Association Between Body Mass Index and Glycemic Control in Type 2 Diabetes Mellitus: A Cross-Sectional Study

Background: Body mass index (BMI) is a known risk factor for poor glycemic control in patients with Type 2 diabetes mellitus (T2DM). However, the extent to which BMI correlates with glycated hemoglobin (HbA1c) levels and its clinical implications require further investigation. Objective: This study aimed to assess the relationship between BMI and HbA1c levels in T2DM patients and to explore the clinical significance of BMI management in optimizing glycemic control. Methods: A cross-sectional study was conducted on 200 T2DM patients from Jinniu District Hospital between 2024/04/01 and 2024/10/03. BMI and HbA1c levels were recorded, and patients were categorized into normal weight (BMI < 25 kg/m²), overweight (25 ≤ BMI < 30 kg/m²), and obese (BMI ≥ 30 kg/m²). Pearson correlation analysis was used to assess the relationship between BMI and HbA1c. One-way ANOVA was employed to compare HbA1c levels across BMI categories. Results: A significant positive correlation between BMI and HbA1c was observed (r = 0.45, P < 0.001). Obese patients had significantly higher HbA1c levels (8.5 [7.8-9.0]%) compared to overweight (7.7 [7.2-8.1]%, P < 0.01) and normal-weight patients (6.9 [6.4-7.5]%, P < 0.001). The graded relationship indicated worsening glycemic control with increasing BMI. Conclusion: Higher BMI is associated with poorer glycemic control in T2DM patients. Obese patients, in particular, may benefit from more intensive weight management strategies to reduce HbA1c levels and prevent diabetes-related complications. These findings underscore the importance of integrating BMI reduction into diabetes management plans to improve clinical outcomes.