NEFL and Alzheimer disease: We found a significant interaction between AD parental family history and weight change on CSF NfL levels (p < 0.05); however, we did not observe any significant association between weight change and CSF NfL levels after stratifying by AD parental family history (FH-: standardized β = 0.328, p = 0.217; FH ≥ 75: standardized β = − 0.127, p = 0.130; FH < 75: standardized β = − 0.068, p = 0.225).