To understand potential pathways to study outcomes, we investigated relationships among EE markers and found LBP was not associated with either MPO or CRP, but MPO was positively associated with CRP in both HIV-uninfected (β = 0.20 (0.03, 0.37; P = 0.02)) and HIV-infected participants (β = 0.23(0.05, 0.43; P = 0.01)) (S3 Table). Here, MPO is linked to Low back pain.