Neonatal vitamin D status is not associated with later risk of type 1 diabetes: results from two large Danish population-based studies

Abstract

Aims/hypothesis The aim of this work was to assess whether neonatal levels of 25-hydroxyvitamin D (25(OH)D) are associated with risk of developing type 1 diabetes before the age of 18 years. Methods Two large-scale studies with different designs-a case-cohort and a case-control-were conducted using Danish national register data and biobank material. Weighted Cox regression and conditional logistic regression were used to calculate HRs and ORs, respectively. The concentration of 25(OH)D was assessed from neonatal dried blood spots using highly sensitive liquid chromatography-tandem mass spectrometry. Quintiles of 25(OH)D 3 were used in the main analyses.Results The case-cohort study included 912 type 1 diabetes cases and 2866 individuals without type 1 diabetes born in Denmark between 1981 and 2002 and followed up until the end of 2012. The case-control study included 527 matched case-control pairs born between 1981 and 1999 and followed up until May 2004. Both studies found no association between 25(OH)D 3 levels and later risk of developing type 1 diabetes. The neonatal total 25(OH)D levels in the studies were low: 46% (case-cohort study) and 51% (case-control study) of individuals had 25(OH)D levels <25 nmol/l. Conclusions/interpretation Our two large-scale national studies showed that 25(OH)D 3 levels around the time of birth were not associated with later type 1 diabetes risk. Whether higher levels of 25(OH)D 3 during pregnancy, acquired by higher doses of supplementation than are recommended today in Ramune Jacobsen and Steffen U. Thorsen are joint first authors.Electronic supplementary material The online version of this article

Maternal dietary supplement use and development of islet autoimmunity in the offspring: TEDDY study

“…Recently, large studies utilizing the extensive data from the Danish National Register and Norwegian Mother and Child Cohort Study have examined the effect of both vitamin D status throughout pregnancy and neonatal status of the infant and found no association with type 1 diabetes. 29,30 Maternal supplementation of vitamin D, DHA, and EPA was not associated with T1D risk in both countries. 30 There have been varied results when studying children as opposed to in utero (maternal) exposure.…”

“…Our current results from TEDDY Study are consistent with multiple studies that have not found an effect of maternal vitamin D supplementation, maternal FA levels, or maternal FA intake on T1D risk in the child. Recently, large studies utilizing the extensive data from the Danish National Register and Norwegian Mother and Child Cohort Study have examined the effect of both vitamin D status throughout pregnancy and neonatal status of the infant and found no association with type 1 diabetes . Maternal supplementation of vitamin D, DHA, and EPA was not associated with T1D risk in both countries …”

25-Hydroxyvitamin D and Peripheral Immune Mediators: Results from Two Nationwide Danish Pediatric Cohorts

“…In the newly diagnosed cohort the median/Q1–Q3 25(OH)D level was 62.0/40.1–95.5 for patients and 57.9/38.0–89.0 nmol/L for controls. It is noteworthy to mention that we have already shown that 25(OH)D levels are not associated with later risk of childhood T1D in the birth cohort and levels between newly diagnosed patients with childhood T1D and their healthy siblings do not differ either [7,9]. Levels of the peripheral immune mediators are presented in Table 2.…”

“…We conducted two separate case-control studies—both study samples are described extensively elsewhere including coding of covariates [7,8,9,10]. …”

“…Sample preparation and analysis was performed using liquid chromatography–mass spectrometry (LC-MS) according to a modified method [17], described in detail elsewhere [9]. …”