What is the risk for overweight children of being overweight at age 18 years? The Wrocław Growth Study

It is widely acknowledged that overweight and/or obesity is associated with elevated morbidity and mortality. A variety of studies have shown that correlations between BMI during childhood and adulthood are generally low but increase during adolescence. However, the use of correlation coefficients has some disadvantages. The aim of this study was to estimate the risk of overweight and obesity at the age of 18 years from the occurrence of overweight and obesity at ages 8 to 17 years in boys and girls from the Wrocław Growth Study, using three different risk estimates: relative risk (RR), odds ratio (OR), and risk differences (RD). Subjects with BMI higher than the value of 85th centile for the BMI, as estimated from the III Anthropological Survey, were defined as overweight and obese. All three risk estimates gave similar results. Until the age of 14 for boys and 13 for girls, risk remained unchanged on relatively low level, and was a little higher for boys than for girls. This suggests that being overweight in pre-adolescence is not a predisposing factor for becoming overweight in adulthood. After adolescence, risk increased steeply both in boys and girls. The results show that adolescence is a critical period for development of obesity in adulthood.