Maternal Serum Levels of 25-Hydroxy-Vitamin D During Pregnancy and Risk of Type 1 Diabetes in the Offspring

Diabetes
Q1
Dec 2011
Citations:183
Influential Citations:3
Observational Studies (Human)
83
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Methods
Nested case-control study within a population-based birth cohort in Norway (approximately 35,940 pregnant women; births 1992–1994). Cases: 109 pregnancies in which the child developed type 1 diabetes before age 15; Controls: 219 pregnancies from non-diabetic offspring. Late-pregnancy serum samples were used to measure 25-OH vitamin D; latest available serum sample from each woman was analyzed.
Results
Lower maternal serum 25-OH D in late pregnancy was associated with higher risk of childhood-onset type 1 diabetes in offspring. Compared with the highest quartile, the lowest quartile had an adjusted odds ratio of 2.38 (95% CI 1.12–5.07); unadjusted OR 2.25 (95% CI 1.14–4.46). There is a significant linear trend across quartiles (P = 0.031). The association persisted after adjusting for sex of the child and season of blood sampling; additional adjustments did not materially change results. Authors suggest these observational findings support testing whether increasing maternal 25-OH D during pregnancy could reduce offspring diabetes risk, advocating replication in independent cohorts and consideration of a randomized intervention.
Limitations
Observational design with potential residual confounding (no data on maternal vitamin D intake or sun exposure, no fetal vitamin D data); serum 25-OHD measured only in late pregnancy and not standardized for season (though season was adjusted for); lack of genetic data to examine HLA interactions; small numbers in extreme quartiles leading to wide confidence intervals; findings limited to Norwegian population and require replication.

Abstract

Previous studies indicate reduced risk of type 1 diabetes after intake of vitamin D supplements during pregnancy or early childhood. We aimed to test whether lower maternal serum concentrations of 25-hydroxy-vitamin D (25-OH D) during pregnancy were ...