Weight trajectories and disordered eating behaviours in 11- to 12-year-olds: A longitudinal study within the Danish National Birth Cohort.

Objective To examine how childhood weight trajectories are associated with disordered eating behaviours (DEBs) in early adolescence. Methods Self-reports on DEBs (fasting, purging, and binge eating) were obtained from 18,337 children in the 11-year follow-up of the Danish National Birth Cohort. For this population, birth register information on gestational age and birth weight was categorized into the following: small, appropriate, and large for gestational age. Prospective parent-reported height and weight data at child ages 1 and 7 years were dichotomized using standardized cut-offs into non-overweight and overweight. A 12-category weight trajectory variable was created, and the associations between weight trajectory and DEBs were estimated using logistic regression. Results In total, 7.0% 11- to 12-year olds reported DEBs. Compared with children born appropriate for gestational age and being non-overweight at age 1 and 7 years, children born small for gestational age and who were overweight at age 1 and 7 years had a very high risk of disordered eating (OR 7.00; CI [2.57, 19.40]). The statistical analyses revealed, however, that overweight at age 7 years was the main contributor and independently of trajectory increased the risk of disordered eating at age 11-12 years significantly (OR 3.16 CI [2.73, 3.65]). Conclusion Overweight not in the first year of life, but at age 7 years was more predictive for DEBs.