Lack of Vitamin D Does Not Raise the Risk of Type 1 Diabetes

Vitamin D levels do not influence the chance of developing 1 diabetes in Europeans, according to a study published in the open-access journal PLOS Medicine by Despoina Manousaki from the CHU Sainte Justine and the University of Montreal, Canada and colleagues.

Type 1 diabetes is a relatively common autoimmune disease that inflicts substantial lifelong illness and significant economic burden.

‘Physicians may not suggest the use of vitamin D supplements as a strategy to prevent type 1 diabetes in individuals at risk.’

Its incidence is increasing worldwide, and there are no known interventions that can be used to prevent the disease. Vitamin D deficiency has been associated with type 1 diabetes in observational studies, but evidence of a causal effect from randomized controlled trials is lacking.

In the new study, the researchers used a Mendelian randomization design to test whether genetically decreased vitamin D levels increase risk of type 1 diabetes. Mendelian randomization is a method of using measured variation in disease-related genes to examine the causal effect of an exposure on a disease.

The two-sample Mendelian randomization study involved a vitamin D genome-wide association study (GWAS) including 443,734 Europeans, and a type 1 diabetes GWAS including 9,358 cases and 15,705 controls.

The results do not support a large effect of vitamin D levels on risk of type 1 diabetes (odds ratio: 1.09, 95% confidence interval: 0.86-1.40, p=0.48). However, smaller effects may exist, and the results may not be applicable to non-European populations.

The findings suggest that the previous epidemiological associations between vitamin D and type 1 diabetes could be due to confounding factors, such as latitude and exposure to sunlight.

According to Dr Manousaki: "Our findings do not support a large effect of vitamin D levels on type 1 diabetes, but there may be smaller effects which we could not detect. Until further evidence from large RCTs, we cannot suggest the use of vitamin D supplements as a strategy to prevent type 1 diabetes in individuals at risk, for instance siblings or offspring of people with type 1 diabetes".



Source: Eurekalert