: Associations between physical performance
and vitamin D status have been contradicted among
studies. Vitamin D deficiency is very common among
geriatric patients and is an established risk
factor for osteoporosis, falls and fractures.
Aim: to analyse the relation between Vitamin
D and basic functional mobility in a sample of
ambulatory Egyptian elderly.
Methods: A cross sectional study was conducted
on 100 elderly patients aged ? 60 years. Participants
were recruited from Geriatric primary health care
clinic at Ain Shams University hospital, Cairo,
Egypt. All participants underwent comprehensive
geriatric assessment, physical performance assessment
using timed up and go (TUG) test and Gait speed
test at four meters; they also had Serum levels
of vitamin D (25OHD) measured by Enzyme- Linked
Immunosorbent Assay method.
Results: Of 100 subjects, 52% showed vitamin
D insufficiency, 16% were vitamin D deficient
and 32% had normal vitamin D levels. Regarding
physical performance 64% of subjects had elevated
TUG test (as defined by the cut off value 14 seconds),
56% of subjects scored a gait speed < 0.6 m/s.
Physical performance was significantly related
to vitamin D deficiency when measured by gait
speed test but not TUG test.
Conclusion: Vitamin D insufficiency is
prevalent among ambulatory elderly and vitamin
D status is strongly associated with basic functional
mobility when measured by gait speed test.
Key words: Vitamin D; Functional mobility
Functional mobility is the ability to move from one
position to another and is extremely important in performing
independently daily activities (1). Recent studies have
documented the relationship between vitamin D supplementation
and functional mobility, muscle strength, sway and the
decreased incidence of falls and fractures (2,3).
Vitamin D (calcitriol) is a hormone that consists of
vitamin D2 (ergocalcipherol) and vitamin D3 (cholecalcipherol).
The main sources of vitamin D are endogenous production
of dermal synthesis due to solar or synthetic ultraviolet
(UV) B light exposure and also could be obtained through
food and supplementation (4,5).
Elderly are prone to develop vitamin D deficiency because
of various risk factors including decreased dietary
intake, diminished sunlight exposure, reduced skin thickness,
impaired intestinal absorption and impaired hydroxylation
in the liver and kidneys.(6,7)
Vitamin D deficiency is very common among institutionalized
elderly, geriatric patients and patients with hip fractures
and it is an established risk factor for osteoporosis,
falls and fractures(8). In an international study conducted
on women with osteoporosis, the highest proportion of
hypovitaminosis D was reported in the Middle East (9).
The Timed Up & Go Test (TUG) is a test of balance
that is commonly used to examine functional mobility
in community-dwelling, frail older adults (10).
Gait speed is highly recommended as the "sixth
vital sign" because of its ability to predict future
health status, its ease of administration, ease of grading
and interpretation and minimal cost involved (11). Studenski
et al reported that gait speed of less than 0.6 m/sec
is predictive for future risk of hospitalization and
decline in health and function(12).
With a growing elder population, there is an increasing
need to identify potentially modifiable risk factors
for disability. This study aimed to determine the relation
between serum vitamin D concentration and functional
mobility in a sample of community dwelling Egyptian
A cross sectional study was conducted on one hundred
elderly; subjects were recruited from Geriatric primary
health care clinic at Ain Shams University hospital
in Cairo city, Egypt, during the period from (April
2014till November 2014).
Sample size justification: based on previous
published literature in Egyptian subjects of 20% prevalence
of vitamin D deficiency and a postulated 35% prevalence
in the elderly group with a power of study 90% and alpha
error 5%, the required sample size is 65 subjects. The
program of sample size calculation is STATA 10.
