DAILY SODIUM CONSUMPTION AND CARDIOVASCULAR MORTALITY IN GENERAL POPULATION. SYSTEMATIC REVIEW AND META-ANALYSIS OF PROSPECTIVE STUDIES

ROSANA POGGIO, MD, MSC ; LAURA GUTIERREZ, MHSC; MARÍA GABRIELA MATTA, MD, NATALIA ELORRIAGA, MHSC; VILMA IRAZOLA, MD, MSC; ADOLFO RUBINSTEIN MD, MSC, PHD

Granada

Congreso; Congreso Mundial de Nutrición; 2013

International Union of Nutritional Sciences(IUNS) Committee

Background and objectives: Sodium intake and blood pressure levels have a well-established causal relationship but the evidence regarding sodium intake and cardiovascular (CV) mortality is still controversial. The important heterogeneity between studies and target populations makes difficult to combine data for evidence synthesis. Therefore, we aimed to determine whether elevated dietary salt intake is associated with CV mortality in a general population with no previous cardiovascular events. Methods: Systematic review and meta-analysis of prospective studies representing general population without previous cardiovascular events assessing the relationship between daily salt intake and CV mortality. Results: 13 studies met the criteria to be included in the analysis. The final population was 259.213 participants with a mean follow-up period of 13.2 years (range 5-20), contributing to 10.967 cardiovascular deaths. Higher sodium intake was significantly associated with higher cardiovascular mortality (RR= 1.12 - CI 95% 1.07-1.17). However, we also found a significant heterogeneity among the studies included (chi2=39.34 [d.f.=17] p 0.002 and I2=56.8%). The most relevant source of heterogeneity was related to the sodium intake assessment. Only when sodium was assessed by urinary sodium excretion the association was not significant (RR= 1.05-CI 95% 0.95-1.16). Variance-weighted least-squares regression showed that for every 50 mmol/day increase in sodium intake, the rate of CV mortality would increases 4.3 %; however that trend was not significant. Conclusions: Higher sodium intake would be associated with higher cardiovascular mortality in general population although this should be taken with caution due to the observation of a significant heterogeneity among studies. Some harmonization efforts to assess sodium intake should be implemented in future observational studies in order to reduce the sources of heterogeneity and make data more comparable for evidence synthesis.