Analysis of variability of high sensitivity C-reactive protein in lowland ecuador reveals no evidence of chronic low-grade inflammation

Objectives: C-reactive protein (CRP) is a central component of innate immune defenses, and high sensitivity CRP has emerged as an important biomarker of chronic inflammation and cardiovascular disease risk. Prior analyses of CRP variability have reported stable between-individual differences in CRP over time, but a limitation of current knowledge is that it is based on research conducted in post-epidemiologic transition populations. Methods: This study evaluated CRP variability among adults in the southeastern region of the Ecuadorian Amazon where rates of infectious diseases remain high. Blood samples were collected from 52 adults at four weekly sampling intervals and were quantified using a high-sensitivity immunoassay. Results: Median CRP concentration was 0.52 mg/l. About 34.6% of participants had CRP >3 mg/l at one time point, but no individuals had CRP >3 mg/l across two or more sampling intervals, and within-individual correlations revealed low levels of stable, between-individual differences in CRP. The application of current guidelines for the assessment of chronic inflammation failed to detect a single case of "high risk" CRP. Conclusions: This study is the first to investigate CRP variability in a nonindustrialized, high infectious disease environment. It documents a pattern of variation over time that is distinct from prior research, with no evidence for chronic low-grade inflammation. These results may have substantial implications for research on inflammation and diseases of aging globally, as well as for scientific understandings of the regulation of inflammation.