Early-life inequalities and biological ageing: A multi-system biological health score approach in the Understanding Society study

Social position is known to play a role in the quality of ageing, notably through the stimulation/dysregulation of key physiological systems in response to external stresses. Using data from one wave of the Understanding Society panel study including 9,088 participants, we defined, as an extension of the Allostatic Load, a synthetic biological health score (BHS) capturing the wear-and-tear of four physiological systems (endocrine, inflammatory, cardiovascular, and metabolic systems), and two organs (liver and kidney). We used 16 established blood-derived biomarkers of these systems to calculate the BHS and explored the relative contribution of socio-economic position to the BHS and its main components across age groups. We identified a systematic decreasing education-related gradient of the BHS (p