The Association between Seasonal Variation in Vitamin D, Postural Sway, and Falls Risk: An Observational Cohort Study
Table 1
Variations in serum vitamin D and dynamic and postural balance over 5 seasons.
Variable
End of spring
End of summer
End of autumn
End of winter
End of spring
ML sway EO (cm) mean (SD)
1.9 (0.7)
1.2 (0.6)
1.3 (0.5)
1.1 (0.5)
1.1 (0.5)
Range
0.7–5.0
0.4–3.8
0.6–2.8
0.4–3.6
0.5–2.5
Change from season 1 mean (95% CI)
−0.6 (−0.7 to −0.5)*
−0.6 (−0.7 to −0.4)*
−0.8 (−0.9 to −0.6)*
−0.7 (−0.8 to −0.4)*
ML sway EC (cm) mean (SD)
2.1 (0.9)
1.4 (0.7)
1.4 (0.7)
1.3 (0.8)
1.4 (0.8)
Range
0.8–4.7
0.4–3.8
0.6–4.2
0.6–5.2
0.5–4.9
Change from season 1 mean (95% CI)
−0.7 (−0.8 to −0.6)*
−0.7 (−0.8 to −0.6)*
−0.8 (−0.9 to −0.6)*
−0.7 (−0.9 to −0.6)*
Foam ML (cm) sway EO mean (SD)
3.8 (1.2)
2.8 (1.1)
3.0 (1.2)
2.4 (0.8)
2.6 (0.8)
Range
1.0–8.4
1.1–7.0
1.2–11.41
1.2–6.0
1.1–5.8
Change from season 1 mean (95% CI)
−1.0 (−1.2 to −0.7)*
−0.8 (−1.0 to −0.5)*
−1.2 (−1.5 to −1.0)*
−1.2 (−1.4 to −0.9)*
Foam ML (cm) sway EC mean (SD)
6.8 (2.7)
5.0 (1.7)
4.7 (2.1)
4.6 (1.9)
4.8 (1.9)
Range
2.0–28.7
1.7–10.5
2.0–14.0
2.0–11.9
1.9–16.2
Change from season 1 mean (95% CI)
−1.7 (−2.3 to −1.2)*
−2.1 (−2.6 to −1.5)*
−2.1 (−2.8 to −1.5)*
−2.1 (−2.8 to −1.3)*
Serum vitamin D (nmol/L) mean (SD)
60 (19)
68 (21)*
58 (21)
52 (21)*
59 (20)
Range
20–115
10–126
13–115
16–107
20–114
Change from season 1 mean (95% CI)
8 (6 to 11)
−2 (−5 to 1)
−8 (−11 to −5)
−2 (−5 to 1)
Data presented as mean (SD), changes from season one presented as mean change (95% CI) (adjusted for age, gender strength, and physical activity), *(), ML: mediolateral, EO: eyes open, EC: eyes closed, cm: centimeter.
