Identification of Sensitive Periods of Weight Status Transition Over the Lifespan in Chinese Population

Background: The prevalence of high body mass index (BMI) is increasing in both children and adults worldwide. However, it is unclear that whether susceptibilities for maintenance and transition between weight statuses vary over time across the lifespan.Objective: We aimed to characterize dynamics and transitions of weight statuses across different life age periods and to identify the sensitive periods for maintenance, onset and resolution of obesity.Methods: This longitudinal study included a total of 23,179 participants aged 6-80 years with 95,994 BMI measurements from the China Health and Nutrition Survey 1989-2015. To examine the heterogeneity in transitions of weight statuses across different life stages, we divided participants into 8 sub-cohorts based on baseline ages by 10-year intervals, ie, 6-10 years, 11-20 years, 21-30 years, 31-40 years, 41-50 years, 51-60 years, 61-70 years, and 71-80 years. We estimated the probabilities of transitioning between weight statuses at a given follow-up year by baseline age using generalized linear mixed-effects model.Results: The predicted prevalence of obesity decreased from 6 years, bottomed at around 20 years, increased thereafter, peaked at around 55 years, and then decreased gradually. In general, participants with underweight had lower probabilities of maintaining the same status compared to those with normal weight, overweight or obesity for all age groups. For 10-year follow-up, individuals aged 21-30 years had the highest probabilities of transitioning from normal weight to obesity and transitioning from overweight to obesity. Individuals aged 6-20 years had higher probabilities of transitioning from obesity to normal weight and from transitioning from overweight to normal weight compared to those in other age groups. Individuals in adult age groups had higher probabilities of maintaining obesity status than children and adolescents.Conclusions: Young adulthood is the most sensitive period for obesity onset, and childhood and adolescence are the most sensitive periods for obesity resolution. The findings suggested the heterogeneity of susceptibilities for weight status transitions across different life stages and highlighted the importance of development of age-appropriate approaches for prevention and intervention of obesity.Funding: This study was supported by the National Nature Science Foundation of China (82073572) and the Beijing Nova Program (20230484467).Declaration of Interest: The authors declared no conflict of interest.Ethical Approval: The CHNS was approved by the institutional review boards of the University of North Carolina at Chapel Hill, the Ministry of Health of the People's Republic of China, the National Institute for Nutrition and Health, and the Chinese Center for Disease Control and Prevention. Informed consent was obtained from participants or their parents.