The hidden influence of type 2 diabetes on bone mineral density across the lifespan: a Mendelian randomization study

This study investigates the causal relationship between type 2 diabetes mellitus (T2DM) and bone mineral density (BMD) across different age groups using Mendelian randomization (MR). The research aims to clarify how T2DM influences BMD and whether BMD variations contribute to the risk of developing T2DM, focusing on age-specific effects.

We conducted a two-sample MR analysis using publicly available data from genome-wide association studies (GWAS). Data sources included T2DM and BMD datasets across various age cohorts.The methodology incorporated diverse MR techniques, such as inverse-variance weighting (IVW), MR-Egger, and weighted median, to enhance robustness and mitigate potential biases. Additionally, reverse MR was performed to explore whether BMD affects the susceptibility to T2DM.

Our findings show a positive association between T2DM and higher BMD in individuals aged 45 and older. No significant relationship was observed in younger age groups (0-45 years). The reverse MR analysis revealed no causal link between BMD and T2DM, except in the 45-60 age group in whom a weak association was noted.

T2DM has a protective effect on BMD in older individuals, highlighting the importance of considering age in the management of bone health in T2DM patients. Further research is needed to understand the underlying mechanisms and to explore the potential clinical implications of these findings.