Association between bmi and ambulatory blood pressure characteristics: evidence from population-based ambulatory blood pressure monitoring cohort

Objective: The aim of our study was to investigate the association between BMI and Chinese hypertensive patients’ ambulatory blood pressure characteristics. Design and method: According to the inclusion criteria and exclusion criteria, recruiting participants for analysis. Overweight was defined as BMI = > 18.5 kg/m 2 , and obesity as BMI = > 25 kg/m 2 . ABPM characteristics were defined according to European guidelines. Hypertension was defined as elevated mean ambulatory BP (>135/85 mmHg in day-time, >120/70 mmHg in the night-time, >130/80 mmHg over 24-h). There are four kinds of blood pressure circadian rhythm, dippers, non-dippers, reverse dippers, and extreme dippers. The effects of BMI on ambulatory blood pressure characteristics were analyzed using between-group analysis of variance and logistic regression analysis. Results: In our cohort, 35367 hypertensive patients who were eligible for this study were analyzed finally, including 19380 men (54.8%) and 15987 women (45.2%) aged from 19 to 99 (mean age 58.86 years). The mean 24hBP of the study subjects was 126.41±16.00/78.79±11.62 mmHg. The different BMI groups showed that ambulatory BP increased with BMI, and the obese group had the highest increase in BP, HR, and systolic BP (P < 0.05). Blood pressure variability and systolic load tended to increase with BMI, while the nocturnal blood pressure drop rate tended to decrease. When analyzing the type of hypertension among the participants, the prevalence of MBPS and morning hypertension increased significantly with the elevated BMI (P < 0.05), and the highest prevalence of MBPS was found in the obese group. Logistic regression analysis revealed that the increased risks of MBPS and morning hypertension were the highest in the obese group, corresponding to a 2.1-fold (P < 0.05) and 1.6-fold (P < 0.05) increase in risk, respectively, with no change in trend after adjustment. Conclusions: BMI may affect the characteristics of hypertensive patients’ ambulatory blood pressure. The blood pressure variability and 24h SBP tended to increase with BMI, and the incidence of MBPS was highest in the obese group.