A new study has identified a key factor in protecting at-risk pre-school children from becoming overweight or obese and the elixir is sleep.

The University of Auckland research examined data from Growing Up in New Zealand, this country's largest longitudinal study of child development, to determine what protects at-risk children from becoming obese.

The research shows that at-risk children who get even an extra hour's sleep at night are 25 per cent more likely to have a healthy body weight, says lead author Dr Samantha Marsh from the National Institute for Health Innovation.

'Our findings highlight the importance of night-time sleep for young children and the protection it offers for children who are potentially vulnerable to becoming overweight or obese.

'However, the relationship between sleep and obesity is likely to be more complex, with organisation in the home and positive parent-child interactions at bedtime and other family routines likely to be important as well.”

The researchers examined information collected from more than 6,000 children in the Growing Up in New Zealand study to compare risk factors and protective factors associated with obesity.

They focused on children who met at least two risk factors for being overweight or obese.

Risk factors included, families experiencing high levels of stress, insecurity and chronic poverty, families living in areas in which the built environment reduces opportunities for physical activity, families experiencing financial stress which could lead to the purchase of low-cost but energy-dense and nutrient poor foods.

Samantha says the researchers then looked at whether these 'at-risk” children were a healthy weight, overweight or obese.

'We know that many children maintain a healthy body weight despite being exposed to a range of risk factors for obesity. We wanted to know what it is that ‘protects' these children or gives them ‘bodyweight resilience'. If we can figure that out, then we can look at ways to help children who may be on a pathway to becoming overweight or obese.”

A range of 'resilience” factors were identified including style of parenting, family routines, child sleep, screen use and the family mealtime environment.

The research found that while less screen time and a higher quality of family meals were found to be important, night-time sleep seemed to be key, she says.

'The fact that sleep is associated with ‘bodyweight resilience' may actually reflect greater organisation in the home environment which is supportive of sleep.

'This means that promoting adequate night-time sleep in pre-schoolers may not be sufficient in and of itself. There may also be a need to reduce household chaos and promote greater family organisation.”

Other studies have found that shorter night-time sleep duration increases the risk of children becoming obese, but have not looked at what might prevent obesity in vulnerable families, Samantha says.

'This research is significant because it highlights ‘resilience' factors that families who face many of the traditional barriers to health may be able to action to help keep their pre-school children a healthy weight.”

She says, further research is now needed to establish the exact relationship between night-time sleep and family organisation.

It's important to focus on how to build long-term healthy sleep routines in pre-schoolers in a way that is developmentally safe, culturally appropriate and protects the parent-child relationship, Samantha says.