. 2018 Sep 1;10(9):1197. doi: 10.3390/nu10091197

Table 2.

Association between plasma 25-hydroxy vitamin D and the age-adjusted standard score (Raven’s Standard Progressive Matrices test) before and after adjusting for potential confounders.

Vitamin D Status	Model 1	Model 2	Model 3	Model 4	Model 5
Vitamin D Status	β [95%CI]	β [95%CI]	β [95%CI]	β [95%CI]	β [95%CI]
25-OH-D levels nmol/L	0.03	0.01	0.00	0.00	−0.01
25-OH-D levels nmol/L	[−0.02, 0.08]	[−0.04, 0.07]	[−0.05, 0.06]	[−0.05, 0.06]	[−0.07, 0.05]
p-value	0.23	0.70	0.95	0.85	0.73
Q1 (25-OH-D < 19.2 nmol/L) (n = 337)	[Reference]	[Reference]	[Reference]	[Reference]	[Reference]
Q2 (25-OH-D ≥ 19.2 to <29.7 nmol/L) (n = 346)	0.86	1.12	−0.39	1.15	0.82
Q2 (25-OH-D ≥ 19.2 to <29.7 nmol/L) (n = 346)	[−2.65, 4.38]	[−2.32, 4.58]	[−4.28, 3.49]	[−2.29, 4.59]	[−2.82, 4.46]
Q3 (25-OH-D from 29.7 to <44.1 nmol/L) (n = 344)	2.67	2.29	−0.26	2.69	0.84
Q3 (25-OH-D from 29.7 to <44.1 nmol/L) (n = 344)	[−0.86, 6.19]	[−1.43, 6.02]	[−6.25−5.72]	[−1.03, 6.41]	[−3.24, 4.92]
Q4 (25-OH-D ≥ 44.1 nmol/L) (n = 343)	2.91	0.95	−0.70	0.50	−0.42
Q4 (25-OH-D ≥ 44.1 nmol/L) (n = 343)	[−0.62, 6.43]	[−3.00, 4.90]	[−7.92, 6.53]	[−3.47, 4.47]	[−4.82, 4.01]
p-value	0.30	0.67	1.00	0.45	0.88
Severe deficiency (25-OH-D < 25 nmol/L) (n = 544)	[Reference]	[Reference]	[Reference]	[Reference]	[Reference]
Deficiency (25-OH-D ≥ 25 to <50 nmol/L) (n = 572)	2.28	2.52	2.70	2.71	1.36
Deficiency (25-OH-D ≥ 25 to <50 nmol/L) (n = 572)	[−0.46, 5.04]	[−0.39, 5.44]	[0.22, 5.63]	[−0.22, 5.63]	[−1.86, 4.59]
Insufficiency (25-OH-D ≥ 50 to <75 nmol/L) (n = 205)	1.40	−0.66	−0.93	−0.94	−1.53
Insufficiency (25-OH-D ≥ 50 to <75 nmol/L) (n = 205)	[−2.36, 5.16]	[−4.66, 3.34]	[−4.94, 3.09]	[−4.97, 3.08]	[−6.01, 2.94]
Sufficiency (25-OH-D ≥ 75 nmol/L) (n = 49)	5.46	4.98	2.79	3.02	1.47
Sufficiency (25-OH-D ≥ 75 nmol/L) (n = 49)	[−1.39, 12.31]	[−1.96, 11.92]	[−4.16, 9.74]	[−3.93, 9.98]	[−5.96, 8.91]
p-value	0.24	0.11	0.11	0.10	0.48

Q1 to Q4: quartile one to quartile four; Model 1: unadjusted; Model 2: adjusted for socio-demographic factors (gender, nationality, governorate, education of the father, education of the mother, type of housing, season of birth, and passive smoking at home); Model 3: adjusted for variables in Model 2 in addition to grade level, sleeping hours during weekends, having nap during weekend, time spent outside during the last 3 months during weekdays and weekends, reporting medical condition, and frequency of consumption of sugary drinks; Model 4: adjusted for variables in Model 3 in addition to BMI categories; Model 5: adjusted for variables in Model 4 in addition to parathyroid hormone, vitamin B₁₂, and transferrin saturation all as quartiles.