Low socioeconomic status is linked to a substantial decrease in life expectancy.
According to a study involving 1.7 million people published by The Lancet, this should be seen as a major risk factor for early death and ill health, in both global and national health policies.
The study used data from France, the UK, Switzerland, Italy, Portugal, the USA and Australia. This is the first study to compare major risk factors on health to the impact of low socioeconomic status. Factors that were taken into account include smoking, physical inactivity, high blood pressure, diabetes, obesity and a high alcohol intake. Socioeconomic status is often overlooked in health policies, even though it is one of the strongest predictors of illness and early death internationally.
Dr Silvia Stringhini from Lausanne University Hospital, Switzerland and lead author, believes that it is vital that governments accept socioeconomic status as a major risk factor and stop excluding it from health policy, especially given its huge impact on health.
She also noted that the central issues that must be addressed to overcome the impact of socioeconomic deprivation include improving education, reducing poverty and creating safe work, school and home environments. Stringhini is convinced that by doing this, socioeconomic status could be targeted and improved, which would lead to better health and wealth for many.
The study combined data from 48 studies consisting of more than 1.7 million people. Using a person’s job title to estimate their socioeconomic status, the study then looked at whether they died early or not.
Researchers compared six of the main risk factors defined by the World Health Organization (WHO) in its Global Action Plan for the Prevention and Control of Non-Communicable Diseases, against socioeconomic status. The objective of the WHO plan is to reduce non-communicable diseases by 25% by 2025. Socioeconomic status is however not listed as a risk factor for these diseases.
When people with low socioeconomic status were compared to their wealthier counterparts, they were almost 46% more likely to die before reaching the age of 85. Among people with low socioeconomic status, 55,600 (9.4% of women and 15.2% of men) died before they were 85 years old, compared to 25,452 (6.8% of women and 11.5% of men) of people with high socioeconomic status.
The study also estimated that that 27% of women and 41% of men had low socioeconomic status. This was associated with a reduced life expectancy of 2.1 years, which is similar to being inactive at 2.4 years. The greatest reductions in life expectancy were for smoking at 4.8 years and diabetes at 3.9 years. High blood pressure, obesity and high alcohol consumption were associated with smaller reductions in life expectancy of 1.6, 0.7 and 0.5 years respectively.
One of the senior authors of the study, Professor Paolo Vineis from Imperial College London, UK, is the leader of the EU LIFEPATH consortium in which this study is embedded. He explained that socioeconomic status is important as it can be seen as a summary measure of lifetime exposures to hazardous behaviors and circumstances. These go beyond the risk factors for non-communicable diseases that are normally addressed by policies. He adds that the study demonstrates that as it is a key risk factor for ill health, it should be included alongside the more conventional risk factors.
Professor Mika Kivimaki from University College London, UK is another senior author and she noted that although it is known that education, income and work affect health, few studies have scrutinized how important these socioeconomic factors truly are. She added that the aim of this study is to compare the major risk factors targeted in global health strategies to the effect of socioeconomic status.
One of the limitations of the study is that the researchers used only occupational position as an indicator of socioeconomic status. Although this measure is commonly used, it has the inherent risk of over simplifying the complexity of socioeconomic status. While the study analyzed and controlled for low socioeconomic status as an autonomous risk factor, the authors admit that it is difficult to separate the effects of other risk factors from socioeconomic status. This emphasizes the importance of targeting it alongside traditional risk factors that are included in global health targets.
Dr Martin Tobias from Tobias + Cheung Consulting in New Zealand wrote in a comment linked to the article that having low social rank implies being deprived of material resources, limited in the prospects open to you and powerless to determine your own destiny. The authors suggest that this shapes both your lifestyle and your life chances. The authors’ key message is clear irrespective of what the exact effect and impact of low social rank might be on the health of individuals and populations: social rank deserves attention alongside the recognized 25 × 25 risk factors. The UN Sustainable Development Goals, having replaced the MDGs, will run from 2016 to 2030. This provides an opportunity to go beyond the WHO 25 × 25 goal and place social determinants squarely as the focus of sustainable development.