Socioeconomic status, non-communicable disease risk factors, and walking speed in older adults: multi-cohort population based studyBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k1046 (Published 23 March 2018) Cite this as: BMJ 2018;360:k1046
- Silvia Stringhini, senior lecturer1,
- Cristian Carmeli, biostatistician1,
- Markus Jokela, associate professor2,
- Mauricio Avendaño, professor of public policy and global health3 4,
- Cathal McCrory, senior research fellow5,
- Angelo d’Errico, epidemiologist6,
- Murielle Bochud, professor of public health and director1,
- Henrique Barros, professor of epidemiology7 8,
- Giuseppe Costa, professor of public health6,
- Marc Chadeau-Hyam, senior lecturer in statistical bioinformatics9,
- Cyrille Delpierre, research director10,
- Martina Gandini, data analyst6,
- Silvia Fraga, postdoctoral fellow7,
- Marcel Goldberg, professor of public health11,
- Graham G Giles, professor of cancer epidemiology12,
- Camille Lassale, research associate13,
- Rose Anne Kenny, professor of medical gerontology5,
- Michelle Kelly-Irving, senior researcher10,
- Fred Paccaud, professor of public health1,
- Richard Layte, professor of sociology14,
- Peter Muennig, professor of health policy and management15,
- Michael G Marmot, professor13,
- Ana Isabel Ribeiro, research associate7,
- Gianluca Severi, research director12 16 17,
- Andrew Steptoe, professor of psychology13,
- Martin J Shipley, senior lecturer in medical statistics13,
- Marie Zins, senior researcher11,
- Johan P Mackenbach, professor of public health18,
- Paolo Vineis, professor of epidemiology9,
- Mika Kivimäki, professor of social epidemiology13 19
- for the LIFEPATH Consortium
- 1Institute of Social and Preventive Medicine, Lausanne University Hospital, Biopôle 2-Route de la Corniche 10, 1010 Switzerland
- 2Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- 3Department of Global Health and Social Medicine, King’s College London, London, UK
- 4Harvard T.H. Chan School of Public Health, Boston MA, USA
- 5The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Dublin, Ireland
- 6Epidemiology Unit, ASL TO3 Piedmont Region, Grugliasco (TO), Italy
- 7EPIUnit-Institute of Public Health, University of Porto, Porto, Portugal
- 8Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of Porto Medical School, Porto, Portugal
- 9MRC-PHE Centre for Environment and Health, School of Public Health, Department of Epidemiology and Biostatistics, Imperial College London, London, UK
- 10INSERM, UMR1027, Toulouse, France, and Université Toulouse III Paul-Sabatier, Toulouse, France
- 11Population-based Epidemiological Cohorts Unit, INSERM UMS 11, Villejuif, France, and Paris Descartes University, Paris, France
- 12Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, VIC, Australia
- 13University College London, Department of Epidemiology and Public Health, London, UK
- 14Department of Sociology, Trinity College Dublin, Dublin, Ireland
- 15Global Research Analytics for Population Health, Health Policy and Management, Columbia University, New York, NY, USA
- 16CESP, Inserm U1018, Université Paris-Saclay, Villejuif, France
- 17Human Genetics Foundation (HuGeF), Turin, Italy
- 18Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
- 19Clinicum, Faculty of Medicine, University of Helsinki, Finland
- Correspondence to: S Stringhini
- Accepted 20 February 2018
Objective To assess the association of low socioeconomic status and risk factors for non-communicable diseases (diabetes, high alcohol intake, high blood pressure, obesity, physical inactivity, smoking) with loss of physical functioning at older ages.
Design Multi-cohort population based study.
Setting 37 cohort studies from 24 countries in Europe, the United States, Latin America, Africa, and Asia, 1990-2017.
Participants 109 107 men and women aged 45-90 years.
Main outcome measure Physical functioning assessed using the walking speed test, a valid index of overall functional capacity. Years of functioning lost was computed as a metric to quantify the difference in walking speed between those exposed and unexposed to low socioeconomic status and risk factors.
Results According to mixed model estimations, men aged 60 and of low socioeconomic status had the same walking speed as men aged 66.6 of high socioeconomic status (years of functioning lost 6.6 years, 95% confidence interval 5.0 to 9.4). The years of functioning lost for women were 4.6 (3.6 to 6.2). In men and women, respectively, 5.7 (4.4 to 8.1) and 5.4 (4.3 to 7.3) years of functioning were lost by age 60 due to insufficient physical activity, 5.1 (3.9 to 7.0) and 7.5 (6.1 to 9.5) due to obesity, 2.3 (1.6 to 3.4) and 3.0 (2.3 to 4.0) due to hypertension, 5.6 (4.2 to 8.0) and 6.3 (4.9 to 8.4) due to diabetes, and 3.0 (2.2 to 4.3) and 0.7 (0.1 to 1.5) due to tobacco use. In analyses restricted to high income countries, the number of years of functioning lost attributable to low socioeconomic status by age 60 was 8.0 (5.7 to 13.1) for men and 5.4 (4.0 to 8.0) for women, whereas in low and middle income countries it was 2.6 (0.2 to 6.8) for men and 2.7 (1.0 to 5.5) for women. Within high income countries, the number of years of functioning lost attributable to low socioeconomic status by age 60 was greater in the United States than in Europe. Physical functioning continued to decline as a function of unfavourable risk factors between ages 60 and 85. Years of functioning lost were greater than years of life lost due to low socioeconomic status and non-communicable disease risk factors.
Conclusions The independent association between socioeconomic status and physical functioning in old age is comparable in strength and consistency with those for established non-communicable disease risk factors. The results of this study suggest that tackling all these risk factors might substantially increase life years spent in good physical functioning.
Contributors: SS and CC contributed equally to the study. MKi and PV are joint last authors. MK, SS, and PV conceived the study. SS wrote the first and successive drafts of the manuscript. CC modelled and analysed the data. CC, MA, and MJ contributed to study conception and design. SS, MJ, CM, MG, and AIR contributed to data analysis. CC, MJ, MB, HB, GC, MG, GGG, RAK, MGM, AS, MJS, MZ, PV, and MK collected the data. All authors revised the manuscript for important intellectual content. SS and CC had full access to the data and take responsibility for the integrity of the data and the accuracy of the data analysis. SS is the guarantor.
Funding: This study was supported by the European Commission (Horizon 2020 grant No 633666) and the Swiss State Secretariat for Education, Research and Innovation SERI. SS was supported by an Ambizione grant (PZ00P3_167732) from the Swiss National Science Foundation. Silvia Fraga is supported by the Portuguese Foundation for Science and Technology (SFRH/BPD/97015/2013). Various sources have supported recruitment, follow-up, and measurements in the 48 cohort studies contributing to this collaborative analysis. MK is supported by the UK Medical Research Council (K013351), NordForsk, the Nordic Programme on Health and Welfare, the Academy of Finland (311492), and the Finnish Work Environment Fund. The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of this manuscript.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: Not required.
Data sharing: No additional data available.
Transparency: The lead authors (SS and CC) affirm that his manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
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