Ultrasound estimates of visceral and subcutaneous-abdominal adipose tissues in infancy

Associations of infant feeding practices with abdominal and hepatic fat measures in childhood in the longitudinal Healthy Start Study

BACKGROUND

Infant feeding patterns have been linked with obesity risk in childhood, but associations with precise measures of body fat distribution are unclear.

OBJECTIVE

We examined associations of infant feeding practices with abdominal fat and hepatic fat trajectories in childhood.

METHODS

This study included 356 children in the Healthy Start Study, a prospective prebirth cohort in Colorado. Infant feeding practices were assessed by postnatal interviews and categorized as any human milk <6 mo compared with ≥6 mo; complementary foods introduced ≤4 mo compared with >4 mo; soda introduced ≤18 mo compared with >18 mo. Abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) areas and hepatic fat (%) were assessed by magnetic resonance imaging in early and middle childhood (median 5 and 9 y old, respectively). We examined associations of infant feeding with adiposity trajectories across childhood using linear mixed models.

RESULTS

In the sample of children, 67% consumed human milk ≥6 mo, 75% were introduced to complementary foods at >4 mo, and 81% were introduced to soda at >18 mo. We did not find any associations between duration of any human milk consumption and childhood adiposity trajectories. Early introduction to complementary foods (≤4 mo) was associated with faster rates of change for SAT and VAT during childhood (Slope [95% CI]: 15.1 [10.7,19.4] cm2/y for SAT; 2.5 [1.9,2.9] cm2/y for VAT), compared with introduction at >4 mo (5.5 [3.0,8.0] cm2/y and 1.6 [1.3,1.9] cm2/y, respectively). Similarly, early introduction to soda (≤18 mo) was associated with faster rates of change for all 3 outcomes during childhood (Slope [95% CI]: 20.6 [15.0,26.1] cm2/y for SAT, 2.7 [2.0,3.3] cm2/y for VAT, 0.3 [0.1,0.5] %/year for hepatic fat) compared with delayed introduction (5.4 [2.8,8.0] cm2/y, 1.7 [1.3, 2.0] cm2/y, -0.1 [-0.2,0.0] %/y, respectively).

CONCLUSIONS

The timing of introduction and quality of complementary foods in infancy was associated with rates of abdominal and hepatic fat accrual during childhood. Experimental studies are needed to assess underlying mechanisms.

Associations between abdominal adiposity, body size and objectively measured physical activity in infants from Soweto, South Africa

OBJECTIVES

Considering the importance of the early life period, in conjunction with the increasing prevalence of adiposity and insufficient physical activity already evident in early childhood, this study aimed to determine associations between abdominal adiposity, body size, and objectively measured physical activity in infancy.

METHODS

Infants (n = 138, aged 3-24 months) from Soweto, South Africa were recruited to this cross-sectional study. Visceral (VAT) and subcutaneous abdominal fat (SAT) were measured using ultrasound. Physical activity was assessed using accelerometry and analysed at the hourly level. Multilevel linear regression analyses were run with body composition exposures adjusted for age, sex, and length; models with VAT and SAT were also adjusted for total abdominal fat.

RESULTS

Mean (SD) age was 11.8 (7.6) months; 86% were normal weight, 7% were underweight and 7% overweight. In linear models, no body composition variable was significantly associated with physical activity. Physical activity was higher with each increasing length tertile (ANOVA p < 0.01); with a mean(95%CI) 29(60-60)mg in the lowest tertile, 39(71-71)mg in the middle tertile, and 50(81-82)mg in the highest tertile. Infants with normal weight had higher mean(95%CI) physical activity (40(70-80)mg) than underweight (34(73-85)mg, p = 0.01) or overweight infants (31(63-78)mg, ANOVA p < 0.01). When also adjusting for total abdominal fat, infants in the lowest SAT tertile had higher physical activity than those in the middle or highest SAT tertiles (p < 0.01).

CONCLUSIONS

These findings lend support for higher physical activity as a marker of healthy growth in the first two years of life.

Increased basal insulin sensitivity in late pregnancy in women carrying a male fetus: a cohort study

BACKGROUND

It has been suggested that fetal sex may be able to modify maternal metabolism and physiology during pregnancy. Recently pregnant women carrying a male fetus were reported to be more insulin sensitive than those carrying females, although related evidence is inconsistent.

