Depression is not associated with inflammation among adults in the Philippines, in contrast to prior research in the US. These results suggest that higher levels of microbial exposure in the Philippines may promote the development of immuno-regulatory pathways that prevent the emergence of a relationship between depression and inflammation.
Depression is positively associated with chronic inflammation in industrialized settings with low burdens of infectious disease, but the pattern of association in environments with higher levels of microbial exposure is not known. We measured C-reactive protein (CRP) and interleukin 6 (IL6) in community-based samples of young adults (20–22 years) and older women (35–69 years) in the Philippines. Concentrations of CRP and IL6 were low, and bivariate and multivariate regression analyses indicated no associations between depressive symptoms and inflammation in either sample. Results are interpreted in light of prior research indicating that higher levels of microbial exposure in infancy have lasting effects on the regulation of inflammation, and may prevent the emergence of a relationship between depression and inflammation in adulthood.