Mild total hypercholesterolemia, elevated serum high-density and non-high-density lipoproteins, across age and disease severity staging, in people with Alzheimer's disease: An observational study

Abstract

Presently, existing information about the lipids and lipoproteins profile characteristics in Alzheimer's disease (AD) is conflicting. We previously reported, mild hypercholesterolemia (total), and normal serum triglycerides level, present in subjects with AD, across age and disease severity staging. The aim of this study was to investigate serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), non-HDL cholesterol (non-HDLc) and triglycerides levels, in subjects with probable AD, and in healthy elderly controls, as well as, a possible correlation with AD. In a retrospective study, measures of fasting plasma TC, HDLc, LDLc, non-HDLc and TG levels, were studied in 87 patients (52 women) with probable AD (DSM-IV; NINCDS-ADRDA criteria); (Mean age: 72.7±8.5 years; range:55–89 years; disease duration:2±1.1y); from a private ambulatory of neurology, recruited in a community elderly in Skikda-Algeria (2009–2012); and in 100 age matched elderly controls (50 women), (Mean age: 72.1±10.1 years). Correlation with dementia severity was assessed by the clinical dementia rating scale (CDR) global score. M ean TC, HDLc, non-HDLc levels were higher for AD compared to control group, (Mean±SD): 201.5±24.8 vs 178.1±12.2; 52.1±6.6 vs 47.8±5.3; 149.4 ± 24.5 vs 130.3±11.7 mg/dl respectively (all p<.0001). There were no differences in mean LDLc: 116.0±18.4 vs 112.8±16.2 mg/dl (p=0.216) or triglycerides: 110.7±19.0 vs 109.2±22.4 mg/dl (p=0.617), levels. When compared by decennial age strata subgroups, TC, HDLc and non-HDLc levels were higher for AD compared to controls among decennial subgroups. Respective, AD and controls, plotted trajectories of change across age, were fairly parallel for TC, for HDLc and for non-HDLc plasma levels. Patients were classified according to the CDR score into four subgroups (CDR=0.5;1;2;3); we did not find significant differences among subgroups in mean TC (p=0.37), HDLc (p=0.514), and non-HDLc (p=0.27) levels. Dementia severity did not correlate significantly with any lipid parameters. These results suggest that patients with Alzheimer disease have mild total hypercholesterolemia, elevated plasma HDL and non-HDL cholesterol levels; and normal plasma triglycerides levels. This biochemical parameters profile is observed across age and dementia severity staging, until the late stage of the disease, and may be present long before a decade at least- the disease symptomatic onset.