TABLE 2.

Serum NfL concentrations by categories of serum 25‐hydroxyvitamin D

25 (OH)D (nmol/L)	NfL (pg/ml)
0‐<25 (N = 5)	11.46 (6.18–12.03)
25‐<50 (N = 14)	10.31 (7.10–12.91)
50‐<75 (N = 27)	13.91 (11.17–17.40)
75‐<100 (N = 23)	12.50 (11.03–19.97)
≥ 100 (N = 10)	11.08 (8.85–13.62)

Serum samples were collected 79 sampling occasions at the study baseline (32 patients, 17 vitamin D, 15 placebo), 6 months (20 patients, 12 vitamin D, and 8 placebo), and at 12 months (25 patients, 13 vitamin D, 12 placebo). The 25(OH)D values are seasonal. Values are given as median (95% confidence interval). Differences between categories were not significant in unpaired t test of log‐transformed sNfL values, and there was no significant correlation between the 25(OH)D values and sNfL in Pearson correlation test.

Abbreviations: 25(OH)D = 25‐hydroxyvitamin D; NfL, neurofilament light.