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\begin{document}

\title{Maternal antenatal vitamin D supplementation and offspring risk of
atopic eczema in the first 4 years of life}



\author[1]{Sarah El-Heis}%
\author[1]{Stefania D’Angelo}%
\author[1]{Elizabeth Curtis M}%
\author[2]{E. Healy}%
\author[1]{Rebecca Moon J}%
\author[1]{Sarah  Crozier}%
\author[1]{Hazel Inskip}%
\author[1]{Cyrus Cooper}%
\author[1]{Nicholas Harvey}%
\author[1]{Keith Godfrey}%
\affil[1]{University of Southampton}%
\affil[2]{University of Southampton Faculty of Medicine}%


\vspace{-1em}



  
  \date{June 17, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
\textbf{Background} Evidence linking prenatal maternal vitamin D
supplementation and offspring risk of atopic eczema is inconsistent,
with most data coming from observational studies. \textbf{Methods}
Within the UK Maternal Vitamin D Osteoporosis Study (MAVIDOS)
double-blind, randomised, placebo-controlled trial, we examined the
relation of maternal vitamin D supplementation during pregnancy with
offspring atopic eczema at ages 12, 24 and 48 months. In MAVIDOS,
pregnant women were allocated to either cholecalciferol 1000 IU/day or
matched placebo, taken from around 14 weeks' gestation until delivery,
with the primary outcome of neonatal whole-body bone mineral content.
The prevalence of atopic eczema in the offspring was ascertained at ages
12 (n=636), 24 (n=611) and 48 (n=450) months, based on the UK Working
Party Criteria for the Definition of Atopic Dermatitis. \textbf{Results}
Mothers and offspring characteristics were similar between the
intervention and placebo groups, apart from longer breastfeeding
duration in the intervention group. Adjusting for breastfeeding
duration, offspring of mothers who received 1000 IU cholecalciferol
daily had a lower odds ratio (OR) of atopic eczema at age 12 months: OR
(95\%CI) 0.55 (0.32-0.97), p=0.04. The ORs of atopic eczema in the
intervention group at ages 24 and 48 months were 0.77 (0.47-1.24) and
0.71 (0.35-1.43), respectively. \textbf{Conclusion} Our data
demonstrated a clinically important reduction in offspring risk of
atopic eczema in infancy following maternal cholecalciferol
supplementation during pregnancy. The findings support a developmental
influence on infantile atopic eczema and point to gestational
cholecalciferol supplementation as a preventive strategy to reduce the
burden of atopic eczema during infancy.%
\end{abstract}%



\sloppy


\textbf{Maternal antenatal vitamin D supplementation and offspring risk
of atopic eczema in the first 4 years of life}

\emph{Sarah El-Heis\textsuperscript{1}} DM

Stefania D'Angelo \textsuperscript{1} MSc

Elizabeth M Curtis \textsuperscript{1} PhD

Eugene Healy\textsuperscript{2} PhD

Rebecca J Moon\textsuperscript{1} PhD

Sarah R Crozier\textsuperscript{1,3} PhD

Hazel Inskip\textsuperscript{1,4} PhD

Cyrus Cooper\textsuperscript{1,4,5} FMedSci

Nicholas C Harvey\textsuperscript{1,4} PhD

Keith M Godfrey\textsuperscript{1,4,6} FMedSci

MAVIDOS Trial Group*

\textsuperscript{1} Medical Research Council Lifecourse Epidemiology
Centre, University of Southampton, Southampton, UK

\textsuperscript{2} Dermatopharmacology, Faculty of Medicine, University
of Southampton, Southampton, UK

\textsuperscript{3} NIHR Applied Research Collaboration Wessex,
Southampton Science Park, Innovation Centre, Southampton, UK

\textsuperscript{4} NIHR Nutrition Biomedical Research Centre,
University of Southampton and University Hospital Southampton NHS
Foundation Trust, Southampton, UK

\textsuperscript{5} NIHR Musculoskeletal Biomedical Research Unit,
University of Oxford, Oxford

\textsuperscript{6} Developmental Sciences, University of Southampton,
Southampton, UK

\emph{NCH \& KMG are joint senior authors}

Members of the MAVIDOS Trial Group for inclusion in the Medline citation
are:

Nigel K Arden, Nicholas J Bishop, Andrew Carr, Elaine M Dennison,
Richard Eastell, Robert Fraser, Saurabh V Gandhi, M Kassim Javaid,
Stephen H Kennedy, M Zulf Mughal, Aris T Papageorghiou, Ann Prentice,
Inez Schoenmakers

\textbf{Correspondence to} :

Professor Keith Godfrey

Medical Research Council Lifecourse Epidemiology Centre (University of
Southampton)

Southampton General Hospital, Mail point 95

Southampton SO16 6YD

United Kingdom.

