Change in prevalence of overweight and obesity in Finnish children - comparison between 1974 and 2001

Objective: To analyse the possible changes in the prevalence of overweight and obesity comparing birth cohorts from four different decades in Finland. Design: A retrospective longitudinal growth study. Methods: The subjects representing five birth cohorts: 1974 (n = 1109), 1981 (n = 987), 1991 (n = 586), 1995 (n = 856) and 2001 (n = 766) in the city of Tampere and three rural municipalities in Finland. Data included five consecutive height and weight measurements from 2 to 15 years of age. Normal weight, overweight and obesity at the time points were classified by body mass index (BMI, kg/m2) according to international age‐ and gender‐specific BMI cut‐off points. The chi‐square test was used to analyse the differences in the between birth cohorts. Results: The combined prevalence of overweight and obesity decreased significantly in 2‐year‐old boys (p = 0.009) and girls (p = 0.002) from 1974 to 2001. Insignificant fluctuation was seen in 5‐ and 7‐year‐old children. Both the prevalence of obesity and the combined prevalence of overweight and obesity showed a significant increase in 12‐ (p = 0.031 and p