Infancy weight gain, parental socioeconomic position, and childhood overweight and obesity: a Danish register-based cohort study

Maternal education and its influence on child growth and nutritional status during the first two years of life: a systematic review and meta-analysis

Background

The first 1000 days of life are critical for a child's health and development. Impaired growth during this period is linked to increased child morbidity, mortality, and long-term consequences. Undernutrition is the main cause, and addressing it within the first 1000 days of life is vital. Maternal education is consistently identified as a significant predictor of child undernutrition, but its specific impact remains to be determined. This study presents a systematic review and meta-analysis investigating the influence of high versus low maternal education levels on child growth from birth to age two, using population-based cohort studies.

Methods

Databases including PubMed, Scopus, EMBASE, Web of Science, ERIC, and Google Scholar were searched from January 1990 to January 2024 using appropriate search terms. We included population-based cohort studies of healthy children aged two years and under and their mothers, categorizing maternal education levels. Child growth and nutritional outcomes were assessed using various indicators. Two reviewers independently conducted data extraction and assessed study quality. The Newcastle Ottawa scale was utilized for quality assessment. Random-effects models were used for meta-analysis, and heterogeneity was assessed using the Cochrane Q and I2 statistic. Subgroup and sensitivity analyses were performed, and publication bias was evaluated.

Findings

The literature search retrieved 14,295 titles, and after full-text screening of 639 reports, 35 studies were included, covering eight outcomes: weight for age z-score (WAZ), height for age z-score (HAZ), BMI for age z-scores (BMIZ), overweight, underweight, stunting, wasting, and rapid weight gain. In middle-income countries, higher maternal education is significantly associated with elevated WAZ (MD 0.398, 95% CI 0.301-0.496) and HAZ (MD 0.388, 95% CI 0.102-0.673) in children. Similarly, in studies with low-educated population, higher maternal education is significantly linked to increased WAZ (MD 0.186, 95% CI 0.078-0.294) and HAZ (0.200, 95% CI 0.036-0.365). However, in high-income and highly educated population, this association is either absent or reversed. In high-income countries, higher maternal education is associated with a non-significant lower BMI-Z (MD -0.028, 95% CI -0.061 to 0.006). Notably, this inverse association is statistically significant in low-educated populations (MD -0.045, 95% CI -0.079 to -0.011) but not in highly educated populations (MD 0.003, 95% CI -0.093 to 0.098).

Interpretation

Maternal education's association with child growth varies based on country income and education levels. Further research is needed to understand this relationship better.

Funding

This study was a student thesis supported financially by Tehran University of Medical Sciences (TUMS).

Growth trajectory of full-term small-for-gestational-age infants: a 3-year longitudinal study in China

OBJECTIVE

Small-for-gestational-age (SGA) infants are at risk of impaired growth and developmental outcomes, even for those who were born at full term. The growth trajectory of full-term SGA infants remains unknown. Therefore, this study aimed to evaluate the growth trajectory of full-term SGA infants from birth to 3 years old in East China.

METHODS

Full-term SGA infants were followed up from birth to 3 years old. The weight and length were measured at 3, 6, 12, 18, 24, 30 and 36 months. Rate of catch-up growth and rates of growth deviations including short stature, emaciation, underweight, overweight and obesity, were calculated at different time points. Latent class analysis was applied to describe growth trajectories from birth to 36 months.

RESULTS

A total of 816 full-term SGA infants were enrolled in this study and 303 had complete follow-up data at 3, 6, 12, 18, 24, 30 and 36 months. At 24 months, the rate of catch-up growth was 42.4% in girls and 48.6% in boys; while at 36 months, this rate was 43.3% in girls and 52.1% in boys. The latent class analysis identified two trajectories of weight and length in boys and girls. Girls showed different growth trajectories of weight since 12 months compared with boys.

CONCLUSIONS

Our study reported a relatively low rate of catch-up growth in full-term SGA infants and has identified different growth trajectories of length and weight in boys and girls. We call for attention from health professionals on the growth trajectory of full-term SGA infants to eventually promote their health potentials.

