Excessive salt intake accelerates the progression of cerebral small vessel disease in older adults

BACKGROUND: It is unclear whether excessive salt intake accelerates the progression of cerebral small vessel disease (CSVD). The major objective of this study was to investigate the harmful effect of excessive salt intake on the progression of CSVD in older individuals. METHODS: Between May 2007 and November 2010, 423 community-dwelling individuals aged 60 years and older were recruited from the Shandong area, China. Salt intake was estimated using 24-hour urine collection for 7 consecutive days at baseline. Participants were classified into low, mild, moderate and high groups according to the salt intake estimation. CSVD including white matter hyperintensities (WMHs), lacunes, microbleeds and an enlarged perivascular space (EPVS) were determined using brain magnetic resonance imaging. RESULTS: During an average of five years of follow-up, the WMH volume and WMH-to-intracranial ratio were increased in the four groups. However, the increasing trends in the WMH volume and WMH-to-intracranial ratio were significantly faster in the higher salt intake groups compared with the lower salt intake groups (P(adjusted) < 0.001). The cumulative hazard ratios of new-incident WMHs (defined as those with Fazekas scale scores ≥ 2), new-incident lacunes, microbleeds or an EPVS, as well as composites of CSVD, were respectively 2.47, 2.50, 3.33, 2.70 and 2.89 for the mild group; 3.72, 3.74, 4.66, 4.01 and 4.49 for the moderate group; and 7.39, 5.82, 7.00, 6.40 and 6.61 for the high group, compared with the low group after adjustment for confounders (P(adjusted) < 0.001). The risk of new-incident WMHs, lacunes, microbleeds or an EPVS, and composites of CSVD was significantly increased with each 1-standard-deviation increment in salt intake (P(adjusted) < 0.001). CONCLUSION: Our data indicates that excessive salt intake is an important and independent contributor to the progression of CVSD in older adults.