Increased arterial stiffness in subjects with pre-diabetes among middle aged population in Beijing, China.

OBJECTIVE: To investigate the relationship between arterial stiffness and pre-diabetes when assessed by the new glycosylated hemoglobin A1c (HbA1c) 5.7%-6.4% criterion or by impaired fasting glucose in middle aged Chinese. METHODS: 1122 adults aged 55 years or younger in the health examination centers for physical check-ups were enrolled in the two large-sized Tertiary Comprehensive Hospitals in Beijing from June 2011 to June 2012 after excluding those who previously had been diagnosed or treated as diabetes or cardiovascular disease. Subjects with a diagnosis of pre-diabetes according to impaired fasting glucose (IFG) (fasting plasma glucose (FPG) levels at 5.6-6.9 mmol/L), HbA1c levels at 5.7%-6.4%, or both, were classified into four groups for observation: (1) Normoglycaemia (HbA1c<5.7% and FPG <5.6 mmol/L); (2) IFG alone (FPG levels at 5.6-6.9 mmol/L and HbA1c<5.7% ); (3) HbA1c 5.7%-6.4% alone (HbA1c levels at 5.7%-6.4% and FPG <5.6 mmol/L); and (4) both HbA1c 5.7%-6.4% and IFG (HbA1c levels at 5.7%-6.4% and FPG levels at 5.6-6.9 mmol/L). All subjects were measured for weight, height, waist circumference, blood pressure, fasting plasma glucose, HbA1c, lipid profile and brachial-ankle pulse wave velocity (baPWV). RESULTS: The mean values of baPWV were 1282±8, 1311±10, 1398±30, and 1418±27 cm/s (Mean±SE) in Normoglycaemia, HbA1c 5.7%-6.4% alone, IFG alone and the both HbA1c 5.7%-6.4% and IFG groups, respectively. After adjusting for age, gender, blood pressure, BMI and triglyceride, baPWV was significantly higher in subjects with both HbA1c 5.7%-6.4% and IFG compared among the subjects with Normoglycaemia (1350±14 vs. 1301±6 cm/s, P=0.002) and HbA1c 5.7%-6.4% alone (1350±14 vs. 1309±8 cm/s, P=0.013). CONCLUSION: Subjects with pre-diabetes exhibited a greater arterial stiffness.

[Features of heart rate, blood pressure, heart rate variability and cerebral blood flow during sequential head-up tilt test].

OBJECTIVE: To investigate the features of BP, HR, cerebral blood flow (CBF) and heart rate variation (HRV) during sequential head-up tilt table test (HUT) and provide information for methodology of testing tendency to syncope in pilots. METHOD: Sixteen healthy male were exposed to HUT +45 degrees 20 min, +60 degrees 20 min, and +75 degrees 20 min respectively with 5 min rests in between. CBFV, HR, HRV, BP were measured with transcranial doppler image (TCI), 12-Lead in phase ECG. RESULT: 1) As the tilt angle became larger, HR and DBP increased gradually (P<0.05), with SBP, PP and CBF Velocity (Vs,Vm,Vd) descended. There were significant differences among the various conditions. CV became smaller before +75 degrees, and then it began to increase. 2) Correlation between physiological indices and techno-indices were analyzed. At the point of 1 min, tilt angle was significantly positively correlated with SBP, DBP, MAP, Vd, and sdRR (P<0.01); At the point of 20 min, tilt angle was significantly positively correlated with HR and sdRR (P<0.01), but negatively correlated with SBP, PP, Vs and mRR (P<0.01), time of exposure was positively correlated with HP (P< 0.01), but negatively correlated with Vm, Vd, and mRR (P<0.01). 3) Correlation among physiological indices were also analyzed. HR were negatively correlated with SBP, Vs, Vm and Vd (P<0.01), SBP were significantly positively correlated with Vd, and mRR (P<0.01). Vs, Vm, Vd were significantly positively correlated with mRR and sdRR (P< 0.01). CONCLUSION: By investigating HR, BP, HRV and CBFV during of different angles, some advises for evaluating the tendency to syncope in pilots were put forward.