Free and Bioavailable Fractions of Vitamin D: Association with Maternal Characteristics in Brazilian Pregnant Women

Table 2

Serum concentrations of vitamin D biomarkers according to general characteristics of the adult Brazilian pregnant women studied.

	25(OH)D3		DBP		PTH		Free 25(OH)D3		Bioavailable 25(OH)D3
	(nmoL/L)		(mg/L)		(pg/mL)		(pg/mL)		(ng/mL)	P
Gestational period
27–31 wk	54.4 ± 14.3	0.145	825 ± 164	0.062	28.7 ± 13.6	0.560	1.38 ± 0.40	0.679	0.40 ± 0.14	0.369
32–36 wk	49.4 ± 13.1		753 ± 146		31.5 ± 17.4		1.35 ± 0.38		0.37 ± 0.11
37–41 wk	48.6 ± 14.1		760 ± 128		28.2 ± 13.3		1.30 ± 0.44		0.36 ± 0.13
BMI before pregnancy
Underweight or normal	49.5 ± 13.2	0.513	768 ± 153	0.072	28.4 ± 13.7	0.632	1.35 ± 0.42^ab	0.048	0.38 ± 0.13	0.065
Overweight	53.3 ± 13.5		746 ± 144		30.3 ± 19.5		1.48 ± 0.42^a		0.42 ± 0.14
Obesity	51.2 ± 16.1		833 ± 130		31.6 ± 13.1		1.20 ± 0.31^b		0.34 ± 0.96
Skin type
Very light or light	50.3 ± 13.0	0.698	756 ± 131	0.311	34.1 ± 18.8	0.470	1.38 ± 0.43	0.877	0.38 ± 0.13	0.946
Intermediate	52.6 ± 13.5		785 ± 152		28.9 ± 16.3		1.37 ± 0.37		0.39 ± 0.12
Tanned	51.2 ± 14.5		814 ± 179		28.2 ± 11.2		1.31 ± 0.41		0.38 ± 0.13
Brown or dark	48.5 ± 14.8		750 ± 155		28.3 ± 13.6		1.32 ± 0.43		0.37 ± 0.13
Previous pregnancy
0	50.1 ± 14.4	0.137	788 ± 112	0.136	27.4 ± 15.9	0.537	1.29 ± 0.36	0.136	0.37 ± 0.12	0.086
1	53.5 ± 14.2		774 ± 150		30.0 ± 14.3		1.43 ± 0.41		0.41 ± 0.13
≥2	47.4 ± 12.5		772 ± 181		31.2 ± 14.8		1.27 ± 0.41		0.35 ± 0.13
Gestational weight gain
<0.30 kg/wk	50.2 ± 14.4	0.675	762 ± 133	0.238	28.6 ± 15.8	0.499	1.33 ± 0.41	0.792	0.38 ± 0.13	0.915
≥0.30 kg/wk	51.3 ± 13.6		795 ± 162		30.5 ± 13.9		1.35 ± 0.40		0.38 ± 0.12
Season
Spring	58.7 ± 13.1^a	<0.001	841 ± 160^a	0.019	31.1 ± 12.7	0.660	1.45 ± 0.38^a	0.014	0.42 ± 0.12^a	0.002
Summer	52.5 ± 13.4^ab		761 ± 159^ab		26.7 ± 15.0		1.42 ± 0.43^ab		041 ± 0.13^ab
Autumn	48.4 ± 13.8^bc		757 ± 120^ab		29.1 ± 16.5		1.31 ± 0.41^ab		0.36 ± 0.12^abc
Winter	41.1 ± 8.6^c		735 ± 126^b		30.6 ± 16.2		1.15 ± 0.33^b		0.31 ± 0.99^c

Values are unadjusted mean ± standard deviation. Values for unadjusted least square means (LSD) post hoc test. For each exposure variable, different superscript letters indicate significant difference between categories on the outcome variable (25(OH)D₃, DBP, PTH, free 25(OH)D₃, and bioavailable 25(OH)D₃).