Proximity to Physical Activity Facilities May Play Role in Body Fat Levels

Greater access to gyms, swimming pools, and playing fields appears to combat the rising tide of obesity, at least in the United Kingdom, according to a new study. Researchers say the findings could have substantial implications for the future of urban planning.

When compared with individuals who had no such facilities near their home, those who lived closer to these physical activity centers had significantly less adiposity, including smaller waist circumference, lower body mass index (BMI), and less body fat. In contrast, though, the relationship between access to fast-food restaurants and adiposity was significantly weaker and inconsistent, report investigators.

Kate Mason, MPH (London School of Hygiene and Tropical Medicine, England), who led the study, told TCTMD that neighborhood planning and development done with an eye toward increasing the physical activity of inhabitants and better access to healthy food has the potential to lead to measurable improvement in population health.

“We tell people what they need to do to be healthy—to eat well and exercise more—but if we plan better, we might actually make it easier for people to make those healthy choices about exercise and food,” Mason said.

The results of the study were published online December 12, 2017, ahead of print in the Lancet.

Greater Interest in the Built Environment

In the past several decades, public health researchers have focused on the relationship between the built environment and health, particularly how neighborhoods within cities and towns contribute to noncommunicable diseases, Mason said.

“One of the reasons for wanting to understand this is because we’re becoming increasingly urbanized globally,” she explained. “So, if there are things going on in cities that impact health, then that’s going to be more and more of an issue as our cities become bigger and we build new developments.”  

Understanding the relationship between urbanization and health, however, is complex, as simple experiments assessing cause and effect are not possible. The evidence base showing links between the built environment and health is mixed, said Mason, although US studies have shown a direct relationship between proximity to fast-food restaurants and increased body weight and obesity.

Using data from the UK Biobank project, Mason and colleagues collected data from individuals 40- to 69-years old living in 21 urban centers, including Manchester, Glasgow, Central London, and Liverpool.

The researchers examined two features of the neighborhoods: proximity to fast-food restaurants and the density of formal physical-activity facilities. In this analysis, density was defined as the number of gyms, swimming pools, and playing fields within 1,000 meters of each individual’s home. Proximity to fast-food outlets was categorized as living closer than 500 meters, 500-999 meters, 1,000-1,999 meters, and more than 2,000 meters from the nearest restaurant.    

In total, they included 401,917 people with waist circumference measurements, 401,435 with BMI assessments, and 395,640 with body-fat measurements in their analysis. On average, individuals had one physical-activity facility within 1,000 meters of their home and lived a median of 1,136 meters from a fast-food outlet.

In the fully adjusted risk model, adiposity was lower among individuals with greater access to physical activity facilities. For example, compared with those who didn’t have a facility within 1,000 meters of home, individuals with access to six or more gyms, swimming pools, and/or playing fields had on average a 1.22 cm smaller waist circumference, 0.57 kg/m2 lower BMI, and an 0.81% lower body fat percentage.

The association between proximity to fast-food outlets and adiposity was significantly weaker, however. Those who lived more than 2,000 meters away from such restaurants had only a trend toward smaller waists (26 cm) compared with those who lived within 500 meters. Similarly, BMI and body-fat percentage were 0.10 kg/m2 and 0.10% lower, respectively, among those who lived furthest, but their results were not significantly different compared with those who lived within 500 meters.

To TCTMD, Mason said it’s possible to incentivize municipal and private developers to build physical activity centers within communities, as well as to restrict the opening of fast-food restaurants within certain distances of residential neighborhoods. The group additionally observed a strong inverse association between access to activity centers and adiposity levels among higher-income households, which they attribute to the fact that gyms often cost money to use. For this reason, when new facilities are developed in residential areas, costs of access need to be managed to avoid widening health disparities, the researchers say.    

Taking Healthy and Unhealthy Foods Into Account     

In terms of limitations, Mason said information available on the food environment in the UK Biobank is limited. For example, while they focused on the proximity of fast-food outlets near the home, they were unable to obtain data on healthy food outlets. Accounting for healthy and unhealthy food choices would result in more precise estimates of the effect on metabolic health.

“Smaller studies that were able to take both into account were able to show stronger associations between the food environment and health,” said Mason. “It’s one of the trade-offs with having big dataset that covered the whole country. We didn’t necessarily have access to all the information we needed for a perfect study.”

In an editorial, Pablo Monsivais, MD, PhD (Washington State University, Spokane, WA), and Thomas Burgoine, MD, PhD (University of Cambridge School of Clinical Medicine, England), also raise concerns that the dataset is too limited to adequately address the relationship between fast-food outlets and adiposity, suggesting it might be a false-positive finding.  

The study is a “substantial and important piece of public health research, undertaken with great care,” write Monsivais and Burgoine. However, given that the study has the potential to influence policy and practice, “superficial appraisals of this work might consider it definitive and, given the apparently null results, lead some to assert that food environments have little relevance for obesity,” they say.

This is not the case, the editorialists argue, stating that the environment remains an important venue for public health intervention but more high-quality evidence is needed to guide policy.