Is restricted fetal growth associated with later adiposity? Observational analysis of a randomized trial

[Association between different growth patterns and metabolic syndrome in children and adolescents aged 7 to 17 years]

OBJECTIVE

To analyze the association between different growth patterns and metabolic syndrome in children and adolescents aged 7 to 17 years, and to provide suggestions for the prevention and control of metabolic syndrome in Chinese children and adolescents.

METHODS

Data were collected from the research project "Development and Application of Technology and Related Standards for Prevention and Control of Major Diseases among Students" of public health industry in 2012. This project is a cross-sectional study design. A total of 65 347 students from 93 primary and secondary schools in 7 provinces including Guangdong were selected by stratified cluster random sampling method. Given the budget, 25% of the students were randomly selected to collect blood samples. In this study, 10 176 primary and middle school students aged 7 to 17 years with complete physical measurements and blood biochemical indicators were selected as research objects. Chi-square test was used to compare the distribution differences of growth patterns under different demographic characteristics. Birth weight, waist circumference and blood biochemical indexes were expressed in the form of mean ± standard deviation, and the differences among different groups were compared by variance analysis. Binary Logistic regression model was used to analyze the relationship between different growth patterns and metabolic syndrome in children and adolescents aged 7 to 17 years.

RESULTS

The prevalence of metabolic syndrome in children and adolescents was 6.56%, 7.18% in boys and 5.97% in girls. The risk of metabolic syndrome was higher in the catch-down growth group than in the normal growth group (OR=1.417, 95%CI: 1.19-1.69), and lower in the catch-up growth group(OR=0.66, 95%CI: 0.53-0.82). After adjusting for gender, age and so on, the risk of developing metabolic syndrome in the catch-down growth group was higher than that in the normal growth group (OR=1.25, 95%CI: 1.02-1.52), but there was no significant difference between the catch-up growth group and the normal growth group (OR=0.79, 95%CI: 0.62-1.01). Stratified analysis showed that the association between different growth patterns and metabolic syndrome was statistically significant in the 7-12 years group, urban population, and Han Chinese student population.

CONCLUSION

There is a correlation between different growth patterns and metabolic syndrome in children and adolescents. The risk of developing metabolic syndrome in children and adolescents with catch-down growth is higher than that in the normal growth group, which suggests that attention should be paid to the growth and development of children and adolescents, timely correction of delayed growth and prevention of adverse health outcomes.

Body composition and physical fitness in adults born small for gestational age at term: a prospective cohort study

There is lack of research on body composition and physical fitness in individuals born small for gestational age (SGA) at term entering mid-adulthood. We aimed to investigate these outcomes in adults born SGA at term. This population-based cohort study included 46 adults born SGA with birth weight < 10th percentile at term (gestational age ≥ 37 weeks) (22 women, 24 men) and 61 adults born at term with birth weight ≥ 10th percentile (35 women, 26 men) at 32 years. Body composition was examined anthropometrically and by 8-polar bioelectrical impedance analysis (Seca® mBCA 515). Fitness was measured by maximal isometric grip strength by a Jamar hand dynamometer, 40-s modified push-up test and 4-min submaximal step test. Participants born SGA were shorter than controls, but other anthropometric measures did not differ between the groups. Men born SGA had 4.8 kg lower grip strength in both dominant (95% CI 0.6 to 9.0) and non-dominant (95% CI 0.4 to 9.2) hand compared with controls. Grip strength differences were partly mediated by height. In conclusion, body composition and physical fitness were similar in adults born SGA and non-SGA at term. Our finding of reduced grip strength in men born SGA may warrant further investigation.

Anthropometric measurements of term singletons at 6 years of age born from fresh and frozen embryo transfer: A multicenter prospective study in Japan

Purpose

The purpose of this study is to compare anthropometric measurements between term singletons conceived via fresh embryo transfer (FreET) and frozen embryo transfer (FET) and those born via natural conception (NC) or fertility treatments milder than assisted reproductive technology (non-ART) at 6 years of age.

Methods

A total of 8149 children were enrolled, and questionnaires about anthropometric measures (weight, height, BMI) were addressed to parents, when the children were 1.5, 3, and 6 years of age. A total of 3299 term singletons were enrolled at birth: 533, 476, 916, and 1374 in the NC, non-ART, FreET, and FET groups, respectively.

Results

A total of 1635 term singletons (290, 176, 467, and 702 in the NC, non-ART, FreET, and FET groups respectively) were enrolled until 6 years of age (follow-up rate, approximately 50%). When non-ART group was used as control, the FreET children were 1.0 cm taller than the non-ART children at 6 years of age, after adjusting for confounding factors. However, no differences were observed in the anthropometric data among the non-ART, ART, and NC children at 6 years of age.

Conclusion

At 6 years of age, term singletons were taller in the FreET group than in the non-ART group, after adjusting for confounders.

An exploration into the influence of birthweight and breastfeeding status on the weight status of 3-year-olds in an Irish cohort

BACKGROUND

Childhood obesity is a growing concern in Ireland. Childhood obesity can increase the risk of developing many non-communicable diseases and have lasting psychological and social consequences.

AIM

The aim of this study is to explore if weight at birth and breastfeeding status influence the weight status of 3-year-olds in an Irish cohort.

METHOD

This retrospective cohort study utilised data (National Child Health Screening Programme) on 3-year-olds born between 1 January 2011 and 3 March 2014 in the North West of Ireland.

RESULTS

Overall, 4144 children were included in the study. The main findings of this study were that 5.4% (n = 222) and 7.1% (n = 296) of the cohort were overweight or obese respectively with a higher percent of males than females in each category. Just under 55% (n = 2266) of the cohort were never breastfed, with only 7.4% breastfed for greater than 6 months. Those born with a high birthweight were more likely to be overweight or obese at 3 years (p ≤ 0.001).

CONCLUSION

These findings provide regionally specific data and highlight the need for focussed public health efforts to reduce the prevalence of overweight and obesity in children aged 3 years in this area. Interventions from pregnancy through childhood are warranted, with an initial emphasis on breast feeding initiation and maintenance.

Small for date preterm infants and risk of higher blood pressure in later life: A systematic review and meta-analysis

BACKGROUND

Historical reports suggest that infants born small for gestational age (SGA) are at increased risk for high blood pressure (BP) at older ages after adjustment for later age body size. Such adjustment may be inappropriate since adiposity is a known cause of cardiovascular and metabolic disease.

