Living near woods may ward off dementia risk in elderly

London, July 12  While exposure to tiny air pollution particles have known to increase the risk of dementia, including Alzheimers disease, researchers find that older adults, especially women staying near greener neighbourhoods would have better brain health as they age.

Older adults, particularly women, who are closer to greener neighbourhoods were found to have slower decline in cognitive functions related to memory, attention and executive functions.

"There is evidence that the risk for dementia and cognitive decline can be affected by exposure to urban-related environmental hazards such as air pollution and noise and lifestyle such as stress and sedentary behaviour," said lead author Carmen de Keijzer, from Barcelona Institute for Global Health in Spain.

In contrast, living near green spaces will increase physical activity and social support, reduce stress, and mitigate exposure to air pollution and noise, she added.

For the study, published in the journal Environmental Health Perspectives, the researchers performed a 10 years follow-up of 6,500 people aged between 45 and 68 years.

At three different points of time during the course of the study, participants completed a battery of cognitive tests that assessed their verbal and mathematical reasoning, verbal fluency and short-term memory, as well as decline in these functions. 

"Our data showed that the decline in the cognitive score after the 10-years follow up was 4.6 per cent lesser in participants living in greener neighbourhoods. Interestingly enough, the observed associations were stronger among women, which make us think that these relations might be modified by gender," Keijzer said.

The study may provide an evidence base for implementing targeted interventions aimed at decelerating cognitive decline in older adults residing in urban areas and hence improving their quality of life, the researchers said.