METHODS

In this study we administered a 75 g oral glucose tolerance test at around week 28 of pregnancy in 813 pregnant women from a contemporary birth cohort (the Cambridge Baby Growth Study), derived surrogate indices of insulin secretion and sensitivity, and related them to the fetal sex.

RESULTS

Carrying a male fetus was associated with lower fasting glucose (difference in mean concentrations ≈ 0.1 mmol/L; β' = 0.063; p = 0.02) and insulin (≈ 1.1 pmol/L; β' = 0.075; p = 0.01) concentrations but not with post-load glucose or insulin concentrations. Male fetal sex was also associated with lower HOMA IR (≈ 1.08 units; β' = 0.071; p = 0.02) and higher QUICKI (≈ 1.06 units; β' = 0.080; p = 0.007) values suggesting increased basal insulin sensitivity. There were no differences in indices of insulin secretion, except for the insulin disposition index which was higher in women carrying a male fetus (≈ 1.15 units; β' = 0.090; p = 0.007). Birth weights were higher in male offspring.

CONCLUSIONS

Women carrying a male fetus were relatively more insulin sensitive in the fasting state and secreted more insulin relative to this degree of insulin sensitivity. These results are consistent with the idea that the fetal sex may be able to modify the maternal glucose-insulin axis.

Human Milk Macronutrients and Bioactive Molecules and Development of Regional Fat Depots in Western Australian Infants during the First 12 Months of Lactation

We investigated associations between intakes of human milk (HM) components (macronutrients and biologically active molecules) and regional fat depots development in healthy term infants (n = 20) across the first year of lactation. Infant limb (mid-arm and mid-thigh) lean and fat areas were assessed by ultrasound imaging at 2, 5, 9 and 12 months of age. Concentrations of HM total protein, whey protein, casein, adiponectin, leptin, lysozyme, lactoferrin, secretory IGA, total carbohydrates, lactose, HM oligosaccharides (total HMO, calculated) and infant 24-h milk intake were measured, and infant calculated daily intakes (CDI) of HM components were determined. This pilot study shows higher 24-h milk intake was associated with a larger mid-arm fat area (p = 0.024), higher breastfeeding frequency was associated with larger mid-arm (p = 0.008) and mid-thigh (p < 0.001) fat areas. Lysozyme (p = 0.001) and HMO CDI (p = 0.004) were time-dependently associated with the mid-arm fat area. Intakes of HM components and breastfeeding parameters may modulate infant limb fat depots development during the first year of age and potentially promote favorable developmental programming of infant body composition; however, further studies are needed to confirm these findings.

Causative Mechanisms of Childhood and Adolescent Obesity Leading to Adult Cardiometabolic Disease: A Literature Review

The past few decades have shown a worrisome increase in the prevalence of obesity and its related illnesses. This increasing burden has a noteworthy impact on overall worldwide mortality and morbidity, with significant economic implications as well. The same trend is apparent regarding pediatric obesity. This is a particularly concerning aspect when considering the well-established link between cardiovascular disease and obesity, and the fact that childhood obesity frequently leads to adult obesity. Moreover, most obese adults have a history of excess weight starting in childhood. In addition, given the cumulative character of both time and severity of exposure to obesity as a risk factor for associated diseases, the repercussions of obesity prevalence and related morbidity could be exponential in time. The purpose of this review is to outline key aspects regarding the current knowledge on childhood and adolescent obesity as a cardiometabolic risk factor, as well as the most common etiological pathways involved in the development of weight excess and associated cardiovascular and metabolic diseases.

Fat mass and fat-free mass track from infancy to childhood: New insights in body composition programming in early life

OBJECTIVE

Early life is a critical window for adiposity programming. This study investigated whether fat mass percentage (FM%), fat mass index (FMI), abdominal fat, and fat-free mass (FFM) in early life track into childhood and whether there are sex differences and differences between infant feeding types.

METHODS

Detailed body composition was longitudinally measured by air-displacement plethysmography, dual-energy x-ray absorptiometry, and abdominal ultrasound in 224 healthy, term-born children. Measurements were divided into tertiles. Odds ratios (OR) of remaining in the highest tertile of FM%, FMI, abdominal subcutaneous and visceral fat, and FFM index (FFMI) were calculated from early life to age 4 years.

