[Analysis of influencing factors on circadian blood pressure of hypertensive patients with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To investigate the effect of obesity, arousal, hypoxia and sympathetic activation on the circadian blood pressure of hypertensive patients with obstructive sleep apnea-hypopnea syndrome. METHODS: Polysomnography (PSG) was performed in 436 hypertensive patients complaining of snoring, daytime sleepiness, lips cyanosis, hyperhemoglobinemia of unknown etiology, or with refractory hypertension. Hypertensive subjects were divided into four groups according to apnea-hypopnea index (AHI): hypertensive with mild obstructive sleep apnea-hypopnea syndrome (OSAHS) (n = 131), hypertensive with moderate OSAHS (n = 95), hypertensive with severe OSAHS (n = 95) and hypertensive without OSAHS as control group (n = 115). The ambulatory blood pressure monitoring (ABPM), PSG, urine electrolyte, and urine vanillylmandelic acid (VMA) were compared among groups. Factor analysis was employed to identify common factors related to the alterations of circadian blood pressure. Multiple linear regression analysis was used to analyze the influencing factors of the observed variables. RESULTS: There were significant differences among groups in age, neck circumference and waist circumference(P < 0.001). In severe group, 24 hour average systolic blood pressure (24 hSBP)[ (137.0 ± 16.8) mm Hg vs.(131.3 ± 11.9)mm Hg, (131.3 ± 13.2)mm Hg (1 mm Hg = 0.133 kPa)], daytime systolic blood pressure (day-SBP) [(140.8 ± 16.8) mm Hg vs. (135.7 ± 11.9) mm Hg, (135.3 ± 13.5) mm Hg]and night systolic blood pressure (night-SBP)[ (130.9 ± 17.0) mm Hg vs.(124.5 ± 14.0 )mm Hg, (124.3 ± 13.2) mm Hg] were significantly higher than those of control or mild OSAS groups (P < 0.01). Factor analysis showed that body mass (BM), life style, urine electrolyte, age and course of disease (ACD) were the common factors influencing circadian blood pressure. OSAHS was correlated with declining percentage of SBP (ß = -0.128, P < 0.01) and declining percentage of DBP (ß = -0.126, P < 0.01). The contribution according to priority was ACD > OSAHS > BM for declining percentage of SBP (ß = -0.148, P = 0.002;ß = -0.128, P = 0.007;ß = 0.099, P = 0.035), OSAHS > ACD > BM for declining percentage of DBP(ß = -0.126, P = 0.008;ß = -0.105, P = 0.026;ß = 0.097, P = 0.042). CONCLUSION: OSAHS, ACD and BM are the independent risk factors contributing to the alterations of circadian blood pressure in hypertensive patients with obstructive sleep apnea-hypopnea syndrome.

[Association study of PRDM16 gene polymorphisms with essential hypertension in Xinjiang Uygur population].

OBJECTIVE: To assess the association of polymorphisms of PR domain containing 16 gene (PRDM16) with essential hypertension in ethnic Uygur population from Xinjiang, China. METHODS: Functional regions of the PRDM16 gene were sequenced in 48 Uygur subjects with essential hypertension selected from 480 hypertensive patients and 819 normotensive controls. Representative variations were genotyped with TaqMan-PCR method. Association of variations of PRDM16 gene with hypertension was analyzed. RESULTS: For the 4 genotyped representative variations (rs2236518, rs2282198, rs2493292 and rs870171), no significant difference in genotype distribution and allele frequencies has been found between the patient and control groups (P>0.05). By ANOVA analysis, none of the polymorphisms was significantly associated with systolic or diastolic blood pressure (P>0.05). Nor was significant difference in haplotypic frequencies between the two groups detected (P>0.05). CONCLUSION: We have found no association between the four polymorphisms (rs2236518, rs2282198, rs2493292 and rs870171) of the PRDM16 gene with essential hypertension in ethnic Uygur population from Xinjiang.

[A study of relationship between obstructive sleep apnea-hypopnea syndrome in hypertension and insulin].

OBJECTIVE: To investigate the association between the obstructive sleep apnea-hypopnea syndrome (OSAHS) in hypertension and insulin. METHODS: A total of 521 patients were divided into 4 groups according to apnea-hypopnea index and OSAHS degrees. The control group (group I), mild OSAHS group (group II), moderate OSAHS group (group III) and severe OSAHS group (group IV) had 89 patients, 194 patients, 118 patients and 120 patients respectively. RESULTS: The BMI [(30.4 ± 3.8) kg/m(2)], apnea-hypopnea index (AHI, 3.8 ± 0.1), Fasting insulin (FIns) [(3.08 ± 0.26) mU/L] and insulin resistance (2.43 ± 0.27) of patients in severe OSAHS group were significantly higher than that of in the control, mild OSAHS group and moderate OSAHS group (P < 0.01). The levels of saturation of minimum oxygen from skin of patients in severe OSAHS group was significantly lower (MSpO(2)) than in that of the control, mild OSAHS group and moderate OSAHS group. Multiple linear regression analysis showed that fasting plasma insulin and insulin resistance was positive correlation with apnea-hypopnea index, while they also negatively associated with saturation of minimum oxygen. CONCLUSIONS: FIns and insulin resistance strongly associate with AHI and levels of saturation of minimum oxygen from skin. Hypertensive patients with OSAHS have more chances to suffer with insulin resistance.

[Negative association of STAMP2 gene polymorphisms with essential hypertension in Xinjiang Uygur population].

OBJECTIVE: To investigate the relationship between the genetic polymorphisms of the six transmembrane protein of prostate 2 gene (STAMP2) and essential hypertension in Xinjiang Uygur population. METHODS: The sequences of STAMP2 gene functional region were sequenced in Xinjiang Uygur population with hypertension. The representative variations selected were genotyped by TaqMan-PCR method in 2047 Uygur individuals, including 810 patients with hypertension and 1237 healthy subjects. The association of the genetic variations of the STAMP2 gene with hypertension in Uygur was analyzed. RESULTS: In the three representative variations (rs8122, rs1981529 and rs34741656) genotyped, there were no significant differences in genotype distribution and allele frequencies between the essential hypertension and control groups (P > 0.05). In ANCOVA analysis, none of the polymorphisms was significantly associated with systolic blood pressure and diastolic blood pressure (P > 0.05). There were no significant differences in haplotype frequencies between the two groups either(P > 0.05). CONCLUSION: There was no association of the three polymorphisms (rs8122, rs1981529 and rs34741656) in the STAMP2 gene with essential hypertension in Xinjiang Uygur population.