Relative contribution of health-related behaviours and chronic diseases to the socioeconomic patterning of low-grade inflammation

Objectives: To test the association of low-grade inflammation with socioeconomic status (SES) and determine the relative contribution of prevalent chronic diseases and health-related behaviours in explaining such association. Methods: Cross-sectional analysis on 19,867 subjects (age ≥35, 48.1% men) recruited within the Moli-sani study from 2005 to 2010 (Italy). A score of low-grade inflammation, including platelet and leukocyte counts, the granulocyte-to-lymphocyte ratio, and C-reactive protein was applied. SES was measured by education, household income, and occupational social class. Results: Low SES was associated with elevated levels of low-grade inflammation. Health behaviours (including adiposity, smoking, physical activity, and Mediterranean diet adherence) explained 53.5, 53.9, and 84.9% of the association between social class, income, and education with low-grade inflammation, respectively. Adiposity and body mass index showed a prominent role, while prevalent chronic diseases and conditions only marginally attenuated SES inequalities in inflammation. Conclusions: Low-grade inflammation was socioeconomically patterned in a large Mediterranean population. Potentially modifiable behavioural factors explained the greatest part of this association with a leading contribution of adiposity, body mass index, and physical activity.