Urinary sodium excretion and risk of cardiovascular disease in the Chinese population: a prospective study

The effect of dietary sodium (salt) on cardiovascular disease (CVD) has been debated for a long time. The present study aims to explore whether salt intake affects the risk of cardiovascular disease in the Chinese population. Data from a prospective cohort study that included 954 men and women aged 35-59 years at baseline from four urban and rural population samples in China were used. Each participant collected their overnight urine for three consecutive days during two seasons to estimate sodium intake. CVD events, including incidences of coronary heart disease (CHD), stroke, and death from CVD, and all-cause mortality were tested by Cox proportional hazards models. After a median of 18.6 years of follow-up, CVD events occurred in 81 (8.5%) participants, including 20 CHD and 64 stroke events. All-cause deaths occurred in 149 (15.6%) participants, including 31 CVD-related deaths, 56 cancer-related deaths and 62 other-cause deaths. The hazard ratios and 95% confidence intervals for CVD events in each of the sodium excretion tertiles were 1.00, 1.66 (0.79-3.47) and 3.04 (1.46-6.34), P for trend = 0.001. This trend was also found for stroke incidence (P for trend < 0.001). The cardiovascular mortality risk increased as the sodium excretion levels rose after adjusting for confounding factors (P for trend = 0.043). However, this trend was not significant after adjusting for the baseline systolic blood pressure and antihypertensive medication use (P for trend = 0.171). No significant associations were found between sodium excretion and all-cause, cancer-related or other-cause mortality. High urinary sodium excretion was independently associated with an increased risk of cardiovascular disease in the general Chinese population.