Vitamin D, Gestational Diabetes, and Measures of Glucose Metabolism in a Population-Based Multiethnic Cohort

Table 1

25-Hydroxyvitamin D (25(OH)D) status and confounding variables in the total sample and stratified by gestational diabetes mellitus (GDM) status, WHO 2013 criteria. Values are mean (95% confidence interval) or (numbers (%)).

		GDM (WHO 2013)
		Yes	No
	Status at inclusion (15 GW^i)
Overall mean 25(OH)D (nmol/L)	50.2 (48.3, 52.1)	47.7 (44.0, 51.3)	51.4 (49.2, 53.7)	0.07
25(OH)D < 50 nmol/L (n (%))	389 (52)	141 (60)	248 (49)	0.01
25(OH)D status during pregnancy^a
Consistently sufficient (n (%))	417 (57)	109 (47)	308 (61)	<0.01
Decreasing (n (%))	63 (8.6)	22 (9.6)	41 (8.1)	0.50
Increasing (n (%))	145 (20)	55 (24)	90 (18)	0.06
Consistently deficient (n (%))	111 (15)	44 (19)	67 (13)	0.03
Prepregnancy maternal status
Age (years)	29.8 (29.5, 30.2)	30.3 (29.6, 30.9)	29.6 (29.2, 30.1)	0.12
Ethnicity (n (%))
Europe	346 (46.4)	82 (35)	264 (52)	<0.01
South Asia	191 (25.6)	81 (35)	110 (22)	<0.01
Middle East and North Africa	115 (15.4)	41 (17)	74 (15)	0.49
Sub-Saharan Africa	53 (7.1)	20 (8.5)	33 (6.5)	0.32
East Asia	40 (5.4)	11 (4.7)	29 (5.7)	0.57
Parity (n (%))
Para 0	340 (46)	104 (44)	236 (46)	0.61
Para 1	256 (34)	73 (31)	183 (36)	0.18
Para ≥ 2	149 (20)	58 (25)	91 (18)	0.03
Education (years) (n (%))^a
<10	122 (16)	50 (21)	72 (14)	0.02
10–12	293 (40)	100 (43)	193 (38)	0.20
>12	324 (44)	84 (36)	240 (48)	<0.01
Prepregnancy BMI^ii (kg/m^2)^a	24.5 (24.2, 24.9)	25.9 (25.2, 26.6)	23.9 (23.5, 24.3)	<0.01
Status at inclusion
Gestational week	15.1 (14.9, 15.4)	15.2 (14.7, 15.6)	15.1 (14.8, 15.4)	0.74
Sum of skinfolds (mm)^b	72.0 (70.6, 73.5)	77.0 (74.3, 79.8)	69.8 (68.1, 71.5)	<0.01
Season for 25(OH)D measurement (n (%))
Summer	347 (47)	130 (55)	217 (43)	<0.01
Winter	398 (53)	105 (45)	293 (57)	<0.01
Status at 28 GW
Gestational week^c	28.3 (28.2, 28.4)	28.2 (28.0, 28.3)	28.3 (28.2, 28.4)	0.20
ΔSum of skinfolds (15 to 28 GW) (mm)^d	5.8 (4.8, 6.8)	6.2 (4.5, 7.9)	5.6 (4.3, 6.8)	0.58
Weight gain (prepregnant to 28 GW) (kg)	8.7 (8.3, 9.0)	8.8 (8.1, 9.4)	8.6 (8.2, 9.0)	0.71
Dietary clusters (n (%))^a
Healthy	239 (33)	54 (23)	185 (37)	<0.01
Unhealthy	493 (67)	179 (77)	314 (63)	<0.01

ⁱGW: gestational week derived from the 1st day of the woman’s last menstrual period; ⁱⁱBMI: body mass index; ^amissing information of 5–13 women; ^b; ^cmissing information of 1–4 women; ^d. Consistently sufficient: 25(OH)D ≥ 37 nmol/L at 15 and 28 GW. Decreasing: 25(OH)D ≥ 37 nmol/L at 15 GW and <37 nmol/L at 28 GW. Increasing: 25(OH)D < 37 nmol/L at 15 GW and ≥37 nmol/L at 28 GW. Consistently deficient: 25(OH)D < 37 nmol/L at 15 and 28 GW. values for the differences between GDM and non-GDM. Bold numbers indicate values < 0.05. Independent t-test or two-sample test of proportions.