Sex difference in sympathetic nervous system activity and blood pressure in hypertensive patients

Increased sympathetic nervous system (SNS) activity leads to increased risk of cardiovascular morbidity and mortality. This study investigated whether there were sex differences in SNS activity among Chinese patients with hypertension. Ethnic Chinese non-diabetic hypertensive patients aged 20-50 years were enrolled in Taiwan. A total of 970 hypertensive patients (41.0 ± 7.2 years) completed the study, 664 men and 306 women. They received comprehensive evaluations including office blood pressure (BP) measurement, 24-h ambulatory BP monitoring, and 24-h urine sampling assayed for catecholamine excretion. Compared to women, men were younger, had higher body mass index (BMI), office systolic BP (SBP), office diastolic BP (DBP), 24-h ambulatory BP, and 24-h urine catecholamine excretion. In men, 24-h urine total catecholamine levels were correlated with 24-h SBP (r = 0.103, p = .008) and 24-h DBP (r = 0.083, p = .033). In women, however, there was no correlation between 24-h urine total catecholamine levels and 24-h ambulatory BP. Multivariate linear regression indicated that being male (β = 1.65, 95% confidence interval [CI] 0.01-3.29, p = .048) and 24-h urine total catecholamine (β = 5.03, 95% CI 0.62-9.44, p = .025) were both independently associated with 24-h SBP; being male was independently associated with 24-h DBP (β = 3.55, 95% CI 2.26-4.85, p < .001). In conclusion, Chinese men with hypertension had higher SNS activity than women, and SNS activity was independently associated with 24-h ambulatory BP in men rather than in women. These findings suggest that different hypertensive treatment strategies should be considered according to patient sex.