Low shearing force can induce vascular inflammatory response, which leads to the occurrence and development of hypertension. Estrogen can regulate the immune system and inflammatory response through estrogen receptor mediated pathway, with a protective effect on hypertension. Cardiovascular diseases have become the leading cause of death in China.

To investigate the current prevalence and influencing factors of hypertension in women, explore the correlation of shearing force and estradiol with hypertension as well as the effect of estradiol on hypertension under various shearing force, so as to further explore the effect of the interaction between estradiol and shearing force on hypertension.

Female patients admitted to the Department of Cardiology of Hunan People's Hospital from January to August 2021 were selected as the study subjects, 288 of whom with essential hypertension were included as the case group, and 296 female non-hypertensive medical examiners in the physical examination department of Hunan People's Hospital were randomly selected as the control group. The self-designed questionnaire was used to investigate the general information of the study subjects, and the fasting venous blood samples of the subjects were taken in the early morning for the examination of laboratory indicators. The color doppler ultrasound was used for ultrasonography on vessels to calculate the shearing force. Multivariate Logistic regression was used to construct the hypertension prediction model and draw the nomogram. Receiver operating characteristic curve (ROC curve) was plotted to evaluate the hypertension prediction model. Stratification analysis was conducted on estradiol in four groups to explore the effect of each estradiol group on the occurrence of hypertension under different shearing force dichotomous groups. The multiplicative interaction model was used to evaluate the interaction between estradiol and shearing force.

There were significant differences in age, education level, body mass index (BMI), menopause, family history of hypertension, triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), estradiol, uric acid (UA), creatinine (Scr), urea nitrogen (BUN), shear force, and blood viscosity between the case group and control group (P<0.05). Multivariate Logistic regression results showed age>60 years old〔OR=2.172, 95%CI (1.361, 3.468) 〕, menopause〔OR=14.940, 95%CI (1.938, 115.176) 〕, family history of hypertension〔OR=1.614, 95%CI (1.014, 2.570) 〕, BMI of 24-28 kg/m²〔OR=3.454, 95%CI (2.072, 5.758) 〕, BMI>28 kg/m²〔OR=6.750, 95%CI (2.380, 19.146) 〕, TG of 1.30-1.83 mmol/L〔OR=1.980, 95%CI (1.114, 3.520) 〕, TG>1.83 mmol/L〔OR=2.311, 95%CI (1.308, 4.082) 〕, TC of 4.29-5.12 mmol/L〔OR=2.222, 95%CI (1.250, 3.950) 〕, TC>5.12 mmol/L〔OR=1.884, 95%CI (1.062, 3.341) 〕, LDL-C>2.81 mmol/L〔OR=1.546, 95%CI (1.150, 2.078) 〕, HDL-C>1.17 mmol/L〔OR=0.140, 95%CI (0.065, 0.301) 〕, BUN>5.47 mmol/L〔OR=3.249, 95%CI (2.380, 4.434) 〕, Scr>69 μmol/L〔OR=1.166, 95%CI (1.126, 1.207) 〕, UA>324 μmol/L〔OR=1.040, 95%CI (1.029, 1.050) 〕, WBV<3.39 mPa·s or >4.41 mPa·s〔OR=3.456, 95%CI (2.557, 4.671) 〕, estradiol of 10.60-<15.39 ng/L〔OR=0.053, 95%CI (0.015, 0.183) 〕, estradiol of 15.39-<23.99 ng/L〔OR=0.022, 95%CI (0.006, 0.077) 〕, estradiol >23.99 ng/L〔OR=0.005, 95%CI (0.001, 0.020) 〕, shearing force >8.21 dyne/cm²〔OR=0.033, 95%CI (0.017, 0.062) 〕were influncing factors for hypertension (P<0.05). ROC curve of clinical prediction model of hypertension was plotted, the results showed that the area under ROC curve of the prediction model was 0.907〔95%CI (0.882, 0.923), P<0.01〕, with sensitivity of 79.60% and specificity of 87.90%. The risk of hypertension tended to decrease in the shearing force≤8.21 dyne/cm² group (P_trend =0.001). In the shearing force ≤8.21 dyne/cm² group, estradiol≥15.39 ng/L was more significantly associated with reduced risk of hypertension〔OR=0.037, 95%CI (0.017, 0.079), P<0.05〕. In the shearing force >8.21 dyne/cm² group, estradiol≥15.39 ng/L was significantly associated with reduced risk of hypertension〔OR=0.012, 95%CI (0.005, 0.019), P<0.05〕.

Estradiol≥10.60 ng/L as a protective factor for hypertension, with higher protective effect of estrogen on hypertension at low shearing force, and there is a multiplicative interaction between shearing force and estradiol on hypertension.