Do green areas affect health? Results from a Danish survey on the use of green areas and health indicators
Introduction
Lifestyle-related diseases are increasing dramatically in western countries. Recent epidemiological studies in Denmark have revealed that physical inactivity represents a high risk of premature development of chronic diseases such as cardiovascular diseases and type 2 diabetes (Klarlund Pedersen and Saltin, 2003). In addition, there is a marked increase in the prevalence of obesity. At present 30–40% of the adult Dane are overweight (BMI>25), and almost 10% are obese (BMI>30). The trend towards low physical activity and increasing BMI is especially alarming when it comes to children (National Board of Health, 2003a). Another lifestyle-related disease on the rise is mental stress. In 2000, 44% of the Danish population experienced stress in everyday life compared to 35% in 1987 (National Institute of Public Health, 2003). Physical diseases together with mental stress, depression and “burn out” syndrome have become a major economic challenge in the contemporary health economy (WHO, 2003; OECD, 2006).
International studies have documented positive health effects of green areas on human health (e.g., Ulrich, 1984; Kaplan and Kaplan, 1989; Marcus and Barnes, 1999). Cardiovascular and mental illnesses as well as low back and neck pain are positively affected (Dilani, 2001; de Vries, 2004). It has also been documented that green areas and daylight are beneficial for children, adults and elderly people (e.g. Relf, 1992; Küller and Wetterberg, 1996; Kielhofner, 1997; Herzog et al., 1997).
In a large-scale epidemiological study in the Netherlands, 17,000 people drawn from the patient records of around a hundred general medical practices throughout the country, was interviewed. Health problems experienced in the previous 14 days and the patients evaluation of their physical and mental health was included in the study. Comparing the availability and volume of green space in the residential environment with health it was found that residents of neighbourhoods with abundant green space tended, on average, to enjoy a better health condition. The positive link was established for the population as a whole, and was found to be relatively strong among the elderly, housewives and for persons with low socio-economic status. However, results of this and similar studies need to be interpreted cautiously, not least because ‘confounders’ such as; differences in lifestyles, and other environmental variables, noise, air quality and dust may influence the association between access to greenery and health outcomes (De Vries et al., 2003; The Health Council of The Netherlands, 2004). The Dutch health Council concluded that it is not possible to conclude whether the availability of green space make people healthier or whether the statistical relationship is spurious and fore instance derived from a self-selection process where healthier people choose to live in green surroundings. As commented by the researchers in a presentation of data and methodologies for further research this uncertainty with respect to the causal status of variables will be common to almost all cross-sectional research (Groenewegen et al., 2006).
In a Swedish study (Grahn and Stigsdotter, 2003), 953 randomly selected individuals from nine Swedish cities answered a questionnaire about their health and their use of urban green spaces in and close to the city. Statistically significant relationships were found between the use of urban green space and the level of experienced stress—regardless of the individual's age, sex and socio-economic status. The results suggest that the more often a person visits green spaces, the less stressed he or she will be. As the distance to the nearest public green space is documented to be of great importance for the use of such spaces, the authors suggests that improving access to green spaces could be an effective component of a preventive health strategy.
Similar studies had previously not been undertaken in Denmark, but would be highly desirable as health problems and health costs are rising, and more and more emphasis is put on the development of preventive strategies. Knowledge on the green space–health connection could provide knowledge to support the planning of urban green networks as part of a preventive health strategy.
This paper addresses the effect of access to green areas on health as well as the effect of formal visits to green areas. The questions asked is: what is the association between distance to green areas and the health measures: experienced stress and body mass index (BMI)?—and what is the role of formal visits to green areas in explaining any general effect of distance to green areas?
Section snippets
Data and methodology
The data used in this article is derived from a questionnaire mailed to a sample of 2000 adult Danes age 18–80 in 2004. The sample was drawn randomly from the central register of persons. After two reminder,s almost 1200 persons or 63% of the original sample had answered the questionnaire. The questionnaire was mainly based on the respondents answering on closed categorical or ordinal scales. A large part of the questionnaire focussed on types of activities undertaken in public green areas, as
Distance to green areas
The distance to green areas was measured based on the repondents evaluation of distance from the home to eight different types of green areas (see Table 2). Response was given on an ordinal scale with eight levels: 0–50 m, 50–100 m, 300 m–1 km, 1–2, 2–5, 5–20 km and more than 20 km. The reported distances were in part used separately to analyse distance decay and in part recoded into distance to nearest green area in metre to be included in the statistical analysis of stress and obesity.