Tel: 44 (0)23 80777624

Fax: +44 (0)23 80704021

Email: kmg@mrc.soton.ac.uk

\textbf{Short title}

Antenatal vitamin D supplementation and offspring eczema

\textbf{Word count}

2728

\textbf{Table and figure count}

5

\textbf{Trial Reg} .

ISRCTN 82927713, EudraCT 2007-001716-23

\textbf{Acknowledgements}

Authors' roles: All authors contributed to the preparation and approval
of the final manuscript. SEH, SD and KMG prepared the first draft. NCH
and CC led and oversaw the MAVIDOS trial. KMG supervised the preparation
of the manuscript and is guarantor.

For the purpose of Open Access, the author has applied a Creative
Commons Attribution (CC BY) licence to any Author Accepted Manuscript
version arising from this submission.

\textbf{Background}

Evidence linking prenatal maternal vitamin D supplementation and
offspring risk of atopic eczema is inconsistent, with most data coming
from observational studies.

\textbf{Methods}

Within the UK Maternal Vitamin D Osteoporosis Study (MAVIDOS)
double-blind, randomised, placebo-controlled trial, we examined the
relation of maternal vitamin D supplementation during pregnancy with
offspring atopic eczema at ages 12, 24 and 48 months. In MAVIDOS,
pregnant women were allocated to either cholecalciferol 1000 IU/day or
matched placebo, taken from around 14 weeks' gestation until delivery,
with the primary outcome of neonatal whole-body bone mineral content.
The prevalence of atopic eczema in the offspring was ascertained at ages
12 (n=636), 24 (n=611) and 48 (n=450) months, based on the UK Working
Party Criteria for the Definition of Atopic Dermatitis.

\textbf{Results}

Mothers and offspring characteristics were similar between the
intervention and placebo groups, apart from longer breastfeeding
duration in the intervention group. Adjusting for breastfeeding
duration, offspring of mothers who received 1000 IU cholecalciferol
daily had a lower odds ratio (OR) of atopic eczema at age 12 months: OR
(95\%CI) 0.55 (0.32-0.97), p=0.04. The ORs of atopic eczema in the
intervention group at ages 24 and 48 months were 0.77 (0.47-1.24) and
0.71 (0.35-1.43), respectively.

\textbf{Conclusion}

Our data demonstrated a clinically important reduction in offspring risk
of atopic eczema in infancy following maternal cholecalciferol
supplementation during pregnancy. The findings support a developmental
influence on infantile atopic eczema and point to gestational
cholecalciferol supplementation as a preventive strategy to reduce the
burden of atopic eczema during infancy.

\emph{Key words:} Atopic eczema, maternal cholecalciferol, pregnancy,
vitamin D

\textbf{Introduction}

Atopic eczema is a chronic inflammatory condition that can substantially
impact affected individuals, their families and the healthcare system.
The estimated prevalence of atopic eczema is 9.5\% in children under age
4 years\textsuperscript{1}, with a rise observed globally over recent
decades.\textsuperscript{2} There is increasing evidence that atopic
eczema partly originates \emph{in utero} , where genetic susceptibility
and environmental exposures can affect the developing immune system and
alter the skin barrier. Understanding the role of early life
environmental exposures, such as maternal micronutrient status, may
identify potential preventative strategies.

Inadequate gestational vitamin D status is highly prevalent in many
populations. Supplementation is recommended to prevent
deficiency.\textsuperscript{3} Maternal serum levels of 25(OH)D
correlate with offspring levels at birth\textsuperscript{4} and maternal
vitamin D status has been extensively linked to offspring risk of atopic
eczema and other atopic diseases, but with inconsistent evidence. One
intervention study with high dose maternal antenatal vitamin D
supplementation (2400 or 4000 IU) daily compared with placebo
demonstrated a 25\% reduction in the offspring's risk of `asthma' at age
0-3 years.\textsuperscript{5} Conversely, in an observational study,
children born to mothers with a late pregnancy serum 25(OH)D
\textgreater{}75nmol/L had a higher risk of infantile eczema at age 9
months and childhood asthma age 9 years compared to children whose
mothers had a concentration of \textless{}30 nmol/l.\textsuperscript{6}A
trial in women at high risk of having offspring with asthma reported no
significant difference in rates of offspring eczema at age 3 years
following maternal antenatal supplementation with high (4400 IU/d) vs
low (400 IU/d) dose vitamin D.\textsuperscript{7} Maternal vitamin D
supplementation during pregnancy (2000 IU/d from 27 weeks gestation)
increased vitamin D activity in breast milk,\textsuperscript{8} raising
the possibility that benefits of gestational supplementation may arise
from higher infant intakes after birth in supplemented mothers who
breastfeed their infant.\textsuperscript{9}

