Breastfeeding, parenting, and early cognitive development

Unraveling the effects of maternal breastfeeding duration and exclusive breast milk on children's cognitive abilities in early childhood

Background

This study investigated the putative associations between mothers' use of exclusive breast milk and the duration of breastfeeding with child cognitive development.

Methods

This study is based on 2,210 Canadian families with children assessed longitudinally from age 4 to 7 years on their memory-span and math skills. These cognitive abilities were measured with standardized tasks. Breastfeeding practices were collected via maternal reports. We applied propensity scores to control the social selection bias for breastfeeding.

Results

Results adjusted for propensity scores and sample weight revealed no significant differences between non-breastfed children with those being non-exclusively breastfed for 5 months or less, and with children being exclusively breastfed for 9.2 months on average, on their early math skills and memory-span. We found that children who were non-exclusively breastfed for 6.8 months on average had a slightly higher levels of memory-span at age 4 than children who were never breastfed, and this small but significant difference lasted up to age 7.

Conclusion

Our findings suggest no significant differences between children being exclusively breastfed and those fed with formula on their early math skills and memory-span. The encouragement of breastfeeding to promote child cognitive school readiness may, in some case (non-exclusive breastfeeding for more than 5 months), show a small but long-lasting advantage in early memory-span.

Preterm Birth and Other Measures of Infant Biological Vulnerability: Associations with Maternal Sensitivity and Infant Cognitive Development

INTRODUCTION

Low birth weight (LBW), biological vulnerability that includes preterm birth (PTB) and small for gestational age (SGA), is associated with reduced maternal sensitivity ("making accurate inferences about an infant's physical and emotional needs and responding appropriately") and impaired infant cognitive development. However, research does not examine if preterm birth, SGA, or both drive these associations. This study separated these measures of biological vulnerability to examine associations of LBW, PTB, and SGA with maternal sensitivity and infant cognitive development (controlling for maternal depression, breastfeeding, and demographic covariates).

METHODS

The sample included 6900 9-month-old infants from the Early Childhood Longitudinal Study-Birth Cohort and used birth certificate data, maternal interviews, assessments of maternal sensitivity and infant cognitive development. Multiple linear regressions examined LBW, PTB, and SGA associations with concurrent measures of maternal sensitivity and infant cognition.

RESULTS

Of the biological vulnerabilities, preterm birth had the strongest negative association with maternal sensitivity (F_1,6450 = 29.48 versus 15.33 and 5.51, ps < .001) and infant cognitive development (F_1,6450) = 390.65 versus 248.02 and 14.43, ps < .001). In the final regression model, preterm birth and maternal sensitivity were uniquely associated with infant cognitive development (R² = .05, p < .001), after controlling for maternal depression, breastfeeding, and demographics.

CONCLUSION

In this nationally representative infant sample infants, PTB had a stronger negative association with both maternal sensitivity and infant cognitive development in comparison to SGA or LBW. The LBW designation combines infants born preterm with SGA infants, potentially minimizing differences in developmental outcomes of PTB and SGA infants.

The Benefits of Breastfeeding on Child Intelligence, Behavior, and Executive Function: A Review of Recent Evidence

Background: The effects of breastfeeding on neurodevelopmental outcomes are unclear. Inconsistent findings have been reported and confounding factors make interpretation of studies difficult. The World Health Organization published a systematic review on breastfeeding and intelligence in 2013, demonstrating a positive association with improved performance on intelligence tests. The objective of this review is to explore published literature since 2013 to examine the association between breastfeeding, cognition, executive function, and behavior. Methods: Duplicate searches were carried out using Web of Science and OVID for publications between January 2012 and March 2022. Non-English articles and those not correcting for maternal IQ or home environment were excluded. Results: Twenty-three studies were included, examining the effects of breastfeeding on cognition (21), executive function (3), and behavior (6). Most studies showed a modest dose-dependent increase in cognitive scores in children who were breastfed, test score differences ranging from 0.19 to 0.96 points per month of breastfeeding comparing any breastfeeding, predominant and exclusive breastfeeding. Four out of six studies showed a positive correlation between breastfeeding and behavior. One out of three studies assessing breastfeeding and executive function showed a positive dose-dependent correlation. Discussion: Recent evidence demonstrates that breastfeeding has a small positive effect on IQ in later childhood. Evidence suggesting that breastfeeding is a protective factor in developing conduct disorders and achieving higher executive function is limited. Further research is required. Limitations include potential confounders and recall bias of breastfeeding.

