Low socioeconomic status was associated with increased risk for a cascade of psychiatric and physical conditions, according to study data published in Lancet Public Health. Compared with more advantaged groups, individuals of low socioeconomic status experienced greater rates of depression, anxiety, substance abuse, and self-harm. In turn, these psychiatric conditions precipitated greater risk for later liver, kidney, heart, and lung conditions.

The investigators pooled data from the Health and Social Support and Finnish Public Sector prospective cohort studies and followed patients for incident health conditions or mortality using Finnish national health registries. They collected demographic information and lifestyle factors at baseline (1998-2013) and calculated socioeconomic status as a composite measure of residential area deprivation and educational attainment. A total of 56 conditions of interest were included in analyses, using World Health Organization diagnostic codes. In addition, the researchers conducted a replication analysis using data from the Whitehall II study, an independent UK cohort.

The pooled cohort comprised data from 109,246 Finnish adults aged 17 to 77 years at study entry (mean age, 44.3±11.0 years; 76% women). According to area-based deprivation scores, 36,216 participants (33.2%) were in the low socioeconomic status group. A total of 245,573 hospitalizations were observed over 1,110,831 person-years at risk.

Compared with the other socioeconomic strata, low socioeconomic status was associated with increased risk for 18 of 56 health conditions (32.1%), including mood disorders, psychotic disorders, substance use disorders, heart disease, heart failure, chronic obstructive pulmonary disease, lung cancer, renal failure, pancreatic disease, liver disease, anemia, dementia, diabetes, and obesity. These associations were significant across both measures of socioeconomic status, area deprivation index and educational attainment. Pairwise analyses found that 16 of these 18 conditions were significantly interconnected in the low socioeconomic stratum, with hazard ratios of 5 or higher for developing a disease if another in the group was present.

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Among patients of high economic status, however, no strong interconnectedness was observed between the most common disorders. A cascade of these interrelated conditions was formulated, in which psychiatric and substance use disorders—typically diagnosed in the mid-40s—precipitated later risk for liver disease, kidney failure, diabetes, heart disease, and chronic obstructive pulmonary disease. In the replication cohort, similar associations were observed: across 186,573 person-years of follow-up, 60,946 hospitalizations occurred. All 18 conditions associated with socioeconomic status in the Finnish cohorts were similarly significant in the UK cohort. 

While socioeconomic status is a known predictor of mental and physical health, the study provided new insights into precise risk relationships and potential cascading trajectories. As study limitations, the investigators cited nonresponse bias and the relatively homogeneous study cohorts. Additionally, data may not be generalizable to health systems outside Finland or the United Kingdom.

Overall, the researchers concluded that “policy and health-care practice addressing mental health issues in social context and early in the life course might be effective strategies for reducing health inequalities.”

Disclosure: Several study authors declared industry affiliations and/or funding. Please see the original reference for a full list of authors’ disclosures.

Reference

Kivimäki M, Batty GD, Pentti J, et al. Association between socioeconomic status and the development of mental and physical health conditions in adulthood: a multi-cohort study. Lancet Public Health. 2020;5(3):e140-e149.