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Socioeconomic position and depression in South African adults with long-term health conditions: a longitudinal study of causal pathways

  • T. Elwell-Sutton (a1), N. Folb (a2), A. Clark (a1), L. R. Fairall (a2), C. Lund (a3) (a4) and M. O. Bachmann (a1)...

Abstract

Aims.

There is convincing evidence that lower socioeconomic position is associated with increased risk of mental disorders. However, the mechanisms involved are not well understood. This study aims to elucidate the causal pathways between socioeconomic position and depression symptoms in South African adults. Two possible causal theories are examined: social causation, which suggests that poor socioeconomic conditions cause mental ill health; and social drift, which suggests that those with poor mental health are more likely to drift into poor socioeconomic circumstances.

Methods.

The study used longitudinal and cross-sectional observational data on 3904 adults, from a randomised trial carried out in 38 primary health care clinics between 2011 and 2012. Structural equation models and counterfactual mediation analyses were used to examine causal pathways in two directions. First, we examined social causation pathways, with language (a proxy for racial or ethnic category) being treated as an exposure, while education, unemployment, income and depression were treated as sequential mediators and outcomes. Second, social drift was explored with depression treated as a potential influence on health-related quality of life, job loss and, finally, income.

Results.

The results suggest that the effects of language on depression at baseline, and on changes in depression during follow-up, were mediated through education and income but not through unemployment. Adverse effects of unemployment and job loss on depression appeared to be mostly mediated through income. The effect of depression on decreasing income appeared to be mediated by job loss.

Conclusions.

These results suggest that both social causation and social selection processes operate concurrently. This raises the possibility that people could get trapped in a vicious cycle in which poor socioeconomic conditions lead to depression, which, in turn, can cause further damage to their economic prospects. This study also suggests that modifiable factors such as income, employment and treatable depression are suitable targets for intervention in the short to medium term, while in the longer term reducing inequalities in education will be necessary to address the deeply entrenched inequalities in South Africa.

Copyright

Corresponding author

*Address for correspondence: T. Elwell-Sutton, Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK. (Email: T.Elwell-Sutton@uea.ac.uk)

