Supplementary Materials
Vitamin D status during fetal life and childhood kidney outcomes
Kozeta Miliku, MD, MSc 1,2,3, Trudy Voortman, MSc 1,2, Oscar H. Franco, MD, PhD 2, John
J. McGrath MD, PhD5,6, Darryl W. Eyles PhD5,6, Thomas H. Burne PhD5,6, Albert Hofman,
MD, PhD 2, Henning Tiemeier, MD, PhD 2,4, Vincent W.V. Jaddoe, MD, PhD* 1,2,3
1. The Generation R Study Group, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
2. Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
3. Department of Pediatrics, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
4. Department of Child and Adolescent Psychiatry, Erasmus MC, University Medical Center, Rotterdam,
the Netherlands
5. Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072 Australia
6. Queensland Centre for Mental Health Research, Park Centre for Mental Health, Wacol QLD, 4076
Australia
Supplementary Table S1. Subject characteristics imputed and non-imputed.
Supplementary Table S2. Subject characteristics between children with kidney measurements and
without kidney measurements .
Supplementary Table S3. Associations of maternal vitamin D levels during pregnancy with kidney
outcomes at the age of 6 years (basic models).
Supplementary Table S4. Associations of vitamin D cord levels with kidney outcomes at the age of 6
years (basic models).
Supplementary Table S5. Associations of maternal and cord vitamin D levels with creatinine and
cystatin C blood levels.
Supplementary Table S6. Associations of maternal 25(OH)D levels during pregnancy with child kidney
outcomes additionally adjusted for child 25(OH)D levels at the age of 6 years (N = 2,644)
Supplementary Table S1. Subject characteristics (N = 4,212)
Maternal characteristics
Maternal age (y)
Maternal body mass index at enrolment (kg/m2)
Education level (%)
- No higher education
- Higher education
Ethnicity (%)
- European
- Cape Verdean
- Dutch Antillean
- Moroccan
- Turkish
- Surinamese
- Other
Smoking during pregnancy (%)
- Never
- Until pregnancy was known
- Continued
Alcohol during pregnancy (%)
- Never
Imputed
Original
31.3 (20.2, 39.4)
22.6 (18.1, 34.3)
31.3 (20.2, 39.4)
22.6 (18.1, 34.2)
51.2
48.8
49.7
50.3
63.2
4.1
2.0
5.6
8.2
7.6
9.3
63.8
4.0
2.0
5.4
8.2
7.5
9.3
75
9.9
15.1
74.9
9.5
15.6
42.8
42.2
-
Until pregnancy was known
14.3
14.4
-
Continued
42.9
43.5
24.5
22.0
Folic acid supplements use (%)
- No
-
Start 1st to 10 weeks
31.2
31.3
-
Start periconceptional
44.3
46.7
2,062 (485)
2,053 (544)
51.9 (7.7, 122.1)
51.9 (7.7, 122.1)
Maternal calories intake (kcal)
Maternal blood levels of 25(OH)D (nmol/L)
Season when blood sample was taken (%)
-
Spring
27.8
27.8
-
Summer
22.6
22.6
-
Autumn
25.5
25.5
-
Winter
24.1
24.1
50.4
40.1 (35.9, 42.3)
3,449 (545)
50.5
40.1 (35.9, 42.3)
3,448 (544)
31.7
61.1
25.7
65.7
Infant characteristics
Girls (%)
Gestational age at birth (wk)
Birth weight (g)
Breastfeeding in the first 4 months (%)
- Exclusive
- Partial
-
Never
Child 25(OH)D level in cord blood at birth (nmol/L)
7.2
8.6
29.3 (5.2, 81.5)
29.3 (5.2, 81.5)
Season when cord blood sample was taken (%)
-
Spring
28.2
28.2
-
Summer
26.5
26.5
-
Autumn
21.4
21.4
-
Winter
23.9
23.9
NI
119 (5.6)
22.2 (17.4, 32.4)
15.8 (13.6, 20.7)
0.86 (0.7, 1.1)
NI
NI
NI
NI
NI
NI
6.0 (5.6, 7.4)
119 (5.6)
22.2 (17.4, 32.4)
15.8 (13.6, 20.7)
0.86 (0.7, 1.1)
120 (22.8)
37.2 (5.5)
784 (80.2)
119 (16.4)
102.5 (14.5)
7.6
Child characteristics at 6y visit
Age (y)
Height (cm)
Weight (kg)
Body mass index (kg/m2)
Body surface area (m2)
Kidney volume (cm3)
Creatinine (µmol/L)
Cystatin C (µg/L)
eGFRcreat ( ml/min/1.73m2)
eGFRcystC( ml/min/1.73m2)
Microalbuminuria (%)
* Values are percentages for categorical variables, means (SD) for continuous variables with a normal distribution,
or medians (95% range) for continuous variables with a skewed distribution.
