Duration of breast feeding and attention-deficit/hyperactivity disorder in United States preschool-aged children

Pathways of atopic disease and neurodevelopmental impairment: assessing the evidence for infant antibiotics

INTRODUCTION

Epidemiologic studies are starting to report associations between antibiotic use in early life and neurodevelopmental disorders. Through mechanisms within the gut microbiota-brain axis, indeed, it is plausible that infant antibiotic treatment plays a role in the development of atopic disease and neurodevelopmental disorders.

AREAS COVERED

This narrative review summarizes and interprets published evidence on infant antibiotic use in future outcomes of atopic disease, and neurodevelopmental delay and disorders, including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). To this end, we critically assess study bias from 2 main confounding factors, maternal/infant infection and infant feeding status. We also discuss common mechanisms that link atopy and neurodevelopment, and propose hypotheses related to immune activation and the gut microbiome.

EXPERT OPINION

Atopic disease and neurodevelopmental disorders share many risk factors and biological pathways. Infant antibiotic use has been linked to both disorders and is likely a marker for prenatal or infant infection. The mediating role of breastfeeding can also not be discounted. The exploration of causal pathways along the gut-brain axis leading towards neurodevelopmental impairment is evolving and of future interest.

Associations of Maternal Milk Feeding With Neurodevelopmental Outcomes at 7 Years of Age in Former Preterm Infants

IMPORTANCE

Maternal milk feeding may have unique long-term neurodevelopmental benefits in very preterm infants.

OBJECTIVE

To examine the extent to which maternal milk feeding after very preterm birth is associated with cognitive, academic, and behavioral outcomes at school age.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study assessed 586 infants born at less than 33 weeks' gestation at 5 Australian perinatal centers and enrolled in the Docosahexaenoic Acid for Improvement of Neurodevelopmental Outcomes study (January 1, 2001, to December 31, 2005) who were evaluated at a corrected age of 7 years. The statistical analysis was completed on January 19, 2022.

EXPOSURES

Maternal milk intake, including mean volume (milliliters per kilogram per day) during neonatal hospitalization and total duration (in months).

MAIN OUTCOMES AND MEASURES

Neurodevelopmental outcomes at 7 years of age were (1) IQ (Wechsler Abbreviated Scale of Intelligence), (2) academic achievement (Wide Range Achievement Test, Fourth Edition), (3) symptoms of attention-deficit/hyperactivity disorder (ADHD) (Conners Third Edition ADHD Index, parent reported), (4) executive function (Behavior Rating Inventory of Executive Functioning, parent reported), and (5) behavior (Strengths and Difficulties Questionnaire, parent reported).

RESULTS

A total of 586 infants (mean [SD] gestational age at birth, 29.6 [2.3] weeks; 314 male [53.6%]) born to 486 mothers (mean [SD] age, 30.6 [5.5] years; 447 [92.0%] White) were included. Mean (SD) maternal milk intake in the neonatal intensive care unit was 99 (48) mL/kg daily, and mean (SD) maternal milk duration was 5.1 (5.4) months. Mean (SD) full-scale IQ was 98.5 (13.3) points. After covariate adjustment, higher maternal milk intake during the neonatal hospitalization was associated with higher performance IQ (0.67 points per additional 25 mL/kg daily; 95% CI, 0.10-1.23 points), reading scores (1.14 points per 25 mL/kg daily; 95% CI, 0.39-1.89 points), and math scores (0.76 points per 25 mL/kg daily; 95% CI, 0.14-1.37 points) and fewer ADHD symptoms (-1.08 points per 25 mL/kg daily; 95% CI, -1.96 to -0.20 points). Longer duration of maternal milk intake was associated with higher reading (0.33 points per additional month; 95% CI, 0.03-0.63 points), spelling (0.31 points per month; 95% CI, 0.01-0.62 points), and math (0.30 points per month; 95% CI, 0.03-0.58 points) scores. Maternal milk was not associated with improved full-scale IQ, verbal IQ, executive function, or behavior. Most associations were stronger among infants born at lower gestational ages, particularly less than 30 weeks (interaction P values <.01).

CONCLUSIONS AND RELEVANCE

In this cohort study of preterm infants, maternal milk feeding during the neonatal hospitalization and after discharge were associated with better school-age performance IQ and academic achievement and with a reduction in ADHD symptoms, particularly among infants born at less than 30 weeks' gestation.

The Role of Motor Coordination, ADHD-Related Characteristics and Temperament among Mothers and Infants in Exclusive Breastfeeding: A Cohort Prospective Study

Although exclusive breastfeeding is recommended for the first 6 months of life, breastfeeding rates are low. Motor skills and ADHD-related characteristics have not yet been examined as breastfeeding barriers. The aim of this study was to explore whether mothers' and infants' motor skills, mothers' ADHD-related characteristics and infants' temperament are associated with exclusive breastfeeding at 6 months after birth. Participants were 164 mothers and their infants recruited 2 days after birth. Mothers completed a demographic and delivery information questionnaire, the Infant Feeding Intentions Scale and the Iowa Infant Feeding Attitude Scale. At 6 months, mothers completed the Adult DCD (developmental coordination disorder)/Dyspraxia Checklist, the Adult ADHD (attention deficit hyperactivity disorder) Self-Report Scale Symptom Checklist-v1.1, and the Infant Characteristics Questionnaire, and provided information about their breastfeeding status. They were then divided into two groups accordingly: EBF (exclusive breastfeeding) and NEBF (non-exclusive breastfeeding). Infants were observed using the Test of Sensory Functions in Infants and the Alberta Infant Motor Scale. At 6 months, NEBF mothers reported higher prevalence of DCD (10.2% vs. 1.9%, χ2 = 5.561, p = 0.018) and ADHD (20.3% vs. 8.6%, χ2 = 4.680, p = 0.030) compared to EBF mothers. EBF infants demonstrated better motor coordination (t = 2.47, p = 0.016, d = 0.511), but no temperament differences compared to NEBF infants. Maternal DCD, ADHD and poor infant motor coordination are associated with non-exclusive breastfeeding and may become exclusive breastfeeding barriers. These findings may assist in identifying women at risk of not exclusively breastfeeding and encourage tailoring interventions for achieving higher exclusive breastfeeding rates.