Relative poverty still matters
Authors: S Vittal Katikireddi, Ruth Dundas
Journal: The Lancet Public Health (2017)

Although great reductions of childhood poverty have been achieved across the world, it remains a substantial cause of poor health and health inequalities.1UNICEFThe state of the world's children 2016. A fair chance for every child. United Nations Children's Fund, New York2016Crossref Google Scholar The commitment expressed in the first Sustainable Development Goal “to end poverty in all its forms everywhere” is therefore crucial to ensure that the next generation has the best chance of leading healthy lives.2UNTransforming our world: the 2030 Agenda for Sustainable Development. United Nations, New York2015Google Scholar However, what does an end to poverty mean? Sophie Wickham and colleagues3Wickham S Whitehead M Taylor-Robinson D Barr B The effect of a transition into poverty on child and maternal health: a longitudinal analysis of the UK Millennium Cohort Study.Lancet Public Health. 2017; (published online Feb 15.)http://dx.doi.org/10.1016/S2468-2667(17)30011-7Summary Full Text Full Text PDF PubMed Scopus (60) Google Scholar shine much needed light on this longstanding and politically heated debate. A common distinction is made between absolute and relative poverty. Absolute poverty involves establishment of an absolute minimum threshold of income that is necessary for survival. By contrast, relative poverty is usually defined as having 60% of the median income within a country.4Her Majesty's GovernmentMeasuring child poverty: a consultation on better measures of child poverty. The Stationary Office, London2012Google Scholar Wickham and colleagues3Wickham S Whitehead M Taylor-Robinson D Barr B The effect of a transition into poverty on child and maternal health: a longitudinal analysis of the UK Millennium Cohort Study.Lancet Public Health. 2017; (published online Feb 15.)http://dx.doi.org/10.1016/S2468-2667(17)30011-7Summary Full Text Full Text PDF PubMed Scopus (60) Google Scholar investigated the effect of movement into relative poverty on childhood socioemotional behavioural problems (measured with the Strengths and Difficulties Questionnaire) and maternal mental health.3Wickham S Whitehead M Taylor-Robinson D Barr B The effect of a transition into poverty on child and maternal health: a longitudinal analysis of the UK Millennium Cohort Study.Lancet Public Health. 2017; (published online Feb 15.)http://dx.doi.org/10.1016/S2468-2667(17)30011-7Summary Full Text Full Text PDF PubMed Scopus (60) Google Scholar Drawing on the UK's Millennium Cohort Study,5University of LondonInstitute of Education. Centre for Longitudinal Studies. Millennium Cohort Study: Fifth Survey, 2012. 2nd Edition. UK Data Service.https://discover.ukdataservice.ac.uk/catalogue/?sn=7464&type=Data%20catalogueDate: 2015Google Scholar the authors identify families who were not in poverty and did not have poor maternal mental health at baseline. They then compared outcomes for families who moved into poverty for the first time with those who did not, finding marked increases in the risk of adverse childhood outcomes and maternal psychological distress. Methodologically, this study marks an important step forward in the understanding of a fundamentally important determinant of health. By contrast with previous research, the authors have explicitly sought to understand the causal relationship between movement into poverty and health. Restriction of the analytical sample to those who are not in poverty and do not have poor mental health at baseline limited the potential for reverse causation in their analysis. The focus on transitions into poverty, rather than comparison of exposure measurements taken at a single timepoint as occurs in most epidemiological studies, is a major strength. The authors attempt to explore the role of maternal mental health in mediating the mechanism between poverty and adverse childhood socioemotional development. Here, the study is arguably at its weakest, with, at most, modest attenuation observed and potential residual confounding could not be addressed through the study design. Furthermore, implications of this part of the analysis are unclear. Interventions that target maternal mental health are unlikely to be adequate to mitigate the adverse effects of poverty on children. What next for research into the health effects of entry into poverty? Ecological evidence suggests that trends in relative poverty are important for mortality,6Fritzell J Rehnberg J Hertzman JB Blomgren J Absolute or relative? A comparative analysis of the relationship between poverty and mortality.Int J Public Health. 