APOE and anemia (phenotype): Anaemia patients had lower levels of CSF Aβ42 (145.03 ± 58.07 pg/ml) than participants without anaemia (157.39 ± 70.32 pg/ml) after adjusting for age, gender, educational levels, APOE ε4 alleles, comorbidities (history of coronary heart disease, history of stroke, hypertension, diabetes mellitus, dyslipidaemia), and glomerular filtration rate (p = 0.035, Fig. 1).