[Association of aldosterone synthase (CYP11B2) gene -344T/C polymorphism with essential hypertension in Mongolian nationality].

OBJECTIVE: To explore the relationship between the -344T/C polymorphism of aldosterone synthase (CYP11B2) gene and essential hypertension in Chinese Mongolian population. METHODS: By cluster-sampling method, a total of 1575 Mongolian people in Tongliao city of Inner Mongolia were included in this study. And 417 subjects were normotension, 596 subjects were prehypertension and 562 subjects were essential hypertension. A survey was conducted to collect data by personal interview using a standard questionnaire, meanwhile fasting blood samples were drawn. Height, weight, waist circumference, blood pressure, blood-fat indexes and fasting plasma glucose were measured. The variant genotypes of CYP11B2 were identified by PCR assays. The relationship between the -344T/C polymorphism of CYP11B2 gene and essential hypertension were analyzed by multinomial logistic regression model. RESULTS: Crude prevalence of prehypertension among Mongolian people was 37.84% (596/1575) and hypertension was 35.68% (562/1575). The age-standardized prevalence of prehypertension was 38.57% and hypertension was 31.53%. The frequency of the T and C allele was 0.66 (481/728) and 0.34 (247/728) for normotension group, 0.69 (696/1042) and 0.33 (346/1042) for prehypertension group, 0.71 (706/998) and 0.29 (292/998) for hypertension group. The multiple logistic models showed CYP11B2 variant genotypes were associated with prehypertension (TT/CC, OR = 1.33, 95%CI: 0.87 - 2.01; TC/CC, OR = 1.74, 95%CI: 1.13 - 2.67; TC + TT/CC, OR = 1.49, 95%CI: 1.01 - 2.22); CYP11B2 variant genotypes were associated with hypertension (TT/CC, OR = 1.70, 95%CI: 1.07 - 2.70; TC/CC, OR = 1.59, 95%CI: 0.98 - 2.50; TC + TT/CC, OR = 1.66, 95%CI: 1.06 - 2.58). CONCLUSION: CYP11B2 gene -344T/C polymorphism were associated with essential hypertension in Chinese Mongolian population.

Interaction between the C(-344)T polymorphism of CYP11B2 and alcohol consumption on the risk of essential hypertension in a Chinese Mongolian population.

The present study aimed to explore gene-gene and gene-environment interactions among three candidate genes and several environmental risk factors, and their impacts on hypertension in Chinese Mongolian population. A cross-sectional study was conducted in 2003-2004 among 1,575 Mongolian people in Tongliao City of Inner Mongolia, China. Epidemiologic and clinical data and blood samples were obtained from subjects. Multifactor dimensionality reduction (MDR) and logistic regression were used to analyze gene-gene and gene-environment interactions. The MDR model indicated a significant interactions among the CYP11B2 gene C(-344)T polymorphism, body mass index, age, and alcohol consumption on the risk of hypertension, with a cross-validation consistency of 10 of 10 and a prediction error of 34% (P < 0.001). Logistic regression suggested alcohol consumption (≥200 g/d) was associated with an OR of 2.4 (95% CI, 1.6-3.5) for hypertension. When stratified by the CYP11B2 genotype, the estimated OR was 1.2 (95% CI, 0.5-3.0) on hypertension for the CC genotype group, but was 3.0 (95% CI, 1.5-5.7) and 2.9 (95% CI, 1.4-5.7) for the TC and TT genotype groups, respectively. A significant interaction between the CYP11B2 genotype and alcohol consumption was also found by the logistic models (P (crude) = 0.035, P (adjusted) = 0.048). This study demonstrates a significant interaction between the CYP11B2 genotype and alcohol consumption on the risk of hypertension in Chinese Mongolian population.

[Impact of gene-environment interaction between the C (-344) T polymorphism of CYP11B2 and drinking index on the risk of hypertension under multifactor dimensionality reduction model in Chinese Mongolian population].

