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Built Environment Attributes andWalking Patterns Among theElderly Population in Bogotá

Luis F. Gómez, MD, MPH, Diana C. Parra, MPH, David Buchner, MD, MPH,Ross C. Brownson, PhD, Olga L. Sarmiento, MD, MPH, PhD, José D. Pinzón, Arq,

Mauricio Ardila, MA, José Moreno, MS, Mauricio Serrato, MD, Felipe Lobelo, MD, PhD

Background: There is increasing evidence that the built environment has an influence on physicalactivity; however, little is known about this relationship in developing countries.

Purpose: This study examined the associations between attributes of the built environment andwalking patterns among the elderly.

Methods: Amultilevel cross-sectional studywas conducted in 2007. Fifty neighborhoodswere selected and1966 participants aged �60 years were surveyed. Objective built environment measures were obtained in abuffer of 500musingGIS. Environmental perceptionswere assessed via questionnaire.

Results: People who lived in areas withmiddle park area (4.53%–7.98% of land) weremore likely towalk for at least 60 minutes during a usual week (prevalence OR [POR]�1.42, 95% CI�1.02, 1.98).Those who lived in areas with the highest connectivity index (1.81–1.99) were less likely to reportwalking for at least 60 minutes (POR�0.64, 95% CI�0.44, 0.93). Participants who reported feelingsafe or very safe from traffıc were more likely to report walking for at least 60 minutes (POR�1.50,95%CI�1.11, 2.03). The presence of Ciclovía (recreational program)wasmarginally associated withhaving walked at least 150 minutes in a usual week (POR�1.29, 95% CI�0.97, 1.73).

Conclusions: This study showed that certain built and perceived environment characteristics wereassociated with walking among older adults living in Bogotá. Further studies should be conducted tobetter understand the potential influence of the built environment on physical activity among theelderly population in the context of Latin American cities.(Am J Prev Med 2010;38(6):592–599) © 2010 American Journal of Preventive Medicine

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rom the Division de Salud, Fundación FES Social (Gomez, Parra,oreno), Prevention Research Center in St. Louis (Parra, Brownson),eorge Warren Brown School of Social Work, Washington University int. Louis; Department of Surgery and Alvin J. Siteman Cancer CenterBrownson),WashingtonUniversity School ofMedicine,WashingtonUni-ersity in St. Louis, St. Louis,Missouri; TheDepartment of Kinesiology andommunity Health (Buchner), University of Illinois, Urbana-Champaign,llinois; Department of Social Medicine (Sarmiento), School of Medicine,niversidad de los Andes; Centro de Estudios Urbanos (Pinzón, Ardila),orporación de Universidades del Centro de la Ciudad; Universidad Na-ional de Colombia (Serrato), Bogotá, Colombia; CDC (Lobelo), Offıce oforkforce and Career Development and Division of Nutrition, Physicalctivity andObesity, PhysicalActivity andHealthBranch,Atlanta,GeorgiaAddress correspondence to: Luis F. Gómez, MD, MPH, Fundación FES

ocial, División de salud, Carrera 7 # 73-55, Ofıcina 1202, Bogotá, Colom-ia. E-mail: lfgomez@fundacionfes.org.

u0749-3797/00/$17.00doi: 10.1016/j.amepre.2010.02.005

92 Am J Prev Med 2010;38(6):592–599 © 2010 Amer

ntroductionhere is strong evidence1 that regular physical activityprovides substantial health benefıts to older adults.Physical activity amongelderly people has beenpos-

tively associated2,3 with prevention of chronic diseases, dis-bility, and bone fractures. In addition, physical activity re-uces the risk of cognitive decline and depressionymptoms, as it improves independent living.4

Walking has been recognized5 as an important form ofhysical activity that can be easily incorporated into dailyife. In addition, walking is an activity that does not re-uire special equipment or facilities, and has a low risk ofnjury.6–9 Despite these benefıts, the prevalence of inac-ivity is relatively high in Latin America. For example, inogotá, only 45% of the adult population meets the min-mum recommended levels of physical activity.10 Olderdults are generally the least active subgroup in any pop-

lation; thus, it is possible that the proportion of active

ican Journal of Preventive Medicine • Published by Elsevier Inc.

