Influence of Salt Intake on Association of Blood Uric Acid with Hypertension and Related Cardiovascular Risk

Background A relationship of blood uric acid (UA) with hypertension and cardiovascular risk is under debate thus salt intake is hypothesized to contribute to such associations. Methods In this cross-sectional study, stratified cluster random sampling elicited a sample of 1805 Kazakhs with 92.4% compliance. Hypertension and moderate-or-high total cardiovascular risk (mTCR) were defined according to guidelines. Sodium intake was assessed by urinary sodium excretion. Prevalence ratios (PRs) were used to express associations of UA with hypertension and mTCR. Results In the highest tertile of sodium intake in women, the adjusted PRs (95% confidence intervals) of low to high quartiles compared with the lowest quartile of UA, were 1.22(0.78-1.91), 1.18(0.75-1.85), and 1.65(1.09-2.51) for hypertension and 1.19(0.74-1.90), 1.39(0.91-2.11), and 1.65(1.10-2.47) for mTCR (P for trend <0.05). However, these findings were not shown for other sodium intake levels. There were similar results in men. PRs markedly increased with a concomitant increase in UA and sodium intake and there was a significant interaction (P = 0.010) for mTCR with PRs of 1.69(1.10-2.60) for men and 3.70(2.09-6.52) for women in those with the highest compared with the lowest quartile of UA and tertile of sodium intake. Similar findings were shown for hypertension. Conclusions This study implied that a high salt intake may enhance the associations of UA with hypertension and cardiovascular risk.