Relationship between urinary sodium with blood pressure and hypertension among a Kazakh community population in Xinjiang, China

Abstract

Urinary sodium levels are reported to be associated with blood pressure in clinical trials and epidemiology studies. Nevertheless, the public health message of reducing sodium intake in free-living community populations remains under debate. Based on an ongoing prospective study initiated in 2012 with a community-based design in Xinjiang, China, 1668 adults (⩾30 years old) were assessed in the current study for associations between urinary sodium and blood pressure and hypertension in a free-living population of Kazakh people. After excluding 223 people on antihypertensive medication, 1445 participants were analyzed. Second urine samples after waking were used to estimate 24-h urinary sodium excretion, which is a marker for sodium intake. Following analyses, we found that the distribution of systolic and diastolic blood pressures moved upward with increasing quartiles of urinary sodium. After adjusting for age, differences in median systolic blood pressure were 8.5 mm Hg for men and 8.0 mm Hg for women between the top and bottom urinary sodium quartiles, and differences for diastolic blood pressure were 4.7 mm Hg for men and 4.3 mm Hg for women. A significant increased risk for hypertension was observed for the top quartile of urinary sodium after adjusting for age, body mass index, smoking, alcohol consumption, fruit and vegetable consumption, with corresponding odds ratios being 1.61 (95% confidence interval (CI): 1.02-2.54) for men and 1.92 (95% CI: 1.13-3.27) for women. Improving education about reducing salt intake is of particular public importance to reduce blood pressure and the risk for hypertension among the Kazakh people.