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Gómez et al / Am J Prev Med 2010;38(6):592–599 593

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lder adults in Bogotá is even lower as compared to theeneral population.Interventions that involve changes in the built envi-

onment have become a promising opportunity for theromotion of physical activity because they considertructural factors that go beyond the individual level andffect the population at large.11–13 Taking into accounthat the environmental determinants of walking may beifferent from those of other physical activity modalities,articularly among elders, specifıc explanatory modelsorwalking are needed. In addition, elderly peoplemay bespecially susceptible to the residential environments asompared to younger populations.14–17 In Latin Amer-ca, little is known about the association between the builtnvironment andwalking patterns among the populations a whole and particularly among the elderly.18,19

As a result of an informal and disorganized pattern ofrban development, Bogotá has several environmentalnequities,20,21 which include dispropor-ionate distribution of public space andreen areas as well as poor quality ofousing and road infrastructure. In anffort to counteract these problems, theity has engaged in several social and ur-an changes during the past few de-ades.22 An important feature of the citys the Ciclovía program, in which 121 kmf the main avenues are closed to motorehicles on Sundays and holidays andpened solely for pedestrians and cy-lists. Another urban feature of the city is TransMilenio, aus rapid transit system that operates in dedicated traffıcanes and has fıxed stations. In addition, between 2001nd 2003, the green area per inhabitant increased from.5 to 4.12 m2. These changes could be potentially associ-ted with the likelihood of older adults to engage in phys-cal activity, particularly in walking. Hence, the currenttudy was set forth to examine the associations betweenhe perceived and objective attributes of the residentialuilt environment and walking patterns among the el-erly population in Bogotá.

ethodstudy Design and Sample

multilevel cross-sectional study was conducted in 2007 using awo-stage randomized sampling design in which the neighbor-oods and the older adults were the primary and the secondarynits of analysis, respectively. Bogotá’s neighborhoods, as defınedy the Major’s Offıce, are not homogeneous in terms of SES andhysical attributes. As a result, the present study used a differentotion of neighborhood, defıned as a residential area of same SES,

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imilar urban characteristics, and bounded by urban or natural c

une 2010

imits. Neighborhoods mean area was 102.377 m2 (median�0,277 m2, SD�98,751) and had a population of 4211 people.Neighborhoods (n�1734) were classifıed in low, middle-low,

nd middle-high SES using the criteria established by the Mayor’sffıce of Bogotá,23 which uses physical attributes of the housingi.e., construction type and materials) and surrounding environ-ents (i.e., road and pedestrian infrastructure) to determineeighborhood SES. Power analysis was conducted based on thexpected precision of the estimates to defıne the sample design. Forhe fırst sampling stage, a probabilistic selection of 58 neighbor-oods was made. In a second stage, a random selection of olderdults who met the following criteria had the probability of beingelected: aged �60 years, at least 1 year of residency, not being oned rest at the time of the survey, and having suffıcient cognitiveapabilities to answer the survey. The fınal sample included 1966lder adults distributed across 50 neighborhoods (approximately9 older adults per neighborhood); data from eight of the original8 neighborhoods were not used because of small sample sizeresponse rate� 67.8%). Because of missing values for some of thenvironmental perception items, the regression analyses showed inhe current study were restricted to 1886 observations. Sampling

weights were calculated considering the unequalprobability of selection.

Measurement Procedures and Variables

A face-to-face interview was administered in 2007to each subject by interviewers who were trainedprior to data collection. The interviews had an av-erage duration of 12 minutes. The IRB of the Fun-dación FES Social approved the protocol prior todata collection.

