Scottish Longitudinal Study
Development & Support Unit
Social inequalities in avoidable mortality
David Pevalin (University of Essex)
Approved on 13-10-2009
Link and Phelan (1995) argue that persistent social inequality is a fundamental cause of disease. The inequalities provide the context for more immediate factors which are often the focus of research and “background” factors such as social inequality are often treated as causally irrelevant. However, the more immediate factors change over time as they are often negated by advances in technology and knowledge but new factors emerge as these pathways are rooted in social inequalities and the differences in resources – physical, intellectual and financial – that stem from them.
Phelan et al. (2004) analyzed data from the US National Longitudinal Mortality Study which has a nine-year follow-up on over 370,000 individuals. They used life tables, Cox proportional hazard models and multinomial regression to investigate the socio-economic status (SES) differentials in mortality from what they classify as low and high preventable causes. They conclude that their results lend support to the theory of “social conditions” being fundamental causes of disease although they do acknowledge that their analyses are a limited test of the theory and have qualifications for their applicability to the theory as a whole.
Earlier, Marshall et al. (1993) examined social class differences in diseases amenable to medical intervention in New Zealand. Marshall et al. used data from a cohort of males aged 15-64 over a ten-year period. The social class differences were more pronounced in the deaths amenable to medical intervention. Other work in the epidemiological literature examines trends and socio-economic differences in amenable/avoidable mortality in both Australia (Korda et al., 2007) and Singapore (Niti and Ng, 2001). In both of these studies the focus was on the contribution of improving health care provision to reducing mortality but both note that socio-economic differences remain and even widened over the time 1986-2002 in Australia.
This project proposes to empirically test part of Link and Phelan’s theory (1995) of social conditions being fundamental causes of disease. The main premise behind the analysis is that for avoidable diseases, or diseases amenable to medical intervention, there will be marked differences by indicators of social inequality such as social class, education and income. Whereas for diseases that are not avoidable, untreatable or incurable there will be little difference across indicators of social inequality. Therefore, this project will test this by way for a series of Cox regression models with survival time from the 1991 Census.
Korda RJ, Butler JRG, Clements MS, Kunitz SJ (2007) Differential Impacts of Health Care in Australia: Trend Analysis of Socioeconomic Inequalities in Avoidable Mortality. International Journal of Epidemiology 36:157-165.
Link BG, Phelan J (1995) Social Conditions as Fundamental Causes of Disease. Journal of Health and Social Behavior, 35(extra issue): 80-94.
Marshall SW, Kawachi I, Pearce N and Borman B (1993) Social Class Differences in Mortality from Diseases Amenable to Medical Intervention in New Zealand. International Journal of Epidemiology, 22: 255-61.
Niti M, Ng TP (2001) Temporal Trends and Ethnic Variations in Amenable Mortality in Singapore 1965-1994: The Impact of Health Care in Transition. International Journal of Epidemiology, 30: 966-973.
Phelan J, Link BG, Diez-Roux A, Kawachi I, Levin B (2004) "Fundamental Causes" of Social Inequalities in Mortality: A Test of the Theory. Journal of Health and Social Behavior, 45: 265-285.