Blood-Stained Colostrum: A Rare Phenomenon at an Early Lactation Stage

The phenomenon described in the literature as rusty pipe syndrome is a rare condition (the estimated incidence is 0.1% in the population of breastfeeding women) where the prenatal milk and the colostrum are rust- or blood-colored. Due to the rare occurrence of this phenomenon and the related nature of the baby’s regurgitated discharge—green, brown or blood-stained, there is a general fear of latching a newborn or continuing to breastfeed if the regurgitation persists. In this care report, a patient’s milk was tested to determine its microbiological and morphological content. No significant abnormalities were noted in these tests. The nutritional profile of the blood-stained colostrum was normal. Breast milk has an indisputably invaluable impact on the newborn’s further development and there is no connection between rusty pipe syndrome, as described in the literature, and any clinical complications. This is crucial to encourage mothers to keep breastfeeding even if they observe blood-stained colostrum.

Does breastfeeding account for the association between maternal sensitivity and infant cognitive development in a large, nationally representative cohort?

Background

Previous research has established that exposure to high maternal sensitivity is positively associated with advances in infant cognitive development. However, there are many fixed and modifiable factors that influence this association. This study investigates whether the association between maternal sensitivity and infant cognitive development in the first year of life is accounted for by other factors, such as breastfeeding, maternal depressive symptoms, maternal alcohol use, infant birth weight or demographic covariates.

Methods

Using data from the Early Childhood Longitudinal Study-Birth (ECLS-B) Cohort, a nationally representative sample of U.S. born children, multi-variable regression analyses was used to examine whether breastfeeding, maternal depressive symptoms and alcohol use were associated with maternal sensitivity, as measured by the Nursing Child Assessment Teaching Scale (NCATS), and with infant cognitive development, as measured by the Bayley Scales of Infant Development, Short Form, Research Edition, after controlling for demographic covariates (infant sex, maternal age, education, race/ethnicity, income, parity, family structure) and infant birth weight.

Results

Breastfeeding, depressive symptoms and alcohol use were not associated with maternal sensitivity scores after controlling for demographic covariates and infant birth weight. However, breastfeeding (β = .079, p < .001), depressive symptoms (β = −.035, p < .05), and maternal sensitivity (β = .175, p < .001) were each significantly associated with infant cognitive development scores, even after controlling for demographic covariates and birthweight (R² = .053, p < .001). The association between maternal sensitivity and infant cognitive development did not attenuate after adjusting for breastfeeding. Instead, both sensitivity and breastfeeding independently contributed to higher infant cognitive development scores.

Conclusion

Maternal sensitivity and breastfeeding are separate means to advancing infant cognitive development. This study is significant because it is the first to examine breastfeeding, maternal depressive symptoms and alcohol use together, upon the association between maternal sensitivity and infant cognitive development, after adjusting for demographic covariates and infant birthweight. Maternal sensitivity, a measurable quality, advances infants’ cognitive development. Moreover, sensitivity and breastfeeding had independent effects upon cognitive development after controlling for multiple fixed and modifiable covariates. Understanding factors impacting the association between sensitivity and infant cognitive development provide avenues for developing more effective parenting interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03133-4.

A mixed methods study of perinatal sleep and breastfeeding outcomes in women at risk for postpartum depression

INTRODUCTION

Pregnant and postpartum women experience significant sleep disruption, but the role of perinatal sleep disturbances in breastfeeding is understudied.

METHODS

In this observational cohort study, we used mixed methods to examine associations between perinatal sleep and breastfeeding. Forty-eight women (mean age 28.2 ± 4.9 years) who were euthymic at enrollment but had a history of major depression (n = 43) or bipolar disorder (n = 5) had sleep recorded with wrist actigraphy. We determined feeding status through daily diaries and used semi-structured interviews to identify themes regarding participants' experiences, breastfeeding decisions, and behaviors. To examine whether sleep disturbance during pregnancy predicted breastfeeding (BF) rates, we defined "lower sleep efficiency" (LSE) and "higher sleep efficiency" (HSE) groups based on the median split of actigraphic SE at 33 weeks' gestation (cutoff SE = 84.9%) and classified mothers as No-BF, Mixed-BF (BF + formula), and Exclusive-BF at 2 weeks postpartum.