RESULTS

High FM% and FMI tracked from age 3 and 6 months to age 4 years (OR = 4.34 [p = 0.002] and OR = 6.54 [p < 0.001]). High subcutaneous abdominal fat tracked from age 6 months to age 4 years (OR = 2.30 [p = 0.012]). High FFMI tracked from age 1, 3, and 6 months to age 4 years (OR = 4.16 [p = 0.005], 3.71 [p = 0.004], and 3.36 [p = 0.019]). In non-exclusively breastfed infants, high FM% tracked from early life to age 4 years, whereas this was not the case for exclusively breastfed infants. There was no tracking in visceral fat or sex differences.

CONCLUSIONS

Infants with high FM%, FMI, subcutaneous abdominal fat, and FFMI in early life are likely to remain in the highest tertile at age 4 years. Exclusive breastfeeding for 3 months is potentially protective against having high FM% at age 4 years.

Development of Visceral and Subcutaneous-Abdominal Adipose Tissue in Breastfed Infants during First Year of Lactation

This study aimed to investigate relationships between infant abdominal visceral and subcutaneous adiposity and human milk (HM) components and maternal body composition (BC) during first year of lactation. Subcutaneous-abdominal depth (SAD), subcutaneous-abdominal fat area (SFA), visceral depth (VD) and preperitoneal fat area of 20 breastfed infants were assessed at 2, 5, 9 and 12 months using ultrasound. Maternal BC was determined with bioimpedance spectroscopy. HM macronutrients and bioactive components concentrations and infant 24-h milk intake were measured and calculated daily intakes (CDI) determined. Maternal adiposity associated with infant SFA (negatively at 2, 5, 12, positively at 9 months, all overall p < 0.05). 24-h milk intake positively associated with infant SAD (p = 0.007) and VD (p = 0.013). CDI of total protein (p = 0.013), total carbohydrates (p = 0.004) and lactose (p = 0.013) positively associated with SFA. Lactoferrin concentration associated with infant VD (negatively at 2, 12, positively at 5, 9 months, overall p = 0.003). CDI of HM components and maternal adiposity have differential effects on development of infant visceral and subcutaneous abdominal adiposity. Maintaining healthy maternal BC and continuing breastfeeding to 12 months and beyond may facilitate favourable BC development reducing risk of obesity.

Extensive Study of Breast Milk and Infant Growth: Protocol of the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF)

Growth and nutrition during early life have been strongly linked to future health and metabolic risks. The Cambridge Baby Growth Study (CBGS), a longitudinal birth cohort of 2229 mother-infant pairs, was set up in 2001 to investigate early life determinant factors of infant growth and body composition in the UK setting. To carry out extensive profiling of breastmilk intakes and composition in relation to infancy growth, the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF) was established upon the original CBGS. The strict inclusion criteria were applied, focusing on a normal birth weight vaginally delivered infant cohort born of healthy and non-obese mothers. Crucially, only infants who were exclusively breastfed for the first 6 weeks of life were retained in the analysed study sample. At each visit from birth, 2 weeks, 6 weeks, and then at 3, 6, 12, 24, and 36 months, longitudinal anthropometric measurements and blood spot collections were conducted. Infant body composition was assessed using air displacement plethysmography (ADP) at 6 weeks and 3 months of age. Breast milk was collected for macronutrients and human milk oligosaccharides (HMO) measurements. Breast milk intake volume was also estimated, as well as sterile breastmilk and infant stool collection for microbiome study.

Folic acid supplementation during pregnancy and associations with offspring size at birth and adiposity: a cohort study

Objective

Previously we observed that maternal multiple micronutrient supplementation in pregnancy was associated with increased offspring size at birth and adiposity, as well as with maternal gestational diabetes risk, in the Cambridge Baby Growth Study. In this study we therefore investigated whether folic acid supplementation specifically is associated with similar changes, to test the hypothesis that folic acid supplementation mediates such changes.