All participants underwent comprehensive geriatric assessment,
cognitive assessment, physical performance assessment
using (TUG) test and Gait speed test at four meters
and had laboratorial measurement of serum vitamin D
Subjects with dementia, clinical cardiopulmonary, neurological
and musculoskeletal problems that prevent them from
following physical performance test instructions were
TUG test was used to assess the basic functional mobility
by measuring the time required to do subsequent activities:
standing up from a 46 centimeter-high chair with back
and arm support, walking for 3 meters, turn back to
the chair, and sit back. Thus, if a subject scored 14
seconds or longer he or she was classified as high-risk
for falling. (13)
Gait speed test at 4 meters was performed. Participants
were asked to walk at their usual pace. Walking speed
was defined as the best performance of two 4 meter walks
at usual pace along a corridor. Time of shortest walk
was scored and Gait speed was calculated for each participant
using distance in meters and time in seconds. (14)
As regards vitamin D (25OHD), blood samples were collected,
centrifuged and stored at -80°C. Serum levels of
vitamin D (25OHD) were measured using Enzyme-Linked
Immunosorbent Assay (ELISA) method. Vitamin D deficiency
was defined as values below 30 nmol/ L and insufficiency
values ranged from 30 to75 nmol/ L.
Covariates included body mass index (BMI; computed as
weight in kg/height in meters squared and classified
according to WHO classification, 1997) (15).
The collected data were coded, tabulated, revised and
statistically analyzed using SPSS program (version 15).
The statistical tests used in this study were student
t test and ANOVA test for quantitative data and chi-square
test for qualitative data. The level of significance
was taken at P value < 0.05.
Analysis of baseline socio-demographic characters of
subjects showed that mean age of
subjects was 72.8 5.1 years, males represented 57% and
females represented 43% of sample.
Regarding body mass index, 53% of studied elderly were
Overweight (BMI=25-29.9) and obese (BMI >30).
Table 1 shows that 52% of subjects had vitamin D insufficiency,
16% had vitamin D deficiency and 32% had normal vitamin
Table 1: Distribution of vitamin D in whole sample
Females showed higher rate of vitamin D deficiency compared
to males (20.9% versus 12.3%), while males showed higher
rate of vitamin D insufficiency compared to females
(66.7% versus 32.6%) and that was statistically significant.
Diabetes and hypertension were the highest prevalent
co-morbidities among studied subjects, 43% and 47% respectively
as shown in Table 2.
Table 2: The Distribution of CO-morbidities among
CLD = chronic liver disease
ISHD = ischemic heart disease
CVS = cerebrovascular stroke
COPD = chronic obstructive pulmonary disease
Sixty four percent of subjects scored TUG test >14
seconds as shown in Table 3.
Table 3: Distribution of Timed up and go (TUG) test
score among subjects
As regards gait speed test, subjects were divided into
2 groups; 56% scored a gait speed < 0.6 m/s and 44%
scored a speed >0.6 m/s.
Table 4 shows higher percentage of elevated TUG among
subjects deficient in vitamin D compared to other groups
but the difference was not statistically significant.
Table 4: Relation between vitamin D status and TUG
Table 5 shows that mean Gait speed test was elevated
among vitamin D deficient subjects 5.4 2.4 compared
to those with normal vitamin D and the difference was
Table 5: Relation between vitamin D status and mean
Table 6 shows higher percentage of Vitamin D deficiency
(60%) among very obese subjects (BMI >40)
compared to other groups and higher percentage of vitamin
D insufficiency (65.2%) among obese subjects (BMI >30).
Table 6: Relation between BMI and vitamin D status among
BMI (body mass index)
The relation between vitamin D status and basic functional
mobility has been investigated in this cross sectional
study. The mean age of subjects was 72.8 (±5.1)
years. TUG test and gait speed test were used as measures
for functional mobility among subjects.
In the present study 52% of subjects showed vitamin
D insufficiency, 16% showed vitamin D deficiency and
32% had normal vitamin D levels. Vitamin D deficiency
was more common among females compared to males while
insufficiency was more among males.
Reviewing literature, Aly et al reported that vitamin
D insufficiency represented 26% and was more common
among males in a study conducted on elderly in Dakhlia
governorate in Egypt (16). In the InCHIANTI study Houston
et al reported that vitamin D deficiency among females
represented 28.8% versus 13.6% among males (17) and
in Jakarta, a study conducted on elderly women reported
23.3% vitamin D deficiency rate (18).