OBJECTIVE: To explore the interaction between C (-344) T polymorphism of CYP11B2 and drinking index (DI) as well as their impact on the risk of hypertension in Chinese Mongolian population. METHODS: A total of 1575 Mongolian people aged 20 and older including 562 hypertensive and 1013 normal-tensive from agricultural and pastoral areas in Tongliao city of Inner Mongolia, were included in this study. A cross-sectional survey was conducted to collect data by personal interview with local residents, using a standard questionnaire. Fasting blood samples were drawn and height, weight and blood pressure were measured. The variant genotypes of CYP11B2, ACE and eNOS were identified by PCR assays. Gene-environment interactions were analyzed, using multifactor dimensionality reduction (MDR) model. Based on the result of the best MDR model, a multiple logistic regression model was constructed as the final cause-effect interpretative model. RESULTS: The interaction between CYP11B2 variant genotype and drinking index appeared the best MDR model with statistical significance (chi(2) = 66.35, P < 0.01). Testing balance accuracy of the model was 0.604. The cross-validation consistency was 10/10. Data from the final multiple logistic regression based on the MDR model showed that the main effects of both CYP11B2 variant genotype and the DI were not significantly different but the interaction between the genotype (TC) and the DI (90-) was, with regard to hypertension (OR, 10.25; 95%CI, 2.23 - 47.18; P = 0.003). The combined effects between CYP11B2 variant genotype and the DI showed that following indices as: genotype TT or TC combining non-zero drinking index, including genotype (TT) combining the drinking index (> or = 168), the genotype (TT) combining the drinking index (> or = 40), the genotype (TT) combining the drinking index (> or = 1) and the genotype (TC) combining the drinking index (> or = 90), were all risk factors of hypertension when comparing with genotype (CC) combining the drinking index (0), and the ORs (95%CI) appeared to be 2.07 (1.15 - 3.70), 2.35 (1.22 - 4.56), 2.05 (1.07 - 3.94) and 5.56 (2.54 - 12.18) respectively. CONCLUSION: Essential hypertension might positively be affected by the interaction of the C (-344) T polymorphism of CYP11B2 and the drinking index in Chinese Mongolian population.

[Sero-epidemiologic study on the relationship between Chlamydia pneumonia infection and hypertension in Chinese Mongolian population].

OBJECTIVE: To explore the relationship between Chlamydia pneumonia (CP) infection and hypertension as well as the interaction of traditional risk factors and CP infections on hypertension in Chinese Mongolian population. METHODS: 1430 inhabitants living in Tongliao city, Inner Mongolia were selected as research subjects, including 488 hypertensives and 942 normotensives. Enzyme-linked immunoassay technique was used to test CP IgG antibody in the blood serum and SPSS 13.0 Microsoft was used to analyze the data. RESULTS: The prevalence rates of hypertension were significantly different between CP IgG positive and negative groups, However, the trend was attenuated after adjusting age, sex, drinking, smoking, body mass index (BMI) and dyslipidemia. The CP infection rate was significant different in diastolic blood pressure groups, which was significantly higher in 80-84 mm Hg than that in the lowest DBP group. The interaction of chronic CP infection and other traditional risk factors were associated with hypertension in Chinese Mongolian ethnic groups. The ranking with significant sequence from high to low were BMI, dyslipidemia, alcohol intake, sex and age. CONCLUSION: CP infection was not related to hypertension in Chinese Mongolian ethnic groups but the interaction with other traditional risk factors would increase the risk of developing hypertension.

Interaction and relationship between angiotensin converting enzyme gene and environmental factors predisposing to essential hypertension in Mongolian population of China.

OBJECTIVE: To investigate the association of specific functional gene ACE (I/D) variants of the renin-angiotensin system with essential hypertension (EH) and interaction between ACE (I/D) gene and risk factors for EH in a genetically homogenous Mongolia rural population of China. METHODS: Individuals (n=1099) were recruited from general population of Kezuohouqi Banner in Inner Mongolian Autonomous Region. RESULTS: The association was found between ACE genotype DD plus ID and EH, with an interaction between ACE genotype DD plus ID and cigarette smoking in an additive model. Cigarette smoking index and ACE gene showed a low exposure-gene (LEG) effect on EH, with interaction indices from 7.10 to 1.16. Interaction between ACE genotype DD plus ID and alcohol drinking on EH appeared an additive model. Alcohol drinking index and ACE gene showed a low exposure-gene (LEG) effect on EH, with interaction indices from 1.66 to 1.09. BMI and ACE gene showed a low exposure-gene (LEG) effect on EH, with interaction indices from 6.15 to 2.49. Interactions between ACE genotype and WHR on EH showed a multiplicative model. In a short,there was an interaction between ACE gene and cigarette smoking, alcohol drinking and BMI on EH, especially in a low dose-exposure effect CONCLUSION: It is important for individuals who carry ACE D allele gene to prevent EH, and furthermore, to prevent and control coronary heart disease, in a view of population-based prevention.