In this study, our aim was to examine the hypothesis that maternal
supplementation with 1000 IU/day cholecalciferol during pregnancy would
decrease the risk of atopic eczema in the offspring in the setting of a
randomised controlled trial. We also sought to determine whether any
associations varied by breastfeeding status and whether genetic variants
previously associated with serum 25(OH)D
concentrations\textsuperscript{10} were related to offspring atopic
eczema.

\textbf{Methods}

Within the Maternal Vitamin D Osteoporosis Study (MAVIDOS), a
multicentre, double-blind, randomised, placebo-controlled trial, women
were randomised to receive cholecalciferol 1000 IU/day or matched
placebo, from 14 weeks' gestation until delivery. The trial methods and
primary findings have been published.\textsuperscript{11, 12}~Pregnant
women were invited to participate at their early pregnancy ultrasound
screening appointment. Eligible women were recruited and randomised at
14 weeks' gestation (or as soon as possible before 17 weeks' gestation
if recruited later) to either cholecalciferol 1000 IU/day or matched
placebo {[}Merck KGaA, Darmstadt, Germany)/Sharp Clinical Services
(previously DHP-Bilcare), Crickhowell, UK{]}, taken until delivery.
Inclusion criteria were women aged over 18 years, having a singleton
pregnancy with a gestational age \textless{}17 weeks based on last
menstrual period and ultrasound measurements, and serum 25(OH)D between
25 and 100nmol/l and calcium \textless{}2.75mmol/l. Due to an ethics
committee stipulation, only women with a baseline 25(OH)D between
25-100nmol/l were eligible to participate. Women were excluded if they
had known metabolic bone disease, renal stones, hyperparathyroidism or
hypercalciuria; were taking medication known to interfere with fetal
growth or more than 400 IU/day vitamin D supplementation, or if their
fetus had a major anomaly. All participants received standard antenatal
care, and could continue self-administration of dietary supplements
containing up to 400 IU/day vitamin D.

The MAVIDOS trial was conducted at three UK study sites 2008-2014:
Southampton, Oxford and Sheffield, with a total of 965
births.\textsuperscript{11} Follow up for this study was restricted to
704 Southampton children (352 intervention group and 352 placebo
(Supplementary Figure 1)), who were assessed for eczema at ages 12
(n=636), 24 (n=611) and 48 (n=450) months. Case definition was based on
the UK Working Party diagnostic criteria for the definition on atopic
eczema,\textsuperscript{13} assessed by trained research nurses who
undertook a standardised questionnaire and examination. Itchy skin
condition in the past 12 months was a mandatory criterion in addition to
three of: onset age \textless{}2 years, history of eczema (flexural or
of cheeks and extensors in under 18 months), history of dry skin the
last year, and visible flexural eczema (or visible eczema of the cheeks
and extensors if under 18 months). A personal history of atopy was
omitted as a criterion given the young age of the infants, who were not
old enough to have developed clearly defined asthma or hay fever.

The trial was approved by the Southampton and South West Hampshire
Research Ethics Committee. MAVIDOS was registered prospectively
(International Standard Randomised Controlled Trial Registry: ISRCTN
82927713; European Clinical Trials Database: EudraCT 2007-001716-23).
Written informed consent was obtained from all parents.

\emph{Statistical analysis}

Participant characteristics are described separately for mothers who
received 1000 IU cholecalciferol and those who received placebo using
frequency and percentage distribution for categorical variables, mean
(SD) for normally distributed continuous variables and median
(interquartile range) for non-normally distributed continuous variables.