OBJECTIVES

To assess the association between SGA births and later BP among preterm births, considering potential background confounders and over-adjustment for later body size.

METHODS

A database search of studies up to October 2022 included MEDLINE, EMBASE and CINAHL. Studies were included if they reported BP (systolic [SBP] or diastolic [DBP]) (outcomes) for participants born preterm with SGA (exposure) or non-SGA births. All screening, extraction steps, and risk of bias (using the Risk of Bias In Non-randomised Studies of Interventions [ROBINS-I] tool) were conducted in duplicate by two reviewers. Data were pooled in meta-analysis using random-effects models. We explored potential sources of heterogeneity.

RESULTS

We found no meaningful difference in later BP between preterm infants with and without SGA status at birth. Meta-analysis of 25 studies showed that preterm SGA, compared to preterm non-SGA, was not associated with higher BP at age 2 and older with mean differences for SBP 0.01 mmHg (95% CI -0.10, 0.12, I²  = 59.8%, n = 20,462) and DBP 0.01 mm Hg (95% CI -0.10, 0.12), 22 studies, (I²  = 53.0%, n = 20,182). Adjustment for current weight did not alter the results, which could be due to the lack of differences in later weight status in most of the included studies. The included studies were rated to be at risk of bias due to potential residual confounding, with a low risk of bias in other domains.

CONCLUSIONS

Evidence indicates that preterm infants born SGA are not at increased risk of developing higher BP as children or as adults as compared to non-SGA preterm infants.

Mild small-for-gestational-age as a non-negligible risk factor for short stature

Risk of subsequent short stature remains unclear among mild small-for-gestational-age (SGA) infants with birthweight <10th percentile and ≥-2 standard deviations. In this multicenter cohort study in Japan, height was found to be <-2 standard deviations at 3 years old even in 18 % of mild-SGA infants.

Is small for gestational age status independently correlated with body composition during childhood?

This study aims to examine if small for gestation age (SGA) status is correlated with alterations in body composition at prepuberty, independently of other factors, comparing SGA-born children with appropriate for gestational age (AGA)-born children. We examined anthropometrics, waist circumference, body mass index (BMI), six skinfold thickness, and body composition using the method of bioelectrical impedance in 636 children aged 7 to 10 years. We also considered age, gender, birth mode, mother's age, prepregnancy weight, weight gain during pregnancy, social status, parental BMI, type of feeding, and daily exercise. We examined 636 children at a mean age of 9 years: 106 SGA-born and 530 AGA-born children. SGA as compared to AGA-born children had a lower BMI z-score (0.26 ± 0.89 kg/cm² vs 0.46 ± 0.84 kg/cm², p < 0.050) and a lower lean mass, although that was not statistically significant (24.0 ± 6.6 kg vs 25.6 ± 6.4 kg, p < 0.100). SGA-born children presented no difference in waist circumference or fat mass in comparison to children born AGA. Logistic regression analysis revealed a strong independent negative association between SGA status and BMI (beta =  - 2.33, OR = 0.70 p = 0.019) and SGA status and lean mass (beta =  - 2.43, OR = 0.95 p = 0.010).  Conclusion: Our findings suggest that SGA-born children had a lower BMI as compared to AGA-born subjects, whereas SGA status was negatively associated with BMI and lean mass. What is Known: • Deviant birth weight for gestation has been associated with an increased risk of childhood adiposity. • Evidence remains scarce on whether small for gestational age status affects body composition and obesity later in childhood. What is New: • Among school-aged children, small for gestational age subjects had a lower body mass index as compared to appropriate for gestational age counterparts, whereas small for gestational age status was negatively associated with body mass index and lean mass. • A meticulous observation is needed during childhood in children born with deviant birth weight.

Serum spexin levels are not associated with size at birth but are associated with metabolic syndrome components in prepubertal children born at term

BACKGROUND

Babies born small for gestational age (SGA) are at risk of obesity and metabolic syndrome (MetS). Spexin (SPX) is a novel peptide implicated in food intake and obesity. Spexin levels are lower in obese subjects. This study investigated the potential association of SPX and some obesity related peptides such as leptin and active ghrelin with size at birth and MetS components in prepubertal children born term and either SGA or appropriate for GA (AGA). Secondary aim was to identify whether any of the investigated peptides were associated with MetS components.

METHODS

We conducted a cross-sectional study of 37 consecutive (median age: 5.6 y) SGA- and 50 (median age: 5.9 y) AGA-born children. Clinical evaluations were performed using standard methods. Several biochemical variables (SPX, total leptin, and active ghrelin levels) were analyzed. Age-dependent cut-off values were used to define MetS components, including excess adiposity, hypertension, insulin resistance, and dyslipidemia. The associations between the assessed clinical and laboratory variables and MetS components were investigated.

RESULTS

Children born SGA had higher frequencies of MetS components than AGA-born peers (p < 0.01). None of the investigated peptides were different between children born SGA and AGA after correcting for body mass index (p > 0.05 for all). Serum SPX levels were lower in children with at least one metS component than those without MetS components (p = 0.018).

CONCLUSIONS

Size at birth had no association with serum SPX. Serum SPX levels are decreased in prepubertal children with MetS components.

The Effect of Growth Rate during Infancy on the Risk of Developing Obesity in Childhood: A Systematic Literature Review

The prevalence of childhood obesity has been trending upwards over the last few decades. Recent evidence suggests that infant growth rate has the potential to increase the risk of obesity development during childhood. This systematic literature review aimed to summarise the existing evidence on the relationship between infant growth rate and subsequent childhood obesity. Studies were sought for that assessed the effect of infant growth rate on outcomes of overweight, obesity, BMI, waist circumference or body composition measures among a population group of children aged 2 to 12 years old. Data sources included PubMed, CINAHL, Web of Science and MedLine. Twenty-four studies were identified as eligible and included in this review, out of 2302 publications. The ADA Quality Checklist was used to assess the quality of individual studies. Ten studies received a positive result and 14 studies a neutral result. A narrative synthesis was completed to present study characteristics and results. Several independent positive associations were determined between rapid growth at different stages during infancy and overweight, obesity, BMI, waist circumference and body composition in childhood. Further investigation is required to determine if a specific period of infancy carries greater associations of risk with childhood outcomes. Determining an ideal rate of infants' growth as a means to minimise the future risk of childhood obesity should be the focus of future research that will also inform early life obesity prevention strategies. Registration no.: CRD42021244029.

