Economic hardship over twenty-two consecutive years of adult life and markers of early ageing: physical capability, cognitive function and inflammation
This study assesses the associations between annual measures of economic hardship (EH) across 22 years of adulthood and objective measures of early ageing in a Danish late-middle-aged population (N = 5575). EH (years < 60% of the National median equivalized household disposable income) was experienced by 18% during 1987–2008. Four or more years in EH (reference = null years in EH) was related to poorer physical capability (chair rise: − 1.49 counts/30 s [95% confidence interval (CI) − 2.36, − 0.61], hand grip strength: − 1.22 kg [95% CI − 2.38, − 0.07], jump height: − 1.67 cm [95% CI − 2.44, − 0.91] and balance: 18% [95% CI 9, 28]), poorer cognitive function (Intelligenz-Struktur-Test: − 1.50 points [95% CI − 2.89, − 0.12]) and higher inflammatory levels (C-reactive protein: 22% [95% CI 4, 44], and Interleukin-6: 23% [95% CI 10, 39]). Comparing four EH trajectories, people with a high versus low probability of EH over time had poorer physical capability (chair rise: − 1.70 counts/30 s [95% CI − 3.38, − 0.01], grip: − 4.33 kg [95% CI − 6.50, − 2.16], jump: − 1.68 cm [95% CI − 3.12, − 0.25] and balance: 31% [95% CI 12, 52]). No associations were observed with tumour necrosis factor-α. Results were adjusted for sex, age, long-term parental unemployment/financial problems, education, baseline income and cohort. This study suggested EH for four or more years to be associated with poorer physical capability, cognitive function and increased inflammatory levels in midlife. High probability of EH across adulthood was similarly related to poorer physical capability and CRP, but not cognitive function and the remaining inflammatory markers. In conclusion, preventive initiatives focusing on reducing the burden of sustained economic hardship may lead to increased healthy ageing.
KeywordsEconomic hardship Early ageing Life course Physical capability Cognitive function Inflammation
The authors thank the staff at Department of Public Health and National Research Centre for the Working Environment, who undertook the data collection. Further thanks to Kirsten Avlund†, Nils-Erik Fiehn, Åse Marie Hansen, Poul Holm-Pedersen and Merete Osler who participated in the initiation and establishment of the Copenhagen Ageing and Midlife Biobank from 2009 to 2011. The authors acknowledge the crucial role of the initiators and steering groups of The Metropolit Cohort, The Copenhagen Perinatal Cohort and The Danish Longitudinal Study in Work, Unemployment and Health. Further, the authors would like to thank the Social Inequalities in Ageing (SIA) project, funded by NordForsk, Project No. 74637, for valuable collaboration relating to this project.
This work was funded by the Center for Healthy Aging established by a grant from the Nordea Foundation. The research leading to these results was carried out as part of the Social Inequalities in Ageing (SIA) project, funded by NordForsk, Project No. 74637. The Copenhagen Ageing and Midlife Biobank has been supported by a generous grant from the VELUX FOUNDATIONS (VELUX26145 and 31539).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Ahnquist J, Fredlund P, Wamala SP (2007) Is cumulative exposure to economic hardships more harzardous to women’s health than men’s? a 16-year follow-up study of the Swedish survey of living conditions. J Epidemiol Community Heal 61:331–336. https://doi.org/10.1136/jech.2006.049395 CrossRefGoogle Scholar
- Amthauer R, Brocke B, Liepmann D, Beauducel A (2001) Intelligenz-Struktur-Test 2000 R. Hogrefe Verlag, GöttingenGoogle Scholar
- Cooper R, Hardy R, Sayer AA, Kuh D (2014a) A life course approach to physical capability. In: Kuh D, Cooper R, Hardy R et al (eds) A life course approach to healthy ageing, First. Oxford University Press, Oxford, pp 16–31Google Scholar
- Eurostat - Statistics Explained (2014) Glossary:At-risk-of-poverty rate. http://ec.europa.eu/eurostat/statistics-explained/index.php/Glossary:At-risk-of-poverty_rate. Accessed 23 Mar 2018
- Glymour MM, Greenland S (2008) Causal diagrams. In: Rothman KJ, Greenland S, Lash TL (eds) Modern epidemiology. Lippincott Williams & Wilkins, Philadelphia, pp 183–210Google Scholar
- Hallqvist J, Lynch J, Bartley M et al (2004) Can we disentangle life course processes of accumulation, critical period and social mobility? an analysis of disadvantaged socio-economic positions and myocardial infarction in the Stockholm heart epidemiology program. Soc Sci Med 58:1555–1562. https://doi.org/10.1016/S0277-9536(03)00344-7 CrossRefGoogle Scholar
- Harper S (2014) Economic and social implications of aging societies. Science (80-) 346:587–591. https://doi.org/10.1126/science.1254405
- Krieger N, Williams DR, Moss NE (1997) Measuring social class in US public health research: concepts, methodologies, and guidelines. Annu Rev Public Health 18:341–378. https://doi.org/10.1146/annurev.publhealth.18.1.341 CrossRefGoogle Scholar
- Kubzansky LD, Seeman TE, Glymour MM (2014) Biological pathways linking social conditions and health - Plausible mechanisms and emerging puzzles. In: Berkman LF, Kawachi I, Glymour MM (eds) Social epidemiology, 2nd edn. Oxford University Press, New York, pp 512–561Google Scholar
- Oakes JM, Andrade KE (2017) The measurement of socioeconomic status. In: Oakes JM, Kaufman JS (eds) Methods in social epidemiology, 2nd edn. Jossey-Bass a Wiley Brand, San Francisco, pp 23–42Google Scholar
- OECD (2018) Poverty rate (indicator). https://data.oecd.org/inequality/poverty-rate.htm. Accessed 28 Mar 2018
- Richards M, Deary IJ (2014) A life course approach to cognitive capability. In: Kuh D, Cooper R, Hardy R et al (eds) A life course approach to healthy ageing, First. Oxford University Press, Oxford, pp 32–45Google Scholar
- UCLA Institute for Digital Research and Education (2016) FAQ How do I interpret a regression model when some variables are log transformed? In: UCLA Inst. Digit. Res. Educ. https://stats.idre.ucla.edu/sas/faq/how-can-i-interpret-log-transformed-variables-in-terms-of-percent-change-in-linear-regression/. Accessed 1 Jun 2018