Multiple Trajectories of Body Mass Index and Waist Circumference and Their Associations with Hypertension and Blood Pressure in Chinese Adults from 1991 to 2018: A Prospective Study

Body mass index (BMI) and waist circumference (WC) have been suggested to be involved in the etiology of hypertension. The present study aimed to determine multiple trajectories of BMI and WC, then examined their associations with the risks of hypertension and high blood pressure in Chinese adults. The study used China Health and Nutrition Survey data from 1991 to 2018. The sample included 9651 adults aged 18 years or older. We used group-based multi-trajectory modeling to identify trajectories. We estimated the relationships between the trajectories and the risks of hypertension with a Cox proportional hazards regression model and the trajectories' relationships with blood pressure levels with a generalized linear model. We identified four trajectories for each gender: low stable BMI, low increasing WC (group 1); medium increasing BMI, medium increasing WC (group 2); increasing BMI to overweight, increasing WC to central obesity (group 3), increasing BMI to obesity, increasing central obesity WC (group 4). Group 1 was the reference group. Among males in groups 2, 3, and 4, the adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) of hypertension were 1.30 (1.15-1.48), 1.86 (1.58-2.18), and 2.60 (2.02-3.34), respectively. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) of males in group 4 increased by 11.90 mm of mercury (mmHg) and 7.75 mmHg, respectively. Among females in groups 2, 3, and 4, the HR and 95% CI of hypertension were 1.35 (1.18-1.54), 1.92 (1.62-2.26), and 2.37 (1.85-3.03), respectively. The SBP and DBP of females in group 4 increased by 8.84 mmHg and 5.79 mmHg, respectively. These data indicated that increases in BMI and WC were associated with unfavorable hypertension risks. Attention to both BMI and WC trajectories has the potential to prevent hypertension.