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.