Search

OBJECTIVES: According to previous studies, vitamin D deficiency might increase the risk of type 2 diabetes mellitus (DM). However, few studies have examined whether vitamin D continues to affect glucose control after DM diagnosis. Therefore, we examined the association between vitamin D and glucose levels in individuals with and without DM.METHODS: We analyzed data for 32,943 adults aged 19 years and older from the 2008 to 2014 Korea National Health and Nutrition Examination Survey. Patients were classified into 3 groups according to the 25-hydroxyvitamin D concentration. DM was defined as a fasting glucose level ≥126 mg/dL, current use of DM medications or insulin injections, or a self-reported diagnosis of DM by a doctor.RESULTS: In male DM patients, the hemoglobin A1c (HbA1c) level increased significantly as vitamin D levels became severely deficient. In male and postmenopausal female with abnormal HbA1c, those with severe vitamin D deficiency had significantly higher HbA1c levels (p for trend=0.004 and 0.022 for male and postmenopausal female, respectively). Significant differences were found between participants with normal and abnormal HbA1c levels in both male and female. However, regardless of sex or menopausal status, there was no significant association between vitamin D and fasting glucose in any of the fasting glucose subgroups.CONCLUSIONS: Male and female with abnormal HbA1c levels showed markedly elevated blood glucose when they also had vitamin D deficiency. A more distinct difference was observed in the HbA1c subgroups than in the fasting glucose subgroups.

OBJECTIVES: This study aims to compare the prevalence of metabolic syndrome between Korean emigrants (KEs) and their host country residents in Japan and China. METHODS: The Korean Emigrant Study (KES) is a cohort study initiated in 2005 to elucidate the effect of genetic susceptibility and environmental change on hypertension, diabetes, and metabolic syndrome. Equal numbers of KEs and host country residents, aged 30 or over, were recruited from three regions; Kobe-Osaka in Japan (total number=965), Yanbian in China (n=1,019), and Changchun in China (n=949). RESULTS: The age-adjusted prevalences of metabolic syndrome among KEs in Kobe-Osaka were significantly higher than those among Japanese (in men 24.0% vs. 15.6%, p=0.04, in women 8.4% vs. 2.7%, p= 0.01), while the age-adjusted prevalences among KEs in Changchun were similar to those among Chinese (in men 11.7% vs. 16.1%, p=0.37, in women 28.3% vs. 30.1%, p=0.91). The age-adjusted prevalences were generally higher in Yanbian than other regions, and KEs had higher prevalence than Chinese in men but not in women (in men 37.9% vs. 28.3%, p=0.03, women 46.0% vs. 50.6%, p=0.44). The components with significant ethnic differences in prevalence were high blood pressure and abdominal obesity in Japan, and triglyceride in China. The most influential component in diagnosing metabolic syndrome was abdominal obesity in men and triglyceride in women. CONCLUSION: The prevalence of metabolic syndrome was higher in KEs than in host country residents in Japan but not in China. Abdominal obesity and triglyceride are both discriminating and influential components in metabolic syndrome.