High serum selenium levels are associated with impaired fasting glucose and elevated fasting serum glucose in Linyi, China

Background: The relationship between selenium level and impaired fasting glucose or elevated fasting serum glucose remains controversial. This study aimed to evaluate these associations in China. Methods: This observational population study adopted a cluster sampling approach to enroll participants. Baseline information on selenium categories was tested using one-way analysis of variance and Kruskal Wallis equality-of-populations rank tests. Multivariable logistic regression was used to investigate the association between serum selenium level and impaired fasting glucose or elevated fasting serum glucose. Results: The mean serum selenium concentration was 121.5 mu g/L which in a relatively high baseline Se status. Differences were observed among individuals with normal, impaired fasting glucose and elevated fasting serum glucose levels in their basic information, physical examination results and laboratory findings. After adjusting for their basic information, physical examination results and laboratory findings, compared with the low-selenium group, the high-selenium groups (124.9-143.9 and above 143.9 mu g/L) had ORs for elevated fasting serum glucose of 2.31 (1.37-3.90) and 2.67 (1.59-4.48), respectively (both P < 0.05). A sex-difference was observed, and a significant association between selenium levels and impaired fasting glucose was observed for males but not for females. Conclusions: The findings of this observational study suggest that relatively high selenium levels might be positively associated with elevated fasting serum glucose and relatively high selenium levels might be positively associated with impaired fasting glucose in men.