Financial stress and sleep duration in immune and neuroendocrine patterning. An analytical triangulation in ELSA

Proinflammatory and neuroendocrine mediators are implicated in disease aetiopathogenesis. Stress increases concentrations of immune-neuroendocrine biomarkers through a complex network of brain-body signalling pathways. Suboptimal sleep further modulates these processes by altering major effector systems that sensitise the brain to stress. Given the ubiquitous, impactful nature of material deprivation, we tested for a synergistic association of financial stress and suboptimal sleep with these molecular processes. With data drawn from the English Longitudinal Study of Ageing (ELSA), associations were tested on 4,940 participants (∼66 ± 9.4 years) across four-years (2008-2012). Through analytical triangulation, we tested whether financial stress (>60 % insufficient resources) and suboptimal sleep (≤5/≥9 h) were independently and interactively associated with immune-neuroendocrine profiles, derived from a latent profile analysis (LPA) of C-reactive protein, fibrinogen, white blood cell counts, hair cortisol, and insulin-like growth factor-1. A three-class LPA model offered the greatest parsimony. After adjustment for genetic predisposition, sociodemographics, lifestyle, and health, financial stress was associated with short-sleep cross-sectionally (RRR = 1.45; 95 %CI = 1.18-1.79; p < 0.001) and longitudinally (RRR = 1.31; 95 %CI = 1.02-1.68; p = 0.035), and it increased risk of belonging to the high-risk inflammatory profile by 42 % (95 %CI = 1.12-1.80; p = 0.004). Suboptimal sleep was not related to future risk of high-risk profile membership, nor did it moderate financial stress-biomarker profile associations. Results advance psychoneuroimmunological knowledge by revealing how inflammation and neuroendocrine markers cluster in older cohorts and respond to financial stress over time. Financial stress associations with short-sleep are supported. The null role of suboptimal sleep, as exposure and mediator, in profile membership, provides valuable insight into the dynamic role of sleep in immune-neuroendocrine processes.