Vitamin D, prediabetes and type 2 diabetes: bidirectional Mendelian randomization analysis

Area of Science:

• Endocrinology
• Nutritional Science
• Genetic Epidemiology

Background:

• Observational studies suggest a link between vitamin D deficiency and glycemic dysregulation.
• Causality remains unclear, particularly in Asian populations.
• Vitamin D's role in diabetes pathogenesis requires further investigation.

Purpose of the Study:

• To investigate the causal relationship between 25-hydroxyvitamin D [25(OH)D] and glycemic status.
• To explore the association with type 2 diabetes and prediabetes.
• To assess the impact on fasting plasma glucose and HbA1c.

Main Methods:

• Bidirectional Mendelian randomization (MR) analysis was employed.
• Genetic risk scores (GRS) were used as instrumental variables for 25(OH)D and diabetes.
• Data from 10,338-10,655 participants in East China (2014-2016) were analyzed.

Main Results:

• No significant causal association was found between genetically determined 25(OH)D and type 2 diabetes (OR 0.985, 95% CI 0.940-1.032) or prediabetes (OR 0.982, 95% CI 0.948-1.016).
• MR estimates for fasting plasma glucose and HbA1c were also not significant.
• No significant causal effect of genetically determined diabetes or prediabetes on 25(OH)D levels was observed.

Conclusions:

• The study concludes no causal association between vitamin D status and type 2 diabetes or prediabetes in the studied Chinese population.
• Bidirectional MR analysis supports the absence of a causal link.
• Findings contribute to understanding vitamin D's role in diabetes etiology.