BACKGROUND: An inverse relationship between coffee intake and mortality has been observed in several population cohorts, but rarely within Mediterranean countries. Moreover, the biological pathways mediating such an association remain unclear.
OBJECTIVES: We assessed the associations between coffee consumption and total and cause-specific mortality and examined the mediating roles of N-terminal pro B-type natriuretic peptide (NTproBNP), high-sensitivity Troponin I, blood glucose, lipid metabolism, and selected biomarkers of inflammation and renal function.
METHODS: We longitudinally analyzed data on 20,487 men and women (35-94 years old at baseline) in the Moli-sani Study, a prospective cohort established in 2005-2010. Individuals were free from cardiovascular disease (CVD) and cancer and were followed-up for a median of 8.3 years. Dietary data were collected by a 188-item semi-quantitative FFQ. Coffee intake was standardized to a 30-mL Italian espresso cup size. HRs with 95% CIs were calculated by multivariable Cox regression.
RESULTS: In comparison with no/rare coffee consumption (up to 1 cup/d), HRs for all-cause mortality across categories of coffee consumption (>1 to ≤2, >2 to ≤3, >3 to ≤4 and >4 cups/d) were 0.79 (95% CI, 0.65-0.95), 0.84 (95% CI, 0.69-1.03), 0.72 (95% CI, 0.57-0.92), and 0.85 (95% CI, 0.62-1.12), respectively. For CVD mortality, a nonlinear (P for non-linearity = 0.021) J-shaped association was found (magnitude of the relative reduction = 37%; nadir at 3-4 cups/d). Circulating levels of NTproBNP explained up to 26.4% of the association between coffee and all-cause mortality, while systolic blood pressure was likely to be on the pathway between coffee and CVD mortality, although to a lesser extent.
CONCLUSIONS: In this large cohort of Italian adults, moderate consumption (3-4 cups/d) of Italian-style coffee was associated with lower risks of all-cause and, specifically, of CVD mortality. Among the known biomarkers investigated here, NTproBNP likely mediates the relationship between coffee intake and all-cause mortality.