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IntroductionThe purpose of this study was to investigate the relationship between first pregnancy age and hypertension later in the life of women from Chinese rural areas.MethodsIn total, 13,493 women were enrolled in the Henan Rural Cohort study. Logistic regression and linear regression were used to evaluate the association between first pregnancy age and hypertension and blood pressure indicators [including systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP)]. The restricted cubic spline was used to examine the dose–response relationship between the first pregnancy age and hypertension or blood pressure indicators.ResultsAfter adjusting for potential confounders, each 1-year increase in first pregnancy age was associated with a 0.221 mmHg increase in SBP values, a 0.153 mmHg increase in DBP values, and a 0.176 mmHg decrease in MAP values (all P < 0.05). The β of SBP, DBP, and MAP showed a trend of first increasing and then decreasing with increasing first pregnancy age and there was no statistical significance after first pregnancy age beyond 33 years on SBP, DBP, and MAP, respectively. A 1-year increment in first pregnancy age was associated with a 2.9% [OR (95% CI): 1.029 (1.010, 1.048)] higher odds of prevalent hypertension. The odds of hypertension increased sharply and then eventually leveled off with an increment of first pregnancy age after adjusting for potential confounders.ConclusionFirst pregnancy age might increase the risk of hypertension later in life and might be an independent risk factor for hypertension in women.

Background The purpose of this study was to investigate the relationship of duration of reproductive period with metabolic syndrome (MetS) and its components in rural population. Methods In all, 14596 menopausal women were enrolled from the Henan Rural Cohort study. Logistic regression and linear regression were used to evaluate the association between duration of reproductive period and MetS and its components (including central obesity, abnormal fasting plasma glucose (FPG), abnormal blood pressure (BP), abnormal triglycerides (TG) and abnormal high-density lipoprotein cholesterol (HDL-C). In addition, the mediation and interaction effects were performed by mediation analyses and generalized linear model. Results Each year of increase reproductive period correlated with an increased risk of MetS (OR = 1.031; 95% CI = 1.023–1.039; P < 0.05). This association changed slightly after adjusting for body mass index (BMI) and remained statistically significant (OR (95% CI): 1.012(1.003, 1.021)). A positive association between duration of reproductive period and central obesity, abnormal FPG, abnormal BP, abnormal TG, and abnormal HDL-C were revealed (all P < 0.05). The relationship with abnormal FPG (OR (95% CI): 1.009(1.000, 1.017)) and abnormal TG (OR (95% CI): 1.013(1.005, 1.021)) were attenuated after adjusting for BMI and remained statistically significant except for central obesity, abnormal BP and abnormal HDL-C. In addition, BMI mediated the relationship between duration of reproductive period and MetS and its components. The significant interaction of high fat diet was found in association between duration of reproductive period and MetS (P interaction = 0.011). Conclusions The longer duration of reproductive period might raise a woman's risk of MetS and its components. More importantly, the association was largely mediated by BMI. There is an interaction effect between duration of reproductive period and high fat diet on the risk of MetS.

Based on PN junction population, flow model is set up to consider the amount of land to simulate the population migration, and take into account the level of economic development, the factors combine and incorporated into the analytical framework of a model derived the probability of a combination of multiple factors under conditions of population migration. The results of this simulation model can effectively explain the process of urbanization of the population flow problems, is an innovative model generality, there is some reference in the theoretical study.