Addressing social inequalities for longevity and living in good health
Authors: D Scott Kehler
Journal: The Lancet Public Health (2019)

Deaths resulting from population ageing have steadily declined, as people live longer with conditions which were historically fatal.1Chang AY Skirbekk VF Tyrovolas S Kassebaum NJ Dieleman JL Measuring population ageing: an analysis of the Global Burden of Disease Study 2017.Lancet Public Health. 2019; 4: e159-e167Summary Full Text Full Text PDF PubMed Scopus (257) Google Scholar However, even in countries with good social circumstances, social inequalities exist that can shorten life expectancy.2Mackenbach JP Valverde JR Bopp M et al.Determinants of inequalities in life expectancy: an international comparative study of eight risk factors.Lancet Public Health. 2019; 4: e529-e537Summary Full Text Full Text PDF PubMed Scopus (67) Google Scholar Whether social inequality will reflect the extent to which longevity can be extended with a lower burden of age-related health problems is uncertain. In The Lancet Public Health, Aline Dugravot and colleagues3Dugravot A Fayosse A Dumurgier J et al.Social inequalities in multimorbidity, frailty, disability, and transitions to mortality: a 24-year follow-up of the Whitehall II cohort study.Lancet Public Health. 2019; (published online Dec 11)https://doi.org/10.1016/S2468-2667(19)30226-9Summary Full Text Full Text PDF PubMed Scopus (77) Google Scholar evaluate whether social inequalities in mortality among people living in a high-income country are related to social patterns in the onset of health problems. They analysed the UK Whitehall II longitudinal cohort (with a median follow-up period of 23·6 years) to study whether social inequalities in education, occupational position, and health literacy were related to developing multimorbidity, disability, and frailty, and consequent death in 6425 healthy adults who were 50 years old at the start of follow-up. As might be expected, multimorbidity (HR 4·12 [95% CI 3·41–4·98), physical frailty (HR 2·38 [95% CI 1·93–2·93), and disability in at least two activities of daily living (HR 1·73 [95% CI 1·34–2·22]) increased the risk of mortality. However, three findings from the analysis by Dugravot and colleagues stand out. First, people at the lowest level of occupation, such as clerical or support grades, were more likely to develop multimorbidity (HR 1·54 [95% CI 1·37–1·73]), frailty (HR 2·08 [95% CI 1·85–2·33]), or disability (HR 1·44 [95% CI 1·18–1·74]) at the highest level of occupation (eg, administrative grades). Low education or literacy level also increased the risk of transitioning to a worse health state (except education for transitioning from healthy to frail), but to a lesser extent than occupational status. Second, social inequalities only increased mortality risk in people who died before their health state worsened. Lastly, when individuals did develop one of the three worse health states, social inequalities did not modify mortality risk. The study by Dugravot and colleagues3Dugravot A Fayosse A Dumurgier J et al.Social inequalities in multimorbidity, frailty, disability, and transitions to mortality: a 24-year follow-up of the Whitehall II cohort study.Lancet Public Health. 2019; (published online Dec 11)https://doi.org/10.1016/S2468-2667(19)30226-9Summary Full Text Full Text PDF PubMed Scopus (77) Google Scholar demonstrates the need for public health initiatives to respond to social inequalities, even in high-income countries, before individuals develop health problems of ageing. Aligning potential strategies that overlap in addressing social inequalities, including smoking, low income, and high bodyweight, with global strategies to reduce mortality risk, such as the WHO 25 × 25 initiative to address seven risk factors for non-communicable disease (tobacco use, physical inactivity, harmful alcohol consumption, elevated blood pressure, sodium intake, diabetes, and obesity), would be of great interest.2Mackenbach JP Valverde JR Bopp M et al.Determinants of inequalities in life expectancy: an international comparative study of eight risk factors.Lancet Public Health. 2019; 4: e529-e537Summary Full Text Full Text PDF PubMed Scopus (67) Google Scholar, 4Stringhini S Carmeli C Jokela M et al.Socioeconomic status and the 25 × 25 risk factors as determinants of premature mortality: a multicohort study and meta-analysis of 1·7 million men and women.Lancet. 