Although (1) AD patients have been found to have increased serum IL-6 levels in a meta-analysis of 175 studies (Lai et al., 2017), and (2) serum IL-6 has been associated with an increased risk of dementia (Engelhart et al., 2004) and worse cognitive function in AD patients (Lai et al., 2017), it was not associated with longitudinal cognitive decline or increased MCI risk in our CU population (Wennberg et al., 2019). Here, IL6 is linked to Alzheimer disease.