We used logistic regression to examine associations between being
randomised to the active group and developing eczema at ages 12, 24 and
48 months, expressing results as odds ratios (ORs) and 95\% confidence
intervals (CIs). Models were adjusted for duration of breastfeeding as
descriptive analyses showed differences in breastfeeding duration
between the groups. Sensitivity analyses were undertaken to examine
whether the effect of the intervention differed in mothers breastfeeding
for \textless{}1 and [?]1 month because of its reported association with
eczema and the influence of gestational supplementation on breast milk
vitamin D content, and to take account of season of birth. We
additionally used logistic regression to examine the associations
between the offspring's risk of atopic eczema at ages 12, 24 and 48
months and maternal late pregnancy serum 25(OH)D concentration and
single-nucleotide polymorphisms (SNPs) in or near key vitamin D
metabolism genes, specifically rs12785878 (encoding 7-dehydrocholesterol
reductase (\emph{DHCR7)} in the epidermal vitamin D biosynthesis
pathway), rs10741657 and rs6013897 (encoding 25-hydroxylase
(\emph{CYP2R1)} and 24-hydroxylase \emph{(CYP24A1)} ,
respectively).\textsuperscript{10} Analyses were performed using Stata
(Stata version 15.1, Statacorp LP, TX).

\textbf{Results}

\emph{Cohort characteristics}

Mother and infant characteristics of the 704 offspring (352 intervention
group and 352 placebo) with data on atopic eczema at any of ages 12
(n=636), 24 (n=611) or 48 (n=450) months were similar in the
intervention and placebo groups with the exception of longer
breastfeeding duration in the intervention group (Table 1). Mother and
infant characteristics apart from breastfeeding duration were also
similar for the subgroups followed up at each of the three postnatal
ages (Supplementary Table 1), and the 704 mothers and offspring included
had characteristics similar to those of the overall group recruited to
MAVIDOS (Supplementary Table 2). Baseline maternal serum 25(OH)D levels
at recruitment in early pregnancy were similar in the intervention and
placebo groups. In late pregnancy, maternal serum 25(OH)D levels were
higher in the intervention group compared with the placebo group (Table
1).

\emph{Association between maternal cholecalciferol supplementation and
offspring atopic eczema}

The prevalences of atopic eczema in the intervention group at ages 12,
24 and 48 months were 7.2\%, 11.4\% and 6.7\% respectively, compared
with 12.0\%, 14.5\% and 8.8\% in the placebo group. Table 2 shows the OR
of atopic eczema at ages 12, 24 and 48 months in offspring whose mothers
received 1000IU cholecalciferol vs placebo. In an unadjusted analysis,
offspring of mothers who received 1000IU cholecalciferol had a lower
risk OR of atopic eczema at age 12 months, 0.57 (95\%CI 0.33, 0.98), p =
0.04 compared to offspring of mothers who received placebo; this changed
little after adjusting for breastfeeding duration as a covariate. The
ORs of atopic eczema in the intervention group compared to the control
group at ages 24 and 48 months were 0.75 (0.47, 1.21) p = 0.25, and 0.75
(0.37, 1.50) p = 0.41, respectively, and changed little in models
adjusted for breastfeeding (Table 2) or season at birth. Adjusted
estimates are presented graphically in Figure 1. Sensitivity analysis
stratified by breastfeeding duration demonstrated a reduced risk of
atopic eczema at age 12 months in the intervention group in infants who
were breastfed for more than one month (OR 0.48 (0.24,0.94), p = 0.03),
but not in those who were breastfed for less than one month (OR 0.80
(0.29,2.17), p = 0.66) (Table 3); however, interaction terms between the
intervention and breastfeeding duration were not statistically
significant at any of the three follow-up ages (p = 0.41, 0.35, 0.13 at
ages 12, 24 and 48 months, respectively).

Sensitivity analyses showed no association between maternal late
pregnancy serum 25(OH)D and offspring atopic eczema at any age
(Supplementary table 3). Examining the SNPs rs12785878 (\emph{DHCR7} ),
rs10741657 (\emph{CYP2R1} ) and rs6013897 (\emph{CYP24A1} ) located in
genes involved in vitamin D metabolism\textsuperscript{10, 14},
demonstrated no associations with offspring atopic eczema, although
there indications of higher ORs for atopic eczema with rs10741657
(\emph{CYP2R1} ) at ages 12 and 24 months, OR 1.44 (0.95, 2.18), p =
0.08, and 1.42 (0.98, 2.04), p = 0.06, respectively (Table 4).

