Body image dissatisfaction (BID) in school-age children is positively associated with weight status in cross-sectional studies; however, it is uncertain whether BID is a risk factor for the development of adiposity over time. The aim of the present study was to examine the association of BID with changes in BMI in school-age children.

Longitudinal study. At recruitment, children were asked to indicate the silhouette that most closely represented their current and desired body shapes using child-adapted Stunkard scales. Baseline BID was calculated as the difference of current minus desired body image. Height and weight were measured at recruitment and then annually for a median of 2·5 years. Sex-specific BMI-for-age curves were estimated by levels of baseline BID, using mixed-effects models with restricted cubic splines.

Public primary schools in Bogotá, Colombia.

Six hundred and twenty-nine children aged 5–12 years.

In multivariable analyses, thin boys who desired to be thinner gained an estimated 5·8 kg/m2 more BMI from age 6 to 14 years than boys without BID (P = 0·0004). Heavy boys who desired to be heavier or thinner gained significantly more BMI than boys without BID (P = 0·003 and P = 0·007, respectively). Thin girls who desired to be heavier or thinner gained significantly less BMI than girls without BID (P = 0·0008 and P = 0·05, respectively), whereas heavy girls who desired to be heavier gained an estimated 4·8 kg/m2 less BMI than girls without BID (P = 0·0006). BID was not related to BMI change in normal-weight children.

BID is associated with BMI trajectories of school-age children in a sex- and weight-specific manner.

The aim of the present study was to identify correlates of body image perception and dissatisfaction among school-aged children from Colombia, a country undergoing the nutrition transition.

Cross-sectional study. Using child-adapted Stunkard scales, children were asked to indicate the silhouette that most closely represented their current and desired body shapes. Body image dissatisfaction (BID) score was estimated as current minus desired silhouette. Height and weight were measured in all children. Sociodemographic data were collected through questionnaires completed by the children's mothers.

Public primary schools in Bogotá, Colombia.

Children aged 5–12 years (n 629) and their mothers.

Mean BID score was 0·1 (sd 1·7). The strongest predictor of BID was actual BMI-for-age Z-score (BAZ). Compared with children with BAZ ≥ −1 and <1, those with BAZ ≥ 2 had a 1·9 units higher BID score (P for trend <0·0001). BID tended to be higher in girls than boys at any level of BAZ. Other correlates of BID included child's height-for-age Z-score, maternal BMI and dissatisfaction with the child's body, and home ownership.

Among school-aged children from a country experiencing the nutrition transition, body image perception was associated with the child's weight and height, and with maternal BMI, dissatisfaction with the child's body and socio-economic level.