HbA1c showed a positive association with carcinoembryonic antigen (CEA) level in only diabetes, not prediabetic or normal individuals

BACKGROUND: This study was conducted to investigate the association of carcinoembryonic antigen (CEA) and glycated hemoglobin (HbA1c) in normal, prediabetic, and diabetic subjects. METHODS: A total of 2,911 participants who underwent general health checkups were enrolled and categorized into the normal, prediabetes, and diabetes groups. Demographic, anthropological, and clinical variables were investigated, and correlations with CEA were analyzed. For 28 diabetic subjects with CEA levels above the upper limit, the follow‐up CEA and HbA1c data were analyzed. RESULTS: Carcinoembryonic antigen levels were significantly different among the normal, prediabetes, and diabetes groups (1.7 ± 1.1 vs 2.0 ± 1.1 vs 2.5 ± 1.5; P < 0.001), and men had higher CEA levels than women in all three groups. Correlation analysis identified a significant positive correlation between serum CEA and HbA1c in the diabetes group using unadjusted and adjusted models (r = 0.189, P < 0.001 and r = 0.218, P < 0.001), and multiple linear regression analysis also revealed that HbA1c was independently and positively correlated with CEA in the diabetes group (β = 0.275, P < 0.001). However, these relationships were inconsistent in the normal and prediabetes groups. The changes in CEA and HbA1c from baseline to follow‐up (delta CEA and delta HbA1c) showed a significant positive correlation (P = 0.021). CONCLUSIONS: In diabetes, the CEA level was independently and positively correlated with glycemic control status. Additionally, the change in CEA level (delta CEA) showed a positive correlation with the change in HbA1c level (delta HbA1c) in the follow‐up data analysis.