Determinants of Infant Adiposity across the First 6 Months of Life: Evidence from the Baby-bod study

Body composition assessment in 6-month-old infants: A comparison of two- and three-compartment models using data from the Baby-bod study

BACKGROUND/OBJECTIVES

An appreciation of infant body composition is helpful to understand the 'quality' of growth in early life. Air displacement plethysmography (ADP) using PEA POD and the deuterium dilution (DD) technique are commonly used body composition approaches in infants. We evaluated the comparability of body composition assessed using both techniques with two-compartment (2C) and three-compartment (3C) models in 6-month-old infants.

SUBJECTS/METHODS

Infant fat mass (FM) and percent fat mass (%FM) obtained from a 2C model using PEA POD (2C-PP) and a 2C model using the deuterium dilution technique (2C-DD) were compared to those derived from a 3C model, and to each other, using Bland-Altman analysis and Deming regression.

RESULTS

Measurements were available from 68 infants (93% Caucasian, 53% male). The mean biases were not significant between any of the method comparisons. However, significant constant and proportional biases were identified in 2C-DD vs 3C and 2C-PP vs 2C-DD, but not in the 2C-PP vs 3C comparison. Furthermore, we observed significant associations between the mean differences and infants' percent total body water (%TBW).

CONCLUSIONS

While no significant between-method mean differences were found in body composition estimates, some comparisons revealed significant constant and proportional biases and notable associations between the mean differences and %TBW were observed. Our results emphasise the importance of method choice, ensuring methodological uniformity in long-term studies, and carefully considering and regulating multiple pre-analytical variables, such as the hydration status of the participants.

Gestational diabetes mellitus and size at birth modify early adiposity accretion. Evidence from the OBESO cohort

AIM

To evaluate the association between maternal obesity, gestational diabetes (GDM), and birth size with infant fat-mass (FM) accretion from 1 to 6 months (M).

METHODS

Healthy pregnant women and their term babies from the OBESO cohort were studied (1 M-3 M, n = 122; 1 M-6 M, n = 90). Registered maternal data was: pregestational body-mass-index (preBMI), GDM (2hOGTT), medications, gestational weight gain. Macrosomia (>4000 g), large/small for gestational age (LGA/SGA)(weight/age > 90° and < 90°, respectively-WHO) were recorded at birth. Infant FM (air-displacement plethysmography) was measured (1 M, 3 M, 6 M) and FM accretion computed (ΔkgFM from 1 M-3 M and 1 M-6 M). Exclusive breastfeeding (EBF) was assessed. Adjusted-multiple linear regression models were performed.

RESULTS

PreBMI was 27.4 ± 5.2 kg/m2. GDM was present in9%(n = 11) of women; 12.3%(n = 15) of them received metformin/insulin. One newborn was LGA; 20.7%(n = 25) were SGA. From 1 M-3 M, SGA was a predictor of higher FM accretion (B:0.28, 95%CI:0.14-0.43); GDM was not associated. From 1 M-6 M, higher FM accretion was observed in SGA newborns (B:0.43, 95%CI:0.19-0.67) and GDM infants (B:0.48, 95%CI:0.06-0.89). In all models (R2 ≥ 0.48, p < 0.001), infant weight and being female were positively associated, while maternal obesity, metformin/insulin, and EBF were not.

CONCLUSIONS

GDM appears to program early higher adiposity accretion, independently of excessive fetal growth. SGA was associated with higher FM accretion in early infancy.

The association of intrauterine and postnatal growth patterns and nutritional status with toddler body composition

BACKGROUND

Growth patterns may be indicative of underlying changes in body composition. However, few studies have assessed the association of growth and body composition in poorly resourced regions experiencing the double-burden of malnutrition exists. Thus, the aims of this study were to investigate the association of intrauterine and postnatal growth patterns with infant body composition at 2 years in a middle-income country.

METHODS

Participants were from the International Atomic Energy Agency Multicentre Body Composition Reference study. Fat mass (FM), fat free mass (FFM), Fat mass index (FMI), fat free mass index (FFMI), and percentage fat mass (%FM) were measured in 113 infants (56 boys and 57 girls), from Soweto, South Africa, using deuterium dilution from 3 to 24 months. Birthweight categories were classified using the INTERGROWTH-21 standards as small (SGA), appropriate (AGA), and large-for gestational age (LGA). Stunting (> -2 SDS) was defined using the WHO child growth standards. Birthweight z-score, conditional relative weight and conditional length at 12 and 24 mo were regressed on body composition at 24 mo.

