Relationships between neonatal weight, limb lengths, skinfold thicknesses, body breadths and circumferences in an Australian cohort.

Emma Pomeroy,Tim J Cole,Jay T Stock,Jonathan C K Wells,Michael O'Callaghan,Lynette K Rogers

doi:10.1371/journal.pone.0105108

Emma Pomeroy, Tim J Cole + Show 4 more

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https://doi.org/10.1371/journal.pone.0105108

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Abstract

BackgroundLow birth weight has been consistently associated with adult chronic disease risk. The thrifty phenotype hypothesis assumes that reduced fetal growth impacts some organs more than others. However, it remains unclear how birth weight relates to different body components, such as circumferences, adiposity, body segment lengths and limb proportions. We hypothesized that these components vary in their relationship to birth weight.MethodsWe analysed the relationship between birth weight and detailed anthropometry in 1270 singleton live-born neonates (668 male) from the Mater-University of Queensland Study of Pregnancy (Brisbane, Australia). We tested adjusted anthropometry for correlations with birth weight. We then performed stepwise multiple regression on birth weight of: body lengths, breadths and circumferences; relative limb to neck-rump proportions; or skinfold thicknesses. All analyses were adjusted for sex and gestational age, and used logged data.ResultsCircumferences, especially chest, were most strongly related to birth weight, while segment lengths (neck-rump, thigh, upper arm, and especially lower arm and lower leg) were relatively weakly related to birth weight, and limb lengths relative to neck-rump length showed no relationship. Skinfolds accounted for 36% of birth weight variance, but adjusting for size (neck-rump, thigh and upper arm lengths, and head circumference), this decreased to 10%. There was no evidence that heavier babies had proportionally thicker skinfolds.ConclusionsNeonatal body measurements vary in their association with birth weight: head and chest circumferences showed the strongest associations while limb segment lengths did not relate strongly to birth weight. After adjusting for body size, subcutaneous fatness accounted for a smaller proportion of birth weight variance than previously reported. While heavier babies had absolutely thicker skinfolds, this was proportional to their size. Relative limb to trunk length was unrelated to birth weight, suggesting that limb proportions at birth do not index factors relevant to prenatal life.

Highlights

Neonatal characteristics such as birth weight, ponderal index, or relative length and head circumference may be considered proxies for prenatal environmental quality and are associated with the risk of developing various non-communicable diseases (NCDs, e.g. type 2 diabetes, cardiovascular disease) in later life [1,2]. These associations formed the basis of the thrifty phenotype hypothesis [3], which has proved highly influential in theorising the cause of relationships between early life conditions, growth, and the risk of NCDs in adulthood
The purpose of this study is to investigate the relationship between birth weight and detailed anthropometric measurements in a large sample (n = 1270) of neonates from Brisbane, Australia, including skinfold measurements, limb segment and trunk lengths, and body breadths and circumferences
Pooling the sexes and adjusting for gestational age and sex, body circumferences showed the highest correlation with birth weight, ranging from 0.70 to 0.82

Summary

Introduction

Neonatal characteristics such as birth weight, ponderal index, or relative length and head circumference may be considered proxies for prenatal environmental quality and are associated with the risk of developing various non-communicable diseases (NCDs, e.g. type 2 diabetes, cardiovascular disease) in later life [1,2] These associations formed the basis of the thrifty phenotype hypothesis [3], which has proved highly influential in theorising the cause of relationships between early life conditions, growth, and the risk of NCDs in adulthood. The body appears to prioritise growth in certain organs such as the brain at the expense of others such as the pancreas, heart, liver, kidneys and skeletal muscle [3,4,5] These trade-offs may have negative consequences in later life, where compromised metabolic function resulting from poor early growth is exposed to a westernised lifestyle (rich diet and reduced activity) [3]. We hypothesized that these components vary in their relationship to birth weight

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