Objective To assess the relation between the level of habitual salt intake and stroke or total cardiovascular disease outcome. Design Systematic review and meta-analysis of prospective studies published 1966-2008. Data sources Medline (1966-2008), Embase (from 1988), AMED (from 1985), CINAHL (from 1982), Psychinfo (from 1985), and the Cochrane Library. Review methods For each study, relative risks and 95% confidence intervals were extracted and pooled with a random effect model, weighting for the inverse of the variance. Heterogeneity, publication bias, subgroup, and meta-regression analyses were performed. Criteria for inclusion were prospective adult population study, assessment of salt intake as baseline exposure, assessment of either stroke or total cardiovascular disease as outcome, follow-up of at least three years, indication of number of participants exposed and number of events across different salt intake categories. Results There were 19 independent cohort samples from 13 studies, with 177 025 participants (follow-up 3.5-19 years) and over 11 000 vascular events. Higher salt intake was associated with greater risk of stroke (pooled relative risk 1.23, 95% confidence interval 1.06 to 1.43; P=0.007) and cardiovascular disease (1.14, 0.99 to 1.32; P=0.07), with no significant evidence of publication bias. For cardiovascular disease, sensitivity analysis showed that the exclusion of a single study led to a pooled estimate of 1.17 (1.02 to 1.34; P=0.02). The associations observed were greater the larger the difference in sodium intake and the longer the follow-up. Conclusions High salt intake is associated with significantly increased risk of stroke and total cardiovascular disease. Because of imprecision in measurement of salt intake, these effect sizes are likely to be underestimated. These results support the role of a substantial population reduction in salt intake for the prevention of cardiovascular disease.

https://www.bmj.com/content/bmj/339/bmj.b4567.full.pdf

Potassium intake, stroke, and cardiovascular disease: a meta-analysis of prospective studies

Objective. —To assess the effects of supplementation with oral potassium on blood pressure in humans. Design. —Meta-analysis of randomized controlled trials. Data Sources. —English-language articles published before July 1995. Study Selection. —Thirty-three randomized controlled trials (2609 participants) in which potassium supplementation was the only difference between the intervention and control conditions. Data Extraction. —Using a standardized protocol, 2 of us independently abstracted information on sample size, duration, study design, potassium dose, participant characteristics, and treatment results. Results. —By means of a random-effects model, findings from individual trials were pooled, after results for each trial were weighted by the inverse of its variance. An extreme effect of potassium in lowering blood pressure was noted in 1 trial. After exclusion of this trial, potassium supplementation was associated with a significant reduction in mean (95% confidence interval) systolic and diastolic blood pressure of-3.11 mm Hg (-1.91 to-4.31 mm Hg) and-1.97 mm Hg (-0.52 to-3.42 mm Hg), respectively. Effects of treatment appeared to be enhanced in studies in which participants were concurrently exposed to a high intake of sodium. Conclusions. —Our results support the premise that low potassium intake may play an important role in the genesis of high blood pressure. Increased potassium intake should be considered as a recommendation for prevention and treatment of hypertension, especially in those who are unable to reduce their intake of sodium.

https://jamanetwork.com/journals/JAMA/articlepdf/416446/jama_277_20_033.pdf

Effects of Oral Potassium on Blood Pressure: Meta-analysis of Randomized Controlled Clinical Trials

This review examines epidemiologic, physiological, and molecular evidence that the interplay between sodium and potassium is central to the development of hypertension. The review concludes with recommendations for reducing sodium and increasing potassium in the diet.