Results

The majority of mothers who reported supplementing with folic acid in pregnancy (n = 776 in total, 526 of which took multiple micronutrient preparations) did so either from pre- (n = 139) or post-conception (n = 637) largely for all or just the first half of pregnancy. A minority of mothers (n = 198) reported not supplementing with folic acid. Folic acid supplementation in pregnancy was not associated with birth weight [β’ = − 0.003, p = 0.9], height [β’ = − 0.013, p = 0.6], head circumference [β’ = 0.003, p = 0.09] or adiposity (ponderal index [β’ = 0.020, p = 0.5], skinfolds thicknesses [β’ = − 0.029 to + 0.008, p = 0.4–0.9]). Neither was it associated with the development of maternal gestational diabetes (risk ratio 1.2 [0.6‒2.2], p = 0.6). These results suggest that folic acid supplementation in pregnancy did not mediate the previously observed increases in offspring size at birth and adiposity, or the raised gestational diabetes risk, in response to supplementation with multiple micronutrients.

Longitudinal telomere length and body composition in healthy term-born infants during the first two years of life

OBJECTIVE

Leukocyte telomere length (LTL) is one of the markers of biological aging as shortening occurs over time. Shorter LTL has been associated with adiposity and a higher risk of cardiovascular diseases. The objective was to assess LTL and LTL shortening during the first 2 years of life in healthy, term-born infants and to associate LTL shortening with potential stressors and body composition.

STUDY DESIGN

In 145 healthy, term-born infants (85 boys), we measured LTL in blood, expressed as telomere to single-gene copy ratio (T/S ratio), at 3 months and 2 years by quantitative PCR technique. Fat mass (FM) was assessed longitudinally by PEAPOD, DXA, and abdominal FM by ultrasound.

RESULTS

LTL decreased by 8.5% from 3 months to 2 years (T/S ratio 4.10 vs 3.75, p<0.001). LTL shortening from 3 months to 2 years associated with FM%(R = 0.254), FM index(R = 0.243) and visceral FM(R = 0.287) at 2 years. LTL shortening tended to associate with gain in FM% from 3 to 6 months (R = 0.155, p = 0.11), in the critical window for adiposity programming. There was a trend to a shorter LTL in boys at 2 years(p = 0.056). LTL shortening from 3 months to 2 years was not different between sexes.

CONCLUSION

We present longitudinal LTL values and show that LTL shortens considerably (8.5%) during the first 2 years of life. LTL shortening during first 2 years of life was associated with FM%, FMI and visceral FM at age 2 years, suggesting that adverse adiposity programming in early life could contribute to more LTL shortening.

Association Between Fat Mass in Early Life and Later Fat Mass Trajectories

IMPORTANCE

A rapid increase in weight in early life is associated with an increased risk for adiposity and cardiovascular diseases at age 21 years and beyond. However, data on associations of early change in measured fat mass percentage (FM%) with adiposity development are lacking.

OBJECTIVE

To investigate whether a rapid increase in FM% in the first months of life is associated with higher trajectories of body fat mass during the first 2 years of life.

DESIGN, SETTING, AND PARTICIPANTS

A birth cohort consisting of 401 healthy, term-born infants of the Sophia Pluto Cohort Study was analyzed. Participants were born between January 7, 2013, and October 13, 2017. Data were analyzed from February 1, 2020, to May 20, 2020.

INTERVENTIONS

Longitudinal measurements of FM% by air-displacement plethysmography and dual-energy x-ray absorptiometry, and abdominal subcutaneous and visceral fat mass (FM) by ultrasonography in infants at ages 1, 3, 6, 9, 12, 18, and 24 months. A rapid increase in FM% was defined as a change in FM% of greater than 0.67 standard deviation scores (SDS).

MAIN OUTCOMES AND MEASURES

Associations between change in FM% SDS in the first and second 6-month period of life with body composition at age 2 years and whether a rapid increase in FM% SDS during the first 6 months leads to higher body FM and abdominal FM trajectories during the first 2 years of life.

RESULTS

Of the 401 participants, 228 infants (57%) were male. Change in FM% SDS from age 1 to 6 months was positively associated with FM% (β, 0.044; 95% CI, 0.017-0.068), FMI (β, 0.061; 95% CI, 0.032-0.091), and abdominal subcutaneous FM (β, 0.064; 95% CI, 0.036-0.092) at age 2 years, but not with visceral FM. In contrast, no associations were found within the 6- to 12-month period. Infants with a rapid increase in FM% of greater than 0.67 SDS in the first 6 months of life had higher trajectories of FM%, FM index, and subcutaneous FM during the first 2 years of life (all P≤.001), but visceral FM index was not significantly different compared with infants without a rapid increase (P = .12).

