• Alzheimer’s disease;
  • blood–brain barrier;
  • gender;
  • plasma creatinine

Objective –  To evaluate the integrity of the blood–brain barrier (BBB) in incident Alzheimer’s disease (AD).

Materials and methods –  The mean age of the 157 patients (45% men) was 69.7(9.4) years (range 51–88 years). The patients had undergone a thorough investigation including magnetic resonance imaging or computed tomography of the brain. The cerebrospinal(CSF)/plasma albumin ratio (albumin ratio) was used as a measure of BBB function.

Results –  There were gender differences with respect to albumin ratio and plasma creatinine with higher values in men (P < 0.001). 42% of the men and 13% of the women (P < 0.001) had a mild to moderate BBB dysfunction when applying the reference limit of the laboratory (<9.2). Both male gender (P = 0.002) and plasma creatinine (P = 0.009) were independently associated with the albumin ratio when controlling for putative confounders.

Conclusions –  The BBB is dysfunctional in a portion of patients with AD, both women and, primarily, men. The dysfunction might influence the clearance of both harmful and beneficial substances across the barrier. Renal function might have an impact on the BBB.