RESULTS

Percentages of women who did any breastfeeding were: Week 2 = 72.3%, Week 6 = 62.5%, Week 16 = 50%. LSE mothers were less likely than HSE mothers to initiate breastfeeding (percent No-BF: LSE = 45.8%, HSE = 16.7%, P < .05). Average actigraphic sleep onset, sleep offset, time in bed, sleep duration, and SE did not differ based on breastfeeding status at any time point. Qualitative themes included insufficient preparation for the demands of breastfeeding, interrupted and nonrestorative sleep, and unrelenting daytime tiredness.

CONCLUSIONS

In our sample, preserved actigraphic SE during pregnancy was associated with initiation and continuation of breastfeeding. Future work should examine whether improving sleep in pregnancy improves mothers' feeding experiences.

Breastfeeding Duration Is Associated With Domain-Specific Improvements in Cognitive Performance in 9-10-Year-Old Children

Significant immunological, physical and neurological benefits of breastfeeding in infancy are well-established, but to what extent these gains persist into later childhood remain uncertain. This study examines the association between breastfeeding duration and subsequent domain-specific cognitive performance in a diverse sample of 9-10-year-olds enrolled in the Adolescent Brain Cognitive Development (ABCD) Study®. The analyses included 9,116 children that attended baseline with their biological mother and had complete neurocognitive and breastfeeding data. Principal component analysis was conducted on data from an extensive battery of neurocognitive tests using varimax-rotation to extract a three-component model encompassing General Ability, Executive Functioning, and Memory. Propensity score weighting using generalized boosted modeling was applied to balance the distribution of observed covariates for children breastfed for 0, 1-6, 7-12, and more than 12 months. Propensity score-adjusted linear regression models revealed significant association between breastfeeding duration and performance on neurocognitive tests representing General Ability, but no evidence of a strong association with Executive Function or Memory. Benefits on General Ability ranged from a 0.109 (1-6 months) to 0.301 (>12 months) standardized beta coefficient difference compared to those not breastfed. Results indicate clear cognitive benefits of breastfeeding but that these do not generalize to all measured domains, with implications for public health policy as it pertains to nutrition during infancy.

Association between breastfeeding during infancy and white matter microstructure in early childhood

INTRODUCTION

Associations between breastfeeding and brain development, in the context of child, perinatal, and sociodemographic variables, remain unclear. This study investigated whether exclusive breastfeeding for the first 6 months and total duration of breastfeeding were associated with brain white matter microstructure in young children.

METHODS

This study included 85 typically developing children (42 males) born to 83 mothers that were predominantly white, highly educated, and in high income households. Children underwent their first diffusion tensor imaging scan between ages 2.34 and 6.97 years; some children returned multiple times, providing a total of 331 datasets. Feeding information was collected from mothers at 3, 6, and 12 months postpartum and at their child's scan to calculate breastfeeding status at 6 months (exclusive or not) as well as total duration of any breastfeeding. Linear regression was used to investigate associations between breastfeeding exclusivity/duration and fractional anisotropy (FA) for the whole brain and 10 individual white matter tracts.

RESULTS

Breastfeeding exclusivity and duration were associated with global and regional white matter microstructure, even after controlling for perinatal and sociodemographic factors. Greater exclusivity was associated with higher FA in females and lower FA in males.

CONCLUSIONS

These findings suggest white matter differences associated with breastfeeding that differ by sex. These may stem from different trajectories in white matter development between males and females in early childhood and suggest possible long-term white matter differences associated with breastfeeding.

The Effect of Parenting Quality on Child Development at 36-48 Months in China's Urban Area: Evidence from a Birth Cohort Study

Environmental exposures, especially parenting quality, are critical for later child development. This study aimed to determine the status of parenting quality and suspected development delay of preschool children in China's urban area and explore the associations between these two factors. The research was based on a birth cohort study conducted in Changsha, Hunan province, China. We used the Parenting Assessment Tool and Ages and Stages Questionnaires, Third Edition (ASQ-3), to measure parenting quality and child development status, respectively. Other data were collected from maternal health manuals and self-administered questionnaires during the follow-up period. The generalized estimating equation was used to examine whether parenting quality was significantly associated with child development outcomes. In the study, good parenting quality was 33.6% measured at 18 months, and suspected development delay was below 10% at 36-48 months among urban China; we observed negative associations between parenting quality scores and child development scores; poor parenting quality had a negative association with suspected development delay [OR and 95% CI: 2.74 (1.17, 6.40)], girls [OR and 95% CI: 0.33 (0.16, 0.69)] and maternal education years (>12 years) [OR and 95% CI: 0.27 (0.12, 0.64)] were protective factors for suspected development delay. Our findings highlighted the importance of good parenting quality among children in urban areas of China through a birth cohort study and may be used to reduce the children at high risk of developmental delay as a future intervention program.

