BMC Public Health. 2025 Dec 5. doi: 10.1186/s12889-025-25342-z. Online ahead of print.
ABSTRACT
BACKGROUND: There is still debatable of the optimal standards for obesity and salt intake, particularly their potential impacts on mortality among older population. This study aimed to characterized the complex relationships among high-salt diet, obesity, and the cardiovascular disease (CVD) and all-cause mortality in US adults, with a focus on individuals aged 50 years or older.
METHODS: This is a retrospective cohort analysis of data from the National Health and Nutrition Examination Survey (2005-2020, n = 11,977). Data on individual body weight status and dietary sodium intake were extracted. Daily salt intake above 9 g is considered a high salt consumption. Adjusted weighted multivariable logistic regression models were was used for the analysis of the association among salt intake, obesity, and CVD outcomes. Cox proportional hazards model to estimate the association between salt intake and mortality. Mediation analysis was performed to investigate whether insulin levels mediate the relationship between salt intake and obesity.
RESULTS: Individuals with high-salt intake were more likely to exhibit both overall (OR: 1.33; 95% CI: 1.16-1.53) and central obesity (OR: 1.29; 95% CI: 1.13-1.48) after adjusting for potential confounders. Among individuals aged 50 years or older, the risks of overall obesity and central obesity were higher in those following a high-salt diet. No such relationships were observed in individuals younger than 50 years of age. High salt intake was associated with lower risks of both all-cause and CVD mortality compared to low salt intake in individuals over 50 years. In the older population with either overall (HR: 0.39, 95% CI: 0.17-0.89, P = 0.0254) or central obesity (HR: 0.40, 95% CI: 0.22-0.72, P = 0.0025), high salt intake was linked to a lower risk of CVD mortality compared to low salt intake. In individuals aged younger than 50 years and without obesity, high salt intake was associated with increased risk of CVD mortality.
CONCLUSION: This study found that higher salt intake was associated with an increased risk of obesity, whereas had an inverse association with all-cause and CVD mortality in adults aged over 50 years. Caution is warranted in interpreting these findings due to potential selection bias. Further longitudinal studies incorporating objective evaluation of salt intake are necessary to establish evidence-based recommendations for healthy lifestyle practices aimed at promoting healthy aging.
PMID:41350864 | DOI:10.1186/s12889-025-25342-z