Causal relationship between basal metabolic rate and intervertebral disc degeneration: a Mendelian randomization study

The role of basal metabolic rate (BMR) in intervertebral disc degeneration (IVDD) is still uncertain. To address this gap, we conducted a Mendelian randomization (MR) study to comprehensively explore the causal relationship between BMR and IVDD.

BMR data were obtained from a large genome-wide association study (GWAS) database, while IVDD data were derived from the FinnGen project. The causal relationship between IVDD and BMR was investigated using MR, with inverse-variance weighting (IVW) as the primary estimate. MR-Egger weighed median and weighed mode were employed for robustness. Sensitivity analyses, including the Cochran Q test, leave-one-out analysis, and MR-Egger intercept analysis, were conducted. Furthermore, the study also identified causal relationships between IVDD and factors associated with BMR (hyperthyroidism, type 2 diabetes, standing height, weight, and body mass index). Multivariable MR was applied to further assess the direct effect of BMR on IVDD.

Genetic predisposition to BMR (after removing outliers OR: 1.49; 95% CI: 1.37–1.63; P = 5.073e-21) were associated with an increased risk of IVDD. Additionally, IVDD risk increased with greater height, weight, and BMI. No causal relationship was observed between hy/thy and T2D and intervertebral disc degeneration (IVDD) (P > 0.05). In multivariable MR, a significant causal association between BMR and IVDD persisted, even after adjusting for BMI, height, and weight.

In this study, we successfully identified that a higher BMR is independently and causally linked to IVDD, indicating an increased risk of developing IVDD. These findings suggest that managing BMR could potentially mitigate the risk of IVDD.