To analyse the possible changes in the prevalence of overweight and obesity comparing birth cohorts from four different decades in Finland.
A retrospective longitudinal growth study.
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/m(2) ) 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.
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