ORCID

0000-0001-7421-3381 (Al-Taiar)

Document Type

Article

Publication Date

2026

DOI

10.1017/S1368980026101906

Publication Title

Public Health Nutrition

Volume

29

Issue

1

Pages

e30 (1-12)

Abstract

Objective:

To determine whether gestational vitamin D status modulates the effect of pre-pregnancy obesity on gestational diabetes mellitus (GDM) risk while stratifying by maternal age.

Design:

Birth cohort.

Setting:

A major maternity hospital in Kuwait.

Participants:

Pregnant women in their second/third trimester of gestation were enrolled. Pre-pregnancy body mass index (BMI, kg/m²) was categorized as under/normal weight (< 25.0), overweight (25.0 to < 30.0), and obesity (≥30.0). Gestational 25-hydroxyvitamin D concentrations were categorized as deficiency (< 50 nmol/L) or insufficiency/sufficiency (≥50 nmol/L). GDM status was ascertained according to international guidelines. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were estimated using logistic regression.

Results:

Data from 957 pregnant women were analyzed, with GDM affecting 166 (17.4%) pregnancies. Pre-pregnancy obesity and gestational vitamin D deficiency was ascertained in 275 (28.7%) and 533 (55.7%) pregnant women, respectively. The association between pre-pregnancy obesity and GDM risk differed according to maternal age and gestational vitamin D status (P(interaction[BMI × age × vitamin D])=0.041). Among women aged < 35 years (n=710), pre-pregnancy obesity compared to under/normal weight was associated with increased GDM risk among women with gestational vitamin D deficiency (aOR: 2.72, 95% CI: 1.18-6.23) and vitamin D insufficiency/sufficiency (2.55, 1.15-5.62). In contrast, among women aged ≥35 years (n=247), pre-pregnancy obesity compared to under/normal weight was associated with increased GDM risk among women with gestational vitamin D deficiency (6.92, 1.45-33.04), but not among women with vitamin D insufficiency/sufficiency (1.13, 0.36-3.56).

Conclusions:

Gestational vitamin D status modulates the effect of pre-pregnancy obesity on GDM risk in an age-specific manner.

Rights

© The Authors, 2026

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.

Original Publication Citation

Ziyab, A. H., Al-Taiar, A., Al-Sabah, R., Hammoud, M. S., & Akhtar, S. (2026). Vitamin D status during pregnancy modulates the effect of pre-pregnancy obesity on gestational diabetes mellitus risk: A birth cohort study. Public Health Nutrition, 29(1), 1-12, Article e30. https://doi.org/10.1017/s1368980026101906

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