Glycemia and levels of cerebrospinal fluid amyloid and tau in patients attending a memory clinic.

Objectives: To determine the association between markers of glycemia and cerebrospinal fluid (CSF) amyloid beta 1-42 (Abeta42) and tau levels in patients attending a memory clinic.
Design: Cross-sectional study.
Setting: Memory clinic.
Participants: Two hundred forty-five consecutive patients attending a memory clinic. Clinical diagnoses were subjective cognitive complaints (n=91), mild cognitive impairment (n=62), Alzheimer's disease (n=58), and other dementia (n=34). Twenty-one patients had diabetes mellitus.
Measurements: Glycosylated hemoglobin (HbA1c); fasting blood glucose levels; and CSF levels of Abeta42, total tau, and p-tau 181.
Results: In regression analyses across the whole study sample adjusted for age, sex, and diagnostic group, there was no relationship between HbA1c or fasting glucose and CSF tau, p-tau 182, or Abeta42 levels. Stratification for diabetes mellitus did not change the results.
Conclusion: These observations do not support the hypothesis that the association between dysglycemia and impaired cognitive functioning is mediated through aberrant amyloid or tau metabolism.