/pdf/sodium-and-potassium-in-the-pathogenesis-of-hypertension-31s2o8oydg.pdf

Sodium and Potassium in the Pathogenesis of Hypertension

Objective To conduct a systematic review of the literature and meta-analyses to fill the gaps in knowledge on potassium intake and health. Data sources Cochrane Central Register of Controlled Trials, Medline, Embase, WHO International Clinical Trials Registry Platform, Latin American and Caribbean Health Science Literature Database, and the reference lists of previous reviews. Study selection Randomised controlled trials and cohort studies reporting the effects of potassium intake on blood pressure, renal function, blood lipids, catecholamine concentrations, all cause mortality, cardiovascular disease, stroke, and coronary heart disease were included. Data extraction and synthesis Potential studies were independently screened in duplicate, and their characteristics and outcomes were extracted. When possible, meta-analysis was done to estimate the effects (mean difference or risk ratio with 95% confidence interval) of higher potassium intake by using the inverse variance method and a random effect model. Results 22 randomised controlled trials (including 1606 participants) reporting blood pressure, blood lipids, catecholamine concentrations, and renal function and 11 cohort studies (127 038 participants) reporting all cause mortality, cardiovascular disease, stroke, or coronary heart disease in adults were included in the meta-analyses. Increased potassium intake reduced systolic blood pressure by 3.49 (95% confidence interval 1.82 to 5.15) mm Hg and diastolic blood pressure by 1.96 (0.86 to 3.06) mm Hg in adults, an effect seen in people with hypertension but not in those without hypertension. Systolic blood pressure was reduced by 7.16 (1.91 to 12.41) mm Hg when the higher potassium intake was 90-120 mmol/day, without any dose response. Increased potassium intake had no significant adverse effect on renal function, blood lipids, or catecholamine concentrations in adults. An inverse statistically significant association was seen between potassium intake and risk of incident stroke (risk ratio 0.76, 0.66 to 0.89). Associations between potassium intake and incident cardiovascular disease (risk ratio 0.88, 0.70 to 1.11) or coronary heart disease (0.96, 0.78 to 1.19) were not statistically significant. In children, three controlled trials and one cohort study suggested that increased potassium intake reduced systolic blood pressure by a non-significant 0.28 (−0.49 to 1.05) mm Hg. Conclusions High quality evidence shows that increased potassium intake reduces blood pressure in people with hypertension and has no adverse effect on blood lipid concentrations, catecholamine concentrations, or renal function in adults. Higher potassium intake was associated with a 24% lower risk of stroke (moderate quality evidence). These results suggest that increased potassium intake is potentially beneficial to most people without impaired renal handling of potassium for the prevention and control of elevated blood pressure and stroke.

https://www.bmj.com/content/bmj/346/bmj.f1378.full.pdf

Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses

SUMMARY
1 An assessment was made of the extent sodium (Na) and potassium (K) intake can be estimated from Na, K and creatinine (Cr) content of a second morning voiding urine (SMU) specimen collected within 4 h after the first voiding upon awakening but before breakfast in 159 clinically healthy, free-living individuals (20–79 years) The SMU and the rest of 24 h urine specimens for a 3–5 day period were collected

2 The following equations for estimating 24 h urinary Na (24HUNaV) and K (24HUKV) excretions were developed, and the accuracy and the reliability of these equations were evaluated Estimated value of 24HUNaV (mEq/day) = 163 √XNa; estimated value of 24HUKV (mEq/day) = 72 √XK, where XNa (or XK) = SMUNa (or SMUK)/SMUCr X predicted 24 h urinary Cr excretion

3 Highly statistically significant correlations were detected between the values estimated and measured for both Na (r= 0728, P < 0001, n= 159) and K (r= 0780, P < 0001, n= 159)

4 These equations were applied to Group 1 subjects, who collected the urine for a single day, and to Group 2, for 3 days The correlation coefficients between the values estimated and measured for Na and K were 0531 and 0443 in Group 1, and 0821 and 0590 in Group 2, respectively No statistically significant differences were observed

5 The SMU specimens provide a satisfactory alternative to both 24HUNaV and 24HUKV in adults for extensive epidemiological surveys but also for clinical application

A simple method for estimating 24 h urinary sodium and potassium excretion from second morning voiding urine specimen in adults.

▪Objective:To determine whether an increase in dietary potassium intake from natural foods reduces the need for antihypertensive medication in patients with essential hypertension. ▪Design...

Angela Giacco

Papers

Increasing the dietary potassium intake reduces the need for antihypertensive medication.