Overweight and Obesity Between Adolescence and Young Adulthood: A 10-year Prospective Cohort Study

Objectives: To assess changes in overweight and obesity between adolescence and young adulthood. Design: Prospective 8-wave cohort study in Victoria, Australia, with 1,520 adolescents tracked from the age of 14 for a period of 10 years. Main outcome measures: Participants aged <18 years were classified as non-overweight, overweight, or obese according to International Obesity Taskforce cutoff points. In those aged >18 years overweight was defined as a body mass index (BMI) >= 25; and obesity as a BMI >= 30. Results: The proportion of overweight individuals increased from 20% in mid-adolescence to 33% at the age of 24 years. Obesity increased from 3.6% to 6.7%. Approximately 40% of young adults with a BMI >= 25 had been persistently at normal weights during adolescence and approximately 80% had been at a normal weight at some point. Around half of obese young adults had never been classified as obese as adolescents. No individual with persistent obesity in adolescence had a BMI <25 at 24 years. A total of 31% of females and 59% of males who had been overweight for only one or two waves of adolescent data collection had a BMI >= 25 at 24 years. Conclusions: Substantial shifts in overweight and obesity occur between adolescence and young adulthood; the extent of continuity depends on both the severity and persistence of adiposity in adolescence. Few adolescents who peak into obesity or are persistently overweight achieve a normal weight in young adulthood. Resolution is more common in those who are less persistently overweight as teenagers, suggesting scope for lifestyle interventions in this subgroup. (C) 2011 Society for Adolescent Health and Medicine. All rights reserved.