References

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Alang, SM (2014). Racial variations in the effects of structural and psychological factors on depressive symptoms: a structural equation modeling approach. Mental Health & Prevention 2, 210.
Andresen, EM, Malmgren, JA, Carter, WB, Patrick, DL (1994). Screening for depression in well older adults: evaluation of a short form of the CES-D (Center for Epidemiologic Studies Depression Scale). American Journal of Preventive Medicine 10, 7784.
Ataguba, JE, Akazili, J, McIntyre, D (2011). Socioeconomic-related health inequality in South Africa: evidence from General Household Surveys. International Journal for Equity in Health 10, 48.
Bachmann, MO, Louwagie, G, Fairall, LR (2009). Quality of life and financial measures in HIV/AIDS in Southern Africa. In Handbook of Disease Burdens and Quality of Life Measures (ed. Preedy, V and Watson, R), pp. 32233243. Springer: Berlin.
Baron, E, Davies, T, Lund, C (2017) Validation of the 10-item Centre for Epidemiological Studies Depression Scale (CES-D-10) in the Zulu, Xhosa and Afrikaans general population. BMC Psychiatry 17, 6.
Benatar, S (2013). The challenges of health disparities in South Africa. South African Medical Journal 103, 154155.
Bollen, KA (1987). Total, direct and indirect effects in structural equation models. Sociological Methodology 17, 3769.
Department of Health (2014). Standard Treatment Guidelines and Essential Medicines List for South Africa. Pretoria.
Dohrenwend, B, Levav, I, Shrout, P, Schwartz, S, Naveh, G, Link, B, Skodol, A, Stueve, A (1992). Socioeconomic status and psychiatric disorders: the causation-selection issue. Science 255, 946952.
Fairall, LR, Folb, N, Timmerman, V, Lombard, C, Steyn, K, Bachmann, MO, Bateman, ED, Lund, C, Faris, G, Gaziano, T, Georgeu-Pepper, D, Zwarenstein, M, Levitt, NS (2016). Educational outreach in an integrated clinical management tool for nurse-led non-communicable chronic disease management in primary care in South Africa: pragmatic cluster randomised controlled trial. PLoS Medicine 13, e1002178.
Folb, N, Lund, C, Fairall, L, Timmerman, V, Levitt, N, Steyn, K, Bachmann, M (2015a). Socioeconomic predictors and consequences of depression among primary care attenders with non-communicable diseases in the Western Cape, South Africa: Cohort study within a randomised trial. BMC Public Health 15, 1194.
Folb, N, Timmerman, V, Levitt, NS, Steyn, K, Bachmann, MO, Lund, C, Bateman, ED, Lombard, C, Gaziano, A, Zwarenstein, M, Fairall, LR (2015b). Multimorbidity, control and treatment of non- communicable diseases among primary healthcare attenders in the Western Cape, South Africa. South African Medical Journal 105, 642647.
Funk, M, Drew, N, Knapp, M (2012). Mental health, poverty and development. Journal of Public Mental Health 11, 166185.
Gadalla, TM (2009). Determinants, correlates and mediators of psychological distress: a longitudinal study. Social Science & Medicine 68, 21992205.
Glymour, MM (2006). Using causal diagrams to understand common problems in social epidemiology. In Social Epidemiology (ed. Oakes, JM and Kaufman, JM) pp. 387422, 393–427. Jossey-Bass: San Francisco.
Herman, AA, Stein, DJ, Seedat, S, Heeringa, SG, Moomal, H, Williams, DR (2009). The South African Stress and Health (SASH) study: 12-month and lifetime prevalence of common mental disorders. South African Medical Journal 99.
Hicks, R, Tingley, D (2011). Causal mediation analysis. Stata Journal 11, 605619.
Hudson, CG (2005). Socioeconomic status and mental illness: tests of the social causation and selection hypotheses. American Journal of Orthopsychiatry 75, 318.
Hudson, DL, Neighbors, HW, Geronimus, AT, Jackson, JS (2012). The relationship between socioeconomic position and depression among a US nationally representative sample of African Americans. Social Psychiatry and Psychiatric Epidemiology 47, 373381.
Leibbrandt, M, Woolard, I, Finn, A, Argent, J (2010). Trends in South African Income Distribution and Poverty Since the Fall of Apartheid. OECD Social, Employment and Migration Working Papers, No. 101, OECD Publishing. http://dx.doi.org/10.1787/5kmms0t7p1ms-en (accessed 1 May 2017).
Leibbrandt, M, Finn, A, Woolard, I, Leibbrandt, M, Finn, A, Woolard, I (2012). Describing and decomposing post-apartheid income inequality in South Africa. Describing and decomposing post-apartheid income inequality in South Africa. Development Southern Africa 29, 1934.
Lund, C, Breen, A, Flisher, AJ, Kakuma, R, Corrigall, J, Joska, JA, Swartz, L, Patel, V (2010). Poverty and common mental disorders in low and middle income countries: a systematic review. Social Science & Medicine 71, 517528.