Associations of Infant Feeding, Sleep, and Weight Gain with the Toddler Gut Microbiome

This study examines how feeding, sleep, and growth during infancy impact the gut microbiome (GM) in toddlers. The research was conducted on toddlers (n = 36), born to Latina women of low-income with obesity. Their mothers completed retrospective feeding and sleeping questionnaires at 1, 6, and 12 months; at 36 months, fecal samples were collected. Sequencing of the 16S rRNA gene (V4 region) revealed that breastfeeding for at least 1 month and the introduction of solids before 6 months differentiated the GM in toddlerhood (Bray-Curtis, pseudo-F = 1.805, p = 0.018, and pseudo-F = 1.651, p = 0.044, respectively). Sleep had an effect across time; at 1 and 6 months of age, a lower proportion of nighttime sleep (relative to 24 h total sleep) was associated with a richer GM at three years of age (Shannon H = 4.395, p = 0.036 and OTU H = 5.559, p = 0.018, respectively). Toddlers experiencing rapid weight gain from birth to 6 months had lower phylogenetic diversity (Faith PD H = 3.633, p = 0.057). These findings suggest that early life nutrition, sleeping patterns, and growth rate in infancy may influence the GM composition. Further verification of these results with objective sleep data and a larger sample is needed.

Determinants of Anishinabeck infant and early childhood growth trajectories in Northwestern Ontario, Canada: a cohort study

BACKGROUND

The Developmental Origins of Health and Disease (DOHaD) paradigm emphasizes the significance of early life factors for the prevention of chronic health conditions, like type 2 diabetes (T2DM) and obesity, which disproportionately affect First Nations communities in Canada. Despite increasing DOHaD research related to maternal health during pregnancy, early childhood growth patterns, and infant feeding practices with many populations, data from First Nations communities in Canada are limited. In partnership with Sandy Lake First Nation, the aims of this project were to characterize birthweights and growth patterns of First Nations infants/children over the first 6 years of life and to study the impact of maternal and infant social and behavioral factors on birthweight and growth trajectories.

METHODS

We recruited 194 families through community announcements and clinic visits. Infant/child length/height and weight were measured at 1 and 2 weeks; 1, 2, 6, 12, and 18 months; and 2, 3, 4, 5 and 6 years. Maternal and infant/child questionnaires captured data about health, nutrition, and social support. Weight-for-Age z-score (WAZ), Height-for-Age z-score (HAZ), and BMI-for-Age z-score (BAZ) were calculated using WHO reference standards and trajectories were analyzed using generalized additive models. Generalized estimating equations and logistic regression were used to determine associations between exposures and outcomes.

RESULTS

WAZ and BAZ were above the WHO mean and increased with age until age 6 years. Generalized estimating equations indicated that WAZ was positively associated with age (0.152; 95% CI 0.014, 0.29), HAZ was positively associated with birthweight (0.155; 95% CI 0.035, 0.275), and BAZ was positively associated with caregiver's BMI (0.049; 95% CI 0.004, 0.090). There was an increased odds of rapid weight gain (RWG) with exposure to gestational diabetes (OR: 7.47, 95% CI 1.68, 46.22). Almost 70% of parents initiated breastfeeding, and breastfeeding initiation was modestly associated with lower WAZ (-0.18; 95% CI -0.64, 0.28) and BAZ (-0.23; 95% CI -0.79, 0.34).

CONCLUSIONS

This work highlights early life factors that may contribute to T2DM etiology and can be used to support community and Indigenous-led prevention strategies.

Association of Maternal BMI and Rapid Infant Weight Gain With Childhood Body Size and Composition

OBJECTIVES

Maternal prepregnancy BMI (ppBMI) and an infant's rapid weight gain (RWG) are each associated with increased risk for childhood obesity. We hypothesized that ppBMI and RWG interact to further raise childhood obesity risk.

METHODS

Mother-infant dyads (n = 414) from the Healthy Start Study, an observational prebirth cohort, were included. RWG was defined as a weight-for-age z score increase of ≥0.67 from birth to 3 to 7 months. Body composition was measured by air displacement plethysmography at age 4 to 7 years. General linear regression models were fit to characterize associations between ppBMI, RWG, and their interaction with the outcomes of childhood BMI-for-age z score and percent fat mass (%FM).