CONCLUSIONS AND RELEVANCE

In this study, only the change in FM% in the first 6 months of life was associated with more adiposity at age 2 years. Infants with a rapid increase in FM% had higher trajectories of FM% and FM index during the first 2 years of life. These findings appear to support a critical window for adiposity programming in early life.

Multiple Micronutrient Supplementation during Pregnancy and Increased Birth Weight and Skinfold Thicknesses in the Offspring: The Cambridge Baby Growth Study

Multiple micronutrient supplementation (MMS) in pregnancy has previously been associated with positive effects on fetal growth, but its value in high-income countries remains controversial. In this study, we investigated effects of pregnancy MMS on offspring size at birth and adiposity, along with risks of various maternal outcomes of pregnancy, using the prospective Cambridge Baby Growth Study. Maternal MMS was reported in 528 out of 970 women who completed pregnancy questionnaires. Gestational diabetes (GDM) was assessed using results from 75 g oral glucose tolerance tests at week 28 of pregnancy. Offspring size at birth was assessed using standard anthropometric measurements and adiposity using skinfold calipers. MMS was associated with increased risk of developing GDM (risk ratio = 1.86 (1.13–3.08), p = 0.02), as well as increased offspring size at birth in terms of weight (p = 0.03), head circumference (p = 0.04), and flank, and subscapular and triceps skinfold thicknesses (p = 0.04, 0.03, and 0.003, respectively). There was no association with quadriceps skinfold thickness (p = 0.2), suggesting that the increased adiposity was partially regionalized. In women who underwent oral glucose tolerance testing, nearly all of these associations were attenuated by adjusting for GDM. These results suggest that the increased offspring size at birth, including (regionalized) adiposity associated with pregnancy, and MMS may be partially related to the development of GDM.

Compliance With Physical Activity and Sedentary Behavior Guidelines and Associations With Abdominal Adiposity in a Sample of Infants and Toddlers From Soweto, South Africa

Background: This study reported compliance with 24-hour physical activity and sedentary behavior guidelines, and associations with adiposity in the first 2 years of life. Methods: Participants (N = 119) were recruited from Soweto, South Africa. Visceral and subcutaneous abdominal adipose tissue was measured by ultrasound. Participation in 2 movement behaviors (physical activity and sedentary time) was reported by mothers. Differences in adiposity between those meeting each individual guideline, as well as the combination of both movement guidelines, compared with those not meeting the guidelines were assessed. Results: Only 5% of infants met the sedentary guidelines; however, 58% met the physical activity guidelines. Subcutaneous adipose tissue was significantly higher in those meeting the physical activity guideline (0.50 [0.01] vs 0.47 [0.01] cm, P = .03) compared with those not meeting the guideline. Meeting the screen time component of the sedentary guideline was associated with higher visceral adipose tissue (β = 0.96, P < .01), while meeting one guideline compared with meeting none was associated with higher subcutaneous adipose tissue (β = 0.05, P = .01). Conclusions: Most infants and toddlers from this low- to middle-income setting were not meeting sedentary behavior guidelines. Both behaviors were associated with abdominal adiposity, but not with body mass index z score; implying these movement behaviors may impact abdominal fat deposition rather than body size.

Longitudinal sonographic assessment of abdominal fat distribution from 2 to 5 years of age

BACKGROUND

To better understand children's adipose tissue (AT) development and distribution, longitudinal data from direct assessment methods are valuable. Previously, we reported sonographic data on abdominal subcutaneous and preperitoneal fat areas ≤1 year of age.

METHODS

Sonographic measurements were annually pursued to assess the development of fat compartments in 2-5 year-old children. The effect of sex and correlations with comprehensive anthropometry (e.g., BMI percentiles, skinfold thickness (SFT) measurements, and waist circumference) are presented.

