A prospective study of the associations between 25-hydroxy-vitamin D, sarcopenia progression and physical activity in older adults.
OBJECTIVE
Low 25-hydroxyvitamin D (25OHD) levels may be associated with both sarcopenia (the age-related decline in muscle mass and function) and low physical activity (PA). Our objective was to describe prospective associations between 25OHD, muscle parameters, and PA in community-dwelling older adults.


METHODS
Prospective, population-based study with a mean follow-up of 2·6 ± 0·4 years.


METHODS
Six hundred and eighty-six community-dwelling older adults (49% women; mean ± SD 62 ± 7 years old).


METHODS
Appendicular lean mass percentage (%ALM) and body fat assessed by Dual-energy X-ray Absorptiometry, leg strength by dynamometer, leg muscle quality (LMQ), PA assessed by pedometer, self-reported sun exposure by questionnaire, and serum 25OHD measured by radioimmunoassay.


RESULTS
Participants with 25OHD ≤50 nM had lower mean %ALM, leg strength, LMQ and PA (all P < 0·05). As a continuous function, baseline 25OHD was a positive independent predictor of change in leg strength (β = 5·74 kg, 95% CI 0·65, 10·82) and LMQ (β = 0·49 kg/kg, 95% CI 0·17, 0·82). Also, change in 25OHD was positively predicted by baseline %ALM (β = 2·03 pM/p.a., 95% CI 0·44, 3·62) leg strength (β = 0·30 pM/p.a., 95% CI 0·06, 0·53), LMQ (β = 4·48 pM/p.a., 95% CI 0·36, 8·61) and PA (β = 2·63 pM/p.a., 95% CI 0·35, 4·92) after adjustment for sun exposure and body fat.


CONCLUSIONS
25OHD may be important for the maintenance of muscle function, and higher skeletal muscle mass and function as well as general PA levels may also be beneficial for 25OHD status, in community-dwelling older adults.
Scott
David
D
Menzies Research Institute, University of Tasmania, Hobart School of Human Life Sciences, University of Tasmania, Launceston, Tas, Australia. dsscott@utas.edu.au
Blizzard
Leigh
L
Fell
James
J
Ding
Changhai
C
Winzenberg
Tania
T
Jones
Graeme
G
D015502:Absorptiometry, Photon; D000368:Aged; D005260:Female; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology; D011446:Prospective Studies; D055948:Sarcopenia / Q000209:etiology*; D013648:Tasmania; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D014807:Vitamin D; C104450:25-hydroxyvitamin D