Plasma adiponectin and biomarker-confirmed Alzheimer's disease in a tertiary memory clinic

Alzheimer's disease (AD) is associated with early metabolic dysfunction and adiponectin, which may play a pathophysiological role. Adiponectin is implicated in the regulation of energy homeostasis, carbohydrate, and lipid metabolism, as well as in inflammation modulation. The aim of this study was to study whether plasma adiponectin levels were different between patients with AD confirmed by biomarkers and neurological control subjects. We performed a monocentric, retrospective, cross-sectional, observational study in AD patients and neurological controls recruited from daily clinical practice in a tertiary memory clinic. Plasma adiponectin levels were measured using a chemiluminescent enzyme immunoassay. We analyzed the relationship between adiponectin and AD using linear regression models including age, gender, and BMI. We also described the distribution of adiponectin concentrations, across age, and gender categories. Two hundred and six patients (142 AD patients and 64 neurological controls) were included, with mean age = 68.8 ± 10.0 years, and 56% were women. Higher adiponectin concentrations were observed in females and in older adults. Plasma adiponectin levels were significantly higher in AD patients (mean = 6.45 ± 3.42 μg/mL) than neurological controls (4.85 ± 3.54 μg/mL) (p < .001). This association was mediated by age, gender, and BMI, which were significantly and independently associated with plasma adiponectin levels (p < .01 for each), while adiponectin was no longer associated with AD in multivariate models. Patients with AD showed higher adiponectin levels, but this association was driven by older age, female gender, and lower BMI in the AD group. Further studies are needed to better characterize the hormonal signature of AD.