Low Serum Vitamin D Is Associated with High Risk of Diabetes in Korean Adults,

Abstract

Vitamin D may play a role in glucose metabolism. A low vitamin D level has been associated with increased risk of diabetes mellitus, but the association has not been confirmed in Asians. Our objective was to examine the association of serum 25-hydroxyvitamin D [25(OH)D] levels with insulin resistance and diabetes mellitus in Korean adults based on a large population-based survey. Cross-sectional analyses were carried out on 5787 Korean adults (2453 men and 3334 women) who were 20 y or older and participated in the Fourth Korea NHANES conducted in 2008. Diabetes mellitus was defined as fasting plasma glucose ≥7 mmol/L or current use of oral hypoglycemic agents or insulin. Insulin resistance was estimated by homeostatic model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI). Compared to individuals with a sufficient serum 25(OH)D concentration ≥75 nmol/L, the OR (95% CI) for diabetes mellitus were 1.73 (1.09-2.74), 1.30 (0.91-1.84), and 1.40 (0.99-1.98) for serum 25(OH)D concentrations <25, 25 to <50, and 50 to <75 nmol/L, respectively, after multiple adjustments (P-trend < 0.0001). Furthermore, the serum 25(OH)D level was inversely associated with HOMA-IR (β = -0.061; P = 0.001) and positively associated with QUICKI (β = 0.059; P = 0.001) in overweight or obese participants. In conclusion, a low serum vitamin D concentration is associated with a high risk of diabetes mellitus in Korean adults and the concentration is inversely associated with insulin resistance in those who are overweight or obese.

Inverse relationship between vitamin D status and insulin resistance and the risk of impaired fasting glucose in Korean children and adolescents: the Korean National Health and Nutrition Examination Survey (KNHANES) 2009–2010

“…Recently, Gagnon et al (4) prospectively demonstrated that lower 25(OH)D levels are associated with increased HOMA-IR and risk of metabolic syndrome in Australian adults. In cross-sectional studies of Chinese (5) and Korean adults (6) , VitD status was inversely related to HOMA-IR. Low 25(OH)D levels are also significantly related to an increased risk of metabolic syndrome in Chinese adults (5) and T2DM in Korean adults (6) .…”

“…In cross-sectional studies of Chinese (5) and Korean adults (6) , VitD status was inversely related to HOMA-IR. Low 25(OH)D levels are also significantly related to an increased risk of metabolic syndrome in Chinese adults (5) and T2DM in Korean adults (6) . Consistent with studies of adult populations (4)(5)(6)8) , cross-sectional nationwide studies of paediatric populations have consistently reported an inverse association between 25(OH)D levels and fasting hyperglycaemia and/or increased HOMA-IR, after adjustment for BMI (9,10) .…”

“…VitD also indirectly improves insulin responsiveness by maintaining normal extracellular calcium levels and effective calcium influx through cell membranes (13) . Many cross-sectional studies have supported an association between 25(OH)D levels and insulin sensitivity in adults (4)(5)(6)8) . Recently, Gagnon et al (4) prospectively demonstrated that lower 25(OH)D levels are associated with increased HOMA-IR and risk of metabolic syndrome in Australian adults.…”

“…The potential effects of VitD on glucose homeostasis are considered to be mediated by autocrine and paracrine functions involving the transcriptional regulation of genes in pancreatic b-cells, skeletal myocytes and immune cells, improving insulin secretion and sensitivity and reducing inflammation (13,16) . Despite theoretical links between VitD and insulin sensitivity and/or secretion, controversy remains regarding the relationship between 25(OH)D levels and surrogate indices of insulin sensitivity (4)(5)(6)(7)25,26) or b-cell function (7,25,26) and the risk of glucose intolerance or T2DM (6,9,27) . These discrepancies in the relationships between VitD status and outcomes related to glucose homeostasis in paediatric or adult populations may be attributable to differences in study sample size, participant characteristics (race, ethnicity and degree of obesity), method of measuring insulin sensitivity and/or b-cell function, and the adjusted markers of adiposity used.…”

“…The VitD receptor is present on most cells of the body; VitD is required not only for bone health but may also play crucial roles in many diseases, including glucose metabolism, CVD, cancer and immune disorders (3) . Low circulating 25-hydroxyvitamin D (25(OH)D) concentrations, an indicator of VitD status, have been linked to type 2 diabetes mellitus (T2DM), metabolic syndrome and other cardiometabolic risk factors in several adult studies (4)(5)(6)(7)(8) . Few epidemiological surveys have addressed paediatric populations (9,10) .…”