Perceptions of the environment, physical activity, and obesity

Abstract

Obesity rates are rising rapidly across the developed and developing world. Until recently obesity research has mainly focused on biological, psychological and behavioural factors. But there is growing agreement that environmental factors play an important role as well. In this study data from the 2003 Health Survey for England ($n=14,836$) were analysed from a multilevel perspective to examine (1) the associations of the perceptions of the local environment with obesity, self-rated health, and physical activity, and (2) whether physical activity mediates the association between the perceptions of the environment, and obesity and self-rated health. This study found that perceptions of the friendliness of the local environment were mainly associated with self-rated health; perceived access to leisure facilities with sports activities; perceived access to a post office with walking; and the presence of social nuisances with obesity and poor self-rated health. In addition, positive perceptions of the social environment (i.e., social support and social capital) were associated with higher levels of physical activity, and lower levels of poor self-rated health and obesity. Only limited support was found for the idea that health behaviours mediate the associations between the perceptions of the environment, obesity, and self-rated health. Controlling for the three physical activity measures only rendered a small number of associations with self-rated health non-significant, and did not affect the associations with obesity. Overall, the results show that certain aspects of the environment may contribute to the risk of obesity and poor health. More research is needed to examine the specific mechanisms that link (the perceptions of) the environment to obesity and health.

Introduction

Obesity rates are rising rapidly across the developed and developing world (Flegal, Carroll, Ogden, & Johnson, 2002; Hill, Wyatt, Reed, & Peters, 2003; International Obesity Task Force, 2002;WHO, 2000). In England the prevalence of obesity has more than trebled in the last two decades (House of Commons Health Committee, 2004). The apparent obesity epidemic is a serious threat to public health, as obesity is associated with a large number of conditions, among which type-2 diabetes, cardiovascular disease and certain types of cancer (Haslam & James, 2005; National Institutes of Health, 1998). Until recently, obesity research has mainly focused on biological, psychological and behavioural factors. However, these individual factors may be unable to fully explain the rapid growth in obesity over the past two decades (Wadden, Womble, Stunkard, & Anderson, 2002). There is growing agreement among researchers and policy makers that the social and physical environment may play an important role as well (Booth, Pinkston, & Poston, 2005). Environments may be obesogenic in the sense that they promote caloric intake and/or discourage the expenditure of energy.

A number of studies have found direct and indirect links between the neighbourhood environment and people's body weight. Different aspects of the local environment have been shown to be associated with weight-related health behaviours, obesity, and people's overall health. In very broad terms this research has focused on the contextual effects of (1) access to amenities, among which food shops, health services, and sports facilities or other leisure centres, (2) physical features of the environment, including the presence of green spaces, pavements and cycle paths, and the degree of urbanization, (3) the reputation of the neighbourhood reflected in, for example, feelings of safety, social nuisances, and crime figures, (4) Aesthetics, or the general attractiveness of the neighbourhood, and (5) the social organization of the local community, reflected in social support and social capital.

Evidence is emerging that all these factors are associated with people's body weight. Recent research has shown that the absence of exercise and recreational facilities increases the risk of being overweight/obese (Catlin, Simoes, & Brownson, 2003; Giles-Corti, Macintyre, Clarkson, Pikora, & Donovan, 2003), and that living in walking distance to stores decreases the risk of being overweight/obese (Giles-Corti et al., 2003). The physical features of the environment are also important for people's body weight. Urban sprawl (i.e., areas with low population density and low street connectivity) is associated with higher BMIs and levels of obesity (Ewing, Schmid, Killingsworth, Zlot, & Raudenbush, 2003; Lopez, 2004; Rutt & Coleman, 2005); living on streets with no or single-sided sidewalks increases the risk of being overweight (Giles-Corti et al, 2003); residents of ‘low walkability’ neighbourhoods tend to have higher BMIs (Saelens, Sallis, Black, & Chen, 2003); and living in mixed land-use areas reduces the risk of obesity (Frank, Andresen, & Schmid, 2004). Furthermore, negative community perceptions (unsafe and unpleasant environments) seem to increase the odds of being overweight (Catlin et al., 2003), and a couple of studies have shown that social capital and support are protective against obesity (Cohen, Finch, Bower, & Sastry, 2006; Holtgrave & Crosby, 2005).