A systematic review indicates an association between birth weight and body fat in childhood

AIM

To summarise the existing evidence regarding the body fat of small or large for gestation subjects, evaluated from birth up to 18 years of age.

METHODS

The PRISMA guidelines were adopted for the current systematic review, including studies having evaluated body fat with bioelectrical impedance analysis, air displacement plethysmography, dual-energy X-ray absorptiometry or magnetic resonance imaging.

RESULTS

A total of 31 studies was included. The balance of evidence suggests that small for gestation infants have decreased fat mass at birth; postnatally they experience increased adiposity. In the long term, however, the evidence is inconclusive, since some studies suggest that foetal-restricted children with increased catch-up growth are at increased risk of fat accumulation, whereas other studies suggest a neutral or even negative association. Large for gestation infants have increased fat mass at birth, but in the long term, they have a lower body fat ratio, especially when they develop a catch-down growth.

CONCLUSION

Some studies suggested that foetal-restricted children with increased catch-up growth are at increased risk of later adiposity, while other studies suggested a neutral or negative association. Given that the evidence is inconclusive, further studies are warranted. Large for gestation subjects have lower body fat when they develop catch-down growth.

Leptin and adiponectin concentrations in infants with low birth weight: relationship with maternal health and postnatal growth

Health in pregnancy and infancy can affect the risk of chronic non-communicable diseases. We aimed to describe leptin and adiponectin concentrations in low birth weight (LBW) infants and identify possible associations with maternal nutritional status, adequacy for gestational age, nutritional recovery, and current dietary intake. A cross-sectional study with LBW infants (9-12 months) including maternal background and pre-pregnancy nutritional condition was performed. From the Infants: anthropometry at birth and current was expressed as z-score (weight: WAZ, length, head circumference), nutritional recovery, dietary intake, leptin, and adiponectin blood concentrations. The mean age of the 54 infants was 10.0 ± 1.5 months, 32 (59.3%) were female, 36 (66.7%) preterm, 23 (42.6%) small for gestational age (SGA), and 25 pregnancies (46.3%) were twin. Almost all (98%) of the infants intake energy and protein above the recommendation, and 47 (87.6%) consumed ultra-processed foods. At the time of the assessment, 8 (14.8%) were overweight and 4 (7.4%) had short stature. SGA infants showed faster weight recovery (WAZ 1.54; 95% CI 1.17, 1.91; p = 0.001), higher leptin's concentration (3.0 ng/ml (1.7, 3.0) versus 1.6 ng/ml (0.9, 2.6); p = 0.032)), and leptin/adiponectin ratio (0.13 ± 0.08 versus 0.07 ± 0.07; p = 0.018). The pre-gestational BMI was a modifier of the effect of WAZ on leptin levels (p = 0.027) in LBW infants. Higher pre-gestational BMI increased the effect of WAZ variation (birth and current) on leptin levels. Concluding, LBW infants showed early changes in leptin and adiponectin concentrations, influenced by maternal (pre-gestational BMI), intrauterine (gestational age adequacy - SGA), and postnatal weight gain. This combination of factors may increase the risk of NCD for this group of children.

Concurrence of stunting and overweight/obesity among children: Evidence from Ethiopia

Background

Nutrition transition in many low- and middle-income countries (LMICs) has led to shift in childhood nutritional outcomes from a predominance of undernutrition to a double burden of under- and overnutrition. Yet, policies that address undernutrition often times do not include overnutrition nor do policies on overweight, obesity reflect the challenges of undernutrition. It is therefore crucial to assess the prevalence and determinants of concurrence stunting and overweight/obesity to better inform nutrition programs in Ethiopia and beyond.

Methods

We analyzed anthropometric, sociodemographic and dietary data of children under five years of age from 2016 Ethiopian Demographic and Health Survey (EDHS). A total of 8,714 children were included in the current study. Concurrence of stunting and overweight/obesity (CSO) prevalence was estimated by basic, underlying and immediate factors. To identify factors associated with CSO, we conducted hierarchical logistic regression analyses.

Results

The overall prevalence of CSO was 1.99% (95% CI, 1.57–2.53). The odds of CSO was significantly higher in children in agrarian region compared to their counter parts in the pastoralist region (AOR = 1.51). Other significant factors included; not having improved toilet facility (AOR = 1.94), being younger than 12 months (AOR = 4.22), not having history of infection (AOR = 1.83) and not having taken deworming tablet within the previous six months (AOR = 1.49).

Conclusion

Our study provided evidence on the co-existence of stunting and overweight/obesity among infants and young children in Ethiopia. Therefore, identifying children at risk of growth flattering and excess weight gain provides nutrition policies and programs in Ethiopia and beyond with an opportunity of earlier interventions through improving sanitation, dietary quality by targeting children under five years of age and those living in Agrarian regions of Ethiopia.

Growth During Infancy and Early Childhood and Its Association With Metabolic Risk Biomarkers at 11.5 Years of Age

The evidence that fetal life and early infancy are "critical" or "sensitive" ages for later development of cardiometabolic disease is based on flawed methods for comparing different age periods. Moreover, most previous studies have limited their focus to weight gain, rather than growth in length/height or body mass index (weight (kg)/height (m)2). We undertook a secondary analysis of data from the Promotion of Breastfeeding Intervention Trial (1996-2010), a birth cohort study nested within a large cluster-randomized trial in the Republic of Belarus, that had repeated measurements of weight and length/height taken from birth to 11.5 years of age. We used mixed-effects linear models to analyze associations of changes in standardized weight, length/height, and body mass index during 5 age periods (conception to birth, birth to age 3 months, ages 3-12 months, ages 12 months-6.5 years, and ages 6.5-11.5 years) with fasting glucose, insulin, insulin resistance, β-cell function, and adiponectin at age 11.5 years. We observed strong associations between the metabolic markers and all 3 growth measures, with the largest magnitudes being observed during the latest age period (ages 6.5-11.5 years) and negligible associations during gestation and the first year of life. Later age periods appear more "sensitive" than earlier periods to the adverse metabolic association with rapid growth in childhood.

The effects of rapid growth on body mass index and percent body fat: A meta-analysis

BACKGROUND & AIMS

Rapid growth in childhood and obesity are highly prevalent in congenital deficiency infants, but the associations between them remain controversial. This meta-analysis was performed to explore the effects of rapid growth on body mass index (BMI) and percent body fat (PBF), and to clarify potential confounders.

