Association of Neighborhood Walkability in Overweight, Obesity, and Diabetes

Hilary T. Box, PharmD- Mercer University College of Pharmacy

The National Health and Nutrition Examination Survey estimated that 69% of US adults were overweight or obese in 2011-2012 resulting in an increase in diabetes prevalence from 15% in the late 1970’s.1-2 Diabetes prevalence has increased from less than 4% in 1990 to 8.3% in 2012.3-4 It is thought that neighborhoods have shifted towards sprawling, car-oriented communities that discourage walking with heavy reliance on motorized transportation. However, it has been shown that neighborhoods with high population density, well-connected streets, and high number of destinations within walking distance of residential areas have higher rates of walking and bicycling for transportation.5-6

Title: Association of Neighborhood Walkability with Change in Overweight, Obesity, and Diabetes
Design Time-series analysis (2011-2012) N= 8,777
Objective To examine whether walkable urban neighborhoods are associated with a slower increase in overweight, obesity, and diabetes than less walkable ones
Study Groups Using annual provincial health care and biennial Canadian Community Health Survey data for adults (30-64 yrs) living in Southern Ontario cities
Methods Neighborhood Walkability

Neighborhood walkability was derived for each dissemination area with a validated composite walkability index.

The index includes four equally weighted components: population density (number of persons per square kilometer), residential density (number of occupied residential dwellings per square kilometer), walkable destinations (number of retail stores, services [eg, libraries, banks, community centers], and schools within a 10-minute walk), and street connectivity (number of intersections with at least three converging roads or pathways).

 

Overweight/Obesity

The prevalence of overweight and obesity was estimated for each quintile of neighborhood walkability with self-reported data from the Canadian Community Health Survey, which is a series of cross-sectional nationally representative health surveys of Canadians aged 12 years and older and is conducted by Statistics Canada.

 

Diabetes Prevalence

Administrative health data collected from April 1, 2001, to

March 31, 2013, were used to calculate the annual incidence of diabetes within each quintile of neighborhood walkability.

Duration January 1, 2001 to December 31, 2012
Primary Outcomes Measure Annual prevalence of overweight, obesity, and diabetes incidence, adjusted for age, sex, area income, and ethnicity
Baseline Characteristics Walkability Quintiles
1 (Least Walkable) 2 3 4 5 (Most Walkable)
No. of neighborhoods 1,757 1,757 1,757 1,759 1,747
Pop per neighborhood, median (IQR) 551

(420-644)

561

(441-747)

533

(435-728)

513

(451-701)

521

(457-677)

Demographic Characteristics
Age, %
   30-49 65.1 65.4 65.8 66.6 70.5
   50-64 34.9 34.6 34.2 33.4 29.5
Sex, %
   Female 50.8 51.2 51.5 51.9 51.1
Nonwhite ethnicity, % 23.9 27.8 31.0 30.6 26.3
Socioeconomic indicators, %
   Poverty , % 11.2 13.9 17.1 21.3 25.1
Retail Indicators, %
No. specialty

coffee shops

per 100,000

0.7 0.6 0.9 0.5 3.1
No. coffee/

doughnut

shops per

100,000

10.5 6.4 5.3 5.7 5.0
Ratio of

specialty     coffee

shops to

coffee/

doughnut

shops

0.06 0.09 0.18 0.09 0.63
Commercial

fitness clubs/

gyms, no per

100,000 pop

25.1 12.2 12.2 11.3 21.0
Built Environment Characteristics
Walkability Score, median (range) 10.1

(0-12.04)

13.7

(12.05-15.22)

16.8

(15.23-18.60)

20.9

(18.61-25.49)

35.2

(25.50-100)

Mean distance to nearest park, m 3,224 3,207 3,182 3,169 3,186
Results Prevalence of Overweight and Obesity
Quintile Change in Prevalence, % 95% CI, % p value
1 5.4 2.1- 8.8 0.002
2 6.7 2.3- 11.1 0.003
3 9.2 6.2- 12.1 <0.001
4 2.8 -1.4- 7.0 0.20
5 2.1 -1.4- 5.5 0.20
1 vs 5 43.3 vs 53.5 -13.5- -6.8 <0.001
Diabetes Incidence
Quintile Absolute change of Adjusted Annual Incidence of Diabetes 95% CI, % p value
1 -0.65 -1.65- 0.39 0.20
2 -0.5 -1.5- 0.5 0.30
3 -0.9 -1.9- 0.02 0.06
4 -1.1 -2.2- -0.05
5 -1.5 -2.6- -0.4
1 vs 5 -1.7 -2.8- -0.7 0.001
Adverse Events Common Adverse Events: none
Serious Adverse Events: none
Percentage that Discontinued due to Adverse Events: none
Study Author Conclusions In Ontario, Canada, higher neighborhood walkability was associated with decreased prevalence of overweight and obesity and decreased incidence of diabetes between 2001 and 2012.

Many other factors can contribute to the incidence of overweight, obesity, and diabetes including genetics, personal health motivation, and lack of health education. Thus, further research is necessary to assess whether the observed associations are actually causal.

References

  1. Ogden CL, Carroll MD, Kit BK, Flegal KM. Prevalence of childhood and adult obesity in the United States, 2011-2012. JAMA. 2014;311(8):806-814.
  2. Fryar CD, Carroll MD, Ogden CL; National Center for Health Statistics, Centers for Disease Control and Prevention. NCHS health e-stat: prevalence of overweight, obesity, and extreme obesity among adults: United States, trends 1960-1962 through 2009-2010. http://www.cdc.gov/nchs/data/hestat/obesityadult/
  3. Geiss LS,Wang J, Cheng YJ, et al. Prevalence and incidence trends for diagnosed diabetes among adults aged 20 to 79 years, United States,1980-2012. JAMA. 2014;312(12):1218-1226.
  4. Nichols GA, Schroeder EB, Karter AJ, et al;SUPREME-DM Study Group. Trends in diabetes incidence among 7million insured adults,2006-2011: the SUPREME-DM project. Am J Epidemiol. 2015;181(1):32-39.
  5. Sallis JF, Cerin E, Conway TL, et al. Physical activity in relation to urban environments in 14 cities worldwide: a cross-sectional study. Lancet. doi:10.1016/S0140-6736(15).
  6. Saelens BE, Handy SL. Built environment correlates of walking: a review. Med Sci Sports Exerc. 2008;40(7)(suppl):S550-S566.
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