Body Mass Index Trajectories in Adolescence And Incident Metabolic Syndrome in Early Adulthood

Background: The incidence of metabolic syndrome (MetS) is increasing each year, and MetS is closely related to cardiovascular diseases. Body mass index (BMI) has been widely used to measure obesity, and the relationship between MetS and BMI has been widely reported. However, the relationship between the trajectory of BMI and MetS is still unclear.Methods: Six waves of the cross-sectional China Health and Nutrition Survey (CHNS) were completed in nine provinces in China from 1993 to 2009, with more than 12,000 participants. We enrolled individuals who were aged 10 to 20 years in 1993, and 554 participants were finally included in our study. A latent class growth mixed model was used to identify different BMI trajectory patterns based on the BMI value measured at each follow-up. Participants completed blood tests and a physical examination in 2009 to allow for the diagnosis of MetS. The primary aim was to explore the relationship between different BMI trajectories and the incidence of MetS through logistic regression, adjusting for baseline age, sex, BMI, waist circumference, residence, educational background, smoking status, alcohol consumption, and nutritional intake.Result: During a follow-up of 16 years, 61 (11.01%) participants developed MetS. In multivariate-adjusted models, different BMI trajectories were significantly associated with the occurrence of MetS in early adulthood. Childhood or adolescents with a low-high BMI trajectory or a high-high BMI trajectory showed a significantly higher risk of MetS in early adulthood than those with a low-low trajectory (low-high: OR=3.40, 95% CI: 1.14-10.13, P <0.05; high-high: OR=5.81, 95% CI: 1.63-20.69, P <0.05).Conclusion: Our study identified three BMI trajectories from adolescence through 16 years of follow-up and found that in addition to baseline BMI, BMI trajectories were also an independent risk factor for incident MetS in early adulthood.