醫學新聞：新的研究顯示維生素D水平低可能和得二型糖尿病及心髒病有關

A new study suggests a possible link between low vitamin D levels and a higher risk of Type 2 diabetes and heart disease. The study was presented at ENDO 2012, the Endocrine Society's Annual Meeting. Lead author Joanna Mitri, MD, and her team found an inverse relationship between the level of vitamin D in the blood and the presence of metabolic syndrome, a group of risk factors that increases the risk of heart disease and Type 2 diabetes. People with the highest blood levels of vitamin D had a 48 percent lower risk of having metabolic syndrome than did those with the lowest vitamin D levels.

The study used data from participants of the Diabetes Prevention Program, a large, now-completed study funded by the National Institutes of Health. They divided subjects into three groups based on plasma 25-hydroxyvitamin D level. The Institute of Medicine recommends a 25-hydroxyvitamin D level of 20 to 30 ng/mL as adequate for healthy people.

In the new study, the group with the highest levels of vitamin D had a median vitamin D concentration of 30.6 nanograms per milliliter, or ng/mL. Those in the lowest group had a median vitamin D concentration of 12.1 ng/mL. The risk of having metabolic syndrome with a high vitamin D level was about one half the risk with a low vitamin D level, Mitri said. The researchers also found an association between vitamin D status and some individual components of metabolic syndrome, which include a large waist size, low HDL cholesterol, high triglycerides, high blood pressure, and high blood glucose (sugar). Study participants with the best vitamin D status had a smaller waist circumference, higher HDL cholesterol, and lower blood sugar.