Outcome variables. An adapted version of theInternational Physical Activity Questionnaire

short-form) was used to determine walking patterns.24 The walk-ng questions included in the survey were the following: Usuallyow many days of the week do you walk outside your home in boutshat last at least 10 minutes? and How much time do you usuallyalk in any of those days?These questions were adapted taking into account the results of

emi-structured interviews and focus groups conducted prior toata collection. The results of this qualitative approach suggestedhat it is diffıcult for older adults to discriminate between physicalctivity during leisure time and physical activity for utilitarianurposes because there is a combination of these types of activityor most individuals.As the authors were interested in exploring how the built envi-

onment was associated with low and high levels of walking, twoinary outcome variables were defıned: having walked for at least0 minutes and having walked for at least 150 minutes during asual week. This cut-point was established considering the recentlypdated U.S. physical activity recommendation guidelines.9 Inddition, some evidence9 shows how people who walk for at least0 minutes during the week are less likely to have cardiovascularvents as compared to inactive individuals.

eographic information system–defined built environ-ent variables. Taking into account the specifıc urban char-

cteristics of Bogotá and fıeld experience from a previous study

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onducted in this city,18 the following built environment vari-

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594 Gómez et al / Am J Prev Med 2010;38(6):592–599

bles were obtained usingISs: public park density,treet connectivity, pres-nce of a Ciclovía corridor,nd number of TransMile-io stations.These GIS variables wereeasured in an as-the-row-flies buffer of 500 mround the centroid of eacheighborhood as recom-ended in an earliertudy25 conducted amongn elderly population. Priorvidence has shown25 thatn cities with a high connec-ivity index, the differencesn the built environment in-icators calculated usingircular buffers and thosebtained using network-ased methods do not haveeaningful differences. Inddition, a buffer of 500 mould be more appropriateonsidering the reduced av-ragewalking speed of olderdults and the high diversityf land uses that exists inogotá. The average area ofhe selected neighborhoodsas smaller than the circu-ar buffer defıned in theresent study (average areaf neighborhoods�102,3772, SD�98,751, area of cir-ular buffer�785,189 m2),nd none of the selectedeighborhoods were adja-ent to each other. There isome overlap in only a fewf the 500-m buffers andainly among the neigh-orhoods that were not in-luded in the analysis be-ause of small sample size.rc View software wassed to generate the infor-ation (ArcInfo, version).Public park density was ob-

ainedbydividingthetotalareafpublicparksbythe totalareaf the buffer and multiplyingy 100. Pocket parks (less than000m2)were not included asheyhavenotbeendesigned toromote physical activitymong older adults. Park den-

Table 1. Study population cthrough a GIS in the 50 neig

Variables

INDIVIDUAL COVARIATES

Gender

Male

Female

Age (years)

60–74

75–98

Years of residence in theneighborhood

Education level

Primary school or less

More than primary school

Walking from your house, howdo the members of youfamily live?

Very far, far, neither

Close, very close

Missing values

ENVIRONMENTAL COVARIAT

SES of the neighborhoods

Low

Middle-low

Middle-upper

Slope of the terrain (buffer of500 m)

�5%

�5%

GIS BUILT ENVIRONMENTATTRIBUTES (BUFFER500 m)

Ciclovía corridorb

Yes

No

Number of TransMilenio stati

0

1

2

3

Park index

ity was classifıed into the fol-

haracteristics and built environment variables obtainedhborhoodsa

nNumber of

neighborhoods M or % Median SD

737 37.5 — —

1229 62.5 — —

1366 69.5 — —

600 30.5 — —

1966 24.5 25 16.1

1302 66.2 — —

664 33.8 — —

farr

1256 65 — —

701 35 — —

72 — —

ES

19 38 — —

26 52 — —

5 10 — —

38 79 — —

12 21 — —

OF

13 26 — —

37 74 — —

onsc

33 66 — —

9 18 — —

7 14 — —

1 2 — —

50 6.61 6.14 5.49

(continued on next page)

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Gómez et al / Am J Prev Med 2010;38(6):592–599 595

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owing tertiles: 0.01%–4.14% m2, 4.53%–7.98% m2, and 8.11%–35.21%2 of land covered byparks.Street connectivity was defıned as the number of street linksivided by the number street nodes within the buffer area. Thisndex ranges from 1 to 2, where 2 represents maximum connectiv-ty. The connectivity index was classifıed into the following tertiles:.46–1.74, 1.75–1.80, and 1.81–1.99. Binary variables were createdo determine the presence of aCiclovía corridor (yes versus no) andhe presence of TransMilenio stations (yes versus no) within the00-m buffer.18

nvironmental perception variables. Based on the resultsf focus groups and cognitive interviews26 conducted prior to dataollection, two environmental perception questions were selectedor this analysis in order to explore their associations with walkingatterns:

Safety from traffıc: categorized as very safe and safe versus nei-ther unsafe nor safe, unsafe, and very unsafe.Satisfaction with the quality of sidewalks in the place of resi-dence: categorized as very satisfıed and satisfıed versus neither

able 1. (continued)

Variables nNumber o

neighborhoo

Connectivity index 50

Land-use mix 50

BUILT ENVIRONMENT PERCEPTIONS

How safe from traffic do you feelcrossing the streets?