Predictors of low perceptual-motor skills in children at 4-5 years of age

Abstract Objectives: the purpose of this study was to evaluate the predictors of low perceptual-motor skills in children at preschool age. Methods: this is a cross-sectional study nested in a birth cohort involving mother-child pairs. The children’s perceptual-motor skills were assessed individually in their homes when they were 4-5 years old using the Pre-Literacy Skills and Knowledge Test (THCP®), a vali-dated Brazilian instrument. Logistic regression analysis was used to estimate the association between cognitive perceptual-motor skills and potential maternal and child risk factors. Results: of the 199 children included in the study, 53.8% were boys, 90.8% attended school, and 91.1% were enrolled in a public school. Among the children, 114 (57.3%), 41 (20.6%) and 44 (22.1%) had low, moderate and high perceptual-motor skills, respectively. Multivariate logistic regression analysis revealed greater odds of children at preschool age having low perceptual motor skills for boys (OR=2.10; CI95%= 1.14-3.88), children who did not attend school (OR=4.61; CI95%= 1.21-17.49), and those with a household income <5 minimum wages (MW) (OR=4.28; CI95%= 1.49-12.26). Conclusions: our study showed that male gender, not attending school and a monthly household income <5 MW were predictors of low perceptual-motor skills in children at 4-5 years of age.

Dysmaturation of Premature Brain: Importance, Cellular Mechanisms, and Potential Interventions

Prematurity, especially preterm birth (less than 32 weeks' gestation), is common and associated with high rates of both survival and neurodevelopmental disability, especially apparent in cognitive spheres. The neuropathological substrate of this disability is now recognized to be related to a variety of dysmaturational disturbances of the brain. These disturbances follow initial brain injury, particularly cerebral white matter injury, and involve many of the extraordinary array of developmental events active in cerebral white and gray matter structures during the premature period. This review delineates these developmental events and the dysmaturational disturbances that occur in premature infants. The cellular mechanisms involved in the genesis of the dysmaturation are emphasized, with particular focus on the preoligodendrocyte. A central role for the diffusely distributed activated microglia and reactive astrocytes in the dysmaturation is now apparent. As these dysmaturational cellular mechanisms appear to occur over a relatively long time window, interventions to prevent or ameliorate the dysmaturation, that is, neurorestorative interventions, seem possible. Such interventions include pharmacologic agents, especially erythropoietin, and particular attention has also been paid to such nutritional factors as quality and source of milk, breastfeeding, polyunsaturated fatty acids, iron, and zinc. Recent studies also suggest a potent role for interventions directed at various experiential factors in the neonatal period and infancy, i.e., provision of optimal auditory and visual exposures, minimization of pain and stress, and a variety of other means of environmental behavioral enrichment, in enhancing brain development.

Is breast feeding associated with offspring IQ at age 5? Findings from prospective cohort: Lifestyle During Pregnancy Study

OBJECTIVES

Breast feeding is associated with health benefits for both mother and child, but many studies focusing on neurodevelopment have lacked information on important confounders and few randomised trials exist. Our objective was to examine the influence of breast feeding on child IQ at 5 years of age while taking maternal IQ and other relevant factors into account.

DESIGN

Prospective observational study.

SETTING

Population-based birth cohort in Denmark.

PARTICIPANTS

We used data from The Lifestyle During Pregnancy Study 1782 mother-child pairs sampled from the Danish National Birth Cohort (n=101 042).

OUTCOME MEASURES

Child IQ was assessed at age 5 years by the Wechsler Primary and Preschool Scales of Intelligence-Revised. On the same occasion maternal intelligence was assessed by Wechsler Adult Intelligence Scale and Raven's Standard Progressive Matrices. Exposure data on duration of breast feeding (n=1385) were extracted from telephone interviews conducted when the child was 6 and 18 months, and analyses were weighted by relevant sampling fractions.

