Serum leptin is not altered nor related to cognitive decline in Alzheimer's disease.

Abstract

Low plasma leptin levels can be a risk factor for Alzheimer's disease (AD) but the relation of leptin with disease progression in clinical AD is unknown. The aim of this study was to investigate the relation between serum leptin concentrations and cognitive decline in clinical AD. Serum leptin levels were analyzed in 295 non-obese subjects including healthy controls (n = 65), patients with subjective memory complaints (n = 99), patients with AD (n = 100), and patients with vascular dementia (n = 31). Leptin levels were related to hippocampal atrophy, baseline Mini-Mental State Examination (MMSE) scores and annual decline in MMSE measured over 2 years (range 0.4-4.5 years). Serum leptin levels were similar in AD patients compared to healthy controls and patients with subjective memory complaints. No correlation was observed between leptin concentrations and MMSE, annual change in MMSE during follow-up or atrophy. Serum leptin levels are not altered in this population of relatively young AD or vascular dementia patients (mean 60) compared to healthy and clinical control groups and were not related to cognitive decline. These results suggest that peripheral leptin levels do not play a role in evolution of AD pathology.