RESULTS

Subcutaneous fat areas increased modestly and were significantly greater in females at each time point investigated. Preperitoneal fat area increased significantly over time (all P values < 0.001) with greater area in females from 3 years onward (e.g., at 3 years estimated mean difference -4.8 mm²; 95% CI: -8.6, -0.9; P = 0.016). The strongest correlations for subcutaneous fat area were consistently observed for SFT measurements. Preperitoneal fat area showed rather weak to moderate correlations, with greater correlation coefficients for SFT measurements compared to waist circumference.

CONCLUSION

For the first time, longitudinal ultrasound data on abdominal body fat covering preschool age are presented. Evaluation revealed a differential development of fat compartments, depending on children's age and sex with SFT measurements as the best predictor for both fat depots.

Air displacement plethysmography (pea pod) in full-term and pre-term infants: a comprehensive review of accuracy, reproducibility, and practical challenges

Air displacement plethysmography (ADP) has been widely utilised to track body composition because it is considered to be practical, reliable, and valid. Pea Pod is the infant version of ADP that accommodates infants up to the age of 6 months and has been widely utilised to assess the body composition of full-term infants, and more recently pre-term infants. The primary goal of this comprehensive review is to 1) discuss the accuracy/reproducibility of Pea Pod in both full- and pre-term infants, 2) highlight and discuss practical challenges and potential sources of measurement errors in relation to Pea Pod operating principles, and 3) make suggestions for future research direction to overcome the identified limitations.

Impact of Early Infant Growth, Duration of Breastfeeding and Maternal Factors on Total Body Fat Mass and Visceral Fat at 3 and 6 Months of Age

BACKGROUND

Accelerated gain in fat mass in the first months of life is considered to be a risk factor for adult diseases, given the tracking of infancy fat mass into adulthood. Our objective was to assess the influence of early growth, type of feeding and maternal variables on fat mass in early life.

METHODS

In 300 healthy term infants, we longitudinally measured fat mass percentage (FM%) by air-displacement-plethysmography at 1, 3, and 6 months and abdominal visceral and subcutaneous fat measured by ultrasound at 3 and 6 months.

RESULTS

Both gain in FM% and weight-for-length in the first 3 months were positively associated with FM% at 6 months of age and visceral fat at 3 months of age. Gain in FM% and weight-for-length between 3 and 6 months were both positively associated with visceral fat at 6 months. Breastfeeding duration associated positively with subcutaneous fat but not with visceral fat at 3 and 6 months. Maternal characteristics did not associate with FM% or visceral fat at 3 or 6 months.

CONCLUSION

Higher gain in FM% or in weight-for-length in the first postnatal months leads not only to higher FM% but also more to accumulation of visceral fat. Exclusive breastfeeding appears to promote subcutaneous but not visceral fat in the first 6 months.

Longitudinal fat mass and visceral fat during the first 6 months after birth in healthy infants: support for a critical window for adiposity in early life

INTRODUCTION

Body composition in early life influences the development of obesity during childhood and beyond. It is, therefore, important to adequately determine longitudinal body composition during the first months of life.

PATIENTS AND METHODS

In 203 healthy term infants, we investigated longitudinal body composition, including fat mass percentage (FM%) and fat-free mass (FFM), by air-displacement plethysmography, at 1, 3 and 6 months of age and abdominal visceral fat and abdominal subcutaneous fat, by ultrasound, at 3 and 6 months.

RESULTS

We found a significant increase in FM% between 1 and 3 months but not between 3 and 6 months (p < 0.001, p = 0.098, respectively). Girls had higher FM% than boys at 1 and 6 months (p = 0.05, p < 0.001 respectively) and less FFM than boys at 1, 3 and 6 months (p = 0.02, p = 0.02, p < 0.001, respectively). There was a large variation in FM% at all ages even between infants with similar weight standard deviation scores. Visceral fat and abdominal subcutaneous fat did not change between 3 and 6 months. FM% was highly correlated with abdominal subcutaneous fat but not with visceral fat.

CONCLUSION

Changes in FM% occur mainly in the first 3 months of life, and FM%, visceral and abdominal subcutaneous fat do not change between 3 and 6 months, supporting the concept of a critical window for adiposity development in the first three months of life. In addition, our study provides longitudinal reference data of FM%, FFM, visceral fat and abdominal subcutaneous fat during the first 6 months of life.