Very unsafe, unsafe, neither 1256

Very safe, safe 701

Missing values

How satisfied are you with the qualityand maintenance of thesidewalks?

Very dissatisfied, dissatisfied, neither 1425

Satisfied, very satisfied 539

Missing values

OUTCOME VARIABLES

Walking for at least 60 minutes duringa usual week

Yes 1687

No 279

Walking for at least 150 minutes duringa usual week

Yes 1226

No 740

500 m around the centroid of each neighborhoodCiclovía�program in which 121 km of the main avenues of the cSundays and holidays and opened solely for pedestrians and cyclisTransMilenio�mass transportation system of Bogotá

satisfıed nor dissatisfıed, dissatisfıed, and very dissatisfıed. v

une 2010

Individual covariates. In-dividual covariates includedgender; age groups (60–74and 75–98 years); educationlevel (elementary educationor less versus more than ele-mentary education); having alimitation to engage in phys-ical activity (measured with asingle SF8 item27: During thepast 4 weeks, how much didphysical health problems limityour usual physical activities[such as walking or climbingstairs]? categorized as couldnot perform physical activitiesand quite a lot versus some-what, very little, and not atall); and the proximity of afamily member (determinedby the following question:Walking from your house,how far do the members fromyour family live? categorizedas very close and close versusneither close nor far, far, andvery far for purposes of theanalysis).

Environmental covaria-tes. SES was measured foreach neighborhood and cate-gorized as low, middle-low,and middle-high. This vari-able was shared by the totalityof households in eachneighborhood.The slope of the terrain

was used as an environmentalcontrol variable and was cal-

ulated as vertical distance in meters � 100/horizontal distance ineters. This calculation was obtained by averaging the degrees oflope in a triangulated irregular network (TIN) previously createdn the terrain levels. Based on the urban criteria for building pedes-rian ramps, two categories were created: less than 5% of slope and% or more of slope.

tatistical Analysis

he data set was cleaned and checked for missing values. Thendividual variables and GIS data sets were merged. Proportion,ean, minimum andmaximum values, as well as SDs were used toescribe the built environment variables and the sociodemo-raphic characteristics and walking levels of the study sample.owess smoothing curves were created for the public park density,nd street connectivity variables and tertiles were defıned for pur-oses of the analysis. Presence of aCiclovía corridor (yes versus no)nd number of TransMilenio stations (none versus one or more)ere treated as binary variables.Multilevel adjusted models were developed for each outcome

M or % Median SD

1.77 1.77 0.1149

0.6346 0.6444 0.0920

64 — —

36 — —

72 — —

28 — —

85.8 — —

14.2 — —

62.4 — —

37.6 — —

e closed to motor vehicles on

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ariable. Final models included all the GIS environmental percep-

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596 Gómez et al / Am J Prev Med 2010;38(6):592–599

ions as well as the individual and environmental covariates. Thenalysis assumed a random intercept, and regression coeffıcientsere considered as fıxed. Collinearity was examined using regres-ion diagnostic tests. Cross-level interactions were explored butere not found. To obtain more-accurate estimations, La Placepproximations were used.28 All statistical analyses were con-ucted in 2008 with Stata 10 software using the command xt-elogit (Stata, version 10).

esultsharacteristics of the Sample

able 1 shows descriptive characteristics of the partici-ants and the neighborhoods included in the analysis.he means of age and time of residence in the neighbor-oods were 70.7 (SD�7.7) and 24.5 (SD�16.1) years,espectively. In all, 63% of the participants were women,nd 66% had an education level of primary or less; 35% ofarticipants reported that family members lived close orery close. Slightlymore than 85% reportedwalking for ateast 60minutes during a usual week, and 62.4% reportedalking for at least 150 minutes and more during theeek.

