Growth patterns and obesity development in overweight or normal-weight 13-year-old adolescents: the STRIP study.

OBJECTIVE: Our goal was to study childhood growth patterns and development of overweight in children who were overweight or normal weight at 13 years of age.

PARTICIPANTS AND METHODS: This study is part of a prospective atherosclerosis-prevention trial Special Turku Coronary Risk Factor Intervention Project for Children). At 7 months of age, 1062 children were randomly assigned to an intervention group (n = 540) receiving biannual fat-oriented dietary counseling or to a control group (n = 522). Height and weight of the children and their parents were monitored annually. Our study group comprised those children who participated in the 13-year study visit (n = 541). At 13 years of age, the child was classified as overweight (n = 84) if his or her BMI exceeded the international age- and gender-specific overweight criteria.

RESULTS: In overweight girls, the annual weight gain increased from 2.8 kg during the third and fourth year of life to 7.5 kg during the 12th year of life, whereas the annual weight gain of the girls who were normal weight ranged from 2.1 to 4.8 kg during the same period. The annual weight gain was similar of overweight boys and in their normal-weight peers until the age of 5 years, but after that it increased from 3.5 to 7.9 kg in overweight and from 2.6 to 5.5 kg in normal-weight boys. The BMI of the girls and boys who were overweight at the age of 13 exceeded the international cutoff point for overweight from the age of 5 and 8 years onward, respectively. The mean BMIs of the mothers and fathers of the overweight children were higher than those of the parents of the normal-weight children. The STRIP intervention had no effect on the examined growth parameters or on parental BMI.

CONCLUSIONS: The children who were overweight at 13 years of age gained more weight than their normal-weight peers by the age of 2 or 3 years onward. The girls became overweight by the age of 5 years, whereas the boys only after 8 years of age. Parental BMI and steep weight gain in early childhood indicate markedly increased risk for becoming overweight.