OMG and neurodegenerative disease: OMG's CSF and brain proteomic signatures reflected broader neuroprotective mechanisms, especially axonal structural integrity, and two-sample Mendelian randomization causally implicated OMG as protective against multiple neurodegenerative diseases.<h4>Conclusions</h4>Our findings implicate OMG as a mechanistic determinant of neurodegenerative resiliency among older adults, which is reliably captured by its abundance in peripheral circulation.