METHODS

A systematic search was performed using electronic databases including EMBASE (1985 to July 2019) and Medline (1966 to July 2019) for English articles. China National Knowledge Infrastructure Chinese citation database (CNKI) and WANFANG database were used to search articles in Chinese. Reference lists were also screened as supplement. All relevant studies that compare BMI or PBF between rapid group and control group were identified. The definition of rapid growth should be clearly specified. Means and standard deviations/95% confidence intervals (CIs) of BMI and PBF should be available. Relevant information was extracted independently by two reviewers. Study quality was reassessed using the Newcastle-Ottawa Scale. Publication bias and heterogeneity were detected. The random effect model was adopted for combined and stratified analysis.

RESULTS

About the effect of rapid growth on BMI, seventeen researches (4473 participants) involving 49 comparisons were included. Pooled analysis showed rapid group had higher BMI of 0.573 (95% CI, 0.355 to 0.791; P < 0.001). Stratified analyses revealed that catch-up weight gain, follow-up age >6 years old, rapid growth duration >2 years, full-term, comparing rapid growth SGA infants with control SGA infants, and from developed and developing countries, would all lead to higher BMI in rapid groups. About the effect of rapid growth on PBF, eleven researches (4594 participants) involving 37 comparisons were included. Pooled analysis showed rapid group had higher PBF of 2.005 (95% CI, 1.581 to 2.429; P < 0.001). Subgroup analyses suggested that catch-up weight gain, follow-up age ≤6 years old, rapid growth duration >2 years, full-term, comparing rapid growth SGA infants with control AGA infants, and participants from developing countries, would lead to increased PBF in rapid groups.

CONCLUSION

Rapid growth has a positive correlation with BMI and PBF. However, stratified analyses show that it is catch-up weight gain that lead to higher BMI and PBF, but not catch-up growth. In addition, rapid growth have long-term effect on BMI and short-term effect on PBF. Rapid growth duration longer than 2 years may increase the risk effect of rapid growth on BMI and PBF. But given that rapid growth would induce multiple health outcomes apart from BMI and PBF, the benefits and risks of rapid growth must be carefully considered and weighted.

Analysis of 'sensitive' periods of fetal and child growth

BACKGROUND

Birth weight and weight gain in infancy and early childhood are commonly studied as risk factors for later cardiometabolic diseases. In this study, we explore methods for quantifying weight gain during different age periods and for comparing the magnitude of the associations with later blood pressure.

METHODS

Based on data from a birth cohort study nested within a large cluster-randomized trial with repeated measures of weight from birth to 16 years of age, we compared the results of four analytic approaches to assess sensitive periods of growth in relation to blood pressure at age 16 years.

RESULTS

Approaches based on z-scores of weight or weight gain velocity (both standardized for age and sex) or on regression-based conditional weight standardized residuals yielded more coherent results than an approach based on absolute weight gain velocity. Weight gain standardized by sex and age was positively associated with blood pressure at 16 years at all postnatal age periods, but the magnitude of association was larger during adolescence (11.5-16 years) than during earlier intervals (0-3 months, 3-12 months, 1-6.5 years or 6.5-11.5 years).

CONCLUSIONS

Standardization of weight and weight gain by age and sex, or regression-based standardized residuals based on conditional weight, reflects relative gain and thus accounts for the rapid weight gains normally observed in early infancy and puberty. Adolescence appears to be a more sensitive period for relative weight gain effects on later blood pressure than earlier periods, even those of similar duration.

Developmental Programming of Body Composition: Update on Evidence and Mechanisms

PURPOSE OF REVIEW

A growing body of epidemiological and experimental data indicate that nutritional or environmental stressors during early development can induce long-term adaptations that increase risk of obesity, diabetes, cardiovascular disease, and other chronic conditions-a phenomenon termed "developmental programming." A common phenotype in humans and animal models is altered body composition, with reduced muscle and bone mass, and increased fat mass. In this review, we summarize the recent literature linking prenatal factors to future body composition and explore contributing mechanisms.

RECENT FINDINGS

Many prenatal exposures, including intrauterine growth restriction, extremes of birth weight, maternal obesity, and maternal diabetes, are associated with increased fat mass, reduced muscle mass, and decreased bone density, with effects reported throughout infancy and childhood, and persisting into middle age. Mechanisms and mediators include maternal diet, breastmilk composition, metabolites, appetite regulation, genetic and epigenetic influences, stem cell commitment and function, and mitochondrial metabolism. Differences in body composition are a common phenotype following disruptions to the prenatal environment, and may contribute to developmental programming of obesity and diabetes risk.

Breastfeeding in children born small for gestational age and future nutritional and metabolic outcomes: a systematic review

OBJECTIVE

To systematically review evidence related to nutritional and cardiometabolic outcomes in children born at term and small for gestational age and the association with breastfeeding.

SOURCE OF DATA

Two independent reviewers searched the MEDLINE, LILACS, SciELO, and Embase databases without time or language restrictions. The PRISMA tool was used, and studies that evaluated infants born at term and small for gestational age, breastfed, and with an evaluation of cardiometabolic outcomes were included. Studies with preterm infants, those that did not have information on breastfeeding, and those with lack of evaluation of the outcome variables were excluded. Also excluded were review articles, editorials, and series of cases.

SUMMARY OF DATA

Only seven articles were found that met the abovementioned criteria. There was a great variability in the type of evaluation, as well as in the age of these children. It was demonstrated that breastfeeding promoted growth without body composition alteration and without increased insulin resistance in children with exclusive breastfeeding, when compared to children receiving a higher calorie formula, except for one article that observed an increase in fat mass in exclusively breastfed children.

CONCLUSION

Breastfeeding seems to be a safe feeding practice for infants born at term and small for gestational age, showing no association with deleterious short-term outcomes. Breastfeeding stimulation in these populations seems to be a way of preventing the health problems associated with the high risk of chronic noncommunicable diseases and obesity.