\textbf{Discussion}

Maternal supplementation with 1000 IU cholecalciferol daily from 14
weeks' gestation until delivery resulted in a reduced odds of infant
atopic eczema at age 12 months. The effects of supplementation, however,
were non-significant at ages 24 and 48 months. Interaction terms between
supplementation during pregnancy and breastfeeding duration were not
statistically significant, but sensitivity analysis showed that the
protective effect of maternal cholecalciferol supplementation on
infantile eczema was only significant in offspring breastfed for more
than one month.

Current evidence relating to maternal vitamin D status and its effect on
offspring atopic eczema is inconsistent, and evidence from
supplementation trials is sparse. A U-shaped association between
maternal vitamin D supply and status and offspring atopic eczema is
biologically plausible, whereby both low and high intakes and 25(OH)D
insufficiency and high 25(OH)D concentrations might be associated with
increased risk of atopic eczema (see below for discussion of potential
mechanisms).\textsuperscript{6} We would note that mothers with serum
25(OH)D levels above 100 mmol/L at baseline were excluded from MAVIDOS,
but found no evidence for an increased risk of atopic eczema with 1000
IU/d cholecalciferol supplementation. A reduced risk of wheeze and
eczema has been reported in children of mothers consumed 174 IU/d or
more of dietary vitamin D during pregnancy\textsuperscript{15}, and
infants with cord blood 25(OH)D levels [?] 75 nmol/L were found to have a
lower risk of eczema in infancy when compared to those with cord blood
levels of \textless{} 50 nmol/L.\textsuperscript{16} There are also
reports of no association between maternal or cord serum 25(OH)D
concentrations and atopic eczema.\textsuperscript{17} Others studies
have reported no clear associations between maternal vitamin D status in
late pregnancy and asthma, wheeze or skin sensitisation at age 1, 3 or 6
years.\textsuperscript{18}

In the VDAART randomised controlled trial in women at high risk of
having children with asthma, the prevalence of offspring asthma at age 6
years was similar in those whose mothers received antenatal
supplementation with 4400 vs 400 IU/d vitamin D, as were the secondary
outcomes of eczema and total IgE levels; a between-group reduction in
asthma and recurrent wheeze was, however, suggested at early time points
through the age of 3 years.\textsuperscript{7, 19} Our study examined
the effect of gestational supplementation on offspring eczema at ages
from 12 to 48 months, also finding an effect at early age, 12 months. We
found no effect on eczema in the past year at ages 24 and 48 months
suggesting that other, post-natal influences might become important at
older ages in affecting the risk of atopic eczema beyond infancy.
Conceivably, supplementation during the postnatal period may be needed
for a sustained effect. There is evidence supportive of postnatal
vitamin D supplementation, with a meta-analysis of 11 intervention
studies in children with atopic eczema reporting a reduction in eczema
severity.\textsuperscript{20}

Vitamin D has immunomodulatory effects on innate and adaptive
responses.\textsuperscript{21} The vast majority of cells of the
adaptive immune system express the vitamin D receptor and CYP27B1,
enabling the production of the active metabolite 1,25(OH)2 D, thought to
act predominantly in an auto-and paracrine fashion. Evidence
from\emph{in vitro} and \emph{in vivo} studies\textsuperscript{22} has
demonstrated that vitamin D supplementation inhibits expression of Th2
response cytokines, the predominant immune response seen acutely in
atopic eczema and other allergic disease. \textsuperscript{23}Vitamin D
deficiency \emph{in utero} and early life has been linked with increased
Th2 lymphocytes and reduced T regulatory cells and interleukin IL-10,
leading to macrophage and dendritic cells producing pro-inflammatory
cytokines.\textsuperscript{24} However, contrary to this, there is
evidence that 1,25(OH)2 D promotes Th2 responses, with inhibition of
IFN-\selectlanguage{greek}γ \selectlanguage{english}and promotion of IL-4, IL-5, and IL-10
production.\textsuperscript{25} Skin barrier function is important in
the pathogenesis of atopic eczema; vitamin D and its metabolites can
impact this through involvement in the synthesis of proteins such as
filaggrin, and through stratum corneum formation, keratinocyte formation
and differentiation and production and the regulation of skin
antimicrobial peptides. \textsuperscript{26}

