Research Article: Dietary sodium, table salt use, and specific depressive symptoms: cross-sectional associations in NHANES and an independent Chinese clinical cohort
Abstract:
The associations of dietary sodium intake and habitual table salt use with depressive symptoms may vary across symptom domains, but their relationships with specific depressive symptoms and potential non-linear patterns remain insufficiently understood. This study examined these associations in a US national sample and assessed whether directionally similar patterns could be observed in an independent Chinese clinical cohort.
We analyzed data from 23,753 adults in the NHANES (2005–2023) and an independent Chinese clinical cohort of 700 participants. Multivariable regression models and restricted cubic spline (RCS) analyses were used to evaluate the associations of habitual table salt addition and dietary sodium intake with individual PHQ-9 depressive symptoms. Subgroup analyses and interaction tests stratified by age, gender, education, and hypertension status were performed to explore potential effect modification.
In NHANES, habitual table salt addition was associated with higher odds of eight depressive symptoms (ORs 1.24–1.37), including low self-esteem, depressed mood, anhedonia, fatigue, difficulty concentrating, psychomotor changes, appetite change, and sleep disturbance. Directionally similar but less consistent nominal associations were observed in the Chinese clinical cohort; however, symptom-level associations in this cohort did not remain statistically significant after multiple-testing correction. Restricted cubic spline analyses suggested non-linear associations between dietary sodium intake and the odds of depressive symptom presence, with the fitted spline curves reaching their nadirs at approximately 4.0–4.6 g/day of sodium in the study data. Subgroup analyses did not identify any interaction that remained statistically significant after multiple-testing correction.
Habitual table salt addition was associated with multiple depressive symptoms in NHANES, with partially consistent patterns observed in the Chinese clinical cohort, particularly for somatic symptoms. Dietary sodium intake showed non-linear associations with the odds of depressive symptom presence. However, the nadir values observed in the spline analyses should not be interpreted as optimal, beneficial, safe, or recommended sodium intake targets, given the cross-sectional design and the limitations of dietary exposure assessment. These findings should be regarded as hypothesis-generating and support the need for prospective and interventional studies to clarify temporality, causality, and clinical relevance.
Introduction:
The associations of dietary sodium intake and habitual table salt use with depressive symptoms may vary across symptom domains, but their relationships with specific depressive symptoms and potential non-linear patterns remain insufficiently understood. This study examined these associations in a US national sample and assessed whether directionally similar patterns could be observed in an independent Chinese clinical cohort.
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