PMID: 15247140Jul 13, 2004Paper

Specimen allocation in longitudinal biomarker studies: controlling subject-specific effects by design

Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology
Shelley S TworogerAnne McTiernan

Abstract

It is important to understand specimen allocation factors that may impact the validity and reliability of results in longitudinal studies examining within-person changes in biomarker levels. Using data from a randomized clinical trial of an exercise intervention in 136 postmenopausal women, we determined the effect of assaying the baseline and follow-up samples of some subjects in different batches on the intervention effect estimates for serum concentrations of estrone, estradiol, testosterone, androstenedione, and dehydroepiandrosterone. Twenty-five subjects had their baseline and 3-month follow-up samples and 50 subjects had their baseline and 12-month samples assayed in different batches; all other subjects had their baseline, 3-month, and 12-month samples assayed in the same batch. Subjects with split samples were reassayed with all samples in the same batch. We compared the estimated regression coefficient for the intervention effect using the split sample data with one estimated excluding the split sample data and one estimated replacing the split sample data with the reassayed data. The median percentage difference in the intervention effect estimate was 59.6% between using versus excluding the split sample data and 74....Continue Reading

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.