Lund, C, De Silva, M, Plagerson, S, Cooper, S, Chisholm, D, Das, J, Knapp, M, Patel, V (2011). Poverty and mental disorders: breaking the cycle in low-income and middle-income countries. Lancet 378, 15021514.
Mayosi, BM, Benatar, SR (2014). Health and Health Care in South Africa – 20 years after Mandela. New England Journal of Medicine 371, 13441353.
McFadden, D (1974) Conditional logit analysis of qualitative choice behavior. In Frontiers in Econometrics (ed. Zarembka, P) pp. 105142. Academic Press: New York.
Myer, L, Smit, J, Le Roux, L, Parker, S, Stein, DJ, Seedat, S (2008a). Common mental disorders among HIV-infected individuals in South Africa: prevalence, predictors, and validation of brief psychiatric rating scales. AIDS Patient Care and STDs 22, 147158.
Myer, L, Stein, DJ, Grimsrud, A, Seedat, S, Williams, DR (2008b). Social determinants of psychological distress in a nationally-representative sample of South African adults. Social Science and Medicine 66, 18281840.
Patel, V, Kleinman, A (2003). Poverty and common mental disorders in developing countries. Bulletin of the World Health Organization 81, 609615.
Patel, V, Araya, R, De Lima, M, Ludermir, A, Todd, C, Centre, S, Porvorim, A (1999). Women, poverty and common mental disorders in four restructuring societies. Social Science and Medicine 49, 14611471.
Patel, V, Lund, C, Hatherill, S, Plagerson, S, Corrigall, J, Funk, M, Flisher, AJ (2010). Mental disorders: equity and social determinants. In Equity, Social Determinants and Public Health Programmes (ed. Blas, E and Kurup, AS) pp 115134. World Health Organisation: Geneva.
Pearl, J (2001). Direct and Indirect Effects. In Proceedings of the Seventeenth Conference on Uncertainty in Artificial Intelligence, pp. 411–420. Morgan Kaufman: San Francisco. http://dl.acm.org/citation.cfm?id=2074022.2074073 (accessed 1 May 2017).
Pretorius, TB (1991). Cross-cultural application of the Center for Epidemiological Studies Depression Scale: a study of black South African students. Psychological Reports 69, 11791185.
Radloff, LS (1977). The CES-D Scale: a self-report depression scale for research in the general population. Applied Psychological Measurement 1, 385401.
Robins, JM, Greenland, S (1992). Identifiability and exchangeability for direct and indirect effects. Epidemiology 3, 143155.
Schermelleh-Engel, K, Moosbrugger, H, Müller, H (2003). Evaluating the fit of structural equation models: tests of significance and descriptive goodness-of-fit measures. Methods of Psychological Research Online 8, 2374.
Slominski, L, Sameroff, A, Rosenblum, K, Kasser, TIM (2011). Longitudinal predictors of adult socioeconomic attainment: the roles of socioeconomic status, academic competence, and mental health. Development of Psychopathology 23, 315324.
Statistics South Africa (2011). Census 2011. Municipal factsheet. Pretoria. http://www.statssa.gov.za/census/census_2011/census_products/Census_2011_Municipal_fact_sheet.pdf
Statistics South Africa (2012). Census 2011. Census in Brief. Pretoria.
Statistics South Africa (2014). Mid-year population estimates. Pretoria.
Sweeting, H, Green, M, Benzeval, M, West, P (2016). The emergence of health inequalities in early adulthood: evidence on timing and mechanisms from a West of Scotland cohort. BMC Public Health 115.
The EuroQol Group (1990). Euroqol – a new facility for the measurement of health-related quality of life. Health Policy 16, 199208.
Tregenna, F, Tsela, M (2012). Inequality in South Africa: the distribution of income, expenditure and earnings. Development Southern Africa 29, 3561.
VanderWeele, T, Vansteelandt, S (2014). Mediation analysis with multiple mediators. Epidemiologic Methods 2, 95115.
Vos, T, Barber, RM, Bell, B, Bertozzi-Villa, A, Biryukov, S, Bolliger, I, Charlson, F, Davis, A, Degenhardt, L, Dicker, D, Duan, L (2015). Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet 386, 743800.
Whiteford, HA, Degenhardt, L, Rehm, J, Baxter, AJ, Ferrari, AJ, Erskine, HE, Charlson, FJ, Norman, RE, Flaxman, AD, Johns, N, Burstein, R, Murray, CJL, Vos, T (2013). Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010. Lancet 382, 15751586.
World Bank (2016). GINI index (World Bank estimate) http://data.worldbank.org/indicator/SI.POV.GINI (accessed 1 May 2017).
Wright, S (1934). The method of path coefficients. Annals of Mathematical Statistics 5, 161215.
Zhang, W, O'Brien, N, Forrest, JI, Salters, KA, Patterson, TL, Montaner, JSG, Hogg, RS, Lima, VD (2012). Validating a shortened depression scale (10 item CES-D) among HIV-positive people in British Columbia, Canada. PLoS ONE 7, e40793.

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