Evidence map›Paper›PMID 25352862›Full record

ArticleFrontiers in genetics2014

Stratified randomization controls better for batch effects in 450K methylation analysis: a cautionary tale.

Olive D Buhule, Ryan L Minster, Nicola L Hawley, Mario Medvedovic, Guangyun Sun, Satupaitea Viali, Ranjan Deka, Stephen T McGarvey, Daniel E Weeks

Open access · goldAbstract read
In one paragraph

Article in Frontiers in genetics, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 38 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
38citing papers in PubMed, 2 pooled it
2.3field-weighted citation impact, top 12% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

38 citing papers in PubMed, 2 syntheses or guidelines pooled it, 54 citations in OpenAlex.

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  12. Small molecule biomarker discovery: Proposed workflow for LC-MS-based clinical research projects.Journal of mass spectrometry and advances in the clinical lab · 2023
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors at 5 institutions in 2 countries.

Olive D BuhuleDepartment of Biostatistics, Graduate School of Public Health, University of Pittsburgh Pittsburgh, PA, USA.
Ryan L MinsterDepartment of Human Genetics, Graduate School of Public Health, University of Pittsburgh Pittsburgh, PA, USA.
Nicola L HawleyDepartment of Chronic Disease Epidemiology, School of Public Health, Yale University New Haven, CT, USA.
Mario MedvedovicDepartment of Environmental Health, University of Cincinnati College of Medicine Cincinnati, OH, USA.
Guangyun SunDepartment of Environmental Health, University of Cincinnati College of Medicine Cincinnati, OH, USA.
Satupaitea VialiFaculty of Medicine, National University of Samoa Apia, Samoa.
Ranjan DekaDepartment of Environmental Health, University of Cincinnati College of Medicine Cincinnati, OH, USA.
Stephen T McGarveyDepartment of Epidemiology, International Health Institute, Brown University School of Public Health Providence, RI, USA.
Daniel E WeeksDepartment of Biostatistics, Graduate School of Public Health, University of Pittsburgh Pittsburgh, PA, USA ; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh Pittsburgh, PA, USA.
University of Cincinnati Medical Center · USUniversity of Pittsburgh · USBrown University · USNational University of Samoa · WSYale University · US

Funding

Integrated cellular, mouse and human research on a novel missense variant influencing adiposity in SamoansR01HL093093 · NHLBI · BROWN UNIVERSITY · PI MCGARVEY, STEPHEN T. · 2009 to 2019
$8.2M
6 · The paper itself

Abstract

backgroundBatch effects in DNA methylation microarray experiments can lead to spurious results if not properly handled during the plating of samples.

methodsTwo pilot studies examining the association of DNA methylation patterns across the genome with obesity in Samoan men were investigated for chip- and row-specific batch effects. For each study, the DNA of 46 obese men and 46 lean men were assayed using Illumina's Infinium HumanMethylation450 BeadChip. In the first study (Sample One), samples from obese and lean subjects were examined on separate chips. In the second study (Sample Two), the samples were balanced on the chips by lean/obese status, age group, and census region. We used methylumi, watermelon, and limma R packages, as well as ComBat, to analyze the data. Principal component analysis and linear regression were, respectively, employed to identify the top principal components and to test for their association with the batches and lean/obese status. To identify differentially methylated positions (DMPs) between obese and lean males at each locus, we used a moderated t-test.

resultsChip effects were effectively removed from Sample Two but not Sample One. In addition, dramatic differences were observed between the two sets of DMP results. After "removing" batch effects with ComBat, Sample One had 94,191 probes differentially methylated at a q-value threshold of 0.05 while Sample Two had zero differentially methylated probes. The disparate results from Sample One and Sample Two likely arise due to the confounding of lean/obese status with chip and row batch effects.

conclusionEven the best possible statistical adjustments for batch effects may not completely remove them. Proper study design is vital for guarding against spurious findings due to such effects.

Indexed as

array databatch effectsDNA methylationepigeneticsobesitystudy design

Identifiers

PMID25352862
PMCPMC4195366
OpenAlexW2037540915

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.