Experts flag limitations in study linking breastfeeding to lower special education needs in children

11 Apr 2023 --- Research is revealing that exclusively breastfed and mixed-fed children (formula and breastfeeding) had a lower risk for all-cause special education needs (SEN). However, experts warn missing data on the children’s parents’ health, education and IQ restrict the validity of these outcomes.

Mixed feeding of babies at six to eight weeks old resulted in a 9% decrease in odds of all-cause SEN, while exclusively breastfeeding decreased these odds by 12%. SEN attributed to learning disabilities and difficulties was also lower for these groups.

The study, which compared formula feeding and exclusive breastfeeding in 191,745 Scottish children, found that 19% experienced lower communication problems, 23% lower social-emotional-behavioral difficulties, 21% lower sensory impairments, 22% lower physical motor disabilities and 24% lower physical health conditions. 

“This is a large and useful study which is all too easy to interpret as showing breastfeeding helps protect a child from risk,” notes Professor Petroc Sumner, head of the School of Psychology at Cardiff University, Wales. “But we must always be careful when reading causes into correlations.”

“Most importantly, the authors note that the data did not allow them to control for parental education level, which is one of the plausible reasons why an association between infant feeding method and educational needs might exist.”Mixed-feeding and exclusively breastfeeding babies of six to eight weeks old resulted in a decrease in the odds of all-cause SEN.

“Correlations are not causal”
The study’s authors suggest that the feeding method in infancy could be a modifiable risk factor for all-cause SEN. They assert that even a short duration of nonexclusive breastfeeding could benefit the development of SEN. 

However, Dr. Danya Glaser, a visiting professor at University College London, warns there could be other factors that are associated with special educational needs, such as low socioeconomic status. 

“There is also a correlation between no breastfeeding and low socioeconomic status. This study has not adequately controlled for this.”

“We know that better-educated parents are more likely to breastfeed their children and it is important to take this into account before we can assume a causal effect of breastfeeding on preventing special educational needs and learning difficulties,” adds Professor Ken Ong from the University of Cambridge, UK. 

“Another limitation is they had information on breastfeeding only at age six weeks and it would have been helpful to know if there is an optimal duration of breastfeeding or whether ‘the longer, the better.’”

The Lancet reports on breastfeeding stress that it has health benefits for the infant as the risk of childhood infectious disease, malnutrition, mortality and developing obesity later in life decreases. 

Parental education and IQ 
The researchers used the mothers’ socioeconomic status at birth as a substitute for unavailable data on parental education levels and intelligence, which literature indicates affects learning difficulties and SEN. 

“For example, women with a higher IQ are more likely to breastfeed and are more likely to have a higher level of education and be in better physical health than women with a lower IQ,” explains Dr. David Hill, Medical Research Council research fellow, University of Edinburgh, Scotland. 

“As such, by measuring the effect of breastfeeding on special educational needs, the authors are also measuring if the physical health, socioeconomic status and the IQ of the mother is associated with the special educational needs of their children.” 

“In addition, parents share genes with their children. Children born to mothers with a higher IQ are likely to have inherited genetic variants that leave them less likely to have special educational needs.”

The authors note that the impact of maternal IQ, parental education level, occupation and alcohol or drug use during pregnancy on children’s SEN levels should be studied in further research. Experts caution that factors other than breastfeeding could be associated with special educational needs. 

Study outcomes 
The researchers used national health data on maternity and birth. Health visitor records indicated how babies were fed at six to eight weeks old. The authors distinguished between exclusive breastfeeding, mixed (both breastfeeding and formula) feeding and formula feeding. 

The research, published in PLOS Medicine, included children born in Scotland from 2004 onward, with available breastfeeding data and who attended schools between 2009 and 2013, with education data from the annual school pupil census. 

Of the children in the study, 66.2% were formula-fed, 25.3% were exclusively breastfed and 8.5% were mixed-fed. Overall, 12.1% of children had a record of SEN, mainly with learning difficulties, social, emotional and behavioral difficulties, communication problems and learning disabilities. 

“Human milk contains a large variety of bioactive components that benefit the breastfed baby and, in some cases, the breastfeeding mother,” Dr. Lars Bode, founding director of the Human Milk Institute, previously told NutritionInsight. He noted that babies that receive human milk and women who breastfeed have a lower risk of developing heart attacks and strokes. 

 The US Food and Drug Administration recently revealed a new strategy to increase resiliency in the country’s infant formula supply and market. Contamination with Cronobacter sakazakii has led to a shortage in formula products. 

By Jolanda van Hal