Anaesthesia as a risk factor for long-term cognitive decline: Results of the prospective MAAS cohort study.

Summary

In a 12-year prospective cohort (n=1,823) with repeated cognitive testing, greater baseline cumulative exposure time to general anesthesia was independently associated with worse trajectories in executive function (CST), selective attention/mental speed (Stroop), and information processing speed (LDST). Age and education remained dominant contributors, while hypertension, diabetes, and smoking also adversely affected cognitive domains.

Key Findings

• Longer cumulative time under general anesthesia at baseline predicted worse longitudinal performance in executive function (CST, P<0.05), attention/mental speed (Stroop, P<0.001), and processing speed (LDST, P<0.005).
• Age and education were the strongest determinants of lifetime cognitive decline; hypertension, diabetes, and smoking also had adverse associations.
• Prospective design with three serial assessments over 12 years in 1,823 adults enhances causal inference compared with cross-sectional studies.

Clinical Implications

Include potential long-term cognitive risks in shared decision-making for patients requiring multiple surgeries; minimize anesthesia exposure where feasible, optimize vascular risk factors (hypertension, diabetes, smoking), and consider cognitive monitoring in high-risk individuals.

Limitations

• Observational design with potential residual confounding; anesthesia exposure quantified as total time at baseline without detailed anesthetic agents/dose.
• Surgical pathology and perioperative factors may contribute to cognitive change and are difficult to fully disentangle.

Future Directions

Integrate granular anesthetic exposure metrics (agents, depth, burst suppression) and perioperative complications; emulate target trials to clarify causality; test mitigation strategies (depth-guided anesthesia, neuroprotective protocols).