Table 2.
Characteristics of included longitudinal studies in systematic review of dietary sodium, potassium, sodium-to-potassium ratio, and cardiovascular disease.
| Author, Year | Country | Participants Characteristics | Study Design | Follow-Up (Years) |
Exposure | Sodium/Potassium Intake Assessment | Outcome Measures | Covariates | Main Findings |
|---|---|---|---|---|---|---|---|---|---|
| Kalogeropoulos AP, 2015 [26] | USA | n = 2642 (1290 men) | Prospective cohort | 10 | Sodium (as continuous variable and categorical variable into 3 groups: <1500 mg/d; 1500–2300 mg/d; >2300 mg/d) | Food frequency questionnaire (at the year 2 visit) | Incident CVD (ncases = 572) (i.e., coronary heart disease (MI, angina, or coronary revascularization), cerebrovascular disease (stroke, transient ischemic attack, or symptomatic carotid artery disease), peripheral arterial disease | Age, sex, race, baseline hypertensive status, BMI, smoking status, PA, prevalent CVD (for HF events), pulmonary disease, diabetes mellitus, depression, BP, heart rate, electrocardiogram abnormalities, and serum glucose, albumin, creatinine, and cholesterol levels | Ten-year incident CVD, or incident HF, were not associated with sodium intake. |
| mean age = 73.6 ± 2.9 years | Incident HF (ncases = 398) | ||||||||
| Saulnier PJ, 2017 [22] | France | n = 1439 types 2 diabetes patients (835 men) | Prospective cohort | Median = 5.7 (IQR: 3.1–8.8) | Sodium (as continuous variable and categorical variable into tertiles: low, <69 mmol/L; intermediate, 69–103 mmol/L; high, >103 mmol/L) Potassium (as categorical variable into tertiles—not specified) |
Spot urinary sample | Cardiovascular death (ncases = 268) | Age, sex, urinary sodium and potassium, urine to plasma creatine ratio, estimated 24 h sodium excretion, BMI, history of urinary albumin to creatine concentration ratio, N-terminal pro-brain natriuretic peptide | It was found significant relationships between cardiovascular mortality, and sodium and potassium tertiles (Log-rank p < 0.001), with patients in the lower tertiles having the highest mortality. For each 1-SD increase of urinary sodium concentration in the adjusted model, cardiovascular mortality was 24% lower (HR: 0.76, 95% CI: 0.66–0.88). |
| mean age = 65.3 ± 10.7 years | |||||||||
| Willey J, 2017 [27] | USA | n = 2496 (902 men) | Prospective cohort | Mean = 12 ± 5 | Sodium to potassium ratio | Food frequency questionnaire (at baseline) | Incident stroke (ncases = 268) | Age, sex, high-school completion, race ethnicity, total calories, Mediterranean diet score, moderate alcohol use, moderate heavy physical activity, smoking, estimated glomerular filtration rate, body mass index, hypertension, hypercholesterolemia, diabetes mellitus, sodium consumption | In adjusted models, a higher sodium:potassium ratio was associated with increased risk for stroke (HR: 1.6, 95% CI: 1.19–2.14) and ischemic stroke (HR: 1.58, 95% CI: 1.20–2.06). |
| mean age= 68.7 ± 10 years (55% Hispanic) | Incident ischemic stroke (ncases = 227) | Marginally positive association was observed for potassium intake and stroke among those with <2300 mg sodium/d and an inverse association was observed for potassium intake among those with ≥2300 mg sodium/d. | |||||||
| Potassium (as continuous variables and quartiles) | |||||||||
| Lelli D, 2018 [29] | Italy | n = 920 (415 men) | Prospective cohort | 9 | Sodium | 24-hour urinary excretion | Incident cardiovascular events (ncases = 169) | Age, sex, education, estimated creatinine clearance, SBP, cigarette smoking, hypertension, diabetes, BMI, caloric intake/body weight, antihypertensive drugs, and diuretics | An association was found between 24-hour sodium excretion and cardiovascular disease (RR 0.95; 95% CI 0.90–1), which did not remain after adjustment for confounders (RR: 0.96, 95% CI: 0.90–1.02). |
| mean age = 74.5 ± 6.99 years | (i.e., angina pectoris, myocardial infarction, heart failure, and stroke) | ||||||||
| Howard G, 2018 [28] | USA | n = 6897 (3125 men; 1807 black participants) | Prospective cohort | 9.4 | Sodium to potassium ratio | Food frequency questionnaire (at baseline) | Incident hypertension (ncases = 836 (298 men) for black and 1679 (837 men) for white participants) | Age, race, and baseline systolic blood pressure for the risk factor of incident hypertension | Among men, the sodium to potassium ratio was associated with incident hypertension (OR: 1.11, 95% CI: 1.01 to 1.20; incidence proportion at 25th percentile, 32.9%, 95% CI: 30.4% to 35.5% and the 75th percentile, 35.8%, 95% CI: 33.5% to 38.2%; absolute risk difference between black and white participants, 2.9%, 95% CI: 0.4% to 5.5%). Among black men, the ratio of sodium to potassium accounted for 12.3% (95% CI: 1.1% to 22.8%) of the excess risk of hypertension. |
| mean age = 62 ± 8 years | Among women, the sodium to potassium ratio was associated with incident hypertension (OR: 1.13, 95% CI: 1.04 to 1.22; incidence proportion at 25th percentile, 31.1%, 95% CI: 29.1% to 33.5% and the 75th percentile, 34.5%, 95% CI: 32.2% to 36.8%; absolute risk difference between black and white participants, 3.3%, 95% CI: 1.1% to 5.5%). Higher dietary ratio of sodium to potassium accounted for 6.8% (95% CI: 1.6% to 11.9%) of the risk of hypertension among black women. | ||||||||
| Averill MM, 2019, USA [30] | n = 6705 (3160 men) | Prospective cohort | 11.7 (±2.2) | Sodium to potassium ratio | Spot urine samples (at baseline) | Incident CVD (ncases = 781) (MI, definite angina, stroke, transient ischemic attack, coronary heart disease death) | Age, sex, race, diabetes mellitus, smoking (current and former), total cholesterol, high-density lipoprotein cholesterol, treated hypertension, education, SBP, DBP, urine creatinine, hip circumference, BMI, aspirin use, intentional exercise, glomerular filtration rate, dietary energy intake, maximum of common carotid artery intimal medial thickness, and IL-6 (interleukin 6) levels | After adjustment, only sodium-to-potassium ratio >1 was associated with the risk of stroke (HR: 1.47, 95% CI: 1.07–2.00). | |
| mean age= 61.2 ± 10.2 | Incident coronary heart disease (ncases = 530) (MI and angina) | ||||||||
| Incident HF (ncases = 274) | |||||||||
| Incident peripheral vascular disease (ncases = 104) | |||||||||
| Incident stroke (ncases = 236) | |||||||||
| SBP |
BP, blood pressure; BMI, body mass index; CI, confidence interval; CVD, cardiovascular disease; DBP, diastolic blood pressure; HF, heart failure; HR, Hazard ration; MI, myocardial infarction; PA, physical activity; SD, standard deviation; SBP, systolic blood pressure; USA, United States of America; IQR, interquartile range; OR, odds ratio; RR, relative risk.