biostudies-literature00650Bell KANICHD NIH HHSNCATS NIH HHSNCRR NIH HHS168-174.e1https://www.ebi.ac.uk/biostudies/studies/S-EPMC5924641biostudies-literatureUnknown196OBJECTIVES:To assess the validity of body mass index (BMI) and age- and sex-standardized BMI z-score (BMIZ) as surrogates for adiposity (body fat percentage [BF%], fat mass, and fat mass index [kg/m2]) at 3 time points in infancy (1, 4, and 7 months) and to assess the extent to which the change in BMIZ represents change in adiposity. STUDY DESIGN:We performed a secondary analysis of 447 full-term infants in a previous trial of maternal vitamin D supplementation during lactation. Study staff measured infant anthropometrics and assessed body composition with dual-energy x-ray absorptiometry at 1, 4, and 7 months of age. We calculated Spearman correlations (rs) among BMI, BMIZ, and adiposity at each time point, and between change in BMIZ and change in adiposity between time points. RESULTS:Infants (N?=?447) were 52% male, 38% white, 31% black, and 29% Hispanic. The BMIZ was moderately correlated with BF% (rs?=?0.43, 0.55, 0.48 at 1, 4, and 7 months of age, respectively). BMIZ correlated more strongly with fat mass and fat mass index, particularly at 4 and 7 months of age (fat mass rs?=?0.72-0.76; fat mass index rs?=?0.75-0.79). Changes in BMIZ were moderately correlated with adiposity changes from 1 to 4 months of age (rs?=?0.44 with BF% change; rs?=?0.53 with fat mass change), but only weakly correlated from 4 to 7 months of age (rs?=?0.21 with BF% change; rs?=?0.27 with fat mass change). CONCLUSIONS:BMIZ is moderately correlated with adiposity in infancy. Changes in BMIZ are a poor indicator of adiposity changes in later infancy. BMI and BMIZ are limited as surrogates for adiposity and especially adiposity changes in infancy. TRIAL REGISTRATION:ClinicalTrials.gov: NCT00412074.The Journal of pediatricsValidity of Body Mass Index as a Measure of Adiposity in Infancy.PMC5924641UL1 TR001450UL1 TR000062M01 RR001070R01 HD043921Wagner CLShypailo RJPerng WFeldman HABell KABelfort MB65falseValidity of Body Mass Index as a Measure of Adiposity in Infancy.OBJECTIVES:To assess the validity of body mass index (BMI) and age- and sex-standardized BMI z-score (BMIZ) as surrogates for adiposity (body fat percentage [BF%], fat mass, and fat mass index [kg/m2]) at 3 time points in infancy (1, 4, and 7 months) and to assess the extent to which the change in BMIZ represents change in adiposity. STUDY DESIGN:We performed a secondary analysis of 447 full-term infants in a previous trial of maternal vitamin D supplementation during lactation. Study staff measured infant anthropometrics and assessed body composition with dual-energy x-ray absorptiometry at 1, 4, and 7 months of age. We calculated Spearman correlations (rs) among BMI, BMIZ, and adiposity at each time point, and between change in BMIZ and change in adiposity between time points. RESULTS:Infants (N?=?447) were 52% male, 38% white, 31% black, and 29% Hispanic. The BMIZ was moderately correlated with BF% (rs?=?0.43, 0.55, 0.48 at 1, 4, and 7 months of age, respectively). BMIZ correlated more strongly with fat mass and fat mass index, particularly at 4 and 7 months of age (fat mass rs?=?0.72-0.76; fat mass index rs?=?0.75-0.79). Changes in BMIZ were moderately correlated with adiposity changes from 1 to 4 months of age (rs?=?0.44 with BF% change; rs?=?0.53 with fat mass change), but only weakly correlated from 4 to 7 months of age (rs?=?0.21 with BF% change; rs?=?0.27 with fat mass change). CONCLUSIONS:BMIZ is moderately correlated with adiposity in infancy. Changes in BMIZ are a poor indicator of adiposity changes in later infancy. BMI and BMIZ are limited as surrogates for adiposity and especially adiposity changes in infancy. TRIAL REGISTRATION:ClinicalTrials.gov: NCT00412074.2018-01-01T00:00:00Z2018 May2021-02-20T08:33:33Z2019-06-06T22:51:15ZS-EPMC59246412955131110.1016/j.jpeds.2018.01.028