The most common risk to a child's development is that their parents suffer from depression, according to new research.
Alcoholism, overcrowded homes and substance abuse were also dangers, as was a parent with a disability. But none of these was as common as depression, which affected a fifth of the families surveyed.
The study by academics from the Institute of Education, University of London, reached the - perhaps unsurprising - conclusion that growing up in an environment where there are multiple problems harmed a child's development. The more "compounding risks" the child faced, the more challenging their grown-up years would be. They found that if a pupil had been exposed to two or more risks in the first few years of their childhood, they were likely to have a negative impact on the rest of their life.
The report may still prove useful to teachers, however, as it gives a clearer picture of the range and frequency of problems their pupils might face.
The study, Multiple Risk Factors in Young Children's Development, was produced by Ricardo Sabates and Shirley Dex from the Centre for Longitudinal Studies at the Institute of Education. They used data from the Millennium Cohort Study of children, a longitudinal survey of 18,818 new babies born in 2000 and 2001, and the 18,552 families bringing them up.
Researchers aimed to find the prevalence of multiple risks for families with very young children in the UK and how these were associated with deficits in developmental outcomes when the children were 3 and 5.
After parental depression, the most common was physical disability, which affected 15 per cent of families. Meanwhile, 12.4 per cent of families in the survey were affected by alcohol abuse and 11.7 per cent by substance abuse.
Looked at from the perspective of families' ethnicity, Bangladeshi families faced the highest rates of multiple risks, followed by black African and Pakistani families. Indian families faced the lowest levels.
The researchers said politicians "should start worrying" about the 27 to 28 per cent of families with young children who in 2001 faced two or more risks.
Although it was "extremely difficult" to help such children, they stressed that each of the 10 risk areas they identified could be addressed individually by government intervention.
"Clearly, government policy aimed at safeguarding children from damaging levels of multiple risks has a challenging task ahead," they said. "It has to address the predominant co-occurring economic disadvantages some families face, such as worklessness and low basic skills among parents, as well as the mental health problems of parents, teenage motherhood and associated overcrowded housing conditions.
"These calculations do not suggest this will be an easy task. The multiple risks experienced by some families were not found to group together very comfortably."
In the case of families facing three risk factors, the most common combination was that of smoking, financial stress and teenage motherhood.
For families facing four risks, the most common combination was parental depression, worklessness, teenage motherhood and low basic skills.
However, the researchers said that there were "not obvious sets of circumstances" that could be described as "risk types".
"This lack of clustering points to a gloomy conclusion that there are no easy wins for policy and intervention," they wrote.
"Our findings point to the conclusion that there is relatively little to be gained by policy from tackling clusters of disadvantage rather than individual disadvantages. However, there may still be some knock-on effects from tackling some individual risk factors and disadvantages, even if not all, according to the extent to which individual risks increase in the presence of others."
Multiple risk factors in young children's development.
Centre for Longitudinal Studies (CLS), Institute of Education, University of London.