Association between 25-hydroxyvitamin D and metabolic syndrome in middle-aged and elderly population

Objective To explore the relationship between vitamin D and metabolic syndrome.Methods A total of 536 subjects aged over 45 years old from Shanghai Changfeng community were included.A standard questionnaire,anthropometric parameters,and blood analysis,including lipid,fasting plasma glucose,2 h plasma glucose after oral glucose tolerance test,25-hydroxyvitamin D [25 (OH) D],and parathyroid hormone (PTH) were conducted.Bone mineral content was examined using dual energy X-ray assay.Metabolic syndrome was diagnosed according to the International Diabetes Federation (IDF) criteria.Results Altogelher,35.6％ of 536 subjects developed metabolic syndrome.Subjects with metabolic syndrome had lower 25 (OH) D and higher PTH concentration than those individuals without metabolic syndrome [25 (OH) D:(42.53 ± 13.58 vs 46.72 ± 16.83) nmol/L,P =0.004; PTH:(41.61 ± 14.06 vs 39.25 ± 12.93) mmol/L,P =0.050].From the highest to the lowest tertile of 25(OH)D,29.1％,38.9％,and 40.0％ of participants,respectively,had metabolic syndrome (Ptrend =0.035).Compared with the highest tertile of 25 (OH) D,the odds ratios (OR) for metabolic syndrome in the middle and lowest tertile were 1.049 (95％ CI 0.683-1.610) and 1.621 (95％ CI 1.040-2.532) respectively.Logistic regression analysis revealed that metabolic syndrome was associated with lowered 25 (OH) D (OR =0.975,95％ CI 0.957-0.994) after adjusted for simple component of metabolic syndrome,PTH,and bone mineral content.Conclusions Lowered 25 (OH) D level seems to be a risk factor for metabolic syndrome,independent of traditional risk factor,such as waist circumference,fasting glucose,triglyceride,PTH,and bone mineral content. Key words: 25-hydroxyvitamin D ;  Metabolic syndrome ;  Parathyroid hormone ;  Bone mineral content