Trajectories of waist circumference during young adulthood and incident hypertension: the China Health and Nutrition Survey

Single measurements of waist circumference (WC) can predict the incident hypertension, while dynamic change patterns of WC during young adulthood and their association with the incidence of hypertension are poorly demonstrated. This study aimed to identify the longitudinal WC trajectories during young adulthood and explore their association with the risk of incident hypertension. We utilized the data from the China Health and Nutrition Survey (1993–2015) and included 6604 participants aged 18–50 years with repeated WC measurements of 3–8 times and information on incident hypertension. The group-based trajectory model was used to identify WC trajectories. Cox proportional hazard model was conducted to evaluate the association of WC trajectories with the risk of incident hypertension. We identified four distinct WC trajectories during young adulthood. Participants with the low-increasing and the moderate-increasing trajectories had increasing but normal WC, while those with the high-increasing and the sharp-increasing trajectories developed from non-abdominal obesity to abdominal obesity. Compared with the low-increasing trajectory, the adjusted hazard ratios (95% confidence intervals) were 1.48 (1.16–1.89), 2.50 (1.84–3.40), and 3.86 (2.40–6.21) for the moderate-increasing, the high-increasing, and the sharp-increasing trajectories, respectively. After further excluding participants with obesity at baseline, this association did not alter substantially. The gender-specific trajectory analyses yielded similar results. WC trajectories during young adulthood were significantly associated with the risk of incident hypertension in Chinese. Moreover, even the increasing WC trajectory within the normal range during young adulthood might increase the risk of hypertension.