ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: JAMA Pediatr 2018;172:1192–1195.

The large prospective Cardiovascular Risk in Young Finns Study included 3596 participants aged 3 to 18 years at baseline, and followed the large majority up to 20–30 years later. Comparing various measures of adiposity at baseline, Body Mass Index (BMI) outperformed the Triponderal Mass Index (TMI) and skinfold thicknesses in predicting later Type 2 diabetes, hypertension and LDL cholesterol levels, and carotid intimal thickness.

A paper we described in Yearbook 2017 reported that the TMI was more accurate than BMI as an indicator of childhood adiposity (1). The biological rationale to that observation was that, in children (but not in adults), BMI is positively related to height – hence an index with a stronger numerical correction for height (TMI=weight/height³, compared to BMI=weight/height²) should correlate more strongly with body ‘ponderance’ and adiposity. However, as we stated in 2017, accurate prediction of adiposity only partially addresses the definition of obesity: ‘a state of excess fat related to adverse health’.

The current paper now addresses the second part of this definition. Intriguingly, it shows that there is a clear disconnect between accurate prediction of adiposity (TMI is better than BMI) and prediction of adverse metabolic health (BMI is much better than TMI). In our opinion, the reason why childhood BMI better predicts later health is that it is a combined marker not only of childhood adiposity, but also of taller stature, possibly related to a faster tempo of growth and pubertal maturation, which we know is promoted by increased nutrition. So we are happy to continue to use BMI to define thresholds of overweight and obesity in children.

Reference: 1. Peterson CM, Su H, Thomas DM, Heo M, Golnabi AH, Pietrobelli A, Heymsfield SB. Tri-Ponderal Mass Index vs Body Mass Index in Estimating Body Fat During Adolescence. JAMA Pediatr 2017; 171(7):629–636.