Although previous research has found that lower vitamin D levels are associated with an increased risk of type 2 diabetes, a new study has found that lower vitamin D levels may not actually cause or contribute to the disease. Published online in Lancet Diabetes & Endocrinology, the study investigated the effect of four genetic variants on diabetes risk; these are variants that exist among individuals and are associated with higher or lower vitamin D levels. Using this type of gene-based analysis, the researchers did not find a statistically significant relationship between vitamin D and type 2 diabetes; they concluded, therefore, that the previously found link between vitamin D and type 2 diabetes is likely to be merely a correlation, and not a cause-and-effect relationship. However, there are a few important points to consider when evaluating these results:
Vitamin D is still an extremely important nutrient. Researchers have found, for example, that it reduces the risk of all-cause mortality (the risk of dying from any cause), colon cancer, and bone fracture.
The new study relied on genetic variants as a marker for vitamin D levels; it did not asses vitamin D levels directly, and was not a placebo-controlled study involving vitamin D supplements.
While vitamin D has not been a primary nutrient in treating type 2 diabetes, there is still plenty of ongoing research to further investigate its effect on diabetes prevention and management, including trials involving vitamin D supplements.
Lancet Diabetes & Endocrinology