The main findings of this study were consistent with the majority of previous research, and inflammation was recognized as one of the key biological mechanisms underlying the association between RA and AD.[36–38] RA was considered to be a systemic inflammatory disease characterized by a sustained increase in the levels of cytokines such as TNF and interleukin (IL).[39] Persistent systemic inflammation could affect the neurodegenerative processes specific to AD. Here, TNF is linked to rheumatoid arthritis.