Catch-Up Growth in Full-Term Small for Gestational Age Infants: A Systematic Review

This is the first systematic review to examine the global prevalence of catch-up growth (CUG) in small for gestational age (SGA) infants who were born at full term (FT). Size at birth and subsequent growth is an important indicator of neonatal and adult health. Globally, 16% of infants are SGA at birth, ranging from 7% in industrialized countries to 41.5% in South Asia. SGA infants are at increased risk for negative developmental and adult health outcomes. Some achieve CUG but others do not. CUG has immediate and late health implications especially in low- and middle-income countries. This systematic review sought to determine the global prevalence of CUG among FT-SGA infants. We performed a literature search of MEDLINE, Pubmed, Embase, Web of Science, and Scopus, as well as grey literature databases, and identified 3137 studies. The final analysis included 11 studies. The median prevalence of CUG was 87.4% across all definitions of SGA and CUG. However, multiple definitions were used to classify SGA and CUG. Nine unique reference populations were used to classify SGA, and 6 to approximate CUG. Due to this heterogeneity, a meta-analysis could not be conducted. Program implementation for this vulnerable group of infants is dependent on proper classification. Given the wide range of definitions and reference standards used in the past, it is not possible to determine the global need for programs to address CUG for FT-SGA infants or to rationally plan any such programs. We highlight the need and propose standard definitions and references for SGA and CUG.

Renal function and blood pressure in 11 year old children born extremely preterm or small for gestational age

Background

Preterm birth and low birth weight are associated with reduced nephron numbers and increased risk of hypertension and kidney disease in later life.

Aims

We tested the hypothesis that extremely preterm birth and intrauterine growth restriction is associated with decreased renal function in mid childhood.

Methods

At 11 years of age the following measures were obtained in a regional cohort of children born extremely premature (EP, i.e. < 28 weeks gestational age—GA) or with extremely low birth weight (ELBW, i.e. BW < 1000 grams) and in matched controls born at term with appropriate BW (AGA): Height, weight, abdominal circumference, triceps and subscapular skin fold thicknesses, blood pressure, plasma levels of creatinine, cystatin C and symmetric dimethyl arginine (SDMA). Small for gestational age (SGA) was defined as a BW < 10^th percentile for GA. Glomerular filtration rate (GFR) was estimated according to the equations by Schwartz, Zappitelli and Gao.

Results

Fifty-seven of 61 eligible EP/ELBW children, 20 (35%) born SGA, and 54 controls, were assessed. Estimated GFR decreased while plasma SDMA increased from the children born AGA at term through those born preterm AGA to preterm SGA. Systolic BP was correlated to fat mass indices (p<0.03), but not to renal function (p>0.2) and did not differ between the groups.

Conclusions

Children born EP/ELBW, particularly those born SGA, had impaired renal function at age 11 years as judged from estimated GFRs and plasma levels of SDMA. Since reduced renal function is associated with an increased risk of later disease, these children should be followed in order to minimize additional risk factors.

Life history trade-offs and the partitioning of maternal investment: Implications for health of mothers and offspring

Lay Summary: This review sets out the hypothesis that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk. Growth patterns in early life predict the risk of non-communicable diseases (NCDs), but adaptive explanations remain controversial. It is widely assumed that NCDs occur either because of physiological adjustments to early constraints, or because early ecological cues fail to predict adult environmental conditions (mismatch). I present an inter-generational perspective on developmental plasticity, based on the over-arching hypothesis that a key axis of variability in maternal metabolism derives from life history trade-offs, which influence how individual mothers partition nutritional investment in their offspring between pregnancy and lactation. I review evidence for three resulting predictions: (i) Allocating relatively more energy to growth during development promotes the capacity to invest in offspring during pregnancy. Relevant mechanisms include greater fat-free mass and metabolic turnover, and a larger physical space for fetal growth. (ii) Allocating less energy to growth during development constrains fetal growth of the offspring, but mothers may compensate by a tendency to attain higher adiposity around puberty, ecological conditions permitting, which promotes nutritional investment during lactation. (iii) Since the partitioning of maternal investment between pregnancy and lactation impacts the allocation of energy to 'maintenance' as well as growth, it is expected to shape offspring NCD risk as well as adult size and body composition. Overall, this framework predicts that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk.

Exercise in Pregnancy and Children's Cardiometabolic Risk Factors: a Systematic Review and Meta-Analysis

BACKGROUND

Maternal metabolic health during the prenatal period is an established determinant of cardiometabolic disease risk. Many studies have focused on poor offspring outcomes after exposure to poor maternal health, while few have systematically appraised the evidence surrounding the role of maternal exercise in decreasing this risk. The aim of this study is to characterize and quantify the specific impact of prenatal exercise on children's cardiometabolic health markers, at birth and in childhood.

METHODS

A systematic review of Scopus, MEDLINE, EMBASE, CENTRAL, CINAHL, and SPORTDiscus up to December 2017 was conducted. Randomized controlled trials (RCTs) and prospective cohort studies of prenatal aerobic exercise and/or resistance training reporting eligible offspring outcomes were included. Four reviewers independently identified eligible citations and extracted study-level data. The primary outcome was birth weight; secondary outcomes, specified a priori, included large-for-gestational age status, fat and lean mass, dyslipidemia, dysglycemia, and blood pressure. We included 73 of the 9804 citations initially identified. Data from RCTs was pooled using random effects models. Statistical heterogeneity was quantified using the I2 test. Analyses were done between June and December 2017 and the search was updated in December 2017.

RESULTS

Fifteen observational studies (n = 290,951 children) and 39 RCTs (n = 6875 children) were included. Observational studies were highly heterogeneous and had discrepant conclusions, but globally showed no clinically relevant effect of exercise on offspring outcomes. Meta-analyzed RCTs indicated that prenatal exercise did not significantly impact birth weight (mean difference [MD] - 22.1 g, 95% confidence interval [CI] - 51.5 to 7.3 g, n = 6766) or large-for-gestational age status (risk ratio 0.85, 95% CI 0.51 to 1.44, n = 937) compared to no exercise. Sub-group analyses showed that prenatal exercise reduced birth weight according to timing (starting after 20 weeks of gestation, MD - 84.3 g, 95% CI - 142.2, - 26.4 g, n = 1124), type of exercise (aerobic only, MD - 58.7 g, 95% CI - 109.7, - 7.8 g; n = 2058), pre-pregnancy activity status (previously inactive, MD - 34.8 g, 95% CI - 69.0, - 0.5 g; n = 2829), and exercise intensity (light to moderate intensity only, MD - 45.5 g, 95% CI - 82.4, - 8.6 g; n = 2651). Fat mass percentage at birth was not altered by prenatal exercise (0.19%, 95% CI - 0.27, 0.65%; n = 130); however, only two studies reported this outcome. Other outcomes were too scarcely reported to be meta-analyzed.

