The contribution of multiple long-term conditions to widening inequalities in disability-free life expectancy over two decades: Longitudinal analysis of two cohorts using the Cognitive Function and Ageing Studies

Background: Disability-free life expectancy (DFLE) inequalities by socioeconomic deprivation are widening, alongside rising prevalence of multiple long-term conditions (MLTCs). We use longitudinal data to assess whether MLTCs contribute to the widening DFLE inequalities by socioeconomic deprivation. Methods: The Cognitive Function and Ageing Studies (CFAS I and II) are large population-based studies of those >65 years, conducted in three areas in England. Baseline occurred in 1991 (CFAS I, n=7635) and 2011 (CFAS II, n=7762) with two-year follow-up. We defined disability as difficulty in activities of daily living, MLTCs as the presence of at least two of nine health conditions, and socioeconomic deprivation by area-level deprivation ter-tiles. DFLE and transitions between disability states and death were estimated from multistate models. Findings: For people with MLTCs, inequalities in DFLE at age 65 between the most and least affluent widened to around 2.5 years (men:2.4 years, 95% confidence interval (95%CI) 0.4-4.4; women:2.6 years, 95%CI 0.7-4.5) by 2011. Incident disability reduced for the most affluent women (Relative Risk Ratio (RRR):0.6, 95%CI 0.4-0.9), and mortality with disability reduced for least affluent men (RRR:0.6, 95%CI 0.5-0.8). MLTCs prevalence increased only for least affluent men (1991: 58.8%, 2011: 66.9%) and women (1991: 60.9%, 2011: 69.1%). However, DFLE inequalities were as large in people without MLTCs (men:2.4 years, 95%CI 0.3-4.5; women:3.1 years, 95% CI 0.8-5.4). Interpretation: Widening DFLE inequalities were not solely due to MLTCs. Reduced disability incidence with MLTCs is possible but was only achieved in the most affluent. Funding: This work was supported by the Dunhill Medical Trust. CFAS II was supported by the UK Medical Research Council (MRC; research grant G0601022), Alzheimer's Society Grant Ref: 294, and received support from the UK National Institute for Health Research (NIHR) comprehensive clinical research networks in West Anglia and Trent, and the Dementias and Neurodegenerative Disease Research Network in Newcastle. HB is sup-ported by the Dunhill Medical Trust (grant number RPGF1806\44), and AK by a Newcastle University Research Fellowship. This research was undertaken within the UK NIHR collaboration for leadership in applied health research and care for Cambridgeshire and Peterborough and the Cambridge Biomedical Research Centre infra-structures, Nottingham city and Nottinghamshire county NHS primary care trusts, and UK NIHR Policy Research Programme, conducted through the NIHR Older People and Frailty Policy Research Unit, PR-PRU-1217-21502. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)