2015; 60: 101-110Crossref PubMed Scopus (21) Google Scholar but many large gaps remain in the evidence base. Although this study has identified some of the short-term effects of poverty, effects are likely to continue throughout the rest of the life course. The focus on relative poverty by the authors, as assessed in relation to median income, is timely. Rather than definition of poverty on the basis of income alone, the UK Government suggested a new definition involving measurement of other aspects that relate to a child's future life opportunities, namely on the basis of worklessness, unmanageable debt, poor housing, parental skill level, access to quality education, parental stability, and parental health.4Her Majesty's GovernmentMeasuring child poverty: a consultation on better measures of child poverty. The Stationary Office, London2012Google Scholar The subsequent legislation included proposals to stop measuring income, therefore ending the longstanding assessment of income-based relative poverty. Although evidence suggests that addressing some of these other aspects of social disadvantage such as worklessness could help to reduce health inequalities,7Katikireddi SV Niedzwiedz CL Popham F Employment status and income as potential mediators of educational inequalities in population mental health.Eur J Public Health. 2016; 26: 814-816Crossref PubMed Scopus (19) Google Scholar this latest study by Wickham and colleagues3Wickham S Whitehead M Taylor-Robinson D Barr B The effect of a transition into poverty on child and maternal health: a longitudinal analysis of the UK Millennium Cohort Study.Lancet Public Health. 2017; (published online Feb 15.)http://dx.doi.org/10.1016/S2468-2667(17)30011-7Summary Full Text Full Text PDF PubMed Scopus (60) Google Scholar reiterates the need to continue assessment of material circumstances and, in particular, income. Socioeconomic measures are not interchangeable.8Geyer S Hemström Ö Peter R Vågerö D Education, income, and occupational class cannot be used interchangeably in social epidemiology. Empirical evidence against a common practice.J Epidemiol Community Health. 2006; 60: 804-810Crossref PubMed Scopus (435) Google Scholar Choices about what is measured can far too easily result in the blame for poverty moving from the most powerful in society to those being adversely affected: measurement choices can stigmatise and provide reasons for inaction.9Katikireddi SV Counting the cost of alcohol: what you measure will shape the policy response.Addiction. 2016; (published online Dec 2.)https://doi.org/10.1111/add.13674Crossref PubMed Scopus (2) Google Scholar, 10Katikireddi SV Valles SA Coupled ethical-epistemic analysis of public health research and practice: categorizing variables to improve population health and equity.Am J Public Health. 2015; 105: e36-e42Crossref PubMed Scopus (30) Google Scholar Although the legislation to drop measurement of relative poverty was ultimately defeated within the UK after opposition from the House of Lords,11Butler P U-turn by government over changes to measurements of child poverty.https://www.theguardian.com/society/2016/feb/26/uk-government-forced-to-retain-household-income-as-measure-of-child-povertyDate: Feb 26, 2016Google Scholar definitions used to monitor poverty are subject to continued debated within the UK and elsewhere. This latest study has important policy implications. Given its unique focus on transitions into poverty, this research provides an indication of the scale of benefits to public health that could be realised by prevention of children from moving into poverty. Much existing policy and research has focused on how best to lift people out of poverty, once they have become impoverished. By contrast, arguably too little thought has been given to prevention of people entering poverty in the first place. Findings from this latest study show that this prize is worth fighting for—the potential benefits for the health of mothers and children could be substantial. SVK and RD are funded by the Medical Research Council (MC_UU_12017/13 and MC_UU_12017/15) and Chief Scientist's Office (SPHSU13 and SPHSU15). SVK is also funded by a National Health Service Research Scotland Scottish Senior Clinical Fellowship (SCAF/15/02). The effect of a transition into poverty on child and maternal mental health: a longitudinal analysis of the UK Millennium Cohort StudyIn a contemporary UK cohort, first transition into income poverty during early childhood was associated with an increase in the risk of child and maternal mental health problems. These effects were independent of changes in employment status. Transitions to income poverty do appear to affect children's life chances and actions that directly reduce income poverty of children are likely to improve child and maternal mental health. Full-Text PDF Open Access