Vitamin D and Health

chair-rising test. Mean baseline serum 25(OH)D concentration was 27 nmol/L (range, 5-87 nmol/L)
which increased to 43 nmol/L in the group supplemented with 10 µg/d (400 IU/d) vitamin D and to
52 nmol/L in the group supplemented with 25 µg/d (1000 IU/d). Vitamin D supplementation had no
significant effect on jump height, handgrip strength or chair-rising test in any group.
6.126 A small RCT in Australia (n=26; mean age, 69y) with the primary aim of assessing the effect of 50 µg/d
(2000 IU/d) of vitamin D 3 for 10 weeks on neuroplasticity, also measured muscle strength and function
(Pirotta et al., 2015). Mean serum 25(OH)D concentration increased from 46 to 81 nmol/L in the
vitamin D treated group, with no change in the placebo group (49 nmol/L at baseline). Compared to
baseline, there was a significant 8-11 % increase in muscle strength in the vitamin D supplemented
group (p < 0.05) but the changes were not significantly different from the placebo group. Vitamin D
supplementation had no effect on muscle power. However, this study was limited by the small
sample size and relatively short duration.
Cohort studies
6.127 Scott et al. (2010) examined the association between baseline serum 25(OH)D concentration and
muscle function in community dwelling adults in Tasmania (n=686; mean age, 62y; 49% women)
followed for 2.6 years. At baseline, participants with a serum 25(OH)D concentration ≤ 50 nmol/L had
significantly lower appendicular lean mass, leg strength, leg muscle quality and physical activity (all
p< 0.05). After adjustment for potential confounders, baseline serum 25(OH)D concentration was an
independent predictor of change in leg strength over time (p=0.027).
6.128 Another prospective study (Menant et al., 2012) of community dwelling adults in Australia (n=463;
age, 70-90y) reported that participants with serum 25(OH)D concentration ≤ 50 nmol/L had weaker
upper and lower limb strength, poorer balance and slower gait speed. Men (but not women) with
serum 25(OH)D concentration ≤ 50 nmol/L also had a significantly higher risk of falls during the 12
months follow up (IRR 49 =1.94; 95% CI, 1.19–3.15; p=0.008).
6.129 A longitudinal analysis in the US (North Carolina) of community dwelling people (n=988; age, 77-100y)
with 3 years follow-up reported that SPPB scores and grip strength were lower in participants with
serum 25(OH)D concentration < 50 nmol/L compared to > 75 nmol/L after adjustment for confounding
factors (Houston et al., 2011). Participants with serum 25(OH)D concentration < 50 nmol/L were at
greater risk of impaired mobility (HR=1.56; 95% CI, 1.06-2.30).
6.130 A longitudinal study in Australia (Bolland et al., 2010) examined the association between serum
25(OH)D concentration and multiple health outcomes in community dwelling women (n=1471; mean
age, 74 y) followed up in a 5 year trial of calcium supplementation. Seasonally adjusted serum
25(OH)D concentration at baseline was < 50 nmol/L in 50% of the women. There was no increase in
risk of adverse consequences for any musculoskeletal outcome including loss of grip strength or falls
after adjustment for comorbidities and other confounding factors.
6.131 Another prospective study in Hong Kong followed community dwelling men (n=714; mean age, 73y)
over 4 years (Chan et al., 2012) and reported that > 90% had a serum 25(OH)D concentration
≥ 50 nmol/L at baseline. After adjustment for potential confounding factors, serum 25(OH)D
concentration was not associated with baseline or change in appendicular skeletal muscle mass or
physical performance measures including grip strength, chair standing time or walking speed.
49 Incident rate ratio.
62