Associations between physical performance and vitamin
D status have been contradicted among studies. In the
current study vitamin D (25- OH ) deficiency was inversely
associated with gait speed which agreed with results
of Houston et al who reported that vitamin D (25- OH)
status was inversely associated with poor physical performance.
(17) On the contrary, Belfrail population-based study
showed no association between gait speed and serum levels
of (25-OHD) in elders.(19)
Possible explanation of this contradiction among studies
is that researchers have not yet identified the circulating
25-OHD concentrations needed to ensure optimal muscle
functioning in elderly people and use a wide range of
cut-off levels to define 25-OHD deficiency.
The present study showed that (TUG) test was elevated
in 68% of subjects with vitamin D deficiency compared
to 52% of subjects with normal vitamin D with no statistical
significant difference. This finding comes in agreement
with Gschwind et al who didn't find significant difference
between cases with the higher quartile of vitamin D
and cases with the lowest quartile in performance of
TUG test (20). Also Dukas et al reported that TUG was
not associated with serum 25-OHD levels in a study conducted
on community-dwelling elders (21). This can be explained
by presence of factors other than vitamin D which affect
TUG test such as nervous system, spine and hip flexibility,
range of motion of the joints, muscles, biomechanical
relationship between body segments, diseases, medications,
Regarding BMI, vitamin D deficiency and insufficiency
were higher among obese and very obese groups compared
to non obese. This comes in agreement with Lagunova
et al who reported a significant decrease in serum 25(OH)
D3 levels with increasing body mass index in elderly(24).
Also Linnebur et al reported that vitamin D deficiency
remained present in obese elderly even after taking
vitamin D supplementation (25). Obesity-associated low
vitamin D levels are likely due to the decreased bioavailability
from cutaneous and dietary sources because of its deposition
in body fat compartments. (26)
Hypovitaminosis D is common among ambulatory Egyptian
elderly and significantly affects gait speed. We recommend
further studies with larger sample sizes; also we recommend
that researchers should agree on ranges and cutoff values
for vitamin D deficiency in elderly.
Informed consent was taken from every elder participating
in this study; also an approval was taken from the head
of Geriatrics and Gerontology Department. The study
methodology was reviewed and approved by the Research
Review Board of the Geriatrics and Gerontology Department,
Faculty of medicine, Ain Shams University.
1. Mix CM, Specht DP. Achieving functional independence.
In: Braddom RL, editor. Physical medicine and rehabilitation.
2nd ed. Philadelphia: WB Saunders. 2000; p. 517-34.
2. Bischoff HA, Stahelin HB, Dick W, Akos R, Knecht
M, Salis C, et al. Effects of vitamin D and calcium
supplementation on falls: a randomized controlled trial.
J Bone Miner Res. 2003; 18:343-51.
3. Holick MF. Sunlight "D"ilemma: risk of
skin cancer or bone disease and muscle weakness. Lancet.
4. Bikle DD. Vitamin D: production, metabolism, and
mechanisms of action. Available from: http://www. endotext.com/hyperlink.htm.
5. Holick MF, Krane SM. Introduction to bone and mineral
metabolism. In: Braunwald E, Fauci AS, Kasper DL, Hauser
SL, Longo DL, Jameson JL, editors. Harrison's principles
of internal medicine. Vol 2. 15th ed. New York: Mc Graw
Hill. 2001; p. 2198-205.
6. Omdahl JL, Garry PJ, Hunsaker LA, Hunt WC, Goodwin
JS. Nutritional status in a healthy elderly population:
vitamin D. Am J Clin Nutr .1982;36:1225-33.
7. Holick MF. Environmental factors that influence the
cutaneous production of vitamin D. Am J Clin Nutr .1995;61(suppl):638S-45S.