RESULTS

A total of 18.6% (n = 77) of offspring experienced RWG. Maternal ppBMI and RWG were both positively associated with offspring BMI z score and %FM. RWG amplified the association between ppBMI and BMI z score, especially among females. Females exposed to maternal obesity and RWG had an average BMI at the 94th percentile (1.50 increase in childhood BMI z score) compared with those exposed to normal ppBMI and no RWG (average childhood BMI at the 51st percentile). RWG had a weaker effect on the association between ppBMI and %FM. Adjustment for breastfeeding status or childhood daily caloric intake did not significantly alter findings.

CONCLUSIONS

Rapid infant weight gain interacts with maternal ppBMI to jointly exacerbate risk of childhood obesity. Pediatric providers should monitor infants for RWG, especially in the context of maternal obesity, to reduce future risk of obesity.

Predicting of excess body fat in children

PURPOSE OF REVIEW

Approximately 370 million children and adolescents worldwide showed overweight or obesity in 2016. The risk of developing severe comorbidities depends on the age of onset and the duration of obesity. This review discusses available methodologies to detect excess body fat in children as well as the early life factors that predict excess body fat and its development.

RECENT FINDINGS

Factors, such as parental nutritional status, maternal weight gain during pregnancy, maternal malnutrition, maternal smoking during pregnancy, low and high birth weight, rapid weight gain, and short infant sleep duration have been independently and positively associated with neonatal, infant, and children adiposity. Early detection of excess body fat in children through the use of various tools is the first step in preventing nutrition-related diseases in adulthood.

SUMMARY

The early detection of excess body fat and the implementation of efficient interventions to normalize the weight of children and adolescents at obesity risk are essential to prevent diseases in adult life.

Metagenomic analysis reveals associations between salivary microbiota and body composition in early childhood

Several studies have shown that body mass index is strongly associated with differences in gut microbiota, but the relationship between body weight and oral microbiota is less clear especially in young children. We aimed to evaluate if there is an association between child growth and the saliva microbiome. We hypothesized that associations between growth and the saliva microbiome would be moderate, similarly to the association between growth and the gut microbiome. For 236 toddlers participating in the New Hampshire Birth Cohort Study, we characterized the association between multiple longitudinal anthropometric measures of body height, body weight and body mass. Body Mass Index (BMI) z-scores were calculated, and dual-energy x-ray absorptiometry (DXA) was used to estimate body composition. Shotgun metagenomic sequencing of saliva samples was performed to taxonomically and functionally profile the oral microbiome. We found that within-sample diversity was inversely related to body mass measurements while community composition was not associated. Although the magnitude of associations were small, some taxa were consistently associated with growth and modified by sex. Certain taxa were associated with decreased weight or growth (including Actinomyces odontolyticus and Prevotella melaninogenica) or increased growth (such as Streptococcus mitis and Corynebacterium matruchotii) across anthropometric measures. Further exploration of the functional significance of this relationship will enhance our understanding of the intersection between weight gain, microbiota, and energy metabolism and the potential role of these relationships on the onset of obesity-associated diseases in later life.

Family socioeconomic status and childhood adiposity in Europe - A scoping review

Childhood obesity is a considerable public health problem worldwide. In Europe, lower parental socioeconomic status (SES) relates to higher childhood adiposity. This scoping review strives to discover, which SES indicators are the most commonly used and meaningful determinants of childhood adiposity (greater level of continuous adiposity indicator, e.g. body mass index z-score, or overweight or obesity categorized by established definitions). The review focused on studies about European general populations from the 21st century (January 2000-April 2021) considering children and adolescents aged 0-17 years. PubMed and reference lists of articles were searched in February-April 2021. Total of 53 studies with 121 association analyses between different SES indicators and adiposity indicators, were identified and reviewed. Different SES indicators were grouped to 25 indicators and further to six indicator groups. The most used indicator was mother's education (n of association analyses = 24) and the most used indicator group was parental education (n of association analyses = 51). Of all association analyses, 55% were inverse, 36% were non-significant, and 8% were positive. Composite SES (80%), parental education (69%) and parental occupation (64%) indicators showed most frequently inverse associations with obesity measures (i.e. lower parental SES associating with higher adiposity), while parental income (50% inverse; 50% non-significant) and property and affluence (42% inverse; 50% nonsignificant) indicators showed approximately even number of inverse and non-significant associations. Instead, majority of parental employment (60%) indicators, showed non-significant associations and 33% showed positive associations (i.e. higher parental SES associating with higher adiposity). Despite some variation in percentages, majority of the associations were inverse in each age group and with different outcome categorizations. In girls and in boys, non-significant associations predominated. It seems that children with parents of higher SES have lower likelihood of adiposity in Europe. Parents' employment appears to differ from other SES indicators, so that having an employed parent(s) does not associate with lower likelihood of adiposity. Positive associations seem to occur more frequently in poorer countries. Criteria for uniform childhood SES and adiposity measures should be established and used in studies in order to be able to produce comparable results across countries.

