Gut Microbiota and Metabolic Dysregulation in Elderly Diabetic Patients: Is There a Gender-Specific Effect

Background/Objectives: The aim of this study was to qualitatively and quantitatively assess the bacterial domain of the gut microbiome in elderly patients with type 2 diabetes (T2D), with a focus on sex differences, glycemic control, and lipid disorders. Methods: This study included 60 older adults with T2D (38 women and 22 men) treated with metformin or a combination of metformin and insulin. The gut microbiota was profiled using 16S rRNA gene sequencing. Statistical analyses, including correlation analysis and multiple regression, were performed to identify the associations between microbial taxa, sex, and metabolic parameters. Results: No statistically significant differences in alpha or beta diversity were observed between the sexes. Multiple regression analysis indicated a positive relationship between Tenericutes and HbA1c in male participants (β = 2.22931, CI [0.75, 3.70], R = 0.67; R² = 0.36; unadjusted p = 0.0052; adjusted p = 0.0496). In female participants, G0' (β = -2.24107, CI [-3.19, -1.30], R = 0.78; R² = 0.58; unadjusted p = 0.00003; adjusted p = 0.0005) and HbA1c (β = -1.86670, CI [-2.61, -1.12], R = 0.78; R² = 0.58; unadjusted p = 0.00001; adjusted p = 0.0003) correlated negatively with Verrucomicrobia as well G0' (β = -1.90427, CI [-2.95, -0.85], R = 0.46; R² = 0.17; unadjusted p = 0.0008; adjusted p = 0.007) and HbA1c (β = -1.69561, CI [-2.52, -0.87], R = 0.46; R² = 0.17; unadjusted p = 0.0002; adjusted p = 0.002) correlated negatively with OD1 bacteria, known as Parcubacteria. Conclusions: In this elderly population with type 2 diabetes, biological sex did not significantly affect the gut microbiota diversity. However, several exploratory associations between microbial taxa and metabolic parameters differed between men and women, suggesting that sex may influence specific aspects of microbiota-metabolism interactions. These preliminary findings underscore the importance of considering both age- and sex-related factors when investigating the gut microbiome in the context of type 2 diabetes.