Morning surge in blood pressure and sympathetic activity in Mongolians and Han Chinese: a multimodality investigation of hypertension and dyssomnia

BACKGROUND Hypertension and dyssomnia are increasing significantly in Mongolians, and the related factors of ethnic differences in hypertension and dyssomnia between Mongolians and Han Chinese are unclear. This study examined the relationship of morning surge in blood pressure (MBP) with ethnicity, sleep situation, and sympathetic activity throughout the day. METHODS Of 692 hypertensive patients screened, 202 subjects with dyssomnia were selected. They were then divided into Mongolian (n = 87) and Han (n = 115) groups. The differences in dyssomnia, 24-h blood pressure, and urinary catecholamine were analyzed in all subjects; they were then further divided according to the degree of dyssomnia (low, moderate, and severe) to determine the differences in blood pressure and catecholamine. RESULTS Mongolians had a lower history of smoking, daytime dysfunction, nocturnal heart rates, and dopamine levels, but their body mass index, triglyceride, fasting glucose, morning surge in systolic blood pressure (MSBP), nocturnal systolic blood pressure (NSBP), nocturnal diastolic blood pressure, daytime systolic blood pressure, daytime heart rates, and dopamine level (D-DA) were higher than those of Han Chinese. With the aggravation of dyssomnia, MSBP, NSBP, D-NE, daytime epinephrine, and D-DA of Mongolians and Han Chinese increased gradually, but the rate of increase was faster in the latter (p < 0.05). D-DA was entered into the MSBP regression model of Mongolians (intercept, 157 mmHg), whereas D-DA and D-NE were entered into the MSBP regression model of Han Chinese (intercept, 142 mmHg). CONCLUSION Worsened dyssomnia induces higher MSBP and augments sympathetic excitability in Mongolians and Han Chinese. Mongolians with hypertension and dyssomnia had higher MSBP baseline and D-DA but lower N-DA. With an increase in D-DA, MSBP in Han and Mongolian patients increased gradually.