“…The primary hypothesis was that the Insomnia group would have lower levels of influenza antibodies at four weeks postvaccination than the No Insomnia group. Exploratory analyses examined other variables previously linked with reduced influenza vaccine response such as gender (Furman et al, 2014), perceived stress (Kiecolt-Glaser, Glaser, Gravenstein, Malarkey, & Sheridan, 1996; Miller et al, 2004), smoking (Cruijff et al, 1999), and obesity (Sheridan et al, 2012) to determine if they might be significant confounders of the relationship between insomnia and influenza antibody levels.…”