Association between rapid weight gain and overweight in children aged 0 to 5 years in Latin America

Abstract Objectives: to assess the prevalence of rapid weight gain (RWG) in children born with normal weight and its association with overweight (OW) in four Latin America countries. Methods: cross-sectional study in children aged 0 to 5 from the Pesquisa Nacional de Demografia e Saúde da Criança e da Mulher in Brazil and the Encuesta Nacional de Demografía y Salud in Bolivia, Colombia and Peru,using a birth weight ≥2,500g. The outcome variable was OW, the exposure was RWG and breastfeeding (BF) was the adjustment variable. Prevalence, odds ratio and 95% confidence intervalwere estimated using multivariate logistic regression model. Results: there was a greater prevalence of RWG and BF at less than 6 months in Brazil, and a greater prevalence of OW in Brazil and Bolivia. The chances of OW when RWG was present and adjusted for BF were 6.1 times (CI95% = 3.8-9.7) in Brazil, 4.4 times (CI95% = 3.6-5.3) in Bolivia, 6.7 times (CI95% = 5.5-8.2) in Colombia, and 12.2 times in Peru (CI95% = 9.4-15.7) with a p < 0.001 for all countries. Conclusions: RWG in children with normal birth weight was associated with a greater chance of being OW in the four observed Latin America countries.

Early-life weight gain patterns of term small-for-gestational-age infants and the predictive ability for later childhood overweight/obesity: A prospective cohort study

OBJECTIVES

We aimed to identify the weight gain patterns of small-for-gestational age (SGA) infants in early life and to explore the predictive value for later overweight/obesity in childhood.

METHODS

We obtained data from a prospective cohort including term SGA infants born between January 2006 and November 2015 who received regular health care from birth to 5 years in West China Second University Hospital, Chengdu, China. A latent class growth analysis (LCGA) was applied to group children with similar growth trajectory patterns. Multiple logistic regression was performed to examine the association between weight gain patterns and later overweight/obesity.

RESULTS

A total of 296 term SGA infants were finally included. Five weight gain trajectories were identified, including excessive rapid catch-up growth (ERCG) (class 1, 10.9%), rapid catch-up growth (RCG) (class 2, 17.9%), appropriate catch-up growth (ACG) (class 3, 53.0%), slow catch-up growth (SCG) (class 4, 13.4%) and almost no catch growth (NCG) (class 5, 4.8%). SGA infants in class 1 and class 2 had a higher BMI according to age- and sex-specific Z scores from 2-5 years of age. In addition, 25% of SGA infants in class 1 and 13.2% of SGA infants in class 2 were found to be overweight/obese at 2-5 years of age. After adjusting for confounders, we found that extremely rapid weight gain (class 1) in the first 2 years of life increased the risk of overweight/obesity by 2.1 times at 2 to 5 years of age (aOR=2.1, 95% CI: 1.3~4.8; P<0.05). Furthermore, the increment of ΔWAZ between 0 and 4 mo was prominently related to the risk of overweight/obesity at 2 to 5 years for term SGA infants (aOR=3.2, 95% CI: 1.7~8.1; P<0.001). A receiver operating characteristic (ROC) curve showed the area under curve (AUC) was 0.7, with a 95% confidence interval (CI) from 0.6 to 0.8 (P<0.001).

