Peripheral leukocyte counts vary with lipid levels, age and sex in subjects from the healthy population

ObjectiveTo evaluate the effect of midlife lipid levels on Alzheimer brain pathology 20 years later in cognitively normal elderly individuals.MethodsThis is a longitudinal cohort study of 318 cognitively normal individuals with data on fasting lipid levels at midlife (mean age 54 years). Presence of β-amyloid (Aβ) and tau pathologies 20 years later (mean age 73 years) were detected by quantifying Alzheimer disease (AD) biomarkers in CSF. In a subset (n = 134), Aβ (18F-flutemetamol) PET was also performed.ResultsCSF Aβ42 and Aβ PET revealed Aβ pathology in approximately 20% of the cognitively healthy population and CSF Aβ42/phosphorylated tau (p-tau) ratio indicated both Aβ and tau pathology in 16%. Higher levels of triglycerides in midlife were independently associated with abnormal CSF Aβ42 (odds ratio [OR] 1.34, 95% confidence interval [CI] 1.03–1.75, p = 0.029) and abnormal Aβ42/p-tau ratio (OR 1.46, 95% CI 1.10–1.93; p = 0.009) adjusting for age, sex, APOE ε4, education, and multiple vascular risk factors. Triglycerides were also associated with abnormal Aβ PET in multivariable regression models, but the association was attenuated in the fully adjusted model. Increased levels of medium and large low-density lipoprotein subfractions were significantly associated with abnormal Aβ PET and large high-density lipoprotein particles were associated with decreased risk of abnormal Aβ PET.ConclusionsIncreased levels of triglycerides at midlife predict brain Aβ and tau pathology 20 years later in cognitively healthy individuals. Certain lipoprotein subfractions may also be risk factors for Aβ pathology. These findings further support an involvement of lipids in the very early stages of AD development.

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Age- and sex-specific pediatric reference intervals for biochemistry analytes as measured with the Ektachem-700 analyzer.

Clinical Chemistry ◽

10.1093/clinchem/34.8.1622 ◽

1988 ◽

Vol 34 (8) ◽

pp. 1622-1625 ◽

Cited By ~ 76

Author(s):

G Lockitch ◽

A C Halstead ◽

S Albersheim ◽

C MacCallum ◽

G Quigley

Keyword(s):

Calcium Phosphate ◽

Total Protein ◽

Reference Intervals ◽

Specific Reference ◽

Healthy Population ◽

Reference Ranges ◽

Older Children ◽

Related Difference ◽

Film Analyzer ◽

Age And Sex

Abstract Using the Ektachem-700 multilayer film analyzer, we defined age- and sex-specific reference intervals for 20 analytes in sera from a healthy population of neonates and children ages one to 19 years. Upper and lower normal reference intervals for each analyte were determined by nonparametric methods as the 0.975 and 0.025 fractiles, respectively. Newborns have lower concentrations of total protein and albumin, and higher concentrations of phosphate, bilirubin, and enzymes in serum than older children do. Concentrations of urea, glucose, calcium, phosphate, and bilirubin change rapidly postnatally. Outside the neonatal period, no significant age- or sex-related difference was found for plasma glucose, serum amylase, conjugated or unconjugated bilirubin, or lipase. There was no sex-related difference in reference intervals for albumin, total protein, calcium, phosphate, or urea. However, concentrations of uric acid and creatine kinase are much higher in postpubertal boys than in girls. Alkaline phosphatase values peak later in boys. Except for lactate dehydrogenase and gamma-glutamyltransferase, the reference intervals defined here do not differ strikingly from data derived with use of other analyzers. The age- and sex-related trends are independent of method. However, each laboratory should determine the degree to which these reference ranges can be directly applied to analyses performed with another analyzer.

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