Salt stroke hazards confirmed in multiethnic study
MedWire News: Salt consumption is strongly linked to stroke risk in the multiethnic Northern Manhattan Study (NOMAS).
"Our study provides evidence for a strong relationship between excess sodium intake and increased stroke risk in a multiethnic population," say Hannah Gardener (University of Miami, Florida, USA) and colleagues.
They say that, until now, the effect of salt intake on stroke has mainly been studied in White populations. The current findings, based on 2657 NOMAS participants with dietary data, show some ethnic differences. For example, 58% of Hispanic participants were in the highest category of salt consumption (≥4000 mg/day), compared with 21% of Black participants and 19% of White participants.
This means that the proportion of stroke attributable to high salt consumption is likely higher in the Hispanic than the Black or White communities, says the team.
The study findings also suggest that some of the stroke risk associated with salt consumption may be independent of blood pressure (BP).
Overall, participants in the highest category of salt consumption at baseline were 2.6-fold more likely to have a stroke over an average 10 years of follow up than were those in the lowest quartile (≤1500 mg/day, within American Heart Association guidelines). Each 500 mg/day increase in salt consumption was associated with a 17% increase in stroke risk.
This association was independent of baseline demographic variables and vascular risk factors, including systolic and diastolic BP, hypertension, and use of antihypertensive agents. However, Gardener et al note that BP could still be a causal factor, as they could not account for changes in BP and its association with salt consumption during follow up.
Editorialists Francesco Cappuccio and Chen Ji (University of Warwick, Coventry, UK) call the study "another small tile of an impressive mosaic of evidence supporting a reduction of population salt intake as an urgent strategy for the global prevention of cardiovascular disease around the world."
They comment that legislation may be required, noting that, although cheaper and less confrontational, "self regulation tends to be less effective than legislation." Cappuccio and Ji say: "When promises are not fulfilled, harm occurs."
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By Eleanor McDermid