[Stability of body mass index from adolescence to adulthood].

BACKGROUND

The purpose of this study was to track the development of body mass index from adolescence into adulthood and to study the association between parental and offspring's body mass index.

MATERIAL AND METHODS

From 1979, 506 children participated in a twenty-years follow-up study. Mean age in 1979 was 13 years. Participants' weight and height were measured in 1979, 1981 and 1991, and self-reported in 1999. Weight and height of parents were reported in 1979 and in 1981. The cohort in this paper was followed up until 1999.

RESULTS

In 1999, 26% of women and 53% of men had body mass index (BMI: weight in kg/height in meters2) > or = 25, and 7% of women and 11% of men had BMI > or = 30. Participants in the highest quartile of BMI in 1981 had significantly higher BMI in 1999 compared to those in the lowest 1981 quartile (mean and 95% confidence interval was 27.7 (27.0-28.3) kg/m2 versus 22.0 (21.3-22.7) kg/m2). The highest 1981 quartile also had a higher proportion of overweight and obese participants in 1999 than those in the lowest quartile; 64.8% overweight and 27% obese versus 18.8% overweight and 0.9% obese. Participants whose both parents were in the normal weight range in 1981 had lower mean body mass index in 1999 than those with one parent overweight, and a smaller proportion of them were overweight than among participants with both parents overweight.

INTERPRETATION

The probability of overweight in adulthood is predicted by both one's own relative weight during adolescence and by parental relative weight 18 years earlier.