2017; 389: 1229-1237Summary Full Text Full Text PDF PubMed Scopus (582) Google Scholar Dubravot and colleagues3Dugravot A Fayosse A Dumurgier J et al.Social inequalities in multimorbidity, frailty, disability, and transitions to mortality: a 24-year follow-up of the Whitehall II cohort study.Lancet Public Health. 2019; (published online Dec 11)https://doi.org/10.1016/S2468-2667(19)30226-9Summary Full Text Full Text PDF PubMed Scopus (77) Google Scholar also show that the number of adverse health states present are important in ageing. They compared groups of people who had one, two, or three adverse health states (multimorbidity, frailty, and disability); although they found no evidence of a stronger effect of social inequality on mortality with a higher number of adverse health conditions, the cumulative effect of adverse health conditions on mortality was notable. Compared with healthy individuals, those with one (HR 2·38 [95% CI 1·93–2·93]), two (HR 1·73 [95% CI 1·34–2·22]), or three adverse health conditions (HR 4·55 [95% CI 3·67–5·65]) had higher mortality, which illustrates the interplay and complexity of age-related health problems in longevity. Although these conditions are important in ageing, other salient problems, whether observed or subclinical, contribute to living in good health. Health in ageing can alternatively be quantified with a frailty index,5Mitnitski AB Mogilner AJ Rockwood K Accumulation of deficits as a proxy measure of aging.ScientificWorldJournal. 2001; 1: 323-336Crossref PubMed Scopus (1482) Google Scholar which measures susceptibility to poor health outcomes using a set of physical, psychological, and social variables, which include cognition, signs, symptoms, and biomarkers, as well as chronic diseases, physical frailty, and disability. Frailty measured as an accumulation of deficits can grade an individual's risk of death6Kojima G Iliffe S Walters K Frailty index as a predictor of mortality: a systematic review and meta-analysis.Age Ageing. 2018; 47: 193-200Crossref PubMed Scopus (312) Google Scholar or requirement for intensive health care.7Gilbert T Neuburger J Kraindler J et al.Development and validation of a Hospital Frailty Risk Score focusing on older people in acute care settings using electronic hospital records: an observational study.Lancet. 2018; 391: 1775-1782Summary Full Text Full Text PDF PubMed Scopus (491) Google Scholar Although health deficits commonly accumulate with old age, frailty remains treatable and might be reversable.8Mitnitski A Song X Rockwood K Trajectories of changes over twelve years in the health status of Canadians from late middle age.Exp Gerontol. 2012; 47: 893-899Crossref PubMed Scopus (50) Google Scholar However, interventions to date are scarce.9Dent E Martin FC Bergman H Woo J Romero-Ortuno R Walston JD Management of frailty: opportunities, challenges, and future directions.Lancet. 2019; 394: 1376-1386Summary Full Text Full Text PDF PubMed Scopus (395) Google Scholar More compelling evidence is required on policies or interventions that address social inequalities and health problems of ageing to prolong lifespans and reduce time spent in ill health. Initiatives are likely to be needed at all levels of health care to address the needs of the increasingly ageing population, who could experience high degrees of frailty.10Hoogendijk EO Afilalo J Ensrud KE Kowal P Onder G Fried LP Frailty: implications for clinical practice and public health.Lancet. 2019; 394: 1365-1375Summary Full Text Full Text PDF PubMed Scopus (758) Google Scholar I declare no competing interests. Social inequalities in multimorbidity, frailty, disability, and transitions to mortality: a 24-year follow-up of the Whitehall II cohort studySocioeconomic status affects the risk of multimorbidity, frailty, and disability, but does not affect the risk of mortality after the onset of these adverse health conditions. Therefore, primary prevention is key to reducing social inequalities in mortality. Of the three adverse health conditions, multimorbidity had the strongest association with mortality, making it a central target for improving population health. 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