People in hotter, poorer neighbourhoods at higher risk of death during extreme heat

In Vancouver, heat exposure and social vulnerability can be a lethal combination.

New research from the University of British Columbia shows a higher risk of mortality during extreme heat events in neighbourhoods that tend to get hotter and where people tend to be poorer.

“Climate change has increased the frequency and intensity of extreme hot weather events,” said Sarah Henderson, senior author on the study and an assistant professor in UBC’s school of population and public health and a research scientist at the BC Centre for Disease Control. “Being able to map and target the most vulnerable areas will be highly beneficial for public health intervention.”

The researchers used maps of urban heat islands where the humidex would climb over 34.4 degrees Celsius, and the Vancouver Area Neighborhood Deprivation Index (VANDIX) to examine the relationship between temperature and mortality on very hot days from 1998 to 2014. The VANDIX is a public health research tool that measures material and social deprivation factors, such as education and unemployment rate.

The study showed pockets of risk throughout the region including Vancouver’s Downtown Eastside but also in neighbourhoods that are not associated with extreme deprivation in Abbotsford, Surrey, New Westminster and throughout the Lower Mainland. The risk of death is higher in neighborhoods with lots of concrete and not a lot of trees and where people were not working because they are either unemployed or retired.

“In one week in 2009, 110 people died simply because it was hot outside,” said Henderson, pointing out that many of the people who died were younger seniors aged 60 to 70 and not the very elderly.

She believes that part of the problem may be that people are staying in hot homes during the day and not heading to offices or other places that might be cooler or air conditioned. More people die at home when it is extremely hot outside.

“Keeping cool is the key to staying safe in hot weather,” said Henderson. “Go to places with air conditioning, wet down your shirt with cool water, and you must drink plenty of water even if you don’t feel thirsty.”

Background

The study was published today in Environmental Health Perspectives: http://www.ehponline.org/EHP224.

The Vancouver Area Neighborhood Deprivation Index (VANDIX) is a combined measure of material and social deprivation that was developed specifically for health research. In ranked order of importance, the census variables used to construct the VANDIX are: per cent of the population that did not finish high school; unemployment rate; per cent of the population with a university education; per cent of single-parent families; average income; percentage of homes owned; and labour participation rate. The latter refers to the per cent of the adult population that is either employed or actively looking for work.