BACKGROUND: Age of onset of multimorbidity and its prevalence are well documented. However, its contribution to inequalities in life expectancy has yet to be quantified. METHODS: A cohort of 1.1 million English people aged 45 and older were followed up from 2001 to 2010. Multimorbidity was defined as having 2 or more of 30 major chronic diseases. Multi-state models were used to estimate years spent healthy and with multimorbidity, stratified by sex, smoking status and quintiles of small-area deprivation. RESULTS: Unequal rates of multimorbidity onset and subsequent survival contributed to higher life expectancy at age 65 for the least (Q1) compared with most (Q5) deprived: there was a 2-year gap in healthy life expectancy for men [Q1: 7.7 years (95% confidence interval: 6.4-8.5) vs Q5: 5.4 (4.4-6.0)] and a 3-year gap for women [Q1: 8.6 (7.5-9.4) vs Q5: 5.9 (4.8-6.4)]; a 1-year gap in life expectancy with multimorbidity for men [Q1: 10.4 (9.9-11.2) vs Q5: 9.1 (8.7-9.6)] but none for women [Q1: 11.6 (11.1-12.4) vs Q5: 11.5 (11.1-12.2)]. Inequalities were attenuated but not fully attributable to socio-economic differences in smoking prevalence: multimorbidity onset was latest for never smokers and subsequent survival was longer for never and ex smokers. CONCLUSIONS: The association between social disadvantage and multimorbidity is complex. By quantifying socio-demographic and smoking-related contributions to multimorbidity onset and subsequent survival, we provide evidence for more equitable allocation of prevention and health-care resources to meet local needs.
Int J Epidemiol
Multimorbidity, health expectancy, inequalities, mortality, multi-state modelling