Abbreviations: eGFRcreat estimated glomerular filtration rate calculated based on creatinine blood levels and
eGFRcystC estimated glomerular filtration rate calculated based on cystatin C blood levels; NI, not imputed
Supplementary Table S2. Subject characteristics with and without kidney measurements
Maternal characteristics
Maternal age (y)
Maternal body mass index at enrolment (kg/m2)
Education level (%)
- No higher education
- Higher education
Ethnicity (%)
- European
- Cape Verdian
- Dutch Antillean
- Moroccan
- Turkish
- Surinamese
- Others
Smoking during pregnancy (%)
- Never
- Until pregnancy was known
- Continued
Alcohol during pregnancy (%)
- Never
N = 4,212
N=1,509
p-value
31.3 (20.2, 39.4)
22.6 (18.1, 34.3)
29.4 (19.0, 38.4)
22.4 (17.6, 35.6)
0.001
0.25
0.001
51.2
48.8
62.0
38.0
0.001
63.2
4.1
2.0
5.6
8.2
7.6
9.3
50.6
4.5
4.3
8.4
11.6
10.4
10.2
75
9.9
15.1
70.7
7.9
21.4
0.001
0.001
42.8
54.2
-
Until pregnancy was known
14.3
12.7
-
Continued
42.9
33.1
Folic acid supplements use (%)
- No
0.001
24.5
33.8
-
Start 1st to 10 weeks
31.2
31.5
-
Start periconceptional
44.3
34.7
2,062 (485)
2,028 (581)
0.09
51.9 (7.7, 122.1)
43.3 (6.7, 111.6)
0.001
Maternal calories intake (kcal)
Maternal blood levels of 25(OH)D (nmol/L)
Season when blood sample was taken (%)
0.03
-
Spring
27.8
30.5
-
Summer
22.6
24.1
-
Autumn
25.5
22.1
-
Winter
24.1
23.3
50.4
40.1 (35.9, 42.3)
3,449 (545)
48.0
40.1 (35.6, 42.3)
3,396 (565)
Infant characteristics
Girls (%)
Gestational age at birth (wk)
Birth weight (g)
Breastfeeding (%)
0.1
0.01
0.002
0.001
-
Exclusive ≥ 4 months
Partial ≥ 4 months
Never or ≤ 4 months
Child 25(OH)D level in cord blood at birth (nmol/L)
31.7
61.1
6.2
20.0
67.2
12.8
29.3 (5.1, 81.5)
25.7 (4.5, 80.5)
Season when cord blood sample was taken (%)
0.001
0.09
-
Spring
28.2
24.4
-
Summer
26.5
29.6
-
Autumn
21.4
22.6
-
Winter
23.9
23.4
* Values are percentages for categorical variables, means (SD) for continuous variables with a normal distribution,
or medians (95% range) for continuous variables with a skewed distribution. Differences in subject characteristics
comparing the groups with and without kidney measurements were evaluated using T-tests for continuous normally
distributed variables, Mann Whitney for non-normally distributed variables, and Chi-squared tests for categorical
variables.
