Low socioeconomic status reduces life expectancy

Posted on: 03 February 2017

Low socioeconomic status reduces life expectancy and should be counted as a major risk factor in health policy, new Lancet study says

A team including Trinity sociologist Professor Richard Layte published research this week in the journal ‘The Lancet’ which brings together data from 48 different population studies from Europe, the US and Australia covering 1.7 million people which shows that people in lower social class positions, on average, lose just over two years of life compared to those in the highest social class group, even adjusting for differences in the healthiness of their lifestyle in terms of factors such as smoking, alcohol consumption and level of physical activity.

Professor Layte commented: “This important piece of research followed 1.7 million people over time to observe how a person’s social class influences their risk of early death. It confirms the role which social position plays not only in how much money we earn or our lifestyle, but in how long we will live.  The effect of social class (2.1 years lost) is larger than drinking too much (0.5 years lost), being obese (0.7 years lost) or having high blood pressure (1.6 years lost) yet we often focus on individual behaviour and lifestyle rather than looking at the structured inequalities in our societies which are just as important.”

Low socioeconomic status is linked to significant reductions in life expectancy and should be considered a major risk factor for ill health and early death in national and global health policies, according to  the  study of 1.7 million people published by ‘The Lancet’.

The study is the first to compare the impact of low socioeconomic status with other major risk factors on health. The authors say that low socioeconomic status should be targeted alongside conventional health risk factors as part of national and global health strategies to help reduce early death.

“Given the huge impact of socioeconomic status on health, it’s vital that governments accept it as a major risk factor and stop excluding it from health policy,” said lead author Dr Silvia Stringhini, Lausanne University Hospital, Switzerland. “Reducing poverty, improving education and creating safe home, school and work environments are central to overcoming the impact of socioeconomic deprivation. By doing this, socioeconomic status could be targeted and improved, leading to better wealth and health for many.”

Although socioeconomic status is one of the strongest predictors of illness and early death worldwide, it is often overlooked in health policies.

In the study, researchers compared socioeconomic status against six of the main risk factors defined by the World Health Organisation in its Global Action Plan for the Prevention and Control of Non-Communicable Diseases. The plan aims to reduce non-communicable diseases by 25% by 2025, but omits socioeconomic status as a risk factor for these diseases.

“Education, income, and work are known to affect health, but few studies have examined how important these socioeconomic factors actually are. Our study aims to compare the effect of socioeconomic status with the major risk factors targeted in global health strategies,” said Professor Mika Kivimaki, University College London, UK, one of the senior authors of the study. 

The meta-analysis included data from 48 studies comprising more than 1.7 million people. The study used a person’s job title to estimate their socioeconomic status and looked at whether they died early.

In the study, 41% of men and 27% of women had low socioeconomic status. Low socioeconomic status was associated with reduced life expectancy of 2.1 years, similar to being inactive (2.4 years). The greatest reductions were for smoking and diabetes (4.8 and 3.9 years, respectively). Comparatively, high blood pressure, obesity and high alcohol consumption were associated with smaller reductions in life expectancy (1.6, 0.7 and 0.5 years, respectively) than low socioeconomic status.

When compared with their wealthier counterparts, people with low socioeconomic status were 46% more likely to die early (under 85 years). Among people with low SES, 55600 (15.2% of men and 9.4% of women) died before the age of 85; compared to 25452 (11.5% of men and 6.8% of women) of people with high SES.

“Socioeconomic status is important because it is a summary measure of lifetime exposures to hazardous circumstances and behaviours,  that goes beyond the risk factors for non-communicable diseases that policies usually address. Our study shows that it should be included alongside these conventional risk factors as a key risk factor for ill health.” said Professor Paolo Vineis, Imperial College London, UK, senior author of the study and leader of the EU LIFEPATH consortium in which this study is embedded. [1]

Limitations of the study include that the researchers only used occupational position as the indicator of socioeconomic status. While it is a commonly used measure, it can risk over simplifying the complexity of socioeconomic status. Although the study analysed and controlled for low socioeconomic status as an independent risk factor, the authors say it is difficult to separate the effects of socioeconomic status from other risk factors, highlighting the importance of targeting it alongside conventional risk factors for health included in global health targets.

Writing  in a linked Comment, Dr Martin Tobias, formerly of the New Zealand Ministry of Health, said: “Being powerless to determine your own destiny, deprived of material resources, and limited in the opportunities open to you – the authors imply – shapes both your lifestyle and your life chances… Whatever the exact effect and impact of low social rank on the health of individuals and populations may be, the authors’ key message is clear: this risk factor deserves consideration alongside the established “25×25” risk factors… The United Nations Sustainable Development Goals, which have replaced the Millennium Development Goals and will run from 2016 to 2030, provide a timely opportunity to go beyond the WHO “25×25” goal and place social determinants squarely at the centre of sustainable development.”