RESULTS

In multivariable linear regression analyses adjusted for potential confounders breast feeding was associated with child IQ at 5 years (categorical χ2 test for overall association p=0.03). Compared with children who were breast fed ≤1 month, children breast fed for 2-3, 4-6, 7-9 and 10 or more months had 3.06 (95% CI 0.39 to 5.72), 2.03 (95% CI -0.38 to 4.44), 3.53 (95% CI 1.18 to 5.87) and 3.28 (95% CI 0.88 to 5.67) points higher IQ after adjustment for core confounders, respectively. There was no dose-response relation and further analyses indicated that the main difference in IQ was between breast feeding ≤1 month versus >1 month.

CONCLUSIONS

Breastfeeding duration of 1 month or shorter compared with longer periods was associated with approximately three points lower IQ, but there was no evidence of a dose-response relation in this prospective birth cohort, where we were able to adjust for some of the most critical confounders, including maternal intelligence.

Association between Breastmilk LC PUFA, Carotenoids and Psychomotor Development of Exclusively Breastfed Infants

The first months of infant life are crucial for proper neurodevelopment, which may be influenced by several factors, including nutrition and nutrients (e.g., long-chain polyunsaturated fatty acids (LC PUFA) and carotenoids) of which the concentration in breastmilk is diet-dependent. This study analysed the relationship between the average concentrations of selected LC PUFA and carotenoids in breastmilk samples from the first and third months of lactation and the psychomotor development of exclusively breastfed infants at the sixth month of life. Infant psychomotor development was assessed using the Children Development Scale (DSR). The average age of infants during the assessment was 6.6 ± 0.2 months and 30.9 ± 3.8 years for mothers (n = 39 mother⁻infant pairs). The average concentration of docosahexaenoic acid (DHA) was 0.50% of fatty acids. The average concentration of carotenoids was 33.3 nmol/L for β-carotene, 121 nmol/L for lycopene and 33.3 nmol/L for lutein + zeaxanthin. The total results of the Performance scale and Motor subscale were 39 centiles and 4.1 points, respectively. Adjusted multivariate regression models revealed associations between breastmilk DHA and motor development (β = 0.275; p ≤ 0.05), α-linolenic acid (ALA; β = 0.432; p ≤ 0.05), n-3 LC PUFA (β = 0.423; p ≤ 0.05) and β-carotene (β = 0.359; p ≤ 0.05). In addition, an association between the Perception subscale and DHA was observed (β = 0.316; p ≤ 0.05; model 2). There were no significant associations between the overall Performance scale scores. Due to the positive association between concentrations of n-3 LC PUFA (ALA and DHA) and β-carotene in breastmilk and infant motor development, it is important to provide these nutrients with breastmilk. According to the diet-dependent concentration of these compounds in breastmilk, breastfeeding mothers should have a diet abundant in dietary sources of these nutrients, e.g., fish, nuts, seeds, vegetable oils, vegetables and fruits.

Complementary feeding and developmental milestones: a systematic review

BACKGROUND

Systematic reviews were conducted as part of the USDA and the US Department of Health and Human Services Pregnancy and Birth to 24 Months Project to examine the relation between complementary feeding and developmental milestones.

OBJECTIVES

The aim of this study was to describe systematic reviews examining the relationship between timing of introduction of complementary foods and beverages (CFB), and the types and amounts of CFB consumed, and developmental milestones.

METHODS

The literature was searched using 4 databases (PubMed, Cochrane, Embase, and CINAHL) to identify articles that met predetermined criteria for inclusion. Data extraction and risk of bias assessment were conducted for each included study. The body of evidence for each systematic review was qualitatively synthesized to develop a conclusion statement, and the strength of evidence was graded.

RESULTS

Three included articles (1 randomized controlled trial; 2 observational studies) examined timing of introduction of CFB. Eight included articles (3 randomized controlled trials; 5 observational studies) examined types and amounts of CFB. There was insufficient evidence to draw conclusions about the relation between either timing of CFB introduction or types and amounts of CFB, and developmental milestones.

CONCLUSIONS

The ability to draw conclusions about the relationship between complementary feeding and developmental milestones was restricted by an inadequate amount of evidence with potential for issues with reverse causality and wide variation in design, type/age of outcome assessment, exposure assessment, and reported results. Additional research to address these gaps and limitations would be useful.