RESULTS

There were no sex differences in FM, FFM, FMI and FFMI between 3 and 24 mo. SGA and AGA both had significantly higher %FM than LGA at 12 mo. LGA had higher FM at 24 mo. Children with stunting had lower FM (Mean = 1.94, 95% CI; 1.63-2.31) and FFM (Mean = 5.91, 95% CI; 5.58-6.26) at 12 mo than non-stunting, while the reverse was true for FFMI (Mean = 13.3, 95% CI; 12.5-14.2) at 6 mo. Birthweight and conditionals explained over 70% of the variance in FM. CRW at both 12 and 24 mo was positively associated with FM and FMI. CRW at 12 mo was also positively associated with FMI, while CH at 24 mo was negatively associated with both FFMI and FMI in boys.

CONCLUSION

Both LGA and SGA were associated with higher body fat suggesting that both are disadvantaged nutritional states, likely to increase the risk of obesity. Growth patterns through infancy and toddler period (1-2 years) are indicative of body fat, while growth patterns beyond infancy are less indicative of fat-free mass.

Beyond the Gut, Emerging Microbiome Areas of Research: A Focus on Early-Life Microbial Colonization

Undoubtedly, the human body harbors trillions of microbes of different kinds performing various physiological activities, such as priming the immune system, influencing host metabolism, and improving health by providing important metabolites such as short-chain fatty acids. Although the gut is considered the "microbial organ" of our body as it hosts the most microbes, there are microbes present in various other important anatomical locations differing in numbers and type. Research has shown the presence of microbes in utero, sparking a debate on the "sterile womb" concept, and there is much scope for more work in this area. It is important to understand the early-life microbiome colonization, which has a role in the developmental origins of health and disease in later life. Moreover, seminal studies have indicated the presence of microbes beyond the gut, for example, in the adipose tissue and the liver. However, it is still unclear what is the exact source of these microbes and their exact roles in health and disease. In this review, we appraise and discuss emerging microbiome areas of research and their roles in metabolic health. Further, we review the importance of the genital microbiome in early-life microbial interactions.

Joint Effects of Prenatal Folic Acid Supplement with Prenatal Multivitamin and Iron Supplement on Obesity in Preschoolers Born SGA: Sex Specific Difference

Prenatal maternal nutrient supplementation has been reported to be associated with offspring obesity, but the reports are inconsistent and have mainly ignored the differences between the total children population and children born small for gestational age (SGA). This study aimed to examine the joint effects of folic acid, iron, and multivitamin supplementation during pregnancy on the risk of obesity in preschoolers born SGA. A total of 8918 children aged 3-6.5 years born SGA were recruited from Longhua District in Shenzhen of China in 2021. Their mothers completed a structured questionnaire about the child's and parents' socio-demographic characteristics, maternal prepregnant obesity, and mothers' prenatal supplementation of folic acid, iron, and multivitamin. In addition, the children's current weight and height were measured by trained nurses. Logistic regression models were used to analyze the associations between prenatal supplementations and the current presence of childhood obesity. After controlling for potential confounders, the results of the logistic regression analysis showed that prenatal supplement of folic acid (OR = 0.72, 95% CI = 0.55~0.93) was associated with a lower likelihood of being an obese preschooler born SGA. In contrast, the ingestion of multivitamin or iron supplements during pregnancy did not seem to be related to the likelihood of childhood obesity in preschoolers born SGA. Moreover, cross-over analysis of prenatal folic acid and multivitamin obtained significant negative associations of prenatal folic acid supplement only (OR = 0.73, 95% CI = 0.55~0.97) and combination supplement of folic acid and multivitamin (OR = 0.67, 95% CI = 0.50~0.90) with obesity of preschoolers born SGA; while the cross-over analysis of prenatal folic acid and iron observed significant negative associations between obesity of preschoolers born SGA and a combination supplement of folic acid and iron (OR = 0.70, 95% CI = 0.52~0.96). Furthermore, the aforementioned significant associations were only found in girls and not in boys when the analyses were stratified by sex. Our findings suggest that the prenatal folic acid supplementation may decrease the risk of obesity in preschool girls born SGA, and that this effect may be modified by prenatal multivitamin or iron supplementation.

