Archives: Obesity & overweight

 

Frank 2006 - "Many Pathways from Land Use to Health"

Lawrence D. Frank, James F. Sallis, et al.
"Many Pathways from Land Use to Health"
Journal of the American Planning Association
72(1):75-87 (Winter 2006)
On the Web
Relevance: high

From the abstract: in King County neighborhoods and found that a 5% increase in walkability was associated with:

  • a per capita 32.1% increase in time spent in physical activity
  • 0.23 point reduction in average body mass index
  • 6.5% fewer vehicle miles traveled
  • 5.6% fewer grams of nitrogen oxides emitted
  • 5.5% fewer grams of volatile organic compounds emitted

See study for more details.

 

Soot n/a - "Are Sprawl and Obesity Related? Evidence from the Chicago Area"

Siim Soot, Lise Dirks, et al
"Are Sprawl and Obesity Related? Evidence from the Chicago Area"
Unpublished: Metropolitan Transportation Support Initiative (METSI) working paper 06-01
Relevance: medium
On the Web

The authors estimate the effect of urban, socio-economic, and personal characteristics on BMI using height, weight, and ZIP code data from 7 million driver's licenses and state IDs in greater Chicago. Their regression finds that population density has a slight but significant effect, dwarfed by other variables. I have many questions about their methodology, but nonetheless don't think they overturn the bulk of sprawl and obesity research.

More notes...

 

Plantinga 2005 - "A Spatial Economic Analysis of Urban Land Use and Obesity"

Plantinga, Andrew J and Bernell, Stephanie
"A Spatial Economic Analysis of Urban Land Use and Obesity"
Journal of Regional Science
August 2005, Vol 45, n.3, pp.473-492
relevance: medium
On the Web

The authors create a theoretical economic model of neighborhood choice and obesity. They basically argue that while obesity and sprawl are linked, it's ok because it's a conscious trade-off for a cheaper house, akin to the trade off with longer commute times.

Key sentences

  • "As such, residents are willing to accept the tradeoff of higher weight for more housing."
  • "In particular, low-density development should not be viewed as a cause of high obesity rates any more than it should be seen as a cause of higher commuting costs."

The paper is pretty technical and full of assumptions, many of which the authors need to verify empirically before moving on to further assumptions and their conclusions. Some quibbles include:

  • How could residents consciously choose house size over body size when the connection has been made only recently?
  • While people with a higher income may consume better quality food, they do not necessarily consume more total calories.

See Cascadia Scorecard weblog post

 

Colman 2001 - "Cost of Obesity in British Columbia"

Colman, Ronald; Dodds, Colin; Wilson, Jeff
"Cost of Obesity in British Columbia"
January, 2001. GPI Atlantic
On the Web
Relevance: high

Direct costs for obesity-related diseases cost the British Columbia health care system at least CAN$217.3 million a year (2.6% of the health care budget) in 1997. This is a very conservative estimate, so a reasonably higher estimate is $380 million, or 4.5% of the provincial health budget. Note that obesity is defined as BMI>27 for the conservative estimate and BMI>25 for the high estimate.

Using the assumption that the direct health care costs are only 45.7% of the total economic burden of illness, obesity could cost a total of $475.5 million to $831.5 million each year. At the time of writing, $830 million was 0.9% of BC's GDP.

Method: The author uses Birmingham's method of population attributable fractions applied to the BC population and 1997 medical costs.

More notes...

 

McCann 2003 - "Measuring the Health Effects of Sprawl"

McCann, Barbara; Ewing, Reid
"Measuring the Health Effects of Sprawl: A National Analysis of Physical Activity, Obesity, and Chronic Disease."
Smart Growth America and Surface Transportation Policy Project
September 2003
On the Web
Relevance: high

This report is based on Ewing et al's earlier article (2003) and is longer with more details and sidebars. The conclusions, of course, are the same, but the report includes sprawl scores for all 448 counties and the web page has fact sheets for counties in most states.

 

Kelly-Schwartz 2004 - "Is Sprawl Unhealthy?"

Kelly-Schwartz, Alexia; Stockard, Jean, et al
"Is Sprawl Unhealthy? A Multilevel Analysis of the Relationship of Metropolitan Sprawl to the Health of Individuals"
Journal of Planning Education and Research
December 2004; v.24, n2; pp.184-196
On the Web
Relevance: high

The authors replicated and extended Ewing et al's work on the effect of sprawl on health. They compared self- and physican-rated health as well as a variety of chronic conditions across metropolitan areas while controlling for income, education, sex, etc. They found that sprawl does affect health somewhat, but in a complex way that is difficult to track.  It appears that a highly gridded street network is associated with better health while more density is associated with poorer health.  While sprawl was not significantly associated with a higher prevalence of chronic conditions, among those with those conditions, the gridded street network was associated with better health.

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Ewing 2005 - "Can the Physical Environment Determine Physical Activity Levels?"

Ewing, Reid
"Can the Physical Environment Determine Physical Activity Levels?"
Exercise and Sport Sciences Reviews
April 2005; v.33, n.2; pp.69-75
On the Web (pdf)
Relevance: medium high

Ewing seems to be primarily reviewing and re-presenting earlier work, but does so in a concise, easy-to-grasp way. Although he doesn't show any of the data or analysis, Ewing offers elasticity estimates for the effect of the physical environment on physical activity and its mediators. The effects are greatest for the mode share of walking and public transportation. CAVEAT: Ewing shows no statistical tests or analysis, so the accuracy of these estimates is unknown.

More notes...

 

Ewing 2003 - "Relationship Between Urban Sprawl and Physical Activity, Obesity, and Mortality"

Ewing, Reid; Schmid, Tom, et al
"Relationship Between Urban Sprawl and Physical Activity, Obesity, and Mortality"
American Journal of Health Promotion
September/October 2003; vol.18, n.1; pp.47-57
On the Web
Relevance: high

The authors estimated the impact of a county and metropolitan area sprawl index on obesity, physical activity, and related diseases. They found that the county  index significantly influenced the number of minutes spent in leisure-time walking, average BMI, obesity status, and prevalence of hypertension.

More notes...

 

Thorpe 2004 - "The Impact of Obesity on Rising Medical Spending"

Thorpe, Kenneth E; Florence, Curtis S; et al
"The Impact of Obesity on Rising Medical Spending"
Health Affairs
October 2004, Web Exclusive W4-480
On the Web
Relevance: high

Comparing data from the 1987 National Medical Expenditure Survey and the 2001 Medical Expenditure Panel Survey, the authors estimate the impact of obesity on inflation-adjusted medical spending. They estimate that 27% of the increase was due to obesity, and that 12% was due to the increased obesity rate alone, exclusive of medical advances. In 2001, medical costs for an obese person were 37% higher than for a comparable normal weight person. The authors also calculate the effect of obesity on the increase in spending on diabetes (38%), hyperlipidemia (22%), and heart disease (41%).

 

Birmingham 1999 - "The Cost of Obesity in Canada"

Birmingham, C. Laird; Muller, Jennifer L; et al
"The Cost of Obesity in Canada"
Canadian Medical Association Journal
February 23, 1999; v.160, n.4; pp.483-488
On the Web
Relevance: high

The authors reviewed the literature to calculate the direct medical cost of obesity in Canada.  They estimate that obesity cost over $1.8 billion, or 2.4% of the total health care expenditures, in Canada in 1997. The three top contributors were hypertension ($656.6 million), type 2 diabetes ($423.2 million), and coronary artery disease ($346.0 million).