Parental socioeconomic position and midlife allostatic load: a study of potential mediators

BACKGROUND

The mechanisms underlying the association of parental socioeconomic position with later life allostatic load remain unclear. The present study aims to examine potential pathways underlying this association: personality, social relations, intelligence and education.

METHODS

The study comprised 361 members of the Copenhagen Perinatal Cohort who participated in two subsequent follow-ups: the Prenatal Development Project (mean age 27 years) and the Copenhagen Aging and Midlife Biobank study (mean age 50 years). Allostatic load was based on 14 biomarkers representing the inflammatory, metabolic and cardiovascular system measured at midlife. Information on potential mediators was collected in young adulthood, and their role in the association of parental socioeconomic position with midlife allostatic load were examined in linear regression path analyses.

RESULTS

Parental socioeconomic position at one year was inversely associated with midlife allostatic load (β = - 0.238, p < .001). No mediation effects were found for personality or social relations. In a model including intelligence and education, a significant indirect effect was found for education (β = - 0.151, p < .001). A significant direct effect remained (β = - 0.111, p = .040).

CONCLUSIONS

Parental socioeconomic position was inversely associated with allostatic load in midlife. Results suggest that part of this association was mediated by education. A better understanding of the non-cognitive pathways related to education is an important prerequisite for the development of effective intervention strategies.

Association between breastfeeding and better preserved cognitive ability in an elderly cohort of Finnish men

BACKGROUND

Being breastfed in infancy has been shown to benefit neurodevelopment. However, whether the benefits persist to old age remains unclear.

METHODS

We examined the associations between breastfeeding and its duration on cognitive ability in young adulthood and old age, and on aging-related cognitive change over five decades. In total, 931 men from the Helsinki Birth Cohort Study born in 1934-1944 in Finland took the Finnish Defence Forces Basic Intellectual Ability Test (total and verbal, arithmetic and visuospatial subtest scores) twice, at ages 20.2 and 67.9 years, and had data on breastfeeding (yes v. no) and its duration ('never breastfed', 'up to 3', '3 to 6' and '6 or more months'). Linear and mixed model regressions tested the associations.

RESULTS

At 20.2 years, breastfed men had higher cognitive ability total and visuospatial subtest scores [mean differences (MDs) ranged between 3.0-3.9, p values < 0.013], and its longer duration predicted higher cognitive ability total and arithmetic and visuospatial subtest scores (MDs ranged between 3.0 and 4.8, p values < 0.039). At 67.9 years, breastfed men had higher total cognitive ability and all subtest scores (MDs ranged between 2.6 and 3.4, p values < 0.044) and its longer duration predicted all cognitive ability scores (MDs ranged between 3.1 and 4.7, p values < 0.050). Verbal subtest scores decreased over five decades in men who were never breastfed or were breastfed for 3 months or less, and increased in those breastfed for longer than 3 months.

CONCLUSIONS

Neurodevelopmental advantages of breastfeeding and its longer duration persist into old age, and longer duration of breastfeeding may benefit aging-related change, particularly in verbal reasoning ability.

Avoiding selection bias without random assignment? The effect of breastfeeding on cognitive outcomes in China

OBJECTIVES

Recent studies suggest that some of the health benefits traditionally attributed to breastfeeding may be overstated due to selection bias problems, since typically breastfeeding is more prevalent in more resourceful households. In this paper we argue that an important antidote against selection bias consists in analyzing data from contexts in which breastfeeding is not normativised, or where it is not systematically associated to socioeconomic advantage and best parenting practices. We estimate the effect of breastfeeding on the cognitive outcomes of Chinese children.

METHODS

We use observational data from a representative sample of children aged 10-15 from the China Family Panel Study. We estimate province fixed effect linear regression models to predict the impact of breastfeeding on test scores.

RESULTS

Our paper shows that there are no advantages in the results obtained by breastfed children when compared with those who were not breastfed, regardless of the duration of breastfeeding.

CONCLUSIONS

Some of the cognitive benefits associated to breastfeeding can be attributed to flaws inherent to the research designs usually adopted.

Breastfeeding is associated with enhanced learning abilities in school-aged children

OBJECTIVE

The majority of studies on the associations between breastfeeding and cognitive functioning have focused on IQ, with only a few investigating learning skills, and none of the latter adjusting for maternal IQ. We examined the association between breastfeeding and learning abilities in school-aged children using a cross-sectional design.

