Objective Copper overload has been implicated in impaired β -cell function and insulin resistance through oxidative stress and inflammatory pathways. As a major lipoprotein component involved in lipid oxidation, apolipoprotein B (apoB) may influence copper-related metabolic effects. This study aimed to examine the association between whole blood copper concentration and glycemic control in patients with type 2 diabetes mellitus (T2DM), and to assess whether apoB levels influence this association. Methods A total of 117 patients with T2DM (mean age 55.15 ± 10.70 years; 62.4% male) were included. Whole blood copper concentration was measured using inductively coupled plasma mass spectrometry. Associations between blood copper and glycemic indicators, including glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG), were evaluated using multivariable linear regression models. Stratified and interaction analyses were performed according to apoB and other lipid-related parameters. Results After adjustment for potential confounders, a significant interaction between blood copper and apoB was observed in relation to HbA1c (P for interaction 0.001). Stratified analyses showed that higher blood copper concentration was significantly associated with higher HbA1c levels among patients with lower apoB levels below the study median, whereas no significant association was observed among those with higher apoB levels. Exploratory analyses further indicated that apoB also influenced the association between blood copper and FPG (P for interaction 0.05), showing a consistent pattern. Conclusion In patients with T2DM, a significant association between blood copper concentration and glycemic control was observed among individuals with lower apoB levels, whereas no such association was found among those with higher apoB levels. These findings suggest that apoB status may influence the relationship between blood copper and glycemic control and merit further investigation in longitudinal studies.
Wu et al. (Thu,) studied this question.