Abbreviations: eGFRcreat estimated glomerular filtration rate calculated based on creatinine blood levels and
eGFRcystC estimated glomerular filtration rate calculated based on cystatin C blood levels
Supplementary Table S3. Associations of maternal 25(OH)D levels during pregnancy with kidney outcomes at the age of 6 years (N = 4,212)
Difference in outcome measure (95% Confidence Interval)
Kidney volume
(cm3)
eGFRcreat
(ml/min/1.73m2)
eGFRcystC
(ml/min/1.73m2)
Microalbuminuria
(odds ratio)
N = 3,897
N= 2,833
N=2,836
N = 4,068
< 25.0 nmol/L (N = 921)
-0.56 (-3.12, 2.00)
1.20 (-1.02, 3.41)
-0.49 (-2.46, 1.48)
1.19 (0.78, 1.82)
25.0 to 49.9 nmol/L (N = 1,083)
2.23 (0.18, 4.27)*
1.28 (-0.46, 3.02)
0.63 (-0.92, 2.19)
0.87 (0.61, 1.25)
50.0 to 74.9 nmol/L (N = 1,055)
1.31 (-0.64, 3.27)
1.53 (-0.15, 3.21)
0.62 (-0.88, 2.12)
1.15 (0.84, 1.58)
Reference
Reference
Reference
Reference
-0.44 (-1.32, 0.44)
-0.82(-1.57, -0.06)*
-0.21 (-0.89, 0,46)
0.96 (0.82, 1.11)
Basic Model#
≥ 75.0 nmol/L (N = 1,153)
Continuously (per SD)
Values are linear and logistic regression coefficients (95% confidence interval). Basic model# is adjusted for child’s sex, age at 6 year visit, season when blood samples were drawn and
maternal ethnicity. * p < 0.05. Continuously = Maternal vitamin D levels analyzed per 1 standard deviation in 25(OH)D.
Abbreviations: SD standard deviation; eGFRcreat estimated glomerular filtration rate calculated based on creatinine blood levels; eGFRcystC estimated glomerular filtration rate calculated based
on cystatin C blood levels.
Supplementary Table S4. Associations of 25(OH)D cord blood levels with kidney outcomes at the age of 6 years (N =2,689)
Difference in outcome measure (95% Confidence Interval)
Kidney volume
(cm3)
eGFRcreat
(ml/min/1.73m2)
eGFRcystC
(ml/min/1.73m2)
Microalbuminuria
(odds ratio)
N = 2,480
N= 1,810
N=1,814
N = 2,598
< 25.0 nmol/L (N = 1,136)
0.71 (-4.14, 5.55)
-0.46 (-4.61, 3.69)
-0.83 (-4.69, 3.04)
0.88 (0.52, 1.50)
25.0 to 49.9 nmol/L (N = 980)
1.84 (-2.80, 6.48)
-1.29 (-5.26, 2.69)
-0.17 (-3.88, 3.53)
0.72 (0.46, 1.12)
50.0 to 74.9 nmol/L (N = 464)
-0.23 (-4.91, 4.45)
-0.73 (-4.85, 3.39)
-1.16 (-4.99, 2.67)
1.09 (0.73, 1.62)
Reference
Reference
Reference
Reference
-0.14 (-1.23, 0.96)
-0.03 (-0.91, 0.97)
0.41 (-0.46, 1.29)
0.97 (0.80, 1.16)
Basic Model#
≥ 75.0 nmol/L (N = 109)
Continuously (per SD)
Values are linear and logistic regression coefficients (95% confidence interval). Basic model# is adjusted for child’s sex and age at 6 year visit, season when blood samples were drawn and
maternal ethnicity. *p < 0.05. Continuously = Cord vitamin D levels analyzed per 1 standard deviation in 25(OH)D. Abbreviations: SD standard deviation; eGFRcreat estimated glomerular
filtration rate calculated based on creatinine blood levels; eGFRcystC estimated glomerular filtration rate calculated based on cystatin C blood levels.
Supplementary Table S5. Associations of 25(OH)D blood levels during pregnancy and in cord blood with creatinine and cystatin C at the age of 6 years
Difference in outcome measure (95% Confidence Interval)
25(OH)D during pregnancy
(N = 2,838)
25(OH)D in cord blood
(N = 1,815)
Creatinine
(umol/L)
Cystatin C
(ug/L)
Creatinine
(umol/L)
Cystatin C
(ug/L)
N = 2,837
N = 2,836
N = 1,814
N = 1,814
Basic Model#
Basic Model#
< 25.0 nmol/L (N = 614)
-0.38 (-1.09, 0.34)
3.50 (-7.40, 14.40)
< 25.0 nmol/L (N = 771)
0.32 (-1.04, 1.68)
2.82 (-17.88, 23.53)
25.0 to 49.9 nmol/L (N = 741)
-0.43 (-0.99, 0.14)
-5.33 (-13.93, 3.27)