CONCLUSIONS

Prenatal exercise does not causally impact birth weight, fat mass, or large-for-gestational-age status in a clinically relevant way. Longer follow up of offspring exposed to prenatal exercise is needed along with measures of relevant metabolic variables (e.g., fat and lean mass).

PROTOCOL REGISTRATION

Protocol registration number: CRD42015029163 .

Small for gestational age and obesity related comorbidities

Infant born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature and metabolic alterations in later life. The result of SGA followed by rapid weight gain during early postnatal life has been associated with increased long-term risks for central obesity, insulin resistance, impaired glucose tolerance, type 2 diabetes, hypertension, increased fat mass, and cardiovascular disease. We should carefully monitor their weight during infancy and childhood to prevent excessive rates of weight gain. 'Healthy catch up growth' may decreased the risk of obesity-related comorbidities in SGA. Establishing the optimal growth patterns in SGA to minimize short- and long-term risks is important, and further studies will be needed. This review discusses recent studies concentrating on obesity-related morbidities in SGA infants that may provide insight into growth monitoring.

Small for gestational age and obesity: epidemiology and general risks

Children born small for gestational age (SGA) have several life-long consequences. Previous epidemiological studies investigated from childhood to adulthood reported that a number of chronic diseases originate in the prenatal period. With the emerging era of obesity epidemic, more concerns are related to being obese than being short-statured in SGA children. The exact mechanisms are uncertain; however, growth hormone-insulin-like growth factor axis disturbance by fetal programming and accelerated postnatal weight gain contributed to central adiposity in SGA children. In this review, we summarized the definitions and prevalence of SGA, epidemiology, and general risks of obesity in SGA children. Early interventions, before and after birth, are needed for healthy catch-up growth to prevent later obesity and related complications.

Methodological challenges in studying the causal determinants of child growth

Background

Previous studies of early life influences on later growth in childhood have varied in their analytical approaches, particularly with respect to 'adjustment' for differences in size at the beginning of the growth period examined.

Methods

We compared three commonly used statistical models to assess the effect of maternal body mass index (BMI) on growth between 6.5 and 11.5 years in a large cohort of Belarusian children, as follows: (Model 1) analysis of the difference in anthropometric measurements between the two ages; (Model 2) analysis of the measurement at 11.5 years after adjustment for the same measurement at 6.5 years; and (Model 3) analysis of the difference in measurements after adjustment for the measurement at 6.5 years (mathematically identical to Model 2).

Results

Among PROBIT children of obese mothers (BMI ≥ 30 kg/m 2 ) vs those of mothers with normal BMI (18.5 to < 25 kg/m 2 ), Model 1 yielded larger increases in most weight and adiposity outcomes than did Model 2. We show that these larger effects arise because Model 2 parameterizes the effect of maternal BMI twice in same model: once for its effect on size at 6.5 years, and a second time for its effect on growth over the 5-year period between 6.5 and 11.5 years. Similar results were obtained in analogous analyses from cohorts in Boston, MA, and Singapore.

Conclusion

Analysing the effect of exposure on change in outcome between two ages (Model 1) is clearly preferable to 'adjustment' for the outcome at the earlier age whenever the exposure under study affects the outcome at the earlier age.

Early Nutrition and Growth until the Corrected Age of 2 Years in Extremely Preterm Infants

BACKGROUND

Extremely preterm birth is associated with a high risk of extrauterine growth retardation, which has been linked with adverse developmental outcomes.

OBJECTIVE

We investigated whether nutritional management during the first 7 days of life affects growth patterns until the corrected age of 2 years in extremely preterm infants.

STUDY DESIGN

A retrospective study of 78 extremely preterm (<28 weeks' gestation) neonates was conducted. Data regarding parenteral and enteral intake of energy, protein, lipids, and carbohydrates during the first 7 days of life were collected from patient records. The outcome measures included weight, height, and head circumference with Z scores at term-equivalent age and the corrected ages of 1 and 2 years. Analyses were performed with hierarchical-linear mixed models.

RESULTS

Nutritional intake during the first week of life did not reach the current recommendations. The total energy intake during the first 7 days of life was statistically significantly associated with weight, length, and head circumference until the corrected age of 2 years after adjusting for potential confounding factors. Individual macronutrient intake displayed no association with growth patterns.

CONCLUSIONS

Energy intake during the first 7 days of life is associated with growth until the corrected age of 2 years. These results provide support for the aggressive early nutritional management of extremely preterm infants.

Body Composition Changes from Infancy to 4 Years and Associations with Early Childhood Cognition in Preterm and Full-Term Children

BACKGROUND

Infants born prematurely are at risk for neurodevelopmental complications. Early growth is associated with improved later cognition. The relationship of early proportionality and body composition with later cognition is not well established.

OBJECTIVES

To assess differences in fat-free mass and adiposity (fat mass, percent body fat) changes in preterm and full-term infants through preschool age and examine associations with early childhood cognition.

METHODS

This is a prospective, observational study in an appropriate for gestational age cohort of 71 patients (20 preterm and 51 full-term) from infancy through preschool age. Anthropometric and body composition measurements via air displacement plethysmography were obtained during infancy at term and 3-4 months (preterm corrected ages), and at 4 years. Cognitive testing occurred at 4 years. Associations of body composition changes between visits with cognitive function were tested using linear regression.

RESULTS

In the preterm group, higher term to 4-month corrected age percent body fat gains were associated with lower working memory performance (p = 0.01), and higher 4-month corrected age to 4-year fat-free mass gains were associated with higher full-scale IQ (p = 0.03) and speed of processing performance (p ≤ 0.02). In the full-term group, higher 4-month to 4-year fat mass gains were associated with lower full-scale IQ (p = 0.03).

CONCLUSIONS

Body composition gains during different time periods are associated with varying areas of cognitive function. These findings may inform interventions aimed at optimal growth.

Growth throughout childhood of children born growth restricted

OBJECTIVE

Many studies that examine growth in growth-restricted children at birth do not discriminate between fetal growth restriction (FGR) and small for gestational age (SGA). These terms however are not synonymous. In SGA, stunting and increased weight gain have been reported. We do not know if this holds true for FGR. Our aim was to study postnatal growth until age 12.5 years in a cohort of children born FGR due to early onset placental insufficiency, and its relation to FGR severity.

