Evidence check: BDNF in the context of Langlebigkeit

BDNF (Brain-Derived Neurotrophic Factor) is crucial for neuronal plasticity and survival. The rs6265 (Val66Met) variant is the most studied and has been linked to cognitive function, mood regulation, and metabolic processes. In the context of longevity, direct strong evidence from human studies is lacking. Some GWAS associations show small effects on body weight and smoking behavior, which could indirectly influence lifespan. The evidence is primarily mechanistic (animal models, cell studies) and based on observational studies with moderate effect sizes. It is important to note that longevity is polygenic and multifactorial; BDNF alone has no predictive power. Lifestyle factors such as exercise, diet, and stress management have a much greater impact. The evidence rating is 'human-moderate' with the caveat that associations are small and not causal.