Associations of Usual 24-Hour Sodium and Potassium Intakes with Blood Pressure and Risk of Hypertension among Adults in China's Shandong and Jiangsu Provinces.

BACKGROUND/AIMS: High sodium intake and low intake of potassium can increase blood pressure (BP) and risk of developing hypertension. Few studies have examined the association between 24-h urinary sodium and potassium excretion and BP or risk of hypertension in China, and most used only a single 24-h urinary sample.

METHODS: We analyzed data on 2281 participants aged 18-69 years by using two 24-h urinary sodium and potassium excretions from the supplemental baseline survey of the Shandong-Ministry of Health Action on Salt Reduction and Hypertension (SMASH) project. We used measurement error models to estimate usual intakes, multivariable linear regression to assess their association with B P, and logistic regression to estimate the risk of hypertension.

RESULTS: The average usual intakes of sodium and potassium, and the mean sodium-potassium ratio, were 166.9 mmol/day, 25.3 mmol/day, and 6.8, respectively. All three measures were significantly associated with systolic BP (SBP) and diastolic BP (DBP), with an increase of 1.39 mmHg (95% confidence interval [CI] 0.44─2.34) in SBP and 0.94 mmHg (95% CI 0.34─1.55) in DBP for a 1-standard deviation (SD) (25.6mmol/day) increase in sodium intake, a decrease of 1.42 mmHg (95% CI -2.37─ -0.47) in SBP and 0.91 mmHg (95% CI -1.52─ -0.30) in DBP for a 1-SD (3.4 mmol/day) increase in potassium intake, and an increase of 0.97 mmHg (95% CI 0.36─1.58) in SBP and of 0.65 mmHg (95% CI 0.26─1.04) in DBP per unit increase in the sodium-to-potassium ratio. The adjusted odds ratios comparing the risk of hypertension among adults in the highest with those in the lowest quintile differ significantly for potassium (0.51; 95% CI 0.29─0.88) and sodium-to-potassium ratio (1.40; 95% CI 1.01─1.94).

CONCLUSIONS: Our results suggested that higher sodium and lower potassium intakes are associated with increased BP and risk of hypertension in the Shandong and Jiangsu adults.