METHODS

We recruited 868 children, aged 8-11 years and parents completed the Learning Disability Evaluation Scale (LDES). Multivariable linear regression models were used and age, gender, area of residence, annual family income, maternal education, and maternal age at delivery, were included as covariates. Maternal IQ was added to further adjust for the effects of maternal cognitive ability. Path analysis was conducted to investigate the mediation effect of maternal IQ between breastfeeding and learning skills.

RESULTS

Children who were ever-breastfed had higher learning quotient scores on the LDES (p = 0.001) as well as higher scores on subscales related to speaking (p = 0.001), reading (p = 0.005), writing (p = 0.004), spelling (p = 0.003), and mathematical calculation (p = 0.003) than the never-breastfed participants. All of these variables remained significant after adjusting for gestational and socioeconomic factors and for maternal IQ as covariates. The path analysis showed that breastfeeding had both indirect and direct effects on the learning quotient.

CONCLUSIONS

The results suggest that breastfeeding is positively associated with learning skills in school-aged children.

Overweight and obese infants present lower cognitive and motor development scores than normal-weight peers

AIMS

Compare the cognitive and motor development in overweight/obese infants versus normal-weight peers and investigate the correlation of body weight, body length and body mass index with cognitive and motor development.

METHODS

We conducted a cross-sectional study with 28 overweight/obese infants and 28 normal-weight peers between 6 and 24 months of age. Both groups were evaluated with cognitive and motor scales of the Bayley-III infant development test. The t-test for independent samples was performed to compare the groups, and the Spearman correlation was used to verify the association between variables.

RESULTS

Overweight/obese infants showed lower cognitive and motor composite scores than their normal-weight peers. A significant negative association was found of body weight and body length with cognitive development and of body mass index with motor development.

CONCLUSION

This is the first study that found an effect on both cognitive and motor development in overweight/obese infants when compared with normal-weight peers between 6 and 24 months of age.

Breastfeeding and child development outcomes: an investigation of the nurturing hypothesis

This study investigated whether the nurturing hypothesis - that breastfeeding serves as a proxy for family socio-economic characteristics and parenting behaviours - accounts for the association of breastfeeding with children's academic abilities. Data used were from the Child Development Supplement of the Panel Study of Income Dynamics, which followed up a cohort of 3563 children aged 0-12 in 1997. Structural equation modelling simultaneously regressed outcome variables, including three test scores of academic ability and two subscales of behaviour problems, on the presence and duration of breastfeeding, family socio-economic characteristics, parenting behaviours and covariates. Breastfeeding was strongly related to all three tests scores but had no relationships with behaviour problems. The adjusted mean differences in the Letter-Word Identification, Passage Comprehension) and Applied Problems test scores between breastfed and non-breastfed children were 5.14 [95% confidence interval (CI): 3.14, 7.14], 3.46 (95% CI: 1.67, 5.26) and 4.24 (95% CI: 2.43, 6.04), respectively. Both socio-economic characteristics and parenting behaviours were related to higher academic test scores and were associated with a lower prevalence of externalising and internalising behaviour problems. The associations of breastfeeding with behaviour problems are divergent from those of socio-economic characteristics and parenting behaviours. The divergence suggests that breastfeeding may not be a proxy of socio-economic characteristics and parenting behaviours, as proposed by the nurturing hypothesis. The mechanism of breastfeeding benefits is likely to be different from those by which family socio-economic background and parenting practices exert their effects. Greater clarity in understanding the mechanisms behind breastfeeding benefits will facilitate the development of policies and programs that maximise breastfeeding's impact.

Breastfeeding duration and offspring conduct problems: The moderating role of genetic risk

RATIONALE

A sizable body of research has examined associations between breastfeeding and various facets of offspring development, including childhood behavioral problems. Notwithstanding the number of studies on the topic, breastfeeding has not consistently been linked to child misbehaviors. Moreover, empirical examinations of whether breastfeeding is differentially predictive of conduct problems among individuals with varying degrees of genetic risk are lacking.

OBJECTIVE

The present study examines whether a short duration of breastfeeding and genetic risk interact to predict conduct problems during childhood.

METHODS

A genetically informative design is employed to examine a subsample of twins from the Early Childhood Longitudinal Study: Birth Cohort (ECLS-B), a nationally representative sample of American children.

RESULTS

The findings suggest that a shorter duration of breastfeeding only enhances the risk of offspring conduct problems among children who possess high levels of genetic risk. Conversely, longer breastfeeding durations were found to protect against childhood behavioral problems when genetic risk was high.