Our data suggest that the effect of vitamin D supplementation on
offspring eczema risk may be seen soon after pregnancy, but weaken as
children grow older, where other risk factors can be influential. We
speculate that during infancy there may be a role of breast milk vitamin
D content. Evidence from MAVIDOS has demonstrated an increase in
maternal serum levels with 1000 IU/d cholecalciferol
supplementation,\textsuperscript{12} but in line with the Southampton
Women's Survey observational study,\textsuperscript{18} our data showed
no association between maternal serum 25(OH)D in late pregnancy and
offspring atopic eczema. Previous studies have shown that gestational
vitamin D supplementation increases breast milk vitamin D
content,\textsuperscript{8, 9} and in MAVIDOS the vitamin D content of
breast milk is likely to have been higher in the supplemented group,
influenced by mobilisation from maternal fat and muscle tissue. This may
explain our finding of a protective effect only in children that were
breastfed for more than 1 month. Heterogeneity in the aetiology and
pathogenesis of atopic eczema in early childhood is increasingly
recognised,\textsuperscript{27} and an alternative possibility is that
vitamin D supplementation may only have an effect on particular atopic
eczema phenotypes.

In MAVIDOS, examination of genetic variants in genes related to the
vitamin D pathway has shown that rs12785878 (DHCR7) was associated with
baseline 25(OH)D, likely influencing cutaneous synthesis; achieved
25(OH)D status following supplementation was associated with rs10741657
(CYP2R1, which determines the efficiency of vitamin D to 25(OH)D
conversion), whereas rs12785878 and rs6013897 (CYP24A1) were
not.\textsuperscript{10} There were weak trends for higher ORs of atopic
eczema with rs10741657 (CYP2R1) at ages 12 and 24 months but no
associations for other SNPs examined. In a case-control study of Chinese
children, rs4674343 on CYP27A1 (27-hydroxylase, an enzyme converting the
pre-vitamin D3 metabolite lumisterol into further downstream metabolites
with biological activity in skin cells\textsuperscript{28}) was reported
to be protective against atopic eczema and CYP2R1 and VDR haplotypes
also influenced atopic eczema risk and eosinophil
count.\textsuperscript{29}

A strength of this study is analysis of data from a placebo-controlled,
double-blind, randomised trial. Atopic eczema was not the primary
outcome in MAVIDOS, but the data collected enabled ascertainment of
offspring atopic eczema using the UKWPDC well-recognised criteria for
the diagnosis of atopic eczema. Furthermore, these criteria were
determined by trained research nurses who examined the offspring. While
some participants were taking vitamin D in addition to the
intervention/placebo provided, supplement use at interview did not
differ between the intervention and placebo groups. A limitation of this
study is that cord blood and offspring 25(OH)D levels were not measured,
precluding examination of these in relation to atopic eczema. Possible
effects of UVB and any interaction with supplementation could not be
investigated because no UVB exposure data were available. Our study
population did not include many women who were not white and we could
not include participants with baseline 25(OH)D concentrations of less
than 25 nmol/L as a result of stipulations made during the ethics
approval process; these reduce the generalisability of our findings.

In conclusion, in a randomised controlled trial maternal supplementation
with 1000 IU/d cholecalciferol from 14 weeks' gestation to delivery led
to a reduced incidence of atopic eczema in the first year of life. Many
international and national guidelines recommend 400-600 IU/d (10-15
micrograms) cholecalciferol throughout pregnancy, with the strongest
evidence for the prevention of neonatal hypocalcaemia and emerging
evidence for effects on other health outcomes affecting skeletal,
respiratory and immune systems.\textsuperscript{30} The current findings
inform understanding of the early life influences on infantile eczema
and support recommendations for routine vitamin D supplementation during
pregnancy.

\textbf{Funding}

This work was supported by grants from the Arthritis Research UK
(17702), Medical Research Council (4050502589), Bupa Foundation,
National Institute for Health Research (NIHR) Southampton Biomedical
Research Centre, University of Southampton and University Hospital
Southampton NHS Foundation Trust, and NIHR Musculoskeletal Biomedical
Research Unit, University of Oxford. IS and AP were funded by the
Medical Research Council (MRC) (programme code U105960371). KMG is
supported by the UK Medical Research Council (MC\_UU\_12011/4), the
National Institute for Health Research (NIHR Senior Investigator
(NF-SI-0515-10042), NIHR Southampton 1000DaysPlus Global Nutrition
Research Group (17/63/154) and NIHR Southampton Biomedical Research
Centre (IS-BRC-1215-20004)), the European Union (Erasmus+ Programme
ImpENSA 598488-EPP-1-2018-1-DE-EPPKA2-CBHE-JP) and the British Heart
Foundation (RG/15/17/3174). The work leading to these results was
supported by the European Union's Seventh Framework Programme
(FP7/2007-2013), projects EarlyNutrition and ODIN under grant agreements
numbers 289346 and 613977, and by the BBSRC (HDHL-Biomarkers,
BB/P028179/1), as part of the ALPHABET project, supported by an award
made through the ERA-Net on Biomarkers for Nutrition and Health (ERA
HDHL), Horizon 2020 grant agreement number 696295. We are extremely
grateful to Merck GmbH for the kind provision of the Vigantoletten
supplement. Merck GmbH had no role in the trial execution, data
collection, analysis or manuscript preparation.

