Table 3.
Included Studies
| Author | Country | Outcome | Population | Intervention/Follow‐Up | Measurement Method | Results | Comments |
|---|---|---|---|---|---|---|---|
| Surrogate markers (one RCT) | |||||||
| Amer et al27 | United States | Headache | 390 participants with prehypertension or stage one hypertension aged ≥22 y | Three levels of dietary sodium intake and two diet patterns (the DASH diet and a control diet). Three 30‐day periods, each at “high” sodium diet with 8.6 g salt (sodium 3400 mg)/d, “intermediate” sodium diet with 5.75 g salt (sodium 2300 mg)/d, and “low” sodium diet with 2.8 g salt (sodium 1120 mg)/d | 24‐h urinary sodium excretion; self‐administered questionnaire to assess severity of headache | Lower risk of headache on the “low” sodium diet with 2.8 g salt (sodium 1120 mg)/d, compared with “high” sodium diet with 8.6 g salt (sodium 3400 mg)/d, both on the control (OR, 0.69; 95% CI, 0.49–0.99; P=.05) and the DASH (OR, 0.69; 95% CI, 0.49–0.98; P=.04) diets | No significant association of diet pattern (DASH vs control) with headache on any sodium level. Headaches not a hard outcome |
| Substantive patient outcomes (two cohort, one systematic review and meta‐analysis, and one meta‐analysis [total of four studies]) | |||||||
| Singer et al28 | United States | All‐cause mortality; cardiovascular mortality | 3505 hypertensive participants | Follow‐up of 18.6 y | 24‐h urinary sodium excretion | There was a significant association between sodium and all‐cause mortality (Q1 vs Q4: HR, 0.81; 95%, CI, 0.66–1.00; P=.05). A significant association between dietary sodium and noncardiovascular mortality (Q1 vs Q4 ratio: HR, 0.57; 95% CI, 0.42–0.80; P=.001) | Exposure was only assessed at baseline. |
| Poggio et al29 | Japan, United States, Belgium, Scotland, the Netherlands, and Finland | Cardiovascular mortality | 229,785 participants | Average follow‐up period of 13.37 y (range 5.5–19 y) | Different methods used for assessment of sodium intake (24‐h urine, 24‐h dietary recall, food Frequency questionnaire and 3‐d dietary record) | There was a significant association between higher sodium intake and cardiovascular mortality (RR, 1.12; 95% CI, 1.06–1.19). Every increase of sodium 0.57 salt (sodium 230 mg)/d in sodium intake, CVD mortality increased by 1% (P=.016) | |
Abbreviations: CI, confidence interval; CVD, cardiovascular disease; DASH, Dietary Approaches to Stop Hypertension; HR, hazard ratio; OR, odds ratio; Q, quartile; RCT, randomized controlled trial; RR, relative risk.