Sex modifies association between dietary sodium intake and cardiovascular disease mortality among US adult with hypertension: a national population-based cohort

Objectives The objective of this study was to examine the relationship between dietary sodium intake and cardiovascular disease (CVD) mortality in hypertensive American adults.Methods A prospective cohort study was conducted to examine the association between dietary sodium intake, as estimated by a single 24-h dietary recall from the National Health and Nutrition Examination Survey (2003-2012), and mortality data obtained from the National Death Index.Results This study included 12,236 adults with hypertension, with 837 CVD-related deaths identified over a median follow-up period of 10.3 years. A nonlinear association between dietary sodium intake and CVD mortality was observed. The inflection point of the curve occurred at a sodium intake level of 2.07 g/day. Below this threshold, higher sodium intake was associated with a reduced risk of CVD mortality, though the association was not statistically significant after full adjustment (aHR: 0.78, 95% CI: 0.58-1.05). In contrast, sodium intake above 2.07 g/day was significantly associated with an increased risk of CVD mortality (aHR: 1.12, 95% CI: 1.02-1.23). The log-likelihood ratio test yielded a P-value of 0.04. This J-shaped association was observed exclusively in females, not males. Among females, the adjusted hazard ratios (95% CI) were 0.65 (0.42, 0.99) below and 1.29 (1.11, 1.53) above the inflection point (P for log-likelihood ratio test = 0.009).Conclusions In American adults with hypertension, dietary sodium intake exceeding 2.07 g/day was significantly associated with an increased risk of CVD mortality, while intake below this threshold was not significantly linked to mortality risk. Additionally, a sex-specific effect of dietary sodium intake on CVD mortality was observed, showing a J-shaped relationship exclusively in females, with no such association found in males.