[Association between plasma selenium and the risk of impaired glucose regulation]

Objective: To investigate the association between plasma selenium exposure and the risk of impaired glucose regulation (IGR). Methods: A case-control study was conducted to select IGR patients who were admitted to the outpatient clinic of the Department of Endocrinology to perform oral glucose tolerance test(OGTT) at the Tongji Hospital affiliated to the Tongji Medical College from September 2004 to 2016 as a case group. Participants with normal glucose tolerance recruited from an unselected group of population undergoing routine health examinations in the same hospital were selected as a control group. The control group was matched according to the age (±5 years old) and sex of the case group. The inclusion criteria for subjects recruited were as follows: age ≥30 years, body mass index (BMI) <40 kg/m(2), no history of a diagnosis of IGR or type 2 diabetes, and no history of receiving pharmacological treatment for hyperlipidemia or hypertension. Patients with any clinically systemic disease such as neurological or endocrine disease, acute illness, chronic inflammatory disease or infectious disease were excluded from the study. A total of 1 957 subjects, 897 in the case group and 1 060 in the control group, were included. Questionnaires were used to collect information of all subjects, and peripheral venous blood was collected after fasting and OGTT, respectively. Plasma selenium, fasting blood glucose, blood lipid (total cholesterol, triglycerides, high density lipoprotein cholesterol, and low density lipoprotein cholesterol) and 2 h OGTT plasma glucose concentration were detected, respectively. The subjects were divided into low, medium and high concentration groups according to the tertiles of plasma selenium concentration in the control group. The multivariate unconditional logistic regression analysis was performed to analyze the association between plasma selenium exposure and IGR. Results: The age (mean±SD) of the case and control group was (53.71±11.38) and (53.95±12.17) years old. The plasma selenium concentration [M (P(25), P(75))] in the case group was 92.81(77.07, 107.05) μg/L, which was significantly higher than the control group [88.73 (77.13, 100.88) μg/L] (P<0.05). The results of multivariate unconditional logistic regression analysis showed that after adjusting for age, sex, BMI, family history of diabetes and hypertension, the risk of IGR was higher in the high-concentration group and the low-concentration group compared with the middle-concentration group, the values of OR (95%CI) were 1.22 (95%CI: 0.94-1.59) and 1.81 (95%CI: 1.42-2.30), respectively. Conclusion: The study suggested a U-shaped association between plasma selenium and IGR.