Pregnancy and child

Brain tests may predict children at risk of becoming 'social burdens'

"Brain tests predict children's futures," BBC News reports. A study found that childhood factors such as low IQ, parental neglect and poor self-control were strongly associated with "socially costly" outcomes in adulthood, including smoking and obesity.

The New Zealand based study followed the lives of 1,037 individuals from birth until midlife.

Children were assessed on four specific risk factors:

  • socio-economic status
  • IQ
  • exposure to parental mistreatment / neglect
  • level of self-control

The researchers aimed to see whether these factors could predict outcomes in adulthood that place a high burden on the economy through costs on healthcare and social services, such as obesity, criminal convictions and cigarette smoking. They found a strong link between poorer adult outcomes and the four factors.

The researchers were keen to stress that their research wasn't an attempt to identify and stigmatise a group of children – "blaming the victims" as they put it. Instead they hoped it could be used to identify children who would benefit most from early-years interventions, such as pre-school education and parental training. They argue that the initial costs of these types of intervention would prove to be a wise investment by avoiding the potential societal costs that could be incurred in the long-term.

However, finding reliable interventions that effectively address such broad and varied issues as social deprivation and child IQ may be quite a challenge.

If you are struggling with parenting issues, or know somebody who is, a wide range of support is available.

Where did the story come from?

The New Zealand based study was carried out by researchers from Duke University in the US, King's College London and the University of Otago in New Zealand. It was funded by grants from the US National Institute on Aging (NIA).

The study was published in the peer-reviewed scientific journal Nature: Human Behaviour.

The UK media's reporting of the study, while not discussing some of the limitations in full, was broadly accurate. And refreshingly, all sources made the point that this research could be used to identify children who would benefit from additional support.

As mentioned above, exactly what support would be best was not discussed in any detail.

What kind of research was this?

This was an analysis of a prospective cohort study (the Dunedin Longitudinal Study) which followed the lives of 1,037 children in New Zealand.

The analysis tested the hypothesis that childhood risks may be able to predict poor outcomes in adulthood (such as obesity, criminal convictions, and rate of cigarette smoking). The researchers believed a small segment of the adult population places a large burden on the economy and that this could be predicted with fairly good accuracy from early childhood.

Prospective cohort studies are useful in determining the potential relationship between an exposure and an outcome, in this case between exposure during childhood and potentially detrimental outcomes in adulthood.

However, the study design does not allow for confirmation of cause and effect, and it isn't possible to rule out the influence of other factors.

What did the research involve?

The Dunedin Multidisciplinary Health and Development Study tracked 1,073 individuals born in Dunedin, New Zealand during the years 1972 and 1973, from birth to midlife. The participants were assessed at age 3, 5, 7, 9, 11, 13, 15, 18, 21, 26, 32 and 38.

The following childhood risk factors were measured:

  • Childhood socioeconomic status – an average of the highest earning parent was measured from birth until age 11 (1 = unskilled labourer and 6 = professional).
  • Childhood maltreatment – evidence of harsh discipline, maternal rejection, changes in the child's primary caregiver, physical abuse etc.
  • Childhood intelligence – measured as IQ at ages 7, 9 and 11 years of age.
  • Childhood self-control – this was determined using parent or teacher reports of hyperactivity, lack of persistence, impulsive aggression etc., from birth until age 10.

"Brain health" was also measured at age three. This was described as a process of creating an index (or scorecard) based on intelligence, language and development, as well as basic functions associated with the brain, such a movement.

When the cohort reached adulthood, clinical data and information from personal interviews were derived using New Zealand's multiple nationwide administrative databases and electronic medical records. Data on the following outcomes was measured:

  • social welfare benefit months
  • fatherless child-years
  • tobacco smoking pack-years
  • excess obese kilograms
  • hospital-bed nights
  • injury insurance claims
  • convictions for crime

The data was analysed to investigate whether there was a link between childhood risk factors and these economic-burden outcomes in adulthood – that is, growing up to become an adult responsible for a high cost to society.

What were the basic results?

Overall, the researchers observed a strong link between poorer adult outcomes and four childhood risk factors: growing up in more socially deprived conditions, experience of child maltreatment, poor childhood IQ score, and exhibition of low self-control.

Each of the four exposures significantly increased risk of social welfare by between 18 and 31%; the more of these factors present in childhood, the greater the risk.

The four childhood risk factors were variably associated with the other economic burdens. The next strongest predictors were for crime, with childhood risk factors being weaker predictors of other outcomes, such as excess weight and injury claims.

The researchers estimated that 22% of the cohort was responsible for:

  • 36% of the cohort's injury claims
  • 40% of excess obese kilograms
  • 54% of cigarettes smoked
  • 57% of hospital nights
  • 66% of welfare benefits
  • 77% of fatherless child-rearing
  • 78% of prescription fills
  • 81% of criminal convictions

"Brain health" at age three – as measured by the child's neurological signs, intelligence, language and development – was estimated to be a strong mediator of economic-burden outcomes.

How did the researchers interpret the results?

The researchers concluded: "This research yielded two results. First, the study uncovered a population segment that featured as high cost across multiple health and social sectors ... Second, by linking administrative data with individual-level longitudinal data, the study provides the strongest effect sizes yet, measuring the connection between an at-risk childhood and costly adult outcomes in the population."


This study aimed to test the hypothesis that childhood risks may be able to predict poor outcomes in adulthood (such as obesity, criminal convictions, rate of cigarette smoking etc.) that are potentially responsible for the greatest economic burden on society.

Overall it found that the four factors – growing up in more socially deprived conditions, experience of child maltreatment, poor childhood IQ score, and exhibition of low self-control – were associated with poorer outcomes in adulthood.

The research benefits from using a fairly large sample of individuals followed up from birth until midlife. As the authors also say, it wouldn't have been possible to identify these factors without the comprehensive databases and electronic health records that they had.

However, cohort studies like this one aren't able to rule out the influence of other factors in the suspected links. We don't know that these four childhood risk factors are directly and independently responsible for the adult outcomes. The researchers' calculations of the proportion of economic burden that they could be contributing are estimates only, not certain answers.

This is also a single New Zealand cohort. Analysing another birth cohort from a different culture or society could identify different high-burden adult outcomes, and different associated child factors.

Even if the four identified risk factors are directly contributing to economic burden in society, what to actually do about it is another question. The researchers hope that early life interventions that address these risk factors "could yield very large returns on investment".

However, finding interventions that effectively tackle such broad and varied issues as social deprivation and child IQ may be quite a challenge.

Though due to the potential long-term savings these interventions could bring, it is arguably a challenge worth undertaking.

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