A linear mixed-effects model was fitted and evaluated for differential expression between miRNA expression in gluteal and abdominal tissues: yijk = µ+βtissue(k)+τgender(i)+ηcaseControl(i)+αbatch(i,j)+γ*agei+λi+κik+εijk. Subjects are indexed by i ∈ {1…70}, aliquots are indexed by j ∈ {1,2} and tissue type is indexed by k ∈ {1,2}. yijk is the miRNA expression level of one of the miRNA probes for subject i, aliquot j and tissue k. µ is overall mean expression level. βtissue(k) is a fixed effect representing the tissue effect for adipose tissue type ∈ {abdominal, gluteal}. τgender(i) is a fixed effect corresponding to gender for subject i, where gender(⋅) is a function mapping individual i to it's gender ∈ {male, female}. ηcaseControl(i) is a fixed effect representing case/control status of subject i, where caseControl(⋅) is a function mapping individual i to it's case/control status for metabolic syndrome ∈ {case, control}, γ is a fixed effect incorporating the effect of age, αbatch(i,j) is a fixed effect included to accommodate an experimental batch effect (96-well plate format), where the function batch(⋅) is a function mapping each sample to a batch (plate)