\textbf{Competing interests}

KMG has received reimbursement for speaking at conferences sponsored by
companies selling nutritional products. KMG is part of an academic
consortium that has received research funding from Abbott Nutrition,
Nestec and Danone. CC reports personal fees from ABBH, Amgen, Eli Lilly,
GSK, Medtronic, Merck, Novartis, Pfizer, Roche, Servier and Takeda,
outside the submitted work. NCH reports personal fees, consultancy,
lecture fees and honoraria from Alliance for Better Bone Health, AMGEN,
MSD, Eli Lilly, Servier, Shire, Radius Health, UCB, Consilient
Healthcare and Internis Pharma, outside the submitted work. The other
authors have no competing interests.

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Table 1: Characteristics of mothers and offspring with eczema data at
age 12, 24 or 48 months. (n=704)\selectlanguage{english}
\begin{longtable}[]{@{}lll@{}}
\toprule
& \textbf{Placebo} & \textbf{Cholecalciferol (1000
IU/day)}\tabularnewline
\midrule
\endhead
N & 352 & 352\tabularnewline
\emph{Maternal characteristics} & &\tabularnewline
Age (years), mean (SD) & 31.1 (5.0) & 31.0 (4.9)\tabularnewline
Ethnicity, \% Caucasian & 95.8\% & 95.2\%\tabularnewline
Parity, \% nulliparous & 43.0\% & 44.1\%\tabularnewline
Smoking in early pregnancy, \% & 6.9\% & 5.3\%\tabularnewline
Educational attainment [?] A level, \% & 77.0\% & 78.9\%\tabularnewline
BMI (kg/m\textsuperscript{2}), median (IQR) & 25.4 (22.8,29.4) & 24.6
(22.2,28.2)\tabularnewline
Sum of all skinfold thicknesses (mm), mean (SD) & 81.3 (27.2) & 77.8
(28.4)\tabularnewline
Early pregnancy 25(OH)D (nmol/l), mean (SD) & 44.7 (16.2) & 46.0
(16.4)\tabularnewline
Late pregnancy 25(OH)D (nmol/l), mean (SD) & 42.4 (20.8) & 67.4
(19.9)\tabularnewline
Change in 25(OH)D from early to late pregnancy (nmol/l), mean (SD) &
-2.0 (20.7) & 21.4 (21.9)\tabularnewline
\emph{Offspring characteristics} & &\tabularnewline
Male, (\%) & 50.1\% & 55.7\%\tabularnewline
Birth weight (g), mean (SD) & 3543.3 (494.9) & 3508.9
(536.2)\tabularnewline
Age last breastfed (months), median (IQR) & 4.0 (0,9.0) & 5.0
(1.0,10.0)\tabularnewline
\bottomrule
\end{longtable}

Table 2. Offspring atopic eczema in the intervention group compared to
the control group\selectlanguage{english}
\begin{longtable}[]{@{}lllllll@{}}
\toprule
& Unadjusted & Unadjusted & Unadjusted & Adjusted* & Adjusted* &
Adjusted*\tabularnewline
\midrule
\endhead
Outcome: Atopic eczema & N & OR (95\%CI) & p & N & OR (95\%CI) &
p\tabularnewline
12 months & 636 & 0.57 (0.33,0.98) & 0.04 & 622 & 0.55 (0.32,0.97) &
0.04\tabularnewline
24 months & 611 & 0.75 (0.47,1.21) & 0.25 & 597 & 0.77 (0.47,1.24) &
0.28\tabularnewline
48 months & 450 & 0.75 (0.37,1.50) & 0.41 & 439 & 0.71 (0.35,1.43) &
0.34\tabularnewline
adjusted for breastfeeding duration & * adjusted for breastfeeding
duration & * adjusted for breastfeeding duration & & & &\tabularnewline
\bottomrule
\end{longtable}

