Association between sodium or salt intake and lower urinary tract symptoms: a systematic review.

Background: High sodium intake is associated with cardiovascular and kidney disease, as well as the development of lower urinary tract symptoms (LUTS). The amount of salt intake can influence the development of symptoms, but reduction may benefit patients by lowering the presentation of LUTS. However, there is a lack of systematization of evidence between salt intake and LUTS. Objectives: Determine the relationship between a high salt intake and LUTS, and the impact of salt intake reduction on the development of LUTS. Design: Systematic review. Data sources and methods: We included observational studies and clinical trials that assessed any clinical manifestations of LUTS and any method of measuring salt intake to establish a comparison between high and low salt intake. A search was conducted on PubMed, Scopus, Ovid-Medline, WOS, and Embase databases in February 2024, including studies published at any time until the date of the search. Risk of bias was assessed using the Newcastle-Ottawa Scale and risk of bias in non-randomized studies of interventions. A qualitative synthesis of the included studies was performed, and a meta-analysis was not conducted due to the heterogeneity of how LUTS and salt intake were measured. Results: We obtained 3085 articles, from which 10 were included in this review. In regards to urinary incontinence and general LUTS, patients who had a salty diet had more frequency and severe symptoms according to the Overactive Bladder Symptom score (H: 286, 1% vs N: 356, 0.6% vs N: 225, 0.8%; p < 0.001) and International Prostate Symptom score (H: 688, 2.5% vs N: 670, 1.7% vs B: 419, 2.3%; p < 0.001) respectively, compared to patients who had neutral or bland diets. Conclusion: Some evidence suggests a possible association between a high salt intake and LUTS, and lowering salt intake might help to improve symptoms. We suggest that future studies improve clinical trial designs to clarify the relationship and methods to assess salt intake and measurement of LUTS.