Salt reduction in England from 2003 to 2011: its relationship to blood pressure, stroke and ischaemic heart disease mortality
Feng J He, Sonia Pombo-Rodrigues, Graham A MacGregor
BMJ Open Published 14 April 2014
Objectives To determine the relationship between the reduction in salt intake that occurred in England, and blood pressure (B.P), as well as mortality from stroke and ischaemic heart disease (IHD).
Design Analysis of the data from the Health Survey for England.
Setting and participants England, 2003 N=9183, 2006 N=8762, 2008 N=8974 and 2011 N=4753, aged ≥16 years.
Outcomes B.P, stroke and IHD mortality.
Results From 2003 to 2011, there was a decrease in mortality from stroke by 42% (p<0.001) and IHD by 40% (p<0.001). In parallel, there was a fall in B.P of 3.0±0.33/1.4±0.20 mm Hg (p<0.001/p<0.001), a decrease of 0.4±0.02 mmol/L (p<0.001) in cholesterol, a reduction in smoking prevalence from 19% to 14% (p<0.001), an increase in fruit and vegetable consumption (0.2±0.05 portion/day, p<0.001) and an increase in body mass index (BMI; 0.5±0.09 kg/m2, p<0.001). Salt intake, as measured by 24 h urinary sodium, decreased by 1.4 g/day (p<0.01). It is likely that all of these factors (with the exception of BMI), along with improvements in the treatments of B.P, cholesterol and cardiovascular disease, contributed to the falls in stroke and IHD mortality. In individuals who were not on antihypertensive medication, there was a fall in B.P of 2.7±0.34/1.1±0.23 mm Hg (p<0.001/p<0.001) after adjusting for age, sex, ethnic group, education, household income, alcohol consumption, fruit and vegetable intake and BMI. Although salt intake was not measured in these participants, the fact that the average salt intake in a random sample of the population fell by 15% during the same period suggests that the falls in B.P would be largely attributable to the reduction in salt intake rather than antihypertensive medications.
Conclusions The reduction in salt intake is likely to be an important contributor to the falls in B.P from 2003 to 2011 in England. As a result, it would have contributed substantially to the decreases in stroke and IHD mortality.
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