25.0 to 49.9 nmol/L (N = 660)
0.75 (-0.56, 2.05)
1.69 (-18.14, 21.51)
50.0 to 74.9 nmol/L (N = 724)
-0.52 (-1.07, 0.02)
-1.97 (-10.27, 6.33)
50.0 to 74.9 nmol/L (N = 312)
0.21 (-1.14, 1.56)
6.81 (-13.72, 27.35)
Reference
Reference
≥ 75.0 nmol/L (N = 72)
Reference
Reference
0.29 (0.04, 0.53)*
1.89 (-1.84, 5.63)
Continuously (per SD)
-0.04 (-0.35, 0.26)
-1.41 (-6.09, 3.28)
≥ 75.0 nmol/L (N = 759)
Continuously (per SD)
Multivariable model£
Multivariable model£
< 25.0 nmol/L (N = 614)
-0.53 (-1.28, 0.23)
2.68 (-8.70, 14.05)
< 25.0 nmol/L (N = 771)
0.05 (-1.30, 1.41)
0.07 (-20.86, 20.99)
25.0 to 49.9 nmol/L (N = 741)
-0.47 (-1.04, 0.10)
-5.34 (-14.09, 3.40)
25.0 to 49.9 nmol/L (N = 660)
0.65 (-0.64, 1.93)
1.47 (-18.41, 21.35)
50.0 to 74.9 nmol/L (N = 724)
-0.50 (-1.04, 0.05)
-1.95 (-10.30, 6.41)
50.0 to 74.9 nmol/L (N = 312)
0.26 (-1.07, 1.59)
7.02 (-13.56, 27.60)
Reference
Reference
Reference
Reference
0.32 (0.07, 0.58)*
2.32 (-1.55, 6.19)
0.20 (-0.09, 0.49)
2.51 (-1.97, 6.98)
≥ 75.0 nmol/L (N = 759)
Continuously (per SD)
≥ 75.0 nmol/L (N = 72)
Continuously (per SD)
Values are linear regression coefficients (95% confidence interval). Basic model# is adjusted for child’s sex, age at 6 year visit and maternal ethnicity. Multivariable adjusted
model £ is adjusted for child’s sex, age at 6 year visit, maternal characteristics (age, body mass index at intake, alcohol consumption, smoking during pregnancy, folic acid and
energy intake during pregnancy, education, prepregnancy comorbidities, season when blood samples were taken) and child characteristics (birthweight adjusted for gestational
age, breastfeeding and body surface area at the age of 6y). *p < 0.05. Continuously = Levels of vitamin D analyzed per 1 standard deviation in 25(OH)D.
Supplementary Table S6. Associations of maternal 25(OH)D levels during pregnancy with child kidney outcomes additionally adjusted for child
25(OH)D levels at the age of 6 years (N = 2,644)
Difference in outcome measure (95% Confidence Interval)
Kidney volume
(cm3)
eGFRcreat
(ml/min/1.73m2)
eGFRcystC
(ml/min/1.73m2)
Microalbuminuria
(odds ratio)
N = 2,472
N= 2,627
N=2,630
N = 2,578
< 25.0 nmol/L (N = 571)
0.18 (-2.80, 3.17)
0.45 (-1.99, 2.88)
-1.05 (-3.21, 1.12)
1.09 (0.61, 1.94)
25.0 to 49.9 nmol/L (N = 688)
2.57 (0.30, 4.84)*
1.12 (-0.71, 2.94)
0.55 (-1.11, 2.20)
0.97 (0.62, 1.51)
50.0 to 74.9 nmol/L (N = 683)
2.17 (0.02, 4.33)*
1.08 (-0.65, 2.82)
0.48 (-1.13, 2.03)
1.01 (0.67, 1.53)
Reference
Reference
Reference
Reference
-0.87 (-1.88, 0.15)
-0.70 (-1.52, 0.15)
-0.10 (-0.84, 0.63)
0.96 (0.73, 1.17)
Multivariable model£
≥ 75.0 nmol/L (N = 702)
Continuously (per SD)
Values are linear and logistic regression coefficients (95% confidence interval). Multivariable adjusted model £ is adjusted for child’s sex, age at 6 year visit, maternal characteristics (age,
body mass index at intake, alcohol consumption, smoking during pregnancy, folic acid and energy intake during pregnancy, education, ethnicity, prepregnancy comorbidities, season when
blood samples were drawn) and child characteristics (birthweight adjusted for gestational age, breastfeeding, and body surface area and 25(OH)D levels at the age of 6y). * p < 0.05.
Continuously = Maternal vitamin D levels analyzed per 1 standard deviation in 25(OH)D.
Abbreviations: SD standard deviation; eGFRcreat estimated glomerular filtration rate calculated based on creatinine blood levels; eGFRcystC estimated glomerular filtration rate calculated based
on cystatin C blood levels.