Body mass index change in relation to longitudinal systolic blood pressure: An age- and sex-matched and repeated measures study.

<bold>Background and Aims: </bold>The positive association between mean systolic blood pressure (SBP) and body mass index (BMI) diminished or reversed over the past four decades. The primary aim of this study was to evaluate effects of BMI change on longitudinal SBP.<bold>Methods and Results: </bold>A total of 3638 participants who had annual health examination from 2015 to 2019 were included and matched by age and sex according to BMI levels. BMI and SBP were measured annually and their association were assessed by a linear mixed-effects regression model. The normal weight participants had a sustained weight gain as well as SBP increase during the study period (all Ptrend <0.001). The obese participants had a sustained weight loss but SBP did not decrease simultaneously. If BMI change was considered, the obese participants with BMI loss had a significant decrease of SBP during the study period (Ptrend = 0.0012). Mixed-effects models showed that weight gain was more influential on longitudinal SBP in the normal weight participants and weight loss was in the obese participants. The obese group with BMI loss had a decrease of SBP by 5.01 mmHg (95% confidence interval: 2.56 mmHg, 7.46 mmHg) compared to their counterparts with BMI maintenance from 2015 to 2019.<bold>Conclusions: </bold>The effect of weight change on longitudinal SBP was varied among BMI groups. With the increase of baseline BMI level, the positive effect of weight loss on SBP became greater and the negative effect of weight gain on SBP were attenuated. [ABSTRACT FROM AUTHOR]