CONCLUSIONS

The extremely rapid weight gain pattern of term SGA infants in the first 2 years of life increased the risk of overweight/obesity at 2 to 5 years of age. It suggests monitoring weight gain across the infant period represents a first step towards primary prevention of childhood obesity.

Longitudinal changes in body mass index Z-scores during infancy and risk of childhood allergies

BACKGROUND

Few studies address the dynamic changes of body mass index (BMI) Z-scores during infancy with breastfeeding and their impact on childhood atopic diseases.

METHODS

A total of 183 children from a birth cohort regularly followed-up for 4 years were enrolled in this study. Time series data of BMI Z-scores from 1 month to 2 years of age was clustered using K-means method in R software. Breastfeeding status during the first 6 months of life was recorded and classified. The total serum and specific immunoglobulin E (IgE) levels to food and inhalant allergens were measured at age 0.5, 1, 1.5, and 2 years.

RESULTS

Using K-means clustering, the dynamic changes in BMI Z-scores were classified into three clusters (cluster A, increasing, n = 62; cluster B; decreasing, n = 62; cluster C, constant low, n = 59). Despite having no statistical association with atopic diseases, a decreasing trend in infantile BMI Z-scores was significantly associated with a higher prevalence of IgE sensitization at age 1 which increased the risk of rhinitis development at age 4 (P = 0.007). No difference in BMI Z-scores was determined between different breastfeeding patterns. However, exclusive formula feeding ≥6 months was found to be significantly associated with mite sensitization at age 1.5 years which risks asthma development at age 4 (P = 0.001).

CONCLUSIONS

A decreasing trend of BMI Z-scores during infancy is determined to be inversely associated with IgE and allergen sensitization, which may potentially increase the risk of allergies in early childhood.

Impact of short-term change of adiposity on risk of high blood pressure in children: Results from a follow-up study in China

This study aimed to examine the impact of short-term adiposity change on risk of high blood pressure (HBP), and to assess the low limit range of body mass index (BMI) and waist-to-height ratio (WHtR) reduction proposed to decrease the HBP risk in children. Children were longitudinally surveyed at baseline and after a short-term follow-up. General obesity (GOB) is categorized by age and gender-specific BMI cut-off points, abdominal obesity (AOB) by WHtR. Logistic regression model was used to estimate relations between adiposity change and HBP risk with adjustment of covariates. A total of 28,288 children (median of baseline age:10 years) were involved with follow-up of 6.88±1.20 months. After the follow-up, 9.4% of the children had persistent general obesity (GOB), 2.8% converted from GOB to non-GOB, 0.9% had newly developed GOB. When compared with children remained non-GOB, children with continuous GOB status, newly developed GOB, converting from GOB to non-GOB had 5.03-fold (95%CI: 4.32~5.86), 3.35-fold (95%CI: 1.99~5.65), 2.72-fold (2.03~3.63) HBP risk, respectively. Similar findings were observed for abdominal obesity (AOB). Reduction of 0.21–0.88 kg/m² of baseline BMI (0.86–3.59%) or 0.009–0.024 of baseline WHtR (1.66–4.42%) in GOB or AOB children, respectively, was associated with significant decrease in HBP risk. Children with persistent obesity, newly developed obesity, or converting from obese to non-obese had significantly higher HBP risk. For children with GOB or AOB, reduction of <3.6% in BMI or <4.5% in WHtR could decrease the HBP risk.

Appetite-Regulating Hormones in Human Milk: A Plausible Biological Factor for Obesity Risk Reduction?

BACKGROUND

Human milk contains appetite-regulating hormones that may influence infant growth and obesity risk.

RESEARCH AIMS

We evaluated whether leptin, peptide tyrosine-tyrosine (PYY), glucagon-like peptide-1 (GLP-1), and ghrelin concentrations in human milk (1) changed during feeding (from foremilk to hindmilk) and during the first 6 months of infancy; (2) were explained by maternal factors; and (3) were associated with infant anthropometrics and growth.

