Effects of a Single Nutrient Supplementation on Dynamic Stability in Community Dwelling Older Adults
Phase: NA
Conditions: Aging
Sponsor: Arizona State University

Relationship between serum 25-hydroxyvitamin D levels and fall risk as measured by dynamic stability 
and mobility-related outcomes in older adults 
Thurmon E. Lockhart1, Sean M. Garvey2, Owen J. Kelly2 
1Arizona State University, Tempe, Arizona, USA  
2Abbott Nutrition R&D, Columbus, Ohio, USA 
 
Background 
Sufficient vitamin D is critical for infant and childhood bone growth, but is additionally implicated in 
chronic disease risk in adults. In particular, low circulating levels of the vitamin D catabolite, 25-
hydroxyvitamin D [25(OH)D], have been reported to be related to decreased muscle function and 
increased risk of falls in older adults1-3. However, the remedial benefits of vitamin D supplementation as 
a standalone treatment to increase muscle strength and reduce fall risk are tenuous and sometimes 
contradictory across published clinical studies4,5. We set out to investigate the relationship between 
serum 25(OH)D and mobility-related outcomes and fall risk among community-dwelling older adults. 
Severe muscle loss in older adults – sarcopenia – is often ancillary to frailty. Similar to frailty, sarcopenia 
is highly correlative of increased risk of falls, impaired ability to perform ADLs, and loss of 
independence6-8. Declining muscle mass and strength are expected components of ageing; however, the 
rate of decline differs across the elderly population, suggesting that modifiable behavioral factors such 
as diet and lifestyle, may influence muscle function and therefore may be amenable to intervention 9,10. 
The role of vitamin D in maintaining skeletal health is well known, however, its role in relation to 
physical performance is still limited, and it is unknown whether vitamin D status can predict decline in 
physical performance.  Moreover, pertinent to our investigation, only a few studies have objectively 
measured dynamic stability of walking in relation to vitamin D status (as measured by serum 25(OH)D 
levels). In small exploratory studies, dynamic stability segregates with fall-prone status in older 
subjects11,12. Dynamic stability may thus explain the link between vitamin D and fall risk.  To our 
knowledge, this is the first study to test dynamic stability and vitamin D status (serum 25(OH)D levels. 
Objective 
The focus of this study was on assessing the relationship between serum 25(OH)D level and fall risk, as 
measured by dynamic stability of walking utilizing gait parameters derived from inertial measurement 
units (IMUs- composed of tri-axial accelerometer and gyroscopes).   
Method 
A total of 34 participants (13 Male, 21 Female) were screened from community dwelling elderly 
individuals from a local retirement community. Prior to data collection a written consent was obtained. 
The participants were divided into three groups: Highly sufficient (HS), Low sufficient (LS) and 
Insufficient (INS). In this analysis, we compared Highly Sufficient (above 40 ng/ml) group to the 
Insufficient group (below 30 ng/ml) in this analysis to clearly differentiate the groups (i.e., at least 
10ng/ml level separation).     (Table 1). 
 

Table 1. Anthropometric table of the participating population with serum level the vitamin D catabolite, 
25-hydroxyvitamin D [25(OH)D] 
Vitamin D levels Analysis Columns 
N 
Mean 
Std. Dev 
Highly Sufficient 
(Above 40ng/ml) 
Age (yrs.) 
9 
82.77 
3.59 
Height (cm) 
167.56 
10.01 
Weight (kg) 
75.86 
18.19 
Vitamin D3 level 
(ng/ml) 
45.84 
4.87 
Insufficient 
(Below 30 ng/ml) 
Age (yrs.) 
9 
74.77 
7.55 
Height (cm) 
163.22 
8.57 
Weight (kg) 
89.72 
22.13 
Vitamin D3 level 
(ng/ml) 
22.88 
6.70 
 
Fig 1. Participant performing walking task and placement of IMU 
 
 
 
 
 
 
 
 
 
 
 
 

Quickly local dynamic stability was quantified by the maximum Lyapunov Exponent (maxLE) from a 
nonlinear dynamics approach. Briefly, each experimental time series measurement (e.g. acceleration 
measures at the whole body center of mass while walking for 6 minute to assess 40 gait cycles) can be 
reconstructed into a state space with sufficient dimensions to describe the target dynamic system 
unambiguously (Figure 2 and 3).  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig 2. Tracing of the whole body COM and resultant trunk acceleration data 
 
 
Results 
One-way ANOVA using the independent variable vitamin D level (Highly Sufficient and Insufficient) and 
the dependent measure dynamic stability indicates a significant differences in dynamic stability 
measures associated with VitD levels (F-ratio =4.60, p=0.049: Highly Sufficient (mean =1.55, SD=0.14) 
and Insufficient (mean=1.70, SD=0.13) (Figure 3) (lower dynamic stability index indicates less trajectory 
divergence and stable motion pattern). 
Bivariate relationship between vitamin D level and dynamic stability measure indicates R2 =0.28, p=0.03 
(Figure 4).  The relationship is expressed as:  
Dynamic Stability = 1.8357457 - 0.0059743*Vitamin D Level (ng/ml) 

 
 
Figure 3. Effects of serum level (the vitamin D catabolite, 25-hydroxyvitamin D [25(OH)D]) and dynamic 
stability (as measured by maxLE_Stitiched_Acc). 
 
 
 
Figure 4. Bivariate relationship between serum level (the vitamin D catabolite, 25-hydroxyvitamin D 
[25(OH)D]) and dynamic stability. 
 
 

Conclusion 
The current study found a significant difference in dynamic stability associated with serum vitamin D 
levels between highly sufficient group and insufficient group.  Additionally, 28% of variability was 
attributed to dynamic stability between groups. These results suggest that fall risk is higher in the 
insufficient group and may benefit from vitamin D supplementation. 
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