Is coffee consumption associated with a lower level of serum C-reactive protein? A meta-analysis of observational studies

The association between coffee consumption and the level of C-reactive protein (CRP) has been evaluated in several epidemiological studies with conflicting results. This study aims to examine the relationship between coffee consumption and the serum CRP level. A comprehensive literature search up to August 2017, using PUBMED, EMBASE and Web of Science databases, was conducted to identify the relevant observational studies that examined the association between coffee consumption and the serum CRP level. A total of nine cross-sectional studies were included in this meta-analysis. According to the combined standard mean difference (SMD) between the highest and the lowest coffee intake category, coffee consumption was associated with a lower level of serum CRP level (SMD = -0.34, 95%CI: -0.62 to -0.06; p = .016). Subgroup analysis for CRP marker showed that coffee consumption was associated with a lower level of serum high-sensitivity CRP (hsCRP) (SMD = -0.51, 95%CI: -0.88 to -0.14; p = .007), but not standard CRP (SMD = 0.02, 95%CI: -0.28 to 0.32; p = .913). The existing evidence suggested that coffee consumption was associated with a lower level of serum CRP. More well-designed prospective cohort studies are needed to elaborate the concerned issues further.