Small Vessel Disease and Dietary Salt Intake: Cross-Sectional Study and Systematic Review

Stephen D.J Makin,Ghaida F Mubki,Fergus N Doubal,Kirsten Shuler,Julie Staals,Martin S Dennis,Joanna M Wardlaw

doi:10.1016/j.jstrokecerebrovasdis.2017.08.004

Abstract

BackgroundHigher dietary salt intake increases the risk of stroke and may increase white matter hyperintensity (WMH) volume. We hypothesized that a long-term higher salt intake may be associated with other features of small vessel disease (SVD).MethodsWe recruited consecutive patients with mild stroke presenting to the Lothian regional stroke service. We performed brain magnetic resonance imaging, obtained a basic dietary salt history, and measured the urinary sodium/creatinine ratio. We also carried out a systematic review to put the study in the context of other studies in the field.ResultsWe recruited 250 patients, 112 with lacunar stroke and 138 with cortical stroke, with a median age of 67.5 years. After adjustment for risk factors, including age and hypertension, patients who had not reduced their salt intake in the long term were more likely to have lacunar stroke (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.10-3.29), lacune(s) (OR, 2.06; 95% CI, 1.09-3.99), microbleed(s) (OR, 3.4; 95% CI, 1.54, 8.21), severe WMHs (OR, 2.45; 95% CI 1.34-4.57), and worse SVD scores (OR, 2.17; 95% CI, 1.22-3.9). There was limited association between SVD and current salt intake or urinary sodium/creatinine ratio. Our systematic review found no previously published studies of dietary salt and SVD.ConclusionThe association between dietary salt and background SVD is a promising indication of a potential neglected contributory factor for SVD. These results should be replicated in larger, long-term studies using the recognized gold-standard measures of dietary sodium.

Highlights

Cerebral small vessel disease (SVD) is common and clinically important: it is responsible for dementia,[1] depression,[2] physical disability,[3] and one fifth of all strokes.[4]
We found that increased dietary salt intake was associated with greater white matter hyperintensity (WMH) volumes, a key feature of SVD.[7]
Dietary salt increases the risk of any type of stroke: in 19 cohort studies (n > 170,000 participants), the relative risk of stroke was 1.23 (95% confidence interval [CI], 1.06-1.4) for higher versus lower salt intake,[8] confirmed in the North Manhattan Stroke Study, which found a 17% increase in the 10-year stroke risk for each additional 500 mg of daily dietary sodium.[9]

Summary

Introduction

Cerebral small vessel disease (SVD) is common and clinically important: it is responsible for dementia,[1] depression,[2] physical disability,[3] and one fifth of all strokes.[4]. To further examine the potential relationship between dietary salt intake and SVD clinical and imaging features, we performed a cross-sectional study in patients presenting with minor stroke and a systematic review of the existing literature. Higher dietary salt intake increases the risk of stroke and may increase white matter hyperintensity (WMH) volume. After adjustment for risk factors, including age and hypertension, patients who had not reduced their salt intake in the long term were more likely to have lacunar stroke (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.10-3.29), lacune(s) (OR, 2.06; 95% CI, 1.09-3.99), microbleed(s) (OR, 3.4; 95% CI, 1.54, 8.21), severe WMHs (OR, 2.45; 95% CI 1.34-4.57), and worse SVD scores (OR, 2.17; 95% CI, 1.22-3.9).

Methods

Results

Conclusion