Association between circulating ascorbic acid, α-tocopherol, 25-hydroxyvitamin D, and plasma cytokine concentrations in young adults: a cross-sectional study

Table 2 Mean cytokine concentrations by vitamin tertiles ¹

Cytokine (pg/mL)	Tertile 1	Tertile 2	Tertile 3	p†
				Model 1	Model 2^2,3,4	Model 3^5,6,7
	Serum ascorbic acid
IL-1RA	310.67 ± 11.46	329.51 ± 9.6	326.03 ± 9.75	0.0624	0.0468	0.0413
IFN-γ	179.79 ± 7.33^a	204.95 ± 7.42^b	204.23 ± 7.15^b	0.0006 §	0.0002 §	0.0002 §
IP-10	594.67 ± 27.52	604.55 ± 22.24	590.56 ± 20.54	0.5878	0.5341	0.558
PDGF-bb	1220.29 ± 132.69	1136.53 ± 84.63	1251.47 ± 114.75	0.0686	0.0788	0.0787
RANTES	2529.99 ± 91.78	2490.87 ± 147.66	2295.8 ± 83.83	0.3554	0.4747	0.4962
	Plasma α-tocopherol
IL-1RA	339.87 ± 12.67	317.07 ± 9.97	309.71 ± 7.54	0.0466	0.0248	0.0247
IFN-γ	211.83 ± 7.83^a	197.65 ± 8.16^b	179.97 ± 5.67^b	0.0018	0.0004 §	0.0003 §
IP-10	608.78 ± 22.85	586.16 ± 23.07	595.28 ± 24.77	0.1821	0.1423	0.143
PDGF-bb	1390.83 ± 167.45	1150.59 ± 85.74	1064.07 ± 44.17	0.7387	0.7313	0.7341
RANTES	2556.83 ± 105.39^a	2524.51 ± 150.75^a	2238.31 ± 65.6^b	<0.0001 §	<0.0001 §	<0.0001 §
	Plasma 25(OH)D
IL-1RA	324.23 ± 10.04	315.19 ± 10.38	327.19 ± 10.45	0.5194	0.4750	0.5239
IFN-γ	203.68 ± 7.97	187.19 ± 6.2	198.56 ± 7.69	0.2111	0.1626	0.2214
IP-10	593.58 ± 28.78	562.99 ± 18.05	633.61 ± 22.56	0.4381	0.4366	0.4027
PDGF-bb	1050.22 ± 81.85	1260.6 ± 148.14	1293.67 ± 92.93	0.9075	0.8993	0.9023
RANTES	2174.88 ± 62.99	2427.65 ± 167.06	2715.98 ± 77.22	0.0561	0.0523	0.0236

¹⁾Shown are crude, untransformed means ± standard errors.
†: p-value from ANCOVA with log_e- or square-root transformed cytokine and vitamin concentrations where necessary.
Model 1: adjusted for age, sex, ethnicity, waist circumference, physical activity, season, total cholesterol, and hormonal contraceptive use among women.
Model 2: ²⁾For ascorbic acid, adjusted for the covariates listed in Model 1 plus serum α-tocopherol; ³⁾For α-tocopherol, adjusted for Model 1 plus ascorbic acid; ⁴⁾For 25(OH)D, adjusted for Model 1 plus ascorbic acid.
Model 3: ⁵⁾For ascorbic acid, adjusted for Model 2 plus 25(OH)D; ⁶⁾For α-tocopherol, adjusted for Model 2 plus 25(OH)D; ⁷⁾For 25(OH)D, adjusted for Model 2 plus α-tocopherol.
§: These p-values meet the Bonferroni level of significance for 45 tests (p = 0.0011; α = 0.05; 5 cytokines x 3 vitamins x 3 models).
^a,b,c: Superscript letters indicate significant differences in cytokine concentrations between tertiles (p < 0.05), after adjustment for all covariates included in Model 3. The Tukey-Kramer procedure was used to adjust for multiple comparisons between groups within each ANCOVA. These post-hoc comparisons were only performed when Model p-values met the Bonferroni level of significance.

ISSN: 1743-7075