The associations of essential metal elements and their mixture with gallstone disease in Chinese older adults: The mediation role of superoxide dismutase.

Prior research has yielded inconsistent results regarding the relationships between individual essential metal elements (EMEs) and gallstone disease (GSD). Furthermore, the association between the EME mixture and GSD, as well as the underlying mechanisms, remains poorly understood. We aimed to assess the associations between individual EMEs and their mixture with GSD, and to investigate the mediation roles of superoxide dismutase (SOD). A total of 3437 Chinese adults aged ≥60 years were included in this study. Urine levels of vanadium (V), strontium (Sr), selenium (Se), cobalt (Co), magnesium (Mg), calcium (Ca) and molybdenum (Mo) were detected by ICP-MS. GSD was determined using a combination of self-report and abdominal ultrasound. SOD was assessed using an automated chemiluminescence immunoassay device. Logistic regression, restricted cubic spline (RCS), quantile-based computation (QGC), and Bayesian kernel machine regression (BKMR) models were employed to assess individual and combined correlations of the EMEs with GSD. Further mediation analyses were conducted to investigate the mediating roles of SOD in aforementioned associations. Adjusted logistic regression revealed significant negative associations of Ca (OR = 0.84, 95 % CI: 0.72-0.99), Mg (OR = 0.86, 95 % CI: 0.76-0.99) with the odds of GSD. The RCS model demonstrated a negative linear association of Ca and Mg with the odds of GSD. Both the QGC and BKMR models showed a significant negative association between the EME mixture and the odds of GSD, with Ca and Mg contributing the most. Mediation analyses suggested that SOD mediated the correlation of the EME mixture with the decreased risk of GSD. In conclusion, the EME mixture is associated with a reduced risk of GSD in older adults, primarily driven by Ca and Mg. Additionally, the negative effect of EMEs on GSD risk may be partly mediated by SOD. Further prospective studies are needed to validate these findings.