Posted on 10 May 2011
There have been few large scale studies carried out so far of a possible link between infant feeding and child behaviour and, of those, findings have been inconsistent. When socio-economic and parental factors were taken into account, findings that previously suggested breastfed children had fewer behaviour problems were sometimes rejected.
Our findings suggest that longer duration of breastfeeding (at all or exclusively) is associated with having fewer parent-rated behavioural problems in term children
Professor Mary Renfrew
Researchers from the Mother and Infant Research Unit in the Department of Health Sciences at York, along with colleagues from the universities of Oxford, Essex, and University College London, set out to examine whether or not there was a link between infant feeding and subsequent child behaviour. The research is published in the Archives of Disease in Childhood.
The researchers used data from a large UK study known as the Millennium Cohort Study involving 10,037 mother-child pairs from a white ethnic background. The Millennium study is a survey of infants born in the UK during a 12-month period in 2000-2001. People who took part were interviewed when their child was nine months old and they were revisited at two-yearly intervals.
Within the data group studied by the researchers, there were 9,525 full-term and 512 pre-term children.
They used a Strengths and Difficulties Questionnaire (SDQ) completed by the parents to score children and identify potential behavioural problems including emotional (eg clinginess, anxiety), hyperactivity (eg restlessness), and conduct (eg lying and stealing), by the time the child was aged five.
Results showed that 29 per cent of children born at full term and 21 per cent of children born prematurely were breastfed for at least four months.
They found that abnormal scores for the questionnaires, which indicate potential behavioural problems, were less common in children breastfed for at least four months (six per cent) than in formula fed children (16 per cent).
The lower risk of a full-term breastfed child having abnormal scores for behaviour were also noted even when the researchers took into account other influences such as socioeconomic or parental factors.
The evidence for an association between breastfeeding and behavioural problems in premature children was unclear.
One possible reason for the findings suggested by the authors was that breast milk contains large amounts of essential long chain polyunsaturated fatty acids, growth factors and hormones which have an important role in the development and function of the brain and central nervous system.
Manufacturers have only started to supplement formula milks with essential fatty acids in the past decade and the effectiveness of such supplementation is unclear.
The results might also be explained, they added, by the fact that breastfeeding leads to more interaction between mother and child, better learning of acceptable behaviours and fewer behavioural problems.
The Director of MIRU, Professor Mary Renfrew, said: “Our findings suggest that longer duration of breastfeeding (at all or exclusively) is associated with having fewer parent-rated behavioural problems in term children.”