Vitamin D Deficiency in Relation to the Risk of Metabolic Syndrome in Middle-Aged and Elderly Patients with Type 2 Diabetes Mellitus

Abstract

Summary Vitamin D deficiency is highly prevalent all over the world and dietary intakes of vitamin D are very low in China. In this study we aimed to determine whether vitamin D deficiency is associated with increased risk of metabolic syndrome (MetS) among Chinese type 2 diabetes mellitus (T2DM) patients aged over 50 y. Vitamin D deficiency is now an increasingly recognized worldwide health concern (1) related to its nonclassical roles, such as diabetes, heart disease, autoimmune diseases and certain types of cancers. Low serum 25-hydroxyvitamin D [25(OH)D] concentrations are also deemed to be related to the high incidence of type 2 diabetes mellitus (T2DM) (2) because of existing vitamin D receptors on pancreatic b cells and the other insulin-sensitive tissue such as skeletal muscle tissue. Outcomes indicated that fasting plasma glucose (FPG) and the insulin sensitive index improved significantly in a study of vitamin D supplementation for patients with T2DM (3). The elderly are at high risk for vitamin D deficiency worldwide. And it is worth noting that the prevalence of T2DM is 11.6% with 50.1% of pre-diabetes (IGT) among adults over 18 y in China according to the latest international clinical diagnostic criteria (HbA1c $6.5%). The burden from T2DM complications and mortality is higher in worldwide.The metabolic syndrome (MetS) is commonly characterized by dyslipidemia, dysglycemia, abdominal obesity and hypertension (4). MetS is associated with an increased risk of T2DM and cardiovascular complications, and is a complex of interrelated risk factors for diabetes (5). We know that obesity is also one of the risk factors for vitamin D deficiency, because the excess fat absorbs and holds onto the vitamin D so that it cannot be used for bone building or cellular health. The elderly are at high risk for vitamin D deficiency worldwide due to reduced ability of active vitamin D synthesis. Moreover, relationships among serum 25(OH)D and dyslipidemia, abdominal obesity, and hypertension have been explored in different regions and various kinds of people (6-8), but data to support those relationships are inconsistent with only a sparse sample from Asian people with T2DM. In addition to these traditional risk factors, some blood biomarkers such as apolipoprotein (Apo) A1 and ApoB (9), C-reactive protein (CRP), fibrinogen, and homocysteine (10-12), and vitamin D status (13-15)

Nutrients in Fish and Possible Associations with Cardiovascular Disease Risk Factors in Metabolic Syndrome

“…Recently, low vitamin D level (<30 ng/mL) was associated with increased risk of MetS (OR 1.90, 95% CI 1.26 to 2.85), and several of the cardiovascular risk factors comprised in MetS; high TG levels (OR 1.55, 95% CI 1.13 to 2.35), and low HDL-C levels (OR 1.60, 95% CI 1.19 to 2.40) [ 104 ]. This have also been found in other studies; MetS [ 105 ], WC [ 106 , 107 ], HDL-C [ 107 , 108 , 109 ], BP [ 107 ], and glucose [ 110 ].…”

The Association of Serum Vitamin D Deficiency and Metabolic Risk Factors in Chinese Adults with Prediabetes: A Cross-Sectional Study

“…Evidence from observational studies have pointed that the role of vitamin D status and metabolic risk factors with non-diabetic adults (24,25) or patients with dia-betes (26), which was assistance with our study among Chinese adults with PreDM. However, the previous study did not find the association between a low serum vitamin D status and central obesity among prediabetic Korean adults (27).…”

“…And vitamin D might have a protective role in the underlying disorders of PreDM (22,23). To our knowledge, there have been several studies reported the positive relationship between vitamin D deficiency and MS and its components among adults with non-diabetic adults (24,25) or patients with diabetes (26). Although there was only one study has examined the association between serum vitamin D levels and metabolic risk factors among adults with PreDM in Korean (27), the result could not be directly applied to a Chinese population due to ethnic differences in vitamin D metabolism and its nutritional status (28).…”

Body Mass Index, Vitamin D, and Type 2 Diabetes: A Systematic Review and Meta-Analysis

“… Authors’ assessment of the risk of bias in the diabetic subject studies: Data shown for each individual study (the plus sign shows a low risk of bias, the minus sign shows a high risk of bias, and the question mark indicates that the risk of bias is unknown) [ 22 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. …”