Vitamin D: An independent indicator of diabetes?

For quite some time the medical world has been familiar with the correlation between obesity and type 2 diabetes.  However, a recent study conducted by Clemente-Postigo et al. (2015) has determined there may be an independent correlation between vitamin D deficiency and type 2 diabetes, that exists regardless of body mass index (BMI). 

This study focused on examining blood glucose levels and 25-hydroxyvitamin D (an inactive vitamin D precursor to active 1,25-dihydroxyvitamin D) levels in patients from a range of measured BMI levels and glycemic status.  The findings indicated that 25-hydroxyvitamin D was negatively correlated to glucose levels, while it had no correlation with BMI (Clemente-Postigo et al., 2015).   Therefore, 25-hydroxyvitamin D blood levels may be an independent indicator of diabetes (Clemente-Postigo et al., 2015).  It has been found that 1 billion individuals in the world suffer from low levels of vitamin D due to lack of adequate sun exposure (Endocrine Society, 2015).  This indicates that understand the role vitamin D plays in type 2 diabetes has great potential applications.  It remains unclear how 1,25-dihydroxyvitamin D mechanistically induces or corresponds to obesity, however this study acknowledges that the role vitamin D plays is essential in understanding diabetes development.  

Additionally, the study examined the effect of 1,25-dihydroxyvitamin D on vitamin D receptors in adipose tissue.  They found that 1,25-dihydroxyvitamin D induced up-regulation of these receptors, which may lead insight to future understandings of the pathway involved in obesity (Clemente-Postigo et al., 2015). As both obesity and diabetes are large healthcare concerns in the United States and the world, this research should be further expanded. Potential issues with the study include using a small sample size (n=148), and BMI measurements.  BMI measurements do not distinguish between fat and muscle accurately, or account for bone density differences among individuals (Alexandra Sifferlin, 2013). Therefore this study should be confirmed with an increased sample size, along with additional measurements to indicate obesity.  

While we still are not sure about how vitamin D effects diabetes or obesity, we are starting to understanding that it does.  Additional studies on this have the potential to significantly improve diabetes understanding and possible preventative measures.  In the meantime, it's not a bad idea to go run around outside in the sunshine!

Alexandra Sifferlin. (2013, August 26). Why BMI Isn’t The Best Measure for Weight (or Health). Retrieved November 20, 2018, from http://healthland.time.com/2013/08/26/why-bmi-isnt-the-best-measure-for-weight-or-health/

Clemente-Postigo, M., Muñoz-Garach, A., Serrano, M., Garrido-Sánchez, L., Bernal-López, M. R., Fernández-García, D., … Macías-González, M. (2015). Serum 25-Hydroxyvitamin D and Adipose Tissue Vitamin D Receptor Gene Expression: Relationship With Obesity and Type 2 Diabetes. The Journal of Clinical Endocrinology & Metabolism, 100(4), E591–E595. https://doi.org/10.1210/jc.2014-3016

Endocrine Society. (2015, February 23). Vitamin D deficiency linked more closely to diabetes than obesity. ScienceDaily. Retrieved November 19, 2018 from www.sciencedaily.com/releases/2015/02/150223140945.html