Are Cities Part Of The Obesity Problem?

http://www.citylb.com/politics/2016/01/the-relationship between-cities-and-obesity--lausanne-switzerland/4235513/

Anonymous woman
citylab.com

Hello Everyone:

It seems that El Niño has taken a leave of absence from Southern California.  The sun is out, the sky is clear, and there is a light breeze. Sorry everyone in the Mid-Atlantic United States who are digging out from Storm Jonas.

Today we look at the complex relationship between cities and obesity.  Blogger does not need to tell you that obesity can lead to some very serious health issues: diabetes, heart disease, greater pregnancy and birth complications, and so forth.  There is ample scientific evidence that points to a myriad of causes of obesity: poverty, social and emotional, sleep deprivation, genetic.  So many causes, that it can be quite difficult to pin point a cause of obesity.  Aria Bendix reports in her CityLab article, "The Complicated Relationship Between Cities and Obesity," You may all be scratching your collective head thinking "cities cause obesity? How is this possible?"

Woman weighing herself
npr.org

Aria Bendix writes, "The relationship between cities and obesity is perhaps even more complicated."  On one side of the equation, urban dwellers "...are frequently exposed to pollution and may lack access to public space like parks and recreational facilities."  On the opposite of the equation, "...cities tend to be more walkable than sprawling suburban areas and therefore encourage a more active lifestyle."  It sounds contradictory, cities maybe more walkable than the suburbs but urban dwellers are more exposed to pollution and may have trouble accessing reliable, affordable transportation.  A 2014 study in the Journal of Transportation and Health (http://www.sciencedirect.com) supported the argument walkability leads to health.  Ms. Bendix reports, "The study found that dense cities with more compact street networks and smaller major roads have lower levels of obesity."  However, Ms. Bendix adds this caveat, "But these findings alone are not enough to conclude that cities are healthier places to live."

"Getis Ord GI Clustering" I
citylab.com

Now, we have evidence to suggest that the exact opposite is true-at least when it comes to obesity and weight gain.  A recent study by the Ecole Polytechnique Fédérale de Lausanne in Switzerland (http://www.sciencedaily.com) and published in the British Medical Journal Open concluded that city living may be connect with higher Body Mass Indices (a typical measure of obesity).

Researchers began by calculation the BMIs of about 6,500 adult residents of Lausanne between 2003 and 2006.  They went back six years later to collect the same information but from a smaller study group-4,500 from the initial group.  In an aside, Ms. Bendix notes, "The fact that BMI was measured in person and not self-reported lends an added degree of credibility to their findings."

The researchers used demographic date to map out the BMIs.  The above map is based on the follow-up observations that took place between 2009 and 2012.  Ms. Bendix explains, "The red dots indicate areas with 'unfavorable' BMIs that were proportionally higher than the rest of the city.  In contrast, the blue dots show areas with 'favorable' or proportionally lower, BMIs."  Aria Bendix writes, "In both the initial study and the follow-up, the researchers noticed a stark divide between working-class, less-educated residents clustered in the city's western edge-who had the higher BMIs-wealthier, well-educated residents farther was, whose BMIs were lower."

A contributor to obesity?
washingtonpost.com

The conclusions reached by the study seem to be consistent with other analysis "...that links obesity to poverty and low-income neighborhoods."  Strangely, when the authors adjusted the information for neighborhood-level median income, the results were not significantly different.  Even subtracting income from the equation, the population of western Lausanne was still in the red (see map above).  This infers that higher BMIs were not solely a product of neighborhood median income.  Nor were the higher BMI directly influenced by other factors, such as: age, race, love of education, tobacco and/or alcohol consumption-all adjusted for in the study.

"Getis Ord GI Clustering" II
citylab.com

The study argues "...that urbanism could be one of the missing links between obesity and this location-based divide."  According to lead researcher Stéphane Joost, "large roads, crowded highways, and metro lines have isolated working-class communities from places that could be very healthy for them-namely green spaces."  Mr. Joost also observes that this type of isolation can limit a person's mobility and impede access to healthy food.  In another aside, Ms. Bendix says, "It is worth noting, however, that making healthy food accessible does not always lead to a change in consumer behavior."  However, access is not the only road block to health.  Mr. Joost also believes that "something called 'spatial dependence'-or the idea that your behavior is influenced by your neighbors-could be partly responsible for the high BMIs in Lausanne's western region."

A better choice
Photograph by Eamonn Mccabe
theguardian.com

According to a 2007 analysis in the Framingham Heart Study (http://www.framinghamheartstudy.org), "obesity occurs in clusters, based largely on social ties."  Specifically and perhaps, shockingly, the analysis revealed "that a person's chance of becoming obese increased by 57 percent if his or her friend was obese."  This trend continued for up to three degrees of separation.  Stéphane Joost postulates "that a similar phenomenon is at work in Lausanne."  He speculates that since large numbers of working-class residents live in subsidized housing, it is entirely possible that these resident are promoting a less than optimally healthy lifestyle within their communities.

Bicycle riders
newsarchive.medill.northwestern.edu

Naturally, people cluster in places where they can afford to live, and according to Ms. Bendix, "the fact still remains that the built environment of Lausanne has forced working-class communities into areas that lack the sort of green space and amenities that foster public health."  Mr. Joost adds,

It's not by chance that people with modest incomes liver where they live.

The conclusions of the study reflect a greater pattern of concentrated inequality that frequently characterizes urban areas.  For example, Mr. Joost's 2014 study of Geneva, Switzerland (http://www.bmjopen.bmj.com), concluded a similar divide between the more affluent residents on one side of the Rhône River and the working-class residents on the opposite side.  Mr. told CityLab,

The fact that we observed the same kind of pattern in Geneva and now in Lausanne, a city which is only 100 kilometers from Geneva, [indicated that] there is probably something to discover related to urban planning.

In short, Blogger agrees with Aria Bendix's conclusion, "...the way our cities are designed could be the difference between a healthy and unhealthy population."  Going forward, urban planning strategies will have place more attention on dissipating inequality "...or connecting isolated neighborhoods."  If the study conclusions are any measure, dealing with obesity will require carefully considered improvements to the urban landscape.