Socio-economic inequalities in C-reactive protein and fibrinogen across the adult age span: Findings from Understanding Society

Apostolos Davillas,Michaela Benzeval,Meena Kumari

doi:10.1038/s41598-017-02888-6

Abstract

Systemic inflammation has been proposed as a physiological process linking socio-economic position (SEP) to health. We examined how SEP inequalities in inflammation –assessed using C-reactive protein (CRP) and fibrinogen– varied across the adult age span. Current (household income) and distal (education) markers of SEP were used. Data from 7,943 participants (aged 25+) of Understanding Society (wave 2, 1/2010-3/2012) were employed. We found that SEP inequalities in inflammation followed heterogeneous patterns by age, which differed by the inflammatory marker examined rather than by SEP measures. SEP inequalities in CRP emerged in 30s, increased up to mid-50s or early 60 s when they peaked and then decreased with age. SEP inequalities in fibrinogen decreased with age. Body mass index (BMI), smoking, physical activity and healthy diet explained part, but not all, of the SEP inequalities in inflammation; in general, BMI exerted the largest attenuation. Cumulative advantage theories and those considering age as a leveler for the accumulation of health and economic advantages across the life-span should be dynamically integrated to better understand the observed heterogeneity in SEP differences in health across the lifespan. The attenuating roles of health-related lifestyle indicators suggest that targeting health promotion policies may help reduce SEP inequalities in health.

Highlights

It is well established that socio-economically disadvantaged groups experience poor health, less is known about how the association between socio-economic position (SEP) and health evolves over the lifecycle[1,2,3,4,5,6]
Using data from a large nationally representative sample of adults aged 25 and older (UKHLS), we find that the negative association between higher SEP and inflammatory biomarkers (CRP and fibrinogen) follows heterogeneous patterns as a function of age
These age patterns vary by the inflammatory biomarker examined (CRP or fibrinogen) rather than the utilised marker of SEP

Summary

Introduction

It is well established that socio-economically disadvantaged groups experience poor health, less is known about how the association between socio-economic position (SEP) and health evolves over the lifecycle[1,2,3,4,5,6]. Most existing studies do not explicitly consider the full adult age span when analysing the association between SEP and inflammation (often assessed using C-reactive protein (CRP) and fibrinogen biomarkers), they are limited to describing associations between measures of SEP at various life stages (such as childhood and adulthood) and the inflammatory biomarkers in adulthood[13,14,15,16,17,18,19]. The effects of health-related lifestyle factors on the incidence of adverse health outcomes are often characterized by cumulative, long-lasting processes[27] These indicate the importance of taking a life span perspective with respect to the relationships between SEP, health-related lifestyle indicators and inflammation

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Conclusion