Unemployment and inflammatory markers in England, Wales and Scotland, 1998-2012: Meta-analysis of results from 12 studies.

INTRODUCTION: Unemployment represents for many affected individuals a substantial source of psychosocial stress, and is linked to both increased risk of morbidity and mortality and adverse health-related behaviours. Few studies have examined the association of unemployment with systemic inflammation, a plausible mediator of the associations of psychosocial stress and health, and results are mixed and context dependent. This study examines the association of unemployment with C-reactive protein (CRP) and fibrinogen, two markers of systemic inflammation. METHODS: A random-effects meta-analysis was performed using a multilevel modelling approach, including 12 national UK surveys of working-age participants in which CRP and fibrinogen were measured between 1998 and 2012 (N=30,037 economically active participants). The moderating impact of participant age and UK country was explored. RESULTS: CRP and fibrinogen were elevated in unemployed compared to employed participants; jobseekers were also more likely (Odds Ratio: 1.39, p<0.001) to have CRP levels corresponding to high cardiovascular risk (>3mg/L), after adjustment for age, gender, education, long-term illness, smoking, and body mass index. Associations were not explained by mental health. Associations peaked in middle-age, and were stronger in Scotland and Wales than in England. CONCLUSIONS: Our study demonstrates that systemic inflammation is associated with an important but little-studied aspect of the social environment, as it is elevated in unemployed compared to employed survey participants. Modifications suggest the association of unemployment and inflammation is substantially influenced by contextual factors, and may be especially strong in Wales, where further investigation of this relationship is needed.