METHODS

Mother-infant dyads (N = 22) participated. Samples of foremilk and hindmilk at 1 month postpartum were collected and analyzed for leptin, PYY, GLP-1, and ghrelin via radioimmunoassay and milkfat percentage estimated via creamatocrit. Samples were also collected in mothers (n = 15) who breastfed through 6 months. Anthropometrics were obtained on all mother-infant dyads at 1 month and all infants at 6 months and 12 months.

RESULTS

At 1 month, milk GLP-1 and milkfat concentration increased from foremilk to hindmilk (p ≤ .05) while leptin and PYY concentrations remained stable during feeding. Milk hormone concentrations and milkfat tended to decline overtime, with lower leptin, PYY, and ghrelin at 6 months versus 1 month (p < .05). At 1 month, milk leptin and milkfat content were associated with maternal markers of adiposity (r = 0.49-0.78, p < .001); whereas, milk PYY was correlated with maternal serum PYY concentration (r = 0.672, p = .001). Average 1-month milk concentrations of GLP-1 and leptin were negatively associated with weight-for-age z-scores at 6 months (r = -0.46, p < .05) and 12 months (r = -0.49, p < .05), respectively.

CONCLUSION

The content of certain appetite-regulating hormones in human milk may be influenced by maternal factors and play a role in infant growth; much needs to be learned about their role in the obesity protection of breastfed infants.

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

Excess adiposity in infancy may predispose individuals to obesity later in life. The literature on determinants of adiposity in infants is equivocal. In this longitudinal cohort study, we investigated pre-pregnancy, prenatal and postnatal determinants of different adiposity indices in infants, i.e., fat mass (FM), percent FM (%FM), fat mass index (FMI) and log-log index (FM/FFM^p), from birth to 6 months, using linear mixed-effects regression. Body composition was measured in 322, 174 and 109 infants at birth and 3 and 6 months afterwards, respectively, utilising air displacement plethysmography. Positive associations were observed between gestation length and infant FM, maternal self-reported pre-pregnancy body mass index and infant %FM, and parity and infant %FM and FMI at birth. Surprisingly, maternal intake of iron supplements during pregnancy was associated with infant FM, %FM and FMI at 3 months and FM/FFM^p at 6 months. Male infant sex and formula feeding were negatively associated with all adiposity indices at 6 months. In conclusion, pre-pregnancy and pregnancy factors influence adiposity during early life, and any unfavourable impacts may be modulated postnatally via infant feeding practices. Moreover, as these associations are dependent on the adiposity indices used, it is crucial that researchers use conceptually and statistically robust approaches such as FM/FFM^p.

Rapid Weight Gain, Infant Feeding Practices, and Subsequent Body Mass Index Trajectories: The CALINA Study

We aimed to study growth patterns according to rapid weight gain (RWG) and infant feeding practices during the first 120 days and whether infant feeding practices mediated the association between RWG in the first semester of life and subsequent body mass index (BMI) z-score in children from age 1 to 6. (1) Methods: 862 children from the Growth and Feeding during Lactation and Early Childhood in Children of Aragon study (CALINA in Spanish) were examined. Repeated-measures ANOVA analyses were conducted to assess growth trajectories according to RWG and type of feeding practice. The product of coefficients mediation method was used to assess the potential contribution of infant feeding practices to the association between RWG and BMI z-score. Mediation models were conducted using IBM SPSS-PROCESS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp. (2) Results: BMI and weight z-score trajectories were significantly higher in the RWG group and the formula-fed group. No significant differences were found regarding height. Infant feeding practices did not mediate the association between RWG and BMI z-score but were associated with BMI at 6 years. (3) Conclusions: Infant feeding practices and RWG determine different growth trajectories of BMI and weight during childhood. Although infant feeding practices did not mediate the association between early RWG and BMI later in life, formula feeding is independently related to higher BMI growth patterns later in childhood.

Appropriate-for-gestational-age infants who exhibit reduced antenatal growth velocity display postnatal catch-up growth

Background

Postnatally, small-for-gestational-age (SGA; birthweight <10th centile) infants who are growth restricted due to uteroplacental insufficiency (UPI) demonstrate ‘catch-up growth’ to meet their genetically-predetermined size. Infants who demonstrate slowing growth during pregnancy are those that cross estimated fetal weight centiles at serial ultrasound examinations. These infants that slow in growth but are born appropriate-for-gestational-age (AGA; ≥10th centile), exhibit antenatal, intrapartum and postnatal indicators of UPI. Here, we examine if and when these infants (labelled as AGA-FGR) also demonstrate catch-up growth like SGA infants, when compared with AGA infants with normal antenatal growth velocity (AGA-NG).