DESIGN

Prospective cohort study, follow-up of an antenatal randomised controlled trial in two tertiary centres.

PATIENTS

Children aged 12.5 years born after FGR, with mothers who had severe early onset hypertensive pregnancy disorders (N=96).

MAIN OUTCOME MEASURES

Anthropometry at age 12.5 years in SD scores (SDS).

RESULTS

Mean height SDS (SD) corrected for target height was -0.09 (0.94), mean body mass index (BMI) SDS was 0.00 (1.16) and mean head circumference SDS was -0.37 (1.11). Catch-up growth was at fastest rate between term age and 3 months and similar for height (0.55 SDS/months) and weight (0.49 SDS/months). Neither FGR severity nor gestational age was related to height and BMI at age 12.5 years.

CONCLUSIONS

Children born growth restricted due to early onset placental insufficiency have height and BMI scores comparable to their age-matched peers at age 12.5 years. FGR severity was not related to height and BMI at age 12.5 years. These reassuring results differ from most studies that examine SGA children.

Systematic review indicates postnatal growth in term infants born small-for-gestational-age being associated with later neurocognitive and metabolic outcomes

We systematically reviewed papers published in English between 1994 and October 2015 on how postnatal weight gain and growth affect neurodevelopment and metabolic outcomes in term‐born small‐for‐gestational‐age (SGA) infants. Two randomised trials reported that enriched infant formulas that promoted early growth also increased fat mass, lean mass and blood pressure (BP), but had no effect on early neurocognitive outcomes. Meanwhile, 31 observational studies reported consistent positive associations between postnatal weight gain and growth with neurocognitive outcomes, adiposity, insulin resistance and BP.

Conclusion: Few intervention studies exist, despite consistent positive associations between early growth and neurocognition in term‐born SGA infants.

Body Composition Trajectories From Infancy to Preschool in Children Born Premature Versus Full-term

OBJECTIVES

The aim of the study was to longitudinally characterize infancy to preschool body composition trajectories and the association of early fat and fat-free mass gains with preschool age body composition in children born premature versus full-term.

METHODS

A cohort of appropriate-for-gestational age preterm (n = 20) and term (n = 51) infants were followed at 3 visits: "neonatal" visit 1 at 2 weeks of age for term and near term corrected age for preterm; "infancy" visit 2 at 3 to 4 months (preterm corrected age); "preschool" visit 3 at 4 years. Body composition via air displacement plethysmography and anthropometrics were measured at all visits. Tracking of infancy weight and body composition with preschool measurements was tested using Pearson partial correlation coefficients. Associations between serial body composition measurements were assessed using multiple linear regression.

RESULTS

Early differences in body composition between premature (mean gestational age 31.9 weeks, mean birth weight 1843 g) and full-term (mean gestational age 39.8 weeks) infants were not present at preschool age. Visit 1 body composition was not correlated with preschool measurements in the preterm infants. Visit 2 measurements were correlated with preschool measures. Fat-free mass accretion from visit 1 to visit 2 was positively associated with preschool lean mass (β = 0.038, P = 0.049) in preterm children, whereas fat accretion was not associated with preschool body composition.

CONCLUSIONS

Children born prematurely and full-term have similar body composition at preschool age. For preterms infancy fat-free mass gains, and not adiposity gains, are positively associated with preschool fat-free mass; this may be associated with lower risk of later obesity and adverse metabolic outcomes.

Does Fetal Growth Restriction Cause Later Obesity? Pitfalls in Analyzing Causal Mediators as Confounders

Recent studies finding that small-for-gestational-age (SGA) birth is associated with increased adiposity in childhood and adulthood have been based on analyses "adjusting" for height, weight, or body mass index (BMI; weight (kg)/height (m)2) measured concurrently with the adiposity measurement. To assess the potential for bias due to overadjustment for a causal mediator, we compared 2 approaches to analyzing the association between SGA birth and adiposity outcomes (skinfold thicknesses and bioelectrical impedance measurement of body fat) at age 11.5 years using the same data set in a cohort of Belarusian children followed from birth in 1996-1997 to age 11.5 years in 2008-2010. We 1) studied the association of SGA birth with adiposity, adjusting for baseline covariates only, and 2) made additional regression adjustment for concurrent height, weight, or BMI. The first approach yielded negative associations between SGA birth and all adiposity outcomes. Additional adjustment for concurrent weight or BMI reversed (i.e., to positive) the SGA-adiposity association. To explore the latter anthropometric measures as causal mediators, we also used marginal structural models to estimate the controlled direct effect of SGA birth. That effect was similar to the effect seen with the first approach when modeled on height, was null when modeled on BMI, but was confounded by differences in lean mass versus fat mass when modeled on weight.

Birth Weight for Gestational Age, Anthropometric Measures, and Cardiovascular Disease Markers in Children

OBJECTIVE

To examine the association of birth weight for gestational age with anthropometric measures and cardiometabolic markers in a population-based sample of Canadian children.

STUDY DESIGN

The study used data from 2016 children aged 6-12 years from the first 2 cycles of the Canadian Health Measures Survey, a population-based survey of Canadian residents. The main exposure was birth weight for gestational age (small [SGA], large [LGA], and appropriate for gestational age [AGA]). The outcomes were anthropometric measures, blood pressure, and laboratory cardiovascular disease markers. The association between the exposure and the outcomes was examined using multiple regression. Analyses were weighted to account for the complex sampling design and for nonresponse.

RESULTS

SGA infants had lower and LGA infants had higher z scores for anthropometric measures compared with the AGA group but most differences were not statistically significant. There were no differences between the SGA or LGA infants and the AGA group in blood pressure or individual cardiometabolic markers but SGA infants were significantly less likely to have elevated levels of 3 or more components of the metabolic syndrome compared with their AGA peers.

CONCLUSIONS

Former SGA and LGA infants have lower (SGA) and higher (LGA) body mass index and waist circumference, respectively, than their AGA peers. The known long-term increased cardiovascular disease risk among SGA or LGA infants was not reflected in the blood pressure and laboratory measurements at age 6-12 years.

