Harmonisation of percentage body fat at birth

The InterConnect consortium aimed to investigate associations between physical activity during pregnancy and neonatal anthropometric outcomes using a federated meta-analysis approach. One of the outcomes investigated was percentage body fat, and this was available in three cohorts. Of these, one assessed neonatal body fat by using the air displacement plethysmography (also known as BOD POD, or PEA POD for infants), while skinfold thickness measurements were available for the second cohort and in a subset of the third.

The data from skinfold measurements in cohorts two and three were converted to the common format target variable (percentage body fat, %) using a previously reported algorithm [1]:

  1. Percentage body fat = 1.21 (triceps skinfold + subscapular skinfold) - 0.008 (triceps skinfold + subscapular skinfold)2 - 1.7

As there were no data with harmonisation potential in the remaining five cohorts, it was necessary to restrict meta-analysis for this outcome to only the three cohorts described above.