A new study from the Barcelona Institute for Global Health (ISGlobal), a centre supported by the ‘la Caixa’ Foundation, has provided further scientific evidence of the health benefits of well-designed urban planning.
The study published in Environment International suggests that the built environment, green space and air pollution can affect cognitive and motor function in children. According to numerous studies, the urban environment can influence neurodevelopment from conception onwards, for example through exposure to air pollution. However, previous research has not evaluated the impact of multiple exposure groups simultaneously using an early-life exposome approach.
A team from the European HELIX project, coordinated by ISGlobal, set out to analyse the impact of 13 urban exposures on the cognitive and motor function of nearly 5,500 children in seven European urban areas–Bradford, United Kingdom; Nancy and Poitiers, France; Gipuzkoa, Sabadell and Valencia, Spain; and Heraklion, Greece–using data from the birth cohorts Born in Bradford, EDEN, the INMA Environment and Childhood Project.
The new study analysed urban residential exposures from pregnancy until age three years. The analysed factors include the built environment (building density, proximity to public transport, facility richness, etc.), natural spaces, and air pollution from nitrogen dioxide (NO2) and fine particulate matter (PM2.5). Cognitive function (verbal and non-verbal abilities) and motor function (fine and gross motor functions) were assessed using validated tests when the children were four to five years old.
The findings showed that exposure to some built environment design factors, natural spaces and air pollution was associated with children’s cognitive and motor function at five years of age. Specifically, higher exposure to greenness within 300 metres of the home during pregnancy was associated with higher verbal abilities. In contrast, greater connectivity (density of street intersections) and land-use diversity during pregnancy were associated with lower verbal abilities.
“To our knowledge, this is the first study to show the negative impact of some factors of the built environment on children’s verbal abilities” commented ISGlobal researcher Anne-Claire Binter, lead author of the study. “In previous studies, the land-use diversity has been associated with positive health effects, so more studies are needed to interpret these results,” she adds.
As for air pollution, in line with previous research, greater exposure to fine particulate matter during pregnancy was associated with lower scores on tests of fine motor function. “During pregnancy, the placenta and the blood-brain barrier, which protects the brain and spinal cord, are still immature defence systems and provide only partial protection to the foetus against environmental pollutants,” said Binter.
The study confirmed the mediating effect of air pollution on the association between green space and verbal skills. In other words, “natural environments could have a beneficial effect on cognitive development by reducing the harmful effects of air pollution,” said study coordinator Monica Guxens, director of the INMA Project. “Beyond urban green space, our findings suggest that other urban characteristics should be considered when studying environmental exposures that may affect children’s cognitive function. The health of the populationshould form the basis of urban planning,” she said.