Genomic ancestry and education level independently influence abdominal fat distributions in a Brazilian admixed population

We aimed to identify the independent associations of genomic ancestry and education level with abdominal fat distributions in the 1982 Pelotas birth cohort study, Brazil. In 2,890 participants (1,409 men and 1,481 women), genomic ancestry was assessed using genotype data on 370,539 genome-wide variants to quantify ancestral proportions in each individual. Years of completed education was used to indicate socio-economic position. Visceral fat depth and subcutaneous abdominal fat thickness were measured by ultrasound at age 29–31y; these measures were adjusted for BMI to indicate abdominal fat distributions. Linear regression models were performed, separately by sex. Admixture was observed between European (median proportion 85.3), African (6.6), and Native American (6.3) ancestries, with a strong inverse correlation between the African and European ancestry scores (ρ = -0.93; p<0.001). Independent of education level, African ancestry was inversely associated with both visceral and subcutaneous abdominal fat distributions in men (both P = 0.001), and inversely associated with subcutaneous abdominal fat distribution in women (p = 0.009). Independent of genomic ancestry, higher education level was associated with lower visceral fat, but higher subcutaneous fat, in both men and women (all p<0.001). Our findings, from an admixed population, indicate that both genomic ancestry and education level were independently associated with abdominal fat distribution in adults. African ancestry appeared to lower abdominal fat distributions, particularly in men.

Appetite-regulating hormones in early life and relationships with type of feeding and body composition in healthy term infants

Introduction

Body composition in early life influences development of obesity during childhood and beyond. Appetite-regulating hormones (ARH) play a role in regulation of food intake and might thus influence body composition in later life. Studies on associations between ARH and body composition in early life are limited.

Methods

In 197 healthy term infants, we measured serum fasting levels of ghrelin, leptin, insulin, glucose-dependent insulinotropic peptide (GIP), pancreatic polypeptide (PP) and peptide YY (PYY) at 3 months and in 41 infants also at 6 months and their associations with type of feeding and longitudinal fat mass percentage (FM%) measured by air displacement plethysmography at 1, 3 and 6 months and abdominal visceral and subcutaneous fat, measured by ultrasound, at 3 and 6 months.

Results

Infants with formula feeding for 3 months had significantly higher serum levels of ghrelin, leptin, insulin, GIP and PP (p = 0.026, p = 0.018, p = 0.002, p < 0.001, resp.) and lower serum levels of PYY (p = 0.002) at 3 months than breastfed infants. Leptin and ghrelin correlated positively with FM% at 3 months and insulin with change in FM% between 1 and 3 months (r = 0.40, p < 0.001, r = 0.23, p < 0.05, r = 0.22, p < 0.01, resp.). Leptin at 3 months correlated with subcutaneous fat at 3 months (r = 0.23, p < 0.001), but not with visceral fat. Other ARH did not correlate with body composition.

Conclusion

Formula-fed infants had a different profile of ARH than breastfed infants, suggesting that lower levels of ghrelin, leptin and insulin in breastfed infants contribute to the protective role of breastfeeding against obesity development. Leptin, ghrelin and insulin were associated with fat mass percentage or its changes.

Body composition during fetal development and infancy through the age of 5 years

Fetal body composition is an important determinant of body composition at birth, and it is likely to be an important determinant at later stages in life. The purpose of this work is to provide a comprehensive overview by presenting data from previously published studies that report on body composition during fetal development in newborns and the infant/child through 5 years of age. Understanding the changes in body composition that occur both in utero and during infancy and childhood, and how they may be related, may help inform evidence-based practice during pregnancy and childhood. We describe body composition measurement techniques from the in utero period to 5 years of age, and identify gaps in knowledge to direct future research efforts. Available literature on chemical and cadaver analyses of fetal studies during gestation is presented to show the timing and accretion rates of adipose and lean tissues. Quantitative and qualitative aspects of fetal lean and fat mass accretion could be especially useful in the clinical setting for diagnostic purposes. The practicality of different pediatric body composition measurement methods in the clinical setting is discussed by presenting the assumptions and limitations associated with each method that may assist the clinician in characterizing the health and nutritional status of the fetus, infant and child. It is our hope that this review will help guide future research efforts directed at increasing the understanding of how body composition in early development may be associated with chronic diseases in later life.

