Table 3.

Multivariate linear regression for square-root-transformed 25(OH)D₃ concentrations with season, BMI and weekly minutes of accelerometry-derived physical activity.

Variable	β-estimate, standard error	p-value	95% confidence interval
6 months n=58
Intercept	+2.27 ±0.73	0.003	+0.82 to 3.73
Age	+0.02±0.01	0.22	−0.01 to 0.04
Sex	+0.23±0.34	0.51	−0.46 to 0.91
BMI (kg/m2)	+0.04 ±0.05	0.47	−0.07 to 0.14
Moderate PAa)	+0.01 ±0.03	0.76	−0.06 to 0.08
Vigorous PAb)	+0.18 ±0.05	0.002	+0.07 to 0.29
Seasonc)	−0.71 ±0.31	0.02	−1.33 to −0.10
12 months n=51
Intercept	+4.18 ±0.77	<0.0001	+2.64 to 5.73
Age	−0.00012±0.02	0.97	−0.03 to 0.03
Sex	−0.72±0.38	0.07	−1.49 to 0.57
BMI (kg/m2)	−0.08 ±0.05	0.13	−0.19 to 0.03
Moderate PAa)	+0.04 ±0.04	0.33	−0.04 to 0.13.
Vigorous PAb)	−0.02 ±0.09	0.84	−0.20 to 0.16
Seasonc)	−1.14 ±0.34	0.002	−1.82 to −0.46
24 months n=28
Intercept	+3.25 ±0.94	0.002	+1.31 to 5.19
Age	−0.02±0.02	0.38	−0.07 to 0.03
Sex	−0.59±0.55	0.29	−1.74 to 0.55
BMI (kg/m2)	−0.01 ±0.05	0.85	−0.12 to 0.10
Moderate PAa)	+0.02 ±0.07	0.80	−0.12 to 0.15
Vigorous PAb)	−0.04 ±0.09	0.67	−0.22 to 0.15
Seasonc)	−0.48 ±0.48	0.33	−1.49 to 0.53

^a)Minutes of moderate physical activity measured by accelerometry, square-root transformed

^b)Minutes of vigorous physical activity measured by accelerometry, square-root transformed

^c)1=summer/fall, 2=winter/spring

Variable features: BMI, moderate-to-vigorous PA, moderate PA: continuous; Season: binary

Abbreviations: min, minutes; BMI, body mass index; kg, kilogram; PA, physical activity; MVPA, moderate-to-vigorous physical activity