BMI in childhood and its association with height gain, timing of puberty, and final height

No large population-based study has addressed the question of how overnutrition is related to subsequent height gain in childhood, timing of puberty, and final height. The present data represent a large Swedish population-based longitudinal growth study. Height gain in childhood, timing of reaching peak height velocity and height gain during adolescence, and final height were regarded as the short-term, interim, and long-term outcomes of childhood nutritional status, i.e. body mass index (BMI) change between 2 and 8 y. Midparental height was adjusted as the genetic influence on linear growth of the child. Childhood BMI gain was related to an increased height gain during the same period, i.e. an increase of 1 BMI unit was associated with an increase in height of 0.23 cm in boys and 0.29 cm in girls. A higher BMI gain in childhood was related to an earlier onset of puberty; the impact on the timing of puberty was 0.6 y in boys and 0.7 y in girls. Each increased unit of BMI gain in childhood also reduced the height gain in adolescence, 0.88 cm for boys and 0.51 cm for girls. No direct correlation was shown between childhood BMI gain and final height. We conclude that overnutrition between 2 and 8 y of age will not be beneficial from a final height point of view, as the temporary increase in height gain in childhood will be compensated by an earlier pubertal maturity and a subnormal height gain in adolescence.