The cross-sectional study, published in the Journal of Clinical Endocrinology & Metabolism, compared vitamin D biomarkers of healthy and diabetic people and obese and non-obese people in order to help clarify the connection between vitamin D, obesity and diabetes.
Led by Mercedes Clemente-Postigo from the Instituto de Investigación Biomédica de Málaga (IBIMA) at the University of Malaga, Spain, the research team noted that previous studies have suggested that people who have low levels of vitamin D are more likely to be obese and are also more likely to have type 2 diabetes, pre-diabetes and metabolic syndrome than people with normal vitamin D levels.
"The major strength of this study is that it compares vitamin D levels in people at a wide range of weights (from lean to morbidly obese subjects) while taking whether they had diabetes into account," said Clemente-Postigo.
The team used serum 25-hydroxyvitamin D - 25(OH)D - and vitamin D receptor (VDR) gene expression as biomarkers of vitamin D status, finding that vitamin D levels directly correlated with glucose levels, but not with BMI.
“25(OH)D levels are diminished in prediabetic and diabetic compared to normoglycemic subjects, independently of BMI, and are closely related to glucose metabolism variables, suggesting that vitamin D deficiency is associated more with carbohydrate metabolism than with obesity," wrote the team.