Breastmilk does a brain good!

Breastfeeding has long been debated as the more beneficial method of infant feeding when compared to bottle-feeding.  Many studies strongly associate breastfeeding with improved infant health; however, the long-term effects on mental health had not previously been measured.

In a three year (1989-1992) Australian longitudinal cohort study, 2366 women between 18-20 weeks gestation were enrolled and their children followed until 14 years after delivery to determine whether duration of breastfeeding independently effects child and adolescent mental health. Participants completed a questionnaire and then were subjected to structured interviews and clinical assessments at each follow-up (1,2,3,5,8,10, and 14 years). Age-appropriate Child Behaviour Checklists (CBCL) were used as a validation tool to assess behavioral psychopathology in children according to several syndrome constructs: withdrawn, anxious/depressed, somatic complaints, attention problems, thought problems, delinquent behavior, and aggressive behavior. Higher mental health scores on the CBCL represented poorer behavior while lower scores represented improved behaviors.  Confounding factors were accounted for, including maternal age at child’s birth, maternal education, maternal smoking, family income, whether biological father lived with family, life stress events, diagnosed maternal postpartum depression.  Birth data included child gender and proportion of optimal birth weight.

Children who were breastfed 6 months or longer had significantly lower mean CBCL mental health scores.  Improved behavior, as indicated by lower mental health scores, was related to longer duration of breastfeeding. Younger maternal age at birth, maternal education of 12 years or less, maternal smoking, and low incomes were associated with shorter duration of breastfeeding and also higher mental health scores. For example, at 14 years old, children who were breastfed 6 months or less had a total mean CBCL score of 48.23 as compared with a mean score of 45.17 by children who were breastfed for greater than 6 months. When considering maternal age, children born to mothers less than 25-years-old who breastfed less than 6 months had lower scores than those who breastfed 6 months or greater. Surprisingly, this trend was reversed for children born to mothers aged 25 years or greater; children breastfed 6 months or greater had higher CBCL scores.  The study also looked at trends of children in mental health morbidity groups (MHMG) at each assessment. Of those children who never breastfed, at the age of 8 years 19.4 percent were in MHMGs as compared to 13.5 percent of their cohorts who breastfed for 12 months or greater.

The authors acknowledge that their observed associations do not equate to a causal effect of breastfeeding on subsequent mental health; however, they state that longer breastfeeding duration appears to have significant benefits on child and adolescent mental health. The authors encourage interventions aimed at promoting longer duration breastfeeding.

Commentary

This and other studies make compelling implications of breastfeeding as the preferred source of infant nutrition.  Breastfeeding is associated with decreased infant infections, respiratory illnesses, sudden infant death syndrome (SIDS), and even postpartum depression.  While these associations exist, to demonstrate breastfeeding as an independent factor affecting child health continues to be a difficult task.  Nonetheless, breastfeeding is the natural source of infant nutrition which has sustained mankind long before formula alternatives.

Of note is the dichotomy of developed and underdeveloped countries in regards to breastfeeding. Studies have shown that breastfeeding is more often practiced by women with lesser resources in underdeveloped countries and, ironically, by women with greater resources in developed countries.

With the advent of US health reform (Patient Protection and Affordable Care Act, Section 4207) is the introduction of a provision in the Fair Labor Standards Act (FLSA) for breastfeeding working mother. Companies with greater than 50 employees are now required to provide a paid break and designated area (other than a bathroom) for breast-pumping mothers for up to one year following delivery. Perhaps, this provision will increase the number of breastfed infants in the US. Will this translate into a healthier society?  Is this just the tip of the iceberg of the new focus on prevention? Only time will tell.

Pediatrics. 2010; 156 (4): 568-574.

by
Renee Volny, MD, MBA