A consistent finding in the epidemiological literature is that health is socially patterned. On average, individuals from more disadvantaged social backgrounds will develop diseases earlier and die earlier compared with their more advantaged peers. Psychosocial frameworks postulate that those growing up in lower socio-economic status (SES) environments are subjected to a greater number of stressors over the life course resulting in greater ‘wear and tear’ on physiological systems which may precipitate earlier biological ageing and premature mortality. We will quantify the effects of SES induced biological damage in a large population based community dwelling sample of 8500 older people aged 50 years and over resident in the Republic of Ireland. SES will be operationalised using education, wealth, and occupation. Life course “wear and tear” will be operationalized using a multi-system, multi-dimensional Allostatic Load (AL) score comprising indices of immunological (e.g. C Reactive Protein), neuroendocrine (e.g Cortisol), cardiovascular (e.g. heart rate, blood pressure), and metabolic (e.g. hba1c, waist circumference, cholesterol) functioning. Dysfunction across these multiple systems will be combined to create the AL score. We examine the utility of the AL score for predicting incident disease and mortality outcomes at up to 8-year follow-up, and the extent to which AL mediates the association between SES and disease. We will examine the life course pathways and risk and protective factors through which SES comes to affect AL. Finally, we will embed AL within a wider conceptual framework linking sociometric, psychometric and biometric (e.g. leukocyte telomere shortening, DNA methylation age) approaches to the study of health inequalities.