Sonographic assessment of abdominal fat distribution during the first year of infancy

BACKGROUND

Longitudinal data regarding the fat distribution in the early postnatal period is sparse.

METHODS

We performed ultrasonography (US) as a noninvasive approach to investigate the development of abdominal subcutaneous (SC) and preperitoneal (PP) fat depots in infants ≤1 y and compared longitudinal US data with skinfold thickness (SFT) measurements and anthropometry in 162 healthy children at 6 wk, 4 mo, and 1 y postpartum.

RESULTS

US was found to be a reproducible method for the quantification of abdominal SC and PP adipose tissue (AT) in this age group. Thickness of SC fat layers significantly increased from 6 wk to 4 mo and decreased at 1 y postpartum, whereas PP fat layers continuously increased. Girls had a significantly higher SC fat mass compared to boys, while there was no sex-specific difference in PP fat thickness. SC fat layer was strongly correlated with SFT measurements, while PP fat tissue was only weakly correlated with anthropometric measures.

CONCLUSION

US is a feasible and reproducible method for the quantification of abdominal fat mass in infants ≤1 y of age. PP and SC fat depots develop differentially during the first year of life.

Abdominal subcutaneous and visceral fat thickness in newborns: correlation with anthropometric and metabolic profile

OBJECTIVE

To correlate abdominal subcutaneous and visceral fat thickness with anthropometric data and metabolic profile in newborns.

STUDY DESIGN

A cross-sectional study with 99 newborns was performed at Instituto de Medicina Integral Professor Fernando Figueira, Brazil. Abdominal subcutaneous and visceral thickness were measured by ultrasound. Glucose, insulin, homeostatic model assessment-insulin resistance (HOMA-IR), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol and triglycerides were determined. Pearson correlation coefficients were calculated.

RESULT

Abdominal subcutaneous fat thickness was positively correlated with birth weight (r=0.31; P<0.001), height (r=0.27; P<0.001) and abdominal circumference (r=0.26; P<0.001), but not with metabolic profile. Abdominal visceral fat thickness was correlated with abdominal circumference (r=0.23; P=0.01), insulin (r=0.21; P=0.04) and HOMA (r=0.24; P=0.02). The results remained the same among males and females.

CONCLUSION

Abdominal fat distribution in newborns has a different correlation with anthropometric and metabolic profile. Abdominal subcutaneous fat thickness is positively correlated with anthropometric data whereas abdominal visceral fat thickness is correlated with insulin and HOMA-IR.

Methodologies to assess paediatric adiposity

INTRODUCTION

Childhood obesity is associated with increased risk of adult obesity, cardiovascular disease, diabetes and cancer. Appropriate techniques for assessment of childhood adiposity are required to identify children at risk. The aim of this review was to examine core clinical measurements and more technical tools to assess paediatric adiposity.

METHODS

The online databases PubMed, CINALH and EMBASE were searched and the abstracts identified were reviewed to determine appropriate studies. Their reference lists were also searched to identify further eligible studies. Publications were included if they described childhood measurement techniques or involved validation.

RESULTS AND DISCUSSION

There are many body composition assessment tools available, none of which are direct. Each technique has limitations and a combination of methods may be used. The main clinical techniques are weight, height, body mass index (BMI) and circumferences which provide sufficient information to enable classification of overweight or obesity when growth centile charts and ratios are employed. Further investigation depends on resources available and examiner skill. Skinfold thicknesses are cost-effective but require technical training and only measure subcutaneous fat. Dual energy X-ray absorptiometry (DEXA), air displacement plethysmography (ADP), magnetic resonance imaging (MRI) and computed tomography (CT) are more costly and intensive, requiring the child to remain still for longer periods. DEXA and ADP are capable of accurately measuring adiposity but are unable to distinguish between fat depots. MRI and CT can distinguish intra-abdominal from subcutaneous adiposity and are considered gold standards, but CT is unsuitable for adiposity measurement in children due to high levels of radiation exposure. Ultrasound is a promising technique capable of measuring intra-abdominal adiposity in children but requires further validation.

CONCLUSION

The core clinical measurements of weight, height, BMI and circumferences are sufficient to enable diagnosis of paediatric overweight and obesity while more technical tools provide further insight.