Trends in the incidence and persistence contributions to the prevalence of obesity at 13 years.

The figure shows trends in the incidence and persistence contributions (in percent with 95% confidence intervals for the persistence contribution) to the prevalence of obesity by birth cohort (1930–69) among 367 13-year-old obese boys (left panel) and 438 13-year-old obese girls (right panel) in the Copenhagen School Health Records Register. Obesity was defined by International Obesity Task Force criteria. P values for non-linearity were 0.92 among boys and 0.97 among girls. P values for linearity were 0.01 among boys and 0.006 among girls.