitamin D may have no further benefit than exercise alone on BMD of individuals who are not vitamin D deficient.
However, this is based on only a small number of clinical trials in non-vitamin D deficient individuals.
Combined vitamin D and exercise may still be of benefit to fracture risk in specific patients.

Considerations for future research

Studies should now extend to looking at exercise in combination with vitamin D supplementation on the BMD and fracture incidence of individuals with vitamin D deficiency.

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Abstract

Exercise is a recognized component in the prevention and therapy of osteoporosis. The present systematic review and meta-analysis aimed to determine the effect of Vitamin D (Vit-D) added to exercise versus exercise alone on bone mineral density (BMD) at the lumbar spine (LS) or hip in older adults. A systematic review based on six literature databases according to PRISMA included (a) exercise trials, with an exercise (EX) and a combined exercise + Vit-D group (EX + Vit-D), (b) intervention ≥ 6 months, and (c) BMD assessments at LS or hip. Effects sizes (MD) and 95%-confidence intervals (95%-CI) were calculated using a random-effect model that includes the inverse heterogeneity model (IVhet). Five studies with 281 participants in the EX and 279 participants in the EX + Vit-D were included. No significant differences between EX versus EX + Vit-D were observed for BMD-LS (MD: 0.002, 95%-CI: -0.033 to 0.036) or BMD-hip (MD: 0.003, 95%-CI: -0.035 to 0.042). Heterogeneity between the trial results was moderate-substantial for LS ( = 0%) and moderate for hip-BMD ( = 35%). The funnel plot analysis suggests evidence for a publication/small study bias for BMD-LS and hip results. In summary, this present systematic review and meta-analysis were unable to determine significant positive interaction of exercise and Vit-D on LS- or hip-BMD. We predominately attribute this finding to (1) the less bone-specific exercise protocols of at least two of the five studies and (2) the inclusion criteria of the studies that did not consequently focus on Vit-D deficiency. This issue should be addressed in more detail by adequately powered exercise trials with promising exercise protocols and participants with Vit-D deficiency. This trial is registered with the International Prospective Register of Systematic Reviews (PROSPERO) ID: CRD42022309813.