Weight gain after childhood traumatic brain injury: a matter of concern.

Aim: The aim of the study was to assess weight changes after traumatic brain injury (TBI) in children and the factors influencing them.

Method: We conducted a longitudinal observational study of children with TBI of mixed severity who were consecutively admitted to one rehabilitation department (39 children; 23 males, 16 females; median age 8y 7mo; 25th to 75th centiles 3y 7mo-11y 6mo). Weight and height before TBI were obtained from the children's records and were measured monthly for 1 year after TBI. Body mass index (BMI) and BMI z-scores were calculated, and pre-TBI values were compared with the final values using paired tests. Linear mixed-effect interaction models were used to assess the effect of various factors on z-score evolution.

Results: Z-score curves revealed early weight loss followed by a rapid increase in weight. The mean BMI gain over the period under study was 0.9 kg/m² (p < 0.001) and the mean z-score gain was 0.4 (p = 0.006). Six children had become overweight by the time of final assessment. Factors associated with a greater rate of increase in the post-TBI z-score were mobility restriction, male sex, and older age. Global pre- to post-TBI weight gain was significantly higher in males (z-score 0.7). Pituitary hormonal testing was available for 17 children at 3 months and for 27 at 1 year. Growth hormone deficiency was detected in one child.

Interpretation: Weight gain of children during the first year after TBI was rapid and excessive. Male sex was a risk factor for excessive weight gain.