孕早期超重/肥胖和血压正常高值对孕20周后血压水平的影响

The impact of maternal overweight/obesity and high-normal blood pressure during first trimester on blood pressure level after 20 weeks of pregnancy

目的 探讨孕早期超重/肥胖和血压正常高值对孕20周后(孕中晚期)高血压发生的单独和联合作用。方法 利用天津市妇幼卫生信息系统,收集分析2009—2010年在天津市市内六区和滨海新区接受妊娠早期第1次产检的34 913名孕妇的基本信息、孕早期体重指数和血压监测结果,以及孕20周以后血压监测结果。根据孕早期体重指数将孕妇分为消瘦、正常、超重和肥胖组,根据孕早期血压将孕妇分为正常血压和正常高值组。通过logistic回归分析孕早期体重指数分组和孕早期血压水平对孕20周后血压水平的单独影响。按照孕早期体重指数和血压水平分为4组:体重指数<24.0 kg/m^(2)且正常血压,体重指数≥24.0 kg/m^(2)且正常血压,体重指数<24.0 kg/m^(2)且正常高值,体重指数≥24.0 kg/m^(2)且正常高值。以体重指数<24.0 kg/m^(2)且正常血压组作为参照组,通过logistic回归和相加交互作用模型,分析孕早期体重指数和血压水平对孕20周后血压的联合作用。结果 与体重指数正常孕妇相比,超重/肥胖组孕妇的孕20周后血压明显升高。孕早期血压正常高值组孕妇孕20周后血压高于孕早期正常血压组[收缩压:(112.6±10.4)比(105.7±9.9)mmHg,t=51.135,P<0.001;舒张压(72.2±7.7)比(67.5±7.0)mmHg,t=46.708,P<0.001]。多因素logistic回归分析显示,与孕早期体重指数正常组相比,超重和肥胖孕妇孕20周后发生高血压的风险升高(OR=2.090,95%CI 1.643~2.659和OR=4.473,95%CI 3.400~5.883)。与孕早期正常血压孕妇相比,孕早期血压正常高值的孕妇孕20周后发生高血压的风险升高(OR=4.465,95%CI 3.604~5.532)。多因素logistic回归分析显示,与孕早期体重指数和血压正常组相比,孕早期体重指数正常合并正常高值组孕20周后发生高血压的风险为6.047(95%CI 4.467~8.185),而孕早期超重/肥胖合并正常高值组风险增至16.780(95%CI 12.684~22.198)。相加交互作用结果显示,孕早期血压正常高值和超重/肥胖对孕20周后高血压的发生存在相加交互作用,超额相对危险度(RERI)为7.888(95%CI 4.346~11.430),交互作用归因比(AP)为0.470(95%CI 0.343~0.597),交互作用指数(S)为2.000(95%CI 1.535~2.605)。结论 孕早期超重/肥胖和血压正常高值是孕20周后发生高血压的独立危险因素,且二者存在相加交互作用。

Objective To evaluate independent and combined effects of overweight/obesity and high-normal blood pressure during first trimester on the risk of gestational hypertension after 20 weeks of pregnancy(middle and late pregnancy). Methods Using Tianjin Maternal and Child Health Information System, the basic information, body mass index(BMI), blood pressure data in the first trimester and after 20 weeks of pregnancy of 34 913 pregnant women who received the first antenatal examination in six districts and Binhai New Area of Tianjin from 2009 to 2010 were collected and analyzed. Pregnant women were divided into emaciated, normal, overweight and obese groups according to their BMI in the first trimester, and into normal and high-normal blood pressure groups according to their blood pressure in the first trimester. Logistic regression analysis was used to analyze the independent influence of BMI grouping and blood pressure level in the first trimester on blood pressure after 20 weeks of pregnancy. According to the level of BMI and blood pressure in early pregnancy, the subjects were divided into four groups: BMI<24.0 kg/m^(2) with normal blood pressure, BMI≥24.0 kg/m^(2) with normal blood pressure, BMI<24.0 kg/m^(2) with high-normal blood pressure, BMI≥24.0 kg/m^(2) with high-normal blood pressure. Using BMI<24.0 kg/m^(2) and normal blood pressure group as the reference group, the combined effect of BMI and blood pressure level in the first trimester of pregnancy on blood pressure after 20 weeks of pregnancy was analyzed by logistic regression analysis and additive interaction model. Results Compared with normal BMI women, overweight/obese women had higher blood pressure after 20 weeks of pregnancy. Women with high-normal blood pressure had significant higher blood pressure than women with normal blood pressure at first trimester [systolic blood pressure:(112.6±10.4) vs(105.7±9.9) mmHg, t=51.135, P<0.001;diastolic blood pressure:(72.2±7.7) vs(67.5±7.0) mmHg, t=46.708, P<0.001]. Multivariate logistic regression analysis demonstrated that compared to women with normal BMI, overweight and obese women were at higher risk of having hypertension after 20 weeks of pregnancy(overweight: OR=2.090, 95%CI 1.643-2.659;obese: OR=4.473, 95%CI 3.400-5.883, respectively). Compared to those with normal blood pressure, women having high-normal blood pressure during the first trimester had increased risk of gestational hypertension after 20 weeks of pregnancy(OR=4.465, 95%CI 3.604-5.532). Multivariate logistic regression analysis showed that compared with the group with normal BMI and normal blood pressure in the first trimester, the risk of hypertension after 20 weeks of pregnancy in the group with normal BMI and high-normal blood pressure was 6.047(95%CI 4.467-8.185), while which increased to 16.780(95%CI 12.684-22.198) in the group with overweight/obesity and high-normal blood pressure. The results of additive interaction showed that high-normal blood pressure and overweight/obesity in the first trimester had additive interaction on the occurrence of hypertension after 20 weeks of pregnancy. The relative excess risk of interaction(RERI) was 7.888(95%CI 4.346-11.430), the attributable proportion of interaction(AP) was 0.470(95%CI 0.343-0.597), and the synergy index(S) was 2.000(95%CI 1.535-2.605). Conclusion Overweight/obesity and high-normal blood pressure in the first trimester are independent risk factors of gestational hypertension after 20 weeks of pregnancy, and there is an additive interaction between the two factors.