Prevalence of diabetes and obesity in association with prematurity and growth restriction

Intrauterine growth restriction (IUGR) is when fetuses and newborn infants have not reached their true growth potential as genetically defined. Fetuses with IUGR develop in a less than ideal environment that leads to epigenetic changes and marks infants' metabolism for the rest of their lives. Epigenetic changes affect insulin-like growth factor-1 (IGF-1) levels and lead to insulin resistance and ultimately to a metabolic syndrome. The metabolic syndrome is a constellation of illnesses that raise one's risk for type 2 diabetes mellitus, coronary artery disease, and ischemic heart disease, including hypertension, dyslipidemia, central obesity, insulin resistance, and inflammation. The association between IUGR or prematurity and long-term insulin resistance, obesity, hypertension, and metabolic syndrome remains unclear. While studies have shown an association, others have not supported such association. If alteration of intrauterine growth can ultimately lead to the development of metabolic derangements in childhood and adulthood, and if such association is true, then early interventions targeting the health of pregnant women will ensure the health of the population to follow.

Birth Size, Early Life Weight Gain, and Midchildhood Cardiometabolic Health

OBJECTIVE

To examine associations of birth size and weight gain during 4 early-life age intervals with midchildhood adiposity and metabolic profile and to evaluate for an interaction between birth size and early-life weight gain.

STUDY DESIGN

Using data from 963 participants of Project Viva, a US prebirth cohort, we used multivariable linear regression to examine relations of birth size (tertiles of birthweight-for-gestational-age z-score) and weight gain (body mass index z-score [BMIZ] change) during 4 age intervals (birth-6 months, 6 months-1 year, 1-2 years, 2-3 years) with body composition and metabolic biomarkers during midchildhood (6.6-10.7 years).

RESULTS

After accounting for confounders and previous growth, greater BMIZ change during all 4 age intervals corresponded with higher midchildhood adiposity, with larger effect sizes for later (1-2 years and 2-3 years) vs earlier (birth-6 months and 6 months-1 year) time frames. We observed effect modification by birth size for the birth-6 months and 6 months-1 year intervals. Greater birth-6 months BMIZ change was associated with higher overall adiposity (0.40 [95% CI 0.29, 0.51] kg dual x-ray absorptiometry total fat mass per z-score) among children in the highest birth size tertile. Similar associations were observed for central adiposity. Each increment in 6 months-1 year BMIZ change corresponded with 0.55 (0.05, 1.05) units higher homeostatic model assessment of insulin resistance and 2.68 (0.96, 4.40) ng/mL higher leptin among the smallest infants.

CONCLUSIONS

BMIZ gain after 1 year is associated with greater midchildhood adiposity regardless of birth size, whereas the long-term influence of weight gain during the first postnatal year may depend on size at birth. Future studies are warranted to validate findings and examine relations with conventional birth size cut-offs.

Health impact of catch-up growth in low-birth weight infants: systematic review, evidence appraisal, and meta-analysis

This study aimed to systematically review and appraise evidence on the short-term (e.g. morbidity, mortality) and long-term (obesity and non-communicable diseases, NCDs) health consequences of catch-up growth (vs. no catch-up growth) in individuals with a history of low birth weight (LBW).We searched MEDLINE, EMBASE, Global Health, CINAHL plus, Cochrane Library, ProQuest Dissertations and Thesis and reference lists. Study quality was assessed using the risk of bias assessment tool from the Agency for Health Care Research and Quality, and the evidence base was assessed using the GRADE tool. Eight studies in seven cohorts (two from high-income countries, five from low-middle-income countries) met the inclusion criteria for short-term (mean age: 13.4 months) and/or longer-term (mean age: 11.1 years) health outcomes of catch-up growth, which had occurred by 24 or 59 months. Of five studies on short-term health outcomes, three found positive associations between weight catch-up growth and body mass and/or glucose metabolism; one suggested reduced risk of hospitalisation and mortality with catch-up growth. Three studies on longer-term health outcomes found catch-up growth were associated with higher body mass, BMI or cholesterol. GRADE assessment suggested that evidence quantity and quality were low. Catch-up growth following LBW may have benefits for the individual with LBW in the short term, and may have adverse population health impacts in the long-term, but the evidence is limited. Future cohort studies could address the question of the consequences of catch-up growth following LBW more convincingly, with a view to informing future prevention of obesity and NCDs. © 2016 John Wiley & Sons Ltd.

Biological, environmental, and social influences on childhood obesity

The prevalence of childhood obesity has increased globally over the past three decades, with evidence of recent leveling off in developed countries. Reduction in the, currently high, prevalence of obesity will require a full understanding of the biological and social pathways to obesity in order to develop appropriately targeted prevention strategies in early life. Determinants of childhood obesity include individual level factors, including biological, social, and behavioral risks, acting within the influence of the child's family environment, which is, in turn, imbedded in the context of the community environment. These influences act across childhood, with suggestions of early critical periods of biological and behavioral plasticity. There is evidence of sex and gender differences in the responses of boys and girls to their environments. The evidence that determinants of childhood obesity act at many levels and at different stages of childhood is of policy relevance to those planning early health promotion and primary prevention programs as it suggests the need to address the individual, the family, the physical environment, the social environment, and social policy. The purpose of this narrative review is to summarize current, and emerging, literature in a multilevel, life course framework.

Auxological perspectives on 'growth' in DOHaD

David Barker established growth as a seminal link between early development and later health attainment and disease risk. This was nothing less than a paradigm shift in health and medicine, turning the focus of disease causality away from contemporary environmental influences to earliest growth as a time when functional anatomy and physiology sets in place critical structures and function for a lifetime. Barker's prodigious work investigated time- and place-specific interactions between maternal condition and exogenous environmental influences, focusing on how growth unfolds across development to function as a mechanistic link to ensuing health. Subsequent applications do not always attend to the specificity and sensitivity issues included in his original work, and commonly overlook the long-standing methods and knowledge base of auxology. Methodological areas in need of refinement include enhanced precision in how growth is represented and assessed. For example, multiple variables have been used as a referent for 'growth,' which is problematic because different body dimensions grow by different biological clocks with unique functional physiologies. In addition, categorical clinical variables obscure the spectrum of variability in growth experienced at the individual level. Finally, size alone is a limited measure as it does not capture how individuals change across age, or actually grow. The ground-breaking notion that prenatal influences are important for future health gave rise to robust interest in studying the fetus. Identifying the many pathways by which size is realized permits targeted interventions addressing meaningful mechanistic links between growth and disease risk to promote health across the lifespan.