The trajectory of body mass index and blood pressure and fasting blood glucose in Chinese aged population: Cohort study

The purpose was to conduct a cohort study to investigate the association between body mass index (BMI) trajectory and future changes in blood pressure and fasting blood glucose (FBG) in Chinese aged people. This cohort included 2576 participants (1544 men and 1032 women; aged 67.7 ± 6.9 years) who were recruited in Shanghai, China. The trajectory of BMI was calculated based on BMI measurement in 2014, 2015 and 2016, and 3 BMI trajectories were determined: low-BMI (n = 418, 17.1%), medium-BMI (n = 1806, 68.5%) and high-BMI (n = 352, 14.4%). All participants were then followed up to 2022. The median follow-up time was 5 years. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and FBG were annually measured. We used MIXED model to evaluate the relationship between BMI trajectory and changes in SBP, DBP and FBG during the follow up. The mean BMI for participants of low-, medium-, and high-BMI trajectories was 20.63 kg/m2, 24.52 kg/m2, and 28.80 kg/m2, respectively. BMI trajectory was significantly associated with future increase in blood pressure and FBG (P < .001). After adjustment of potential covariates, compared with low-BMI trajectory the mean increase in SBP was 4.9 mm Hg (95% CI: 2.5, 7.2 mm Hg) for those with medium-BMI trajectory and it was 3.8 mm Hg (95% CI: 0.7, 6.9 mm Hg) for those with high-BMI trajectory. It was 1.0 mm Hg (95% CI: -0.4, 2.4 mm Hg) and 2.2 mm Hg (95% CI : 0.4, 4.0 mm Hg) for DBP while it was 0.2 mmol/L (95% CI: 0, 0.4 mmol/L) and 0.3 mmol/L (95% CI: 0.1, 0.6 mmol/L) for FBG for those with medium-BMI and high-BMI trajectories compared with those low-BMI trajectory. Sex and age interacted with the association between BMI trajectory and changes in blood pressure and FBG. BMI trajectory was significantly associated with future increase in blood pressure and FBG in aged population, indicating maintenance of optimal BMI was important for the prevention of metabolic diseases.