It is likely that the associations between the different characteristics of the environment and body weight are mediated by people their health behaviours. That is, certain aspects of the environment may promote or discourage physical activity, and therefore have an indirect influence on people's body weight. Easy access to amenities, green spaces, good pavement/cycle lane connectivity, and the general attractiveness or reputation of the neighbourhood may positively influence walking and outdoor (sports) activity, and leisure centres or other sports facilities are most likely to promote sports activity. It is still unclear how social support and capital are linked with obesity. It has been hypothesized that communities with high levels of social capital may help to provide support for positive health behaviours, such as sports activities, and help to exercise social control over deviant health behaviours, such as smoking and alcohol abuse (see e.g., Kawachi & Berkman, 2000). The pattern of results from studies examining the association between environmental factors and weight-related health behaviours is fairly consistent. They show that living in a ‘convenient’ environment (e.g., shops are in walking distance) increases the likelihood of walking (Ball, Bauman, Leslie, & Owen, 2001; Booth, Owen, Bauman, Clavisi, & Leslie, 2000), and that access to exercise and/or leisure facilities increases walking as well as participation in sports activities (Addy et al., 2004; Li, Fisher, Brownson, & Bosworth, 2005). Furthermore, people living near green spaces, including parks, playgrounds and sports fields are more likely to walk and to have higher levels of physical activity (Addy et al., 2004; Foster, Hillsdon, & Thorogood, 2004; Li et al., 2005). Other physical features of the environment, such as street connectivity or the presence of pavements, are also positively associated with various physical activity measures (Addy et al., 2004; Booth et al., 2000; Brownson, Baker, Housemann, Brennan, & Bacak, 2001). Living in an attractive or aesthetically pleasing neighbourhood seems to encourage walking and overall physical activity (Ball et al., 2001; Duncan & Mummery, 2005; King et al., 2000; Saelens et al., 2003), whilst living in unsafe and unpleasant environment discourages walking and overall physical activity (Ball et al., 2001; Brennan, Baker, Haire-Joshu, & Brownson, 2003; Duncan & Mummery, 2005; Foster et al., 2004; Li et al., 2005). In addition, there is some support for the idea that social support and social capital are beneficial for a wide range of physical activity outcomes, among which walking, cycling, sports, and general physical activity (Addy et al., 2004; Fisher, Li, Michael, & Cleveland, 2004; Lindström, Hanson, & Östergren, 2001; Lindström, Moghaddassi, & Merlo, 2003; Poortinga, 2006c; Stahl et al., 2001).

Environmental factors associated with physical activity and obesity are also likely to be associated with people and their overall health. Direct associations have been found between various aspects of the social and physical environment and a variety of general health outcomes. The importance of social support and social capital for people's physical and psychological well-being is well established in the social-epidemiological literature (e.g., Cummins, Stafford, Macintyre, Marmot, & Ellaway, 2005; Kawachi, Kim, Coutts, & Subramanian, 2004; Pickett & Pearl, 2001; Poortinga, 2006a). In addition, a couple of recent studies have linked perceptions of the neighbourhood to health (e.g., Cummins et al., 2005; Wilson et al., 2004). These studies show that self-assessed health status is associated with perceived neighbourhood problems (e.g., Cummins et al., 2005; Ellaway, Macintyre, & Kearns, 2001; Steptoe & Feldman, 2001), access to green spaces and amenities (Wilson et al., 2004), and the perceived friendliness of the local community (Poortinga, 2006b). However, no systematic research has been conducted to examine whether the environmental factors that are associated with physical activity and obesity also have an influence on people's overall health.