>"CTRA gene expression was analyzed using mixed effect linear models (43) testing association between average expression of 53 CTRA indicator transcripts (44, 4

>"CTRA gene expression was analyzed using mixed effect linear models (43) testing association between average expression of 53 CTRA indicator transcripts (44, 45) and either continuous UCLA Loneliness Scale scores or a 1/0 indicator of chronically high PSI (12) (UCLA Loneliness Scale score of ≥41 in at least 60% of measurements taken during study years 1–5) while controlling for study year, age, sex, race/ethnicity, marital status, household income, BMI, alcohol consumption, smoking history, and gene-specific differences in average expression level." http://www.pnas.org/content/early/2015/11/18/1514249112.abstract http://www.pnas.org/content/early/2015/11/18/1514249112.abst... They forgot that immune activity and gene expression are reported to be seasonal[1]. They should control for week of year that data was collected. If, for example, people who come by in the winter months are scored as "lonely" more often, this would correlate with expression levels of various genes even if the two are largely unrelated. [1] http://www.ncbi.nlm.nih.gov/pubmed/25965853 http://www.ncbi.nlm.nih.gov/pubmed/25965853