Table 3. Offspring atopic eczema in the intervention group, stratified
by breastfeeding duration\selectlanguage{english}
\begin{longtable}[]{@{}lllllll@{}}
\toprule
& Breastfed up to 1 month & Breastfed up to 1 month & Breastfed up to 1
month & Breastfed more than 1 month & Breastfed more than 1 month &
Breastfed more than 1 month\tabularnewline
\midrule
\endhead
Outcome: Atopic eczema & N & OR (95\%CI) & p & N & OR (95\%CI) &
p\tabularnewline
12 months & 248 & 0.80 (0.29,2.17) & 0.66 & 374 & 0.48 (0.24,0.94) &
0.03\tabularnewline
24 months & 227 & 1.03 (0.47,2.27) & 0.95 & 370 & 0.64 (0.35,1.17) &
0.15\tabularnewline
48 months & 164 & 1.69 (0.44,6.52) & 0.45 & 275 & 0.49 (0.22,1.13) &
0.10\tabularnewline
\bottomrule
\end{longtable}

Table 4. SNP associations with offspring atopic eczema at ages 12, 24
and 48 months\selectlanguage{english}
\begin{longtable}[]{@{}llllllll@{}}
\toprule
\textbf{SNP} & \textbf{Reference allele} & \textbf{Univariate} &
\textbf{Univariate} & \textbf{Univariate} & \textbf{Adjusted for
breastfeeding} & \textbf{Adjusted for breastfeeding} & \textbf{Adjusted
for breastfeeding}\tabularnewline
\midrule
\endhead
& & \textbf{n} & \textbf{OR\textsuperscript{*} (95\%CI)} & \textbf{p} &
\textbf{n} & \textbf{OR\textsuperscript{*} (95\%CI)} &
\textbf{p}\tabularnewline
Atopic eczema at 12 months & & & & & & &\tabularnewline
\textbf{rs12785878} (\emph{DHCR7}) & G & 621 & 0.86 (0.56,1.32) & 0.48 &
607 & 0.89 (0.57,1.38) & 0.60\tabularnewline
\textbf{rs10741657} (\emph{CYP2R1}) & A & 613 & 1.42 (0.95,2.12) & 0.09
& 599 & 1.44 (0.95,2.18) & 0.08\tabularnewline
\textbf{rs6013897} (\emph{CYP24A1}) & A & 615 & 0.78 (0.50,1.22) & 0.27
& 601 & 0.76 (0.48,1.19) & 0.22\tabularnewline
Atopic eczema at 24 months & & & & & & &\tabularnewline
\textbf{rs12785878} (\emph{DHCR7}) & G & 594 & 1.00 (0.67,1.50) & 0.99 &
580 & 0.97 (0.64,1.47) & 0.89\tabularnewline
\textbf{rs10741657} (\emph{CYP2R1}) & A & 587 & 1.37 (0.96,1.97) & 0.09
& 573 & 1.42 (0.98,2.04) & 0.06\tabularnewline
\textbf{rs6013897} (\emph{CYP24A1}) & A & 590 & 0.95 (0.62,1.46) & 0.83
& 576 & 0.97 (0.63,1.48) & 0.88\tabularnewline
Atopic eczema at 48 months & & & & & & &\tabularnewline
\textbf{rs12785878} (\emph{DHCR7}) & G & 438 & 1.29 (0.68,2.45) & 0.43 &
428 & 1.32 (0.70,2.50) & 0.40\tabularnewline
\textbf{rs10741657} (\emph{CYP2R1}) & A & 430 & 1.10 (0.66,1.83) & 0.71
& 420 & 1.12 (0.67,1.87) & 0.66\tabularnewline
\textbf{rs6013897} (\emph{CYP24A1}) & A & 434 & 0.85 (0.47,1.56) & 0.61
& 424 & 0.83 (0.45,1.52) & 0.54\tabularnewline
\bottomrule
\end{longtable}

\textsuperscript{*}OR are per risk allele

\textbf{Figure legends}

Figure 1. Offspring odds ratios of atopic eczema at ages 12, 24 and 48
months in the intervention group whose mothers received 1000IU
cholecalciferol daily during pregnancy vs placebo group.

\textbf{Hosted file}

\verb`Allergy El-Heis et al Antenatal vitamin D supplementation and offspring eczema Figure 1.docx`  available at \url{https://authorea.com/users/588773/articles/713307-maternal-antenatal-vitamin-d-supplementation-and-offspring-risk-of-atopic-eczema-in-the-first-4-years-of-life}

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