Growth and body composition trajectories in infants meeting the WHO growth standards study requirements

BACKGROUND

While the World Health Organization (WHO) developed postnatal growth standards for infants, corresponding body composition data remains scarce. This study explores growth and body composition trajectories in infants meeting the WHO Multicentre Growth Reference Study (MGRS) eligibility criteria.

STUDY DESIGN

Infants enrolled in this longitudinal cohort underwent anthropometric and body composition measurement by air displacement plethysmography (ADP) at 6 weeks, 12 weeks, and 5 months postnatally. Age and sex-specific growth and body composition percentiles were generated using GAMLSS, with extrapolated data at 5 months for those exceeding ADP weight limits. We evaluated which anthropometric measure (body mass index (BMI), weight for length or mid upper arm circumference) was most closely related to adiposity.

RESULTS

Of the 225 infants with body composition measures, 187 met the WHO MGRS criteria. Their length and weight curves were comparable with WHO growth curves. Trajectory curves for fat and fat-free mass were developed. Of the anthropometric measures, BMI z score was most closely related to fat mass index z score at all timepoints.

CONCLUSION

This study presents body composition trajectories for infants meeting the WHO growth standard criteria. BMI z score is the best anthropometric metric to estimate adiposity in infants.

IMPACT

While postnatal growth standards derived from the WHO Multicentre Growth Reference Study (MGRS) exist for the routine clinical assessment of infant growth, this study fills the previous gap in the availability of corresponding body composition data for term-born, healthy, breastfed infants meeting the MGRS criteria. Extrapolation was used to obtain body composition values for infants exceeding the weight limit of the ADP device, to avoid construction of biased body composition curves. Sex-specific growth curves for fat mass, fat-free mass, fat mass index, and fat-free mass index are presented for a population meeting the World Health Organization growth standard criteria.

Context Matters: Preliminary Evidence That the Association between Positive Affect and Adiposity in Infancy Varies in Social vs. Non-Social Situations

Previous studies have suggested that infants high in negative affect have higher levels of adiposity, arising in part via changes in nutrition (e.g., “feeding to soothe”). Few studies have examined whether positive affect shows similar or inverse associations with adiposity. The current study examined cross-sectional and longitudinal relationships between adiposity and observations of positive affect in both a social and a non-social context, using data from infants at four (n = 125) and 12 (n = 80) months of age. Our analyses did not find any cross-sectional associations between positive affect and adiposity (all p > 0.05). However, in the longitudinal analyses, positive affect in a non-social context, when observed at four months of age, was positively associated with weight-for-length at 12 months of age (zWFL; ß = 1.49, SE = 0.67, p = 0.03), while positive affect observed at four months of age in a social context was inversely associated with body fat percentage at 12 months of age (ß = −11.41, SE = 5.44, p = 0.04). These findings provide preliminary evidence that the p positive affect is related to adiposity in infancy and suggest that the direction of association (i.e., direct or inverse) may be specific to the context in which positive affect is measured. Future research should examine the role of nutritional status in any relationships between adiposity and emotion at this early stage.

WHO Child Growth Standards in context: The Baby-bod Project - Observational study in Tasmania

OBJECTIVE

This research evaluated (1) differences in body size and composition of Tasmanian infants at birth and 3 and 6 months postpartum compared with WHO child growth standards and (2) body composition changes in Tasmanian infants at the extremes of the weight-for-length (WFL) spectrum.

DESIGN

Observational study.

SETTING

A hospital in Northern Tasmania, Australia.

PATIENTS

315 healthy infants (~90% Caucasian) born between 2017 and 2019 in Tasmania.

INTERVENTIONS

Body composition and anthropometric measures at 0, 3 and 6 months.

MAIN OUTCOME MEASURES

Growth characteristics at birth and growth trajectories from 0 to 6 months were compared against WHO child growth standards for 0-2 years.

RESULTS

Overall, growth of Tasmanian infants in the first 6 months of life was similar to the global prescriptive standards. Trajectories of fat mass (FM) and fat-free mass (FFM) accrual in infants from the extremes of the size spectrum appear to converge at the 6-month time point. Infants in the lower extremity demonstrated the most precipitous accrual in percentage FM (and the steepest decline in percentage FFM), compared with all other infants.

CONCLUSION

No significant deviations of growth were observed in Tasmanian infants from 0 to 6 months in comparison to the WHO prescriptive growth standards. Infants below the third percentile WFL showed the most precipitous increase in FM accretion. Periodic comparisons local infants with global standards will enable identification of significant deviations from optimal growth patterns.