Oxidative Stress In Relation To Blood Pressure And Hypertension In Chinese Population

ObjectivesTo investigate the associations of serum superoxide dismutase (SOD), malondialdehyde(MDA), and uric acid (UA) with blood pressure and presence of hypertension in aChinese population.MethodsFrom May to July2010, we invited1443workers (aged20-83years) to participate in thepresent study. We collected medical history using a standard questionnaire, and measuredbody height, body weight, waist circumference, hip circumference, blood pressure by atrained physician. Overnight fasting blood was collected to test plasma glucose, serumtotal cholesterol, uric acid, and creatinine. We also measured serum superoxide dismutase(SOD), malondialdehyde (MDA) in506randomly selected participants. For databasemanagement and statistical analysis, we used the SAS9.13Software.Results1. One thousand four hundred and forty three participants included870men and573women. There was statistically significant difference in body mass index, waistcircumference, waist-to-hip ratio, blood pressure, uric acid, and high-density lipoproteincholesterol, triglycerides, and prevalence of hyperuricemia, alcohol intake, and smoking.2. In1229participants without antihypertensive treatment, serum uric acid (+100mol/l)was significantly associated with systolic and diastolic blood pressure both before and after adjusted for covariates (P0.0003). However, after further adjusted for body massindex, smoking, alcohol intake, pulse rate, fasting plasma glucose, total cholesterol, highdensity lipoprotein cholesterol, triglycerides, and estimated glomerular filtration rate,serum uric acid was only significantly associated with blood pressure in men (P0.0002),but not in women (P0.47).3. Men and women were divided into three groups according to sex-specific tertiles ofserum levels of uric acid. Men in the highest tertile compared with those in the lowesttertile had a significantly higher risk of hypertension both before and after adjusted forcovariates (P0.005). Women in the highest tertile compared with those in the lowesttertile had a2.96fold higher risk of hypertension (OR=2.96,95%CI:1.88-4.64, P0.0001)before adjusted for covariates. However, the association was significantly attenuated andbecame nonsignificant after further adjustment for covariates (OR=1.70,95%CI:0.92-3.14, P=0.09).4. Five hundred and six participants with the measurement of oxidative stress makers,included187women (37.0%) and103hypertensive subjects (20.4%), of whom22(21.4%) took antihypertensive treatment. Compared with normotensive participants,hypertensive patients had significantly lower serum levels of superoxide dismutaseactivity (P=0.0002), and higher serum levels of malondialdehyde and uric acid (P0.05).Univariate analysis indicated that serum superoxide dismutase activity was reverselyassociated with blood pressure, and serum levels of uric acid (P0.0001); while serumlevels of malondialdehyde was positively associated with blood pressure, and serumlevels of uric acid (P0.05).5. There was significant difference in systolic (Ptrend=0.02) and diastolic blood pressure(Ptrend=0.04) between three groups defined by tertiles of serum levels of superoxide dismutase, with a lower blood pressure in the highest tertile than in the lowest tertile.Furthermore, the systolic (Ptrend=0.01) and diastolic blood pressure (Ptrend=0.003) inthe highest tertile, which defied by the serum levels of malondialdehyde, weresignificantly higher than those in the lowest tertile.Conclusions1. Increased serum levels of uric acid are associated with elevated blood pressure andincreased risk of hypertension in men but not in women in a Chinese population.2. Hypertensive patients have a disturbed oxidative and anti-oxidative balance. Oxidativestress may play a role in the pathogenesis of hypertension in Chinese.