Methods

We followed-up the infants of women who had previously undergone ultrasound assessment of fetal size at 28- and 36-weeks’ gestation, enabling calculation of antenatal growth velocity. To assess postnatal growth, we asked parents to send their infant’s growth measurements, up to two years post-birth, which are routinely collected through the state-wide Maternal-Child Health service. Infants with medical conditions affecting postnatal growth were excluded from the analysis. From the measurements obtained we calculated age-adjusted z-scores for postnatal weight, length and body mass index (BMI; weight(kg)/height(m²)) at birth and 4, 8, 12, 18 and 24 months. We used linear spline regression modelling to predict mean weight, length and BMI z-scores at intervals post birth. Predicted mean age-adjusted z-scores were then compared between three groups; SGA, AGA with low antenatal growth (AGA-FGR; loss of >20 customised estimated fetal weight centiles), and AGA-NG to determine if catch-up growth occurred. In addition, we compared the rates of catch-up growth (defined as an increase in weight age-adjusted z-score of ≥0.67 over 1 year) between the groups with Fisher’s exact tests.

Results

Of 158 (46%) infant growth records received, 146 were AGA, with low antenatal growth velocity occurring in 34/146 (23.2%). Rates of gestational diabetes and SGA birthweight were higher in those lost to follow-up. Compared to AGA-NG infants, AGA-FGR infants had significantly lower predicted mean weight (p<0.001), length (p = 0.04) and BMI (p = 0.001) z-scores at birth. These significant differences were no longer evident at 4 months, suggesting that catch-up growth had occurred. As expected, the catch-up growth that occurred among the AGA-FGR was not as great in magnitude as that demonstrated by the SGA. When assessed categorically, there was no significant difference between the rate of catch-up growth among the AGA-FGR and the SGA. Catch-up growth was significantly more frequent among both the AGA-FGR and the SGA groups compared to the AGA-NG.

Conclusions

AGA infants that have exhibited reduced antenatal fetal growth velocity also exhibit significant catch-up growth in the first 12 months of life. This finding represents further evidence that AGA fetuses that slow in growth during pregnancy do so due to UPI.

Associations of birth size, infancy, and childhood growth with intelligence quotient at 5 years of age: a Danish cohort study

BACKGROUND

The correlates of prenatal and postnatal growth on Intelligence Quotient (IQ) in childhood in term-born children living in high-income countries are not well known.

OBJECTIVES

We examined how birth size and growth in infancy and childhood were associated with IQ at age 5 y in term-born children using path analysis.

METHODS

The study sample comprised 1719 children from the Danish National Birth Cohort who participated in a substudy in which psychologists assessed IQ using the Wechsler Primary and Preschool Scales of Intelligence-Revised. Measured weight, length/height, and head circumference at birth, 5 mo, 12 mo, and 5 y were included in a path model to estimate their total, indirect, and direct effects on IQ. All growth measures were included in the model as sex- and age-standardized z-scores.

RESULTS

After adjusting for potential confounders, a positive association between birth weight and IQ was observed, and 88% of the association was direct. Weight gain in infancy was associated with IQ [per z-score increase from 5 to 12 mo, IQ increased by 1.53 (95% CI: 0.14; 2.92) points] whereas weight gain from 12 mo to 5 y was not associated with IQ. Height and head circumference growth in childhood was associated with IQ [per z-score increase from 12 mo to 5 y, IQ increased by 0.98 (95% CI: 0.17; 1.79) and 2.09 (95% CI: 0.78; 3.41) points, respectively].

CONCLUSIONS

In children born at term in an affluent country with free access to health care, higher IQ was seen with greater size at birth and greater weight gain in infancy. Also, greater growth in height and head circumference throughout the first 5 y of life was associated with higher childhood IQ whereas greater weight gain after the first year of life was not.