Having breast milk in the first few weeks of life may help to reduce the risk of having special educational needs (SEN), or the learning disabilities and difficulties that often cause this, according to new research led by the University of Glasgow.
The study of nearly 200,000 children showed that those who were either exclusively breast-fed or fed a mix of formula and breast milk for the first 6-8 weeks of life were at lower risk of SEN and learning disabilities compared with formula-fed infants.
The findings might be encouraging for women who struggle to breast-feed exclusively for the full 6 months now recommended by the World Health Organisation. They provided "evidence that a shorter duration of non-exclusive breast-feeding may still be beneficial for a child’s later learning development".
Escalating Rates of Special Needs
The researchers noted that SEN were increasingly recorded among Scottish schoolchildren. Between 2010 and 2018, there was an almost fourfold increase, and by 2020 almost a third of pupils in Scotland had an SEN record.
Children with SEN experience lower educational attainment, higher rates of school absenteeism and exclusion, and higher rates of bullying and maltreatment, all of which are inimical to physical and mental health and well-being. "Discovering modifiable early life risk factors for SEN is, therefore, important to enable these burdens potentially to be eased through prevention or earlier detection," they said.
As infant breast-feeding has been associated with a reduced incidence of various childhood physical and mental health problems, they set out to investigate the impact of early life feeding on later intellectual development.
For their retrospective study, published in PLOS Medicine, they linked health (maternity, birth, and health visitor records) and education (annual school pupil census) databases for a cohort of 191,745 singleton children born in Scotland from 2004 onwards, who attended either local authority mainstream or special schools between 2009 and 2013. Children who were born in private hospitals, privately educated, or home-schooled were not included.
Among the children overall, 23,141 (12.1%) required SEN help; 126,907 (66.2%) had been formula fed, 48,473 (25.3%) exclusively breast-fed, and 16,365 (8.5%) mixed-fed for the first 6-8 weeks of life.
When compared with formula feeding, mixed feeding was associated with around a 10% decrease in the risk of having all-cause SEN (odds ratio [OR] 0.90, 95% CI 0.84 to 0.95, P<0.001). SEN was about 20% less likely following exclusive breast-feeding (OR 0.78, 95% CI 0.75 to 0.82, P<0.001).
SEN specifically attributed to learning disabilities was also decreased by about a quarter for mixed feeding (OR 0.75, 95% CI 0.65 to 0.87, P<0.001) and a third for exclusive breast-feeding (OR 0.66, 95% CI 0.59 to 0.74, P<0.001). Learning difficulties per se were also lower (mixed feeding OR 0.85, 95% CI 0.77 to 0.94, P=0.001 and breast-feeding OR 0.75, 95% CI 0.70 to 0.81, P<0.001).
Emotional, Behavioural, and Physical Problems Also Lower After Exclusive Breast-feeding
Moreover, exclusively breast-fed children were around 20% less likely to have emotional or behavioural difficulties and 25% less likely to have physical health problems, after adjusting for available sociodemographic and maternity factors. Compared with formula feeding, odds ratios for exclusively breast-fed children were significantly lower for:
- Communication problems (OR 0.81, 95% CI 0.74 to 0.88, P=0.001)
- Social-emotional-behavioural difficulties (OR 0.77, 95% CI 0.70 to 0.84, P=0.001)
- Sensory impairments (OR 0.79, 95% CI 0.65 to 0.95, P=0.01)
- Physical motor disabilities (OR 0.78, 95% CI 0.66 to 0.91, P=0.002)
- Physical health conditions (OR 0.74, 95% CI 0.63 to 0.87, P=0.01)
There were no significant associations with emotional, behavioural, or physical problems for mixed-fed children.
Feeding method was not significantly associated with mental health conditions or autism, although there was a trend towards reductions in the exclusively breast-fed group (mental health OR 0.58, 95% CI 0.33 to 1.03, P=0.061; autism OR 0.88, 95% CI 0.77 to 1.01, P=0.074).
Advantages of Breast-feeding Reinforced
The authors concluded: "Both breast-feeding and mixed feeding at 6-8 weeks were associated with lower risk of all-cause SEN, and SEN attributed to learning disabilities and learning difficulty."
They added: "Our findings augment the existing evidence base concerning the advantages of breast-feeding and reinforce the importance of breast-feeding education and support."
The team acknowledged that higher case ascertainment may have contributed to the recent dramatic leap in SEN numbers in Scotland but said that SEN "nonetheless represents a significant burden on the education, health, and social sectors".
Corresponding author Dr Michael Fleming PhD, lecturer in public health at the University of Glasgow, said: "The results of this study suggest that feeding method in infancy could be a modifiable risk factor for the causes of SEN, which in turn has the potential to help reduce the burden for affected children, their families and wider society."
The researchers acknowledged that they had no data on parental education level, IQ, employment status, race/ethnicity, or mental and physical health that could have affected the results.
Confounding Influence of Parental IQ and Education Level
Commenting on the study to the Science Media Centre, Professor Petroc Sumner, head of the school of psychology at Cardiff University, said: "This is a large and useful study which is all too easy to interpret as showing breast-feeding helps protect a child from risk.
"But we must always be careful when reading cause 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."
Dr David Hill, MRC research fellow, Lothian Birth Cohorts, Department of Psychology, University of Edinburgh, agreed that the lack of data on parental health, education, or IQ placed "some severe limitations on the claim that breast-feeding in infancy could be a modifiable risk factor for the causes of SEN." He noted that women with a higher IQ were more likely to breast-feed, and more likely to have a higher level of education and to be in better physical health.
"As such, by measuring the effect of breast-feeding on SEN, the authors are also measuring if the physical health, socioeconomic status, and the IQ of mothers 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 study was funded by Health Data Research UK.