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By Jason Boudville

A first ever study by UWA and Yale University has examined the relationship between neighbourhood greenness and weight status using satellite remote sensing.

Results showed that in neighbourhoods with greater greenness, there are lower odds of being overweight or obese.

Using self-reported height and weight (Body Mass Index) from 10,208 adults across three age segments, researchers were able to reference this against Landsat imagery sourced by Landgate.

Dr Gavin Pereira from UWA's Centre for the Built Environment and Health, and Yale Centre for Perinatal, Paediatric and Environmental Epidemiology, led the study which used satellite remote sensing of vegetation.

"Body weight is influenced by a range of factors such as genetics, diet and exercise," Dr Pereira said.

"Previous studies have also linked weight status to socioeconomic position and social networks. But the potential influence of the built and natural environment on weight status is not well understood."

The odds of being obese were 22 per cent lower for people in the greenest neighbourhoods in comparison to the least green when considering greenness as an absolute measure (mean greenness).

However, when considering variability of mean greenness, for example tree-lined streets connecting built destinations, this had the strongest impact on levels of obesity by a 25 per cent difference when comparing greenest versus least green.

"More striking was that the absolute level of greenness was not as important as the variability of greenness in a neighbourhood," Dr Pereira says.

"Our results might indicate the importance of well-connected tree-lined routes to walkable destinations such as shops and services.

"Equally, it might reflect the indirect health benefits from the presence of well-maintained parks with sufficient road access and parking."

While the study was able to assess greenness on a sheer numbers level, a limitation was the attractiveness of the greenness or ‘quality'-known to influence behaviour in populations.

Using a measure of greenness, NDVI (Normalised Difference Vegetation Index), map data was assigned lower numerical values for rock, sand, rooftops, and roads, and higher values for grassland, bushland and healthy green vegetation. Bodies of water were removed from the index.

Dr Pereira says further research is necessary to identify the specific attributes of greenness that indirectly promote health.

Obesity in Australia continues to rise.

It is an important modifiable risk factor in preventing cardiovascular disease, hypertension and type II diabetes.

(This story was first published online by Science Network WA)