Health Science Writer Paul Webster looks at Built Environment and focus on Housing as a risk factor for chronic diseases.
The homes, neighborhoods, communities and cities we live in – our “built environments” – frame social relations and imprint lifestyles, cultures, and economies. They can also inflict health problems. “When we say the physical and social conditions in which people live have enormous health impacts,” explains Nazeem Muhajardine, a professor of community health and epidemiology at the University of Saskatoon who heads a multifaceted project probing urban design and health, “it’s often built environment we’re talking about. Built environment is a kind of primordial ‘cause of causes’.”
This sounds sensible. But pinpointing the actual health effects caused by built environments can be as maddeningly confusing as urban sprawl itself. Disentangling the role of the built environment from confounding factors such as ethnicity, genetics, and lifestyle is forbiddingly difficult. Many researchers seeking a way out of this maze have settled on housing as a potent focal point for research. A growing number of studies indicate that the design, quality and location of housing all warrant attention in disease risk factor surveillance.
In Vancouver, for example, a batch of studies funded by the Mental Health Commission of Canada probing the associations between housing security and health outcomes for homeless people has established that housing yields health benefits that strongly justify investments in housing for the homeless. In the Montérégie region of Quebec, the Public Health Department is probing different aspects of housing and built environment to highlight residential and environmental inequalities. Neighbourhoods are being compared based on the proportion of homeowners, the year the house was constructed, distance to leisure, food and health services, access to cycling paths, social and material deprivation, and the presence of sources of air pollution.
Substantial evidence indicates that the location of housing is a key variable in the health conditions of residents: At Carleton University, a team led by bio-statistician Paul Villeneuve investigating associations between non-occupational exposure to ambient volatile organic compounds and lung cancer based on a case-control study of 445 incident lung cancers and 948 controls in Toronto between 1997 and 2002 tracked exposures linked to residential addresses. It concluded that long-term exposure to ambient volatile organic compounds and nitrogen dioxide at relatively low concentrations is associated with lung cancer. Similarly, a team of Health Canada researchers probing the relative risk of mortality from all non-accidental, respiratory-, and cardiovascular-related causes, associated with exposure to four air pollutants, by weather type and season, in 10 major Canadian cities for 1981 through 1999 found statistically significant relationships of mortality among urban dwellers due to short-term exposure to carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone.
Not all studies of dwelling locations yield such robust findings. Although a recent review of mental health literature on the linkages between depression and neighborhood types by University of Montreal psychologist Dominic Julien supported the notion that some neighborhood variables – especially those related to poverty and material deprivation – impact on mental health, firm proof is scant. “Thus far, there is limited empirical evidence to fully ascertain this notion, and information is even more scarce on the processes that might explain any relationships between neighborhood variables and depressive mood among older adults,” Julien reported.
“Although lack of housing is linked with adverse health outcomes, little is known about the impacts of the qualitative aspects of housing on health,” agrees Sean Rourke, scientific director for the Ontario HIV Treatment Network, who closely investigated the association between structural elements of housing, housing affordability, housing satisfaction and health-related quality of life over a 1-year period for 509 individuals living with HIV in Ontario. “We found significant cross-sectional associations between housing and neighborhood variables – including place of residence, housing affordability, housing stability, and satisfaction with material, meaningful and spatial dimensions of housing – and both physical and mental health-related quality of life,” Rourke and his team reported.
These findings, Rourke believes, are broadly applicable to the general population. “Housing is health,” he’s concluded. Research from the UK indicates that poor housing conditions can increase the risk of severe health issues or disability by up to 25 percent in childhood or early adulthood, notes Housing and Health: Examining the Links, a 2012 study published by Toronto’s Wellesley Institute.
In recent years, the relationship between housing and physical activity, body weight and obesity has become a central preoccupation for numerous researchers probing built environment impacts. One of the current buzzwords for researchers in this area is “sedentariness” (a term used to define physical inactivity), notes Muhajardine, who describes obesity as a “gateway condition” for chronic diseases.
The design of homes and neighborhoods can be described as a path leading to that gateway: In Ontario, a study revealed that children with a park or playground within 1 km from home were five times more likely to be at healthy weight than children without such access. And children who live in neighbourhoods with fewer amenities or lacking neighbourhood access to sidewalks, walking paths, parks or playgrounds, or recreation or community centres have 45 percent higher odds of being obese or overweight.
“The empirical body of evidence regarding the determinants of obesity – especially those most upstream, such as the built environment, time use and technology change – is only now taking shape,” Muhajardine explains. “We’re at the point now where we need to start doing systematic surveillance. But before we do that we need to agree on common indicators to measure.”
Karen Lee, an adjunct professor at the University of Alberta’s School of Public Health who has advised numerous cities on healthy housing, sees the role of housing in health as an emerging literature in Canada. “A lot of the built environment research in Canada has focused on the role of transportation and land use planning” she explains, while noting that much new work has been seeded since the 2009 launch of Healthy Canada by Design Coalitions Linking Science and Action for Prevention, a national network for collaboration in built environment health research and interventions funded by the Canadian Partnership Against Cancer, the Public Health Agency of Canada (PHAC), and the Heart and Stroke Foundation. As part of this project, Toronto Public Health produced software for planners to model how urban planning and transportation planning affect health outcomes.
To increase the momentum, the Canadian Institutes of Health Research has adopted built environment as a strategic research area, and the PHAC is working to coordinate the development of a pan-Canadian framework identifying which indicators of built environment health effects warrant surveillance. These may include “urbanization, proximity and accessibility to recreational facilities and parks, neighbourhood walkability, transportation, food production and quality and safety” according to a summary of the issue from PHAC. A growing body of evidence “shows a link between the built environment and its impact on maintaining healthy lifestyles, safer and less polluted communities, and on social inequalities” the Agency says. “In order to document and follow the trends associated with health and the built environment, a solid evidence base is vital; surveillance systems need to be established based on survey and administrative data.”
In Ontario, newly-revised Public Health Standards emphasise that built environment should be viewed as a chronic disease risk factor. To back that up, the Standards contain a surveillance protocol requiring Boards of Health to collect data on physical environment factors. The province’s Public Health Sector Strategic Plan prioritizes built environment as one of five action areas, stating that it can “play a significant role in improving health and reducing health and social costs, particularly by promoting healthy physical activity and reducing the risk of injuries and social isolation – which lead to better physical and mental health.”
Alberta, British Columbia and Quebec have also recognized that built environment matters to public health. Alberta has adopted a Built Environment Health Promotion Strategy to promote physical activity, nutrition, injury prevention, and environmental safety, as well as to identify common built environment disease risk indictors. In Québec, work is underway to develop surveillance indicators based on six classes of built environment indicators – including density, and land use, road networks, non-motorized transport, and transit infrastructure, and urban design with specific regard to recreational facilities and food shops. <>