Aim: To evaluate a method based on measurements of skinfold thickness (SFT) in infants under four months of age.
Methods: Adipose tissue volume was assessed by means of magnetic resonance imaging and total body fat (TBF) by means of a method based on skinfold measurements previously developed for children under two years of age (TBF-SFT). Estimates of TBF obtained by means of body water dilution (TBF-BWD) represented reference values. The subjects were 45 fullterm infants, 4-131 days old, and eight premature infants born in gestational weeks 30-33 and studied at a postnatal age of 63 ± 10 days.
Results: In fullterm infants TBF-SFT and TBF-BWD were 23.3 ± 3.4 and 21.8 ± 7.0 %, respectively, and the difference between the two methods was non-significant. However TBF-SFT minus TBF-BWD (%, y) was significantly con-elated (p<0.0001) with the average TBF-SFT and TBF-BWD (%, x), showing that the skinfold method overstimated TBF in lean infants while it underestimated TBF in infants with a high body fat content. In fullterm infants adipose tissue (AT) contained 0.68 ± 0.14 g fat/ml. Significant correlations were found between the AT fat content (g/ml, y) and TBF-BWD (%, x) (p<0.0001 ), as well as between the AT fat content (g/ml, x) and TBF-SFT minus TBF-BWD (%, y) (p<0.0001). In premature infants TBF-SFT (%), TBF-BWD (%) and the AT fat content were similar to the corresponding figures for nine fullterm newborns.
Conclusion: In fullterm infants the skinfold method produced biased estimates of TBF, which to a large extent can be explained by a variation in the AT fat content. However, the method has the potential to provide meaningful results in groups of infants with similar AT fat content.