Distance decay in the use of green areas
A distance decay in the use of recreational facilities is a known phenomenon also at the micro scale (e.g. Coles and Bussey, 2000; Llewelyn-Davis Planning Environment Trust Associates Limited, 1992; Hörnstein and Bredman, 2000). A distance decay in the use of green areas was also found in the present survey for green and recreational areas in general and across all the categories of green areas singled out in the survey. Bivariate correlations between the frequency of visits to eight types of
Experienced stress
The relations between experienced stress and access to green areas or private/shared gardens were analysed using multinomial regression. For this purpose, the respondents in the dataset were divided into 4 groups of equal size based on quartiles on the additive stress index. Multinomial regression was then used to identify covariates and factors contributing to the likelihood of a respondent falling in a given “stress quartile”—compared to falling in the quartile that experienced the lowest
Obesity
To analyse the relations between obesity and access to green areas and gardens it was chosen to model whether the respondent was above or below a discrete BMI threshold—that could be taken as an indication of overweight/obesity.
The resulting logistic regression model can be seen in Table 6. As it was the case with experienced stress there appears to be an inverse correlation between “Access to private garden or shared green area at the dwelling” and overweight/obesity. The ones that have access
Conclusion
Controlling for differences stemming from level of education, urbanity, gender, age, employment, second home ownership and bicycling to work, the results of the analysis suggests that there is a geography of overweight (BMI>27.5) and experienced stress in relation to distance to publicly accessible green areas—as well as access to a private garden or a shared green area at the dwelling. Enquiries were made as to what a degree the effect of distance to green areas could be interpreted as the
Planning perspectives
The empirical results presented in this article do support the “salutary” effects of the exposure to natural environments on human health (Frumkin, 2001) as well as the significance of residential environments to counteract “sedentary” lifestyles (Sallis and Owen, 1999) and that greening of urban areas could make a contribution to increase physical activity and halt the obesity epidemic—as described by Hill et al. (2003). Thus, a green health perspective in urban planning and park management
Acknowledgement
The research was funded by the Danish Outdoor Council.
References (44)
- et al.
Urban-fringe afforestation projects and taxable hedonic values
Urban Forestry and Urban Greening
(2005) - et al.
Urban forest landscapes in the UK-progressing the social agenda
Landscape and Urban Planning
(2000) - et al.
Does housing tenure predict health in the UK because it exposes people to different levels of housing related hazards in the home or its surroundings?
Health and Place
(1998) Beyond toxicity. Human health and the natural environment
American Journal of Preventive Medicine
(2001)- et al.
Landscape planning and stress
Urban Forestry and Urban Greening
(2003) Methodologies for exploring the link between urban form and travel behaviour
Transportation Research Part D: Transport and the Environment
(1996)- et al.
Tracking restoration in natural and urban field settings
Journal of Environmental Psychology
(2003) - et al.
Reflection and attentional recovery as distinctive benefits of restorative environments
Journal of Environmental Psychology
(1997) - et al.
Residents perceptions of walkability attributes in objectively different neighbourhoods: a pilot study
Health & Place
(2005) - et al.
Property prices and urban forest amenities
Journal of Environmental Economics and Management
(2000)
The role of neighbourhood land use design in influencing transportation activity
Transportation Planning Systems
Travel by Design. The Influence of Urban form on Travel
Bystruktur og transportadfærd. Faglig rapport fra DMU
Preleminary Analysis of Transportation Surveys
Many pathways from land use to health
Journal of the American Planning Association
The environmental economic-impact of woodland—a 2 stage hedonic price model of the amenity value of forestry in Britain
Applied Economics
Vitamin G: effects of green space on health, well-being, and social safety
BMC Public Health
Nature and Health
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