8. Mosekilde L. Vitamin D and the elderly. Clinical
Endocrinology 2005;62, 265-281
9. Vitamin D status in Middle East and Africa, American
University of Beirut Medical Center, Department of Internal
Medicine, Beirut, Lebanon, BY Rola El-Rassi, Ghassan
Baliki and Ghada El-Hajj Fuleihan. International Osteoporosis
10. Podsiadlo D, Richardson S. The timed "Up &
Go": a test of basic functional mobility for frail
elderly persons. J Am Geriatr Soc.1991 ;39:142-148.
11. Fritz S, Lusardi M. White Paper: Walking Speed:
the Sixth Vital Sign. J Geriatr Phys Ther. 2009;32(2):2-5.
12. Studenski S, Perera S, Wallace D, Chandler JM, Duncan
PW, Rooney E, et al. J Am Geriatr Soc. 2003 Mar;51(3):314-22.
13. Shumway-Cook A, Brauer S, Woollacott M. Predicting
the probability for falls in community-dwelling older
adults using the timed up & go test. Phys Ther.
14. Short physical performance battery. National Institute
on Aging available at (www.grc.nia.nih.gov/branches/ledb/sppb/).
15. "Preventing and Managing the Global Epidemic
of Obesity. Report of the World Health Organization
Consultation of Obesity." WHO, Geneva, June 1997P.
16. Aly WW, Hussein MA, Ebeid SA, Mortagy AK. Prevalence
of vitamin D insufficiency among community dwelling
elderly. Aging clin exp res . 2014; 26:47-51.
17. Houston DK, Cesari M, Ferrucci L, Cherubini A, Maggio
D, Bartali B, et al. Association Between Vitamin D Status
and Physical Performance: The InCHIANTI Study J Gerontol
A Biol Sci Med Sci. 2007 April; 62(4): 440-446.
18. Laksmi PW, Setiati S, Oemardi M, Aries W, Siregar
P. Correlation Between Vitamin D Concentration and Basic
Functional Mobility in Elderly Women. Acta Med Indones-Indones
J Intern Med .2007; Vol 39 o Number 3 .
19. Matheï C, Van Pottelbergh G, Vaes B, Adriaensen
W, Gruson D and Degryse J-M. No relation between vitamin
D status and physical performance in the oldest old:
results from the Belfrail study Age Ageing (2013) 42
(2): 186-190. doi: 10.1093/ageing/afs186 First published
online: January 29, 2013( Age and Ageingageing.oxfordjournals.org.).
20. Gschwind YJ, Bischoff-Ferrari
HA, Bridenbaugh SA, Härdi I, Kressig RW. Association
between Serum Vitamin D Status and Functional Mobility
in Memory Clinic Patients Aged 65 Years and Older. Gerontology.
2013 Dec 7. [Epub ahead of print]
21. Dukas L, Staehelin HB, Schacht E, Bischoff HA. Better
functional mobility in community-dwelling elderly is
related to D-hormone serum levels and to daily calcium
intake. J Nutr Health Aging. 2005;9:347-51.
22. Postural Control. In: Shumway-Cook A, Woollacott
MH, editors. Motor control: theory and practical applications.
2nd ed. Philadelphia: Lippincott Williams & Wilkins;
2001. p. 163-91
23. Elble RJ. Changes in gait with normal aging. In:
Masdeu JC, Sudarsky L, Wolfson L, editors. Gait disorders
of aging: falls and therapeutic strategies. Philadelphia:
24. Lagunova Z, Porojnicu AC, Lindberg F, Hexeberg S,
Moan J. The dependency of vitamin D status on body mass
index, gender, age and season. Anticancer Res. 2009
25. Linnebur SA, Vondracek SF, Vande Griend JP, Ruscin
JM, McDermott MT. Prevalence of vitamin D insufficiency
in elderly ambulatory outpatients in Denver, Colorado.
Am J Geriatr Pharmacother. 2007 Mar;5(1):1-8.
26. Wortsman J, Matsuoka LY, Chen TC, Lu Z, Holick MF.
Decreased bioavailability of vitamin D in obesity. Am
J Clin Nutr September 2000 ;vol. 72 no. 3 690-693.