Modifiable factors of 20-year blood pressure trajectories among normotensives and their associations with hypertension : a prospective study.

Little is known about the impact of modifiable risk factors on blood pressure (BP) trajectories and their associations with hypertension (HTN). We aimed to identify BP trajectories in normotensive Chinese adults and explore their influencing factors and associations with HTN. We used data from 3436 adults with at least four BP measurements between 1989 and 2018 in the China Health and Nutrition Survey, an ongoing cohort study. We measured BP using mercury sphygmomanometers with appropriate cuff sizes in all surveys. We used group-based trajectory modelling to identify BP trajectories between 1989 and 2009 and multiple logistic and Cox regression models to analyse their influencing factors and associations with HTN in 2011-2018. We identified five systolic blood pressure (SBP) trajectories, 'Low-increasing (LI)', 'Low-stable (LS)', 'Moderate-increasing (MI)', 'High-stable (HS)' and 'Moderate-decreasing (MD)', and four diastolic blood pressure (DBP) trajectories classified as 'Low-increasing (LI)', 'Moderate-stable (MS)', 'Low-stable (LS)' and 'High-increasing (HI)'. People with higher physical activity (PA) levels and lower waist circumferences (WC) were less likely to be in the SBP LI, MI, HS and MD groups (P < 0·05). People with higher fruit and vegetable intakes, lower WCs and salt intakes and higher PA levels were less likely to be in the DBP LI, MS and HI groups (P < 0·05). Participants in the SBP HS group (hazard ratio (HR) 2·01) or the DBP LI, MS and HI groups (HR 1·38, 1·40, 1·71, respectively) had higher risks of HTN (P < 0·05). This study suggests that BP monitoring is necessary to prevent HTN in the Chinese population.