CONCLUSIONS

Indicators of genetic risk may help to distinguish individuals whose behavioral development is most sensitive to the duration of breastfeeding. Future research should seek to replicate and extend these findings by considering genetic factors as potential markers of differential susceptibility to breastfeeding duration.

Breastfeeding and maternal alcohol use: Prevalence and effects on child outcomes and fetal alcohol spectrum disorders

OBJECTIVE

Determine any effects that maternal alcohol consumption during the breastfeeding period has on child outcomes.

METHODS

Population-based samples of children with fetal alcohol spectrum disorders (FASD), normally-developing children, and their mothers were analyzed for differences in child outcomes.

RESULTS

Ninety percent (90%) of mothers breastfed for an average of 19.9 months. Of mothers who drank postpartum and breastfed (MDPB), 47% breastfed for 12 months or more. In case control analyses, children of MDPB were significantly lighter, had lower verbal IQ scores, and more anomalies in comparisons controlling for prenatal alcohol exposure and final FASD diagnosis. Utilizing a stepwise logistic regression model adjusting for nine confounders of prenatal drinking and other maternal risks, MDPB were 6.4 times more likely to have a child with FASD than breastfeeding mothers who abstained from alcohol while breastfeeding.

CONCLUSIONS

Alcohol use during the period of breastfeeding was found to significantly compromise a child's development.

Using linked educational attainment data to reduce bias due to missing outcome data in estimates of the association between the duration of breastfeeding and IQ at 15 years

Background: Most epidemiological studies have missing information, leading to reduced power and potential bias. Estimates of exposure-outcome associations will generally be biased if the outcome variable is missing not at random (MNAR). Linkage to administrative data containing a proxy for the missing study outcome allows assessment of whether this outcome is MNAR and the evaluation of bias. We examined this in relation to the association between infant breastfeeding and IQ at 15 years, where a proxy for IQ was available through linkage to school attainment data.

Methods: Subjects were those who enrolled in the Avon Longitudinal Study of Parents and Children in 1990–91 (n = 13 795), of whom 5023 had IQ measured at age 15. For those with missing IQ, 7030 (79%) had information on educational attainment at age 16 obtained through linkage to the National Pupil Database. The association between duration of breastfeeding and IQ was estimated using a complete case analysis, multiple imputation and inverse probability-of-missingness weighting; these estimates were then compared with those derived from analyses informed by the linkage.

Results: IQ at 15 was MNAR—individuals with higher attainment were less likely to have missing IQ data, even after adjusting for socio-demographic factors. All the approaches underestimated the association between breastfeeding and IQ compared with analyses informed by linkage.

Conclusions: Linkage to administrative data containing a proxy for the outcome variable allows the MNAR assumption to be tested and more efficient analyses to be performed. Under certain circumstances, this may produce unbiased results.

Maternal risk factors for fetal alcohol spectrum disorders in a province in Italy

BACKGROUND

Maternal risk factors for fetal alcohol spectrum disorders (FASD) in Italy and Mediterranean cultures need clarification, as there are few studies and most are plagued by inaccurate reporting of antenatal alcohol use.

METHODS

Maternal interviews (n = 905) were carried out in a population-based study of the prevalence and characteristics of FASD in the Lazio region of Italy which provided data for multivariate case control comparisons and multiple correlation models.

RESULTS

Case control findings from interviews seven years post-partum indicate that mothers of children with FASD are significantly more likely than randomly-selected controls or community mothers to: be shorter; have higher body mass indexes (BMI); be married to a man with legal problems; report more drinking three months pre-pregnancy; engage in more current drinking and drinking alone; and have alcohol problems in her family. Logistic regression analysis of multiple candidate predictors of a FASD diagnosis indicates that alcohol problems in the child's family is the most significant risk factor, making a diagnosis within the continuum of FASD 9 times more likely (95%C.I. = 1.6 to 50.7). Sequential multiple regression analysis of the child's neuropsychological performance also identifies alcohol problems in the child's family as the only significant maternal risk variable (p < .001) when controlling for other potential risk factors.

CONCLUSIONS

Underreporting of prenatal alcohol use has been demonstrated among Italian and other Mediterranean antenatal samples, and it was suspected in this sample. Nevertheless, several significant maternal risk factors for FASD have been identified.