Causal association of basal metabolic rate on systemic sclerosis: a bidirectional mendelian randomization study

Prior evidence suggests that altered energy metabolism plays a crucial role in the development of fibrotic diseases. Recent research indicates that systemic sclerosis (SSc) patients have potentially benefited from energy management, implying that basal metabolic rate (BMR), a vital energy metabolic parameter, may be related to SSc. However, the causal effect of BMR on SSc remains unknown. Thus, we aimed to elucidate the causal links between BMR and SSc. Based on summary statistics from the genome-wide association studies (GWAS) database, two-sample Mendelian randomization (MR) was applied to explore causality between BMR and SSc. The causal relationships were assessed employing inverse variance weighted (IVW), MR-Egger, and weighted median (WM) methods. Meanwhile, several sensitivity analyses were carried out to ensure the robustness of the findings. There was an underlying genetic association of BMR on SSc (OR = 0.505, 95% CI: 0.272-0.936, P = 0.030). Moreover, no significant causal effect between SSc and BMR was observed in the reverse MR analysis (OR = 0.999, 95% CI: 0.997-1.001, P = 0.292). According to the sensitivity analysis, the presence of heterogeneity and genetic pleiotropy was not detected. Our findings, derived from a genetic perspective, provide robust evidence of a causal connection between BMR and SSc. To verify these results and clarify the potential mechanisms, further research is warranted.