nvironmental Variables and Walking ateast 60 Minutes per Week

s it is shown inTable 2, older adults who resided in areasn the highest tertile of the connectivity index (1.81–1.99)ere signifıcantly less likely towalk for at least 60minutesuring the week as compared to those in the lowest tertileprevalence OR [POR]�0.64, 95% CI�0.44, 0.93,�0.021). Those who resided in areas within the middleertile of public park density (4.53�7.98) were moreikely to walk for at least 60 minutes than those who livedn areas within the lowest tertile (POR�1.42, 95%I�1.02, 1.98, p�0.039). The slope of the terrain wasegatively associated, as those who lived in slope terrain�5%)were less likely to walk for at least 60minutes thanhose in areas with slope of �5% (POR�0.61, 95%I�0.38, 0.97, p�0.038). Those participants who reportedeeling safe or very safe fromtraffıcwhencrossing the streetsere more likely to walk for at least 60 minutes than thoseho felt very unsafe, unsafe, or neither (POR�1.50, 95%I�1.11, 2.03, p�0.007).

nvironmental Variables and Walking ateast 150 Minutes per Week

iclovía corridor was positively but marginally associ-ted with having walked for at least 150minutes duringusual week (POR�1.29, 95% CI�0.97, 1.73,

�0.079). This same marginal and positive association

as found with feeling safe or very safe from traffıc d

hen crossing the streets (POR�1.19, 95% CI�0.97,.47, p�0.088).

iscussionhepresent study suggests thatbothperceivedandobjectivettributes of the neighborhood built environment aressociated with walking patterns in older adults living inogotá. In view of the fact that built environment attributesay link differentlywithwalkingpatternsdependingontheut-points defıned, the present study provides new insights toetterunderstandthis issue inthecontextofahighlyurbanizedity in LatinAmerica.The negative association between street connectivity

nd walking for at least 60 minutes differs from theajority of the evidence gathered from studies29–33 inurope and the U.S., as well as previous research18

onducted in Bogotá among younger adults. Thesetudies have documented a positive association be-ween high connectivity levels and physical activity.ne study conducted in Baltimore found a similaresult to that found here, documenting a negative as-ociation between street connectivity and walkingrips,34 and other studies35,36 have found no associa-ions. These conflicting fındings may be due to differ-nces in study designs, diverse urban characteristics,r differences in the sampled population (younger ver-us older adults) from the studied cities. The currentesults can in part be explained by the high levels ofompactness and connectivity of Bogotá. A high con-ectivity level is linked with more intersections andedestrian crosswalks, which could be associated withperception of higher risk of traffıc accidents amonglder adults, thus discouraging them from walking.Public parks density was positively associated with walk-

ng for at least 60 minutes during a usual week, which isimilar to the fındings of several studies37,38 conducted inhis area. However, this association was found only amonglder adults who resided in those areas within the secondertile of public parks density. This could be due to the facthat the indicator of park density calculated for the presenttudy included various types of public parks, which mayave different designs, and did not take into account differ-nces in the type of equipment or other surrounding at-ributes, that may facilitate or deter walking among elderlyopulation.Although the presence of Ciclovía wasmarginally associ-

ted with walking for at least 150 minutes during the week,his fınding is meaningful and potentially has large publicealth implications, because this recreational program is

edicated to not only bikers but also pedestrians and has

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Gómez et al / Am J Prev Med 2010;38(6):592–599 597

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een identifıedasan innovative strategy topromotephysicalctivity.22

The positive association between the perception ofraffıc safety and walking is consistent with an earliereta-analysis14 andmay suggest the need to advocate forolicy and regulatory actions aimed at improving pedes-

able 2. Multilevel models for walking at least 60 and 15eek among older adults, adjusted POR (95% CI)

Variables

Having walked>60 minutes/

week p-va

GIS VARIABLES

Slope

�5% 1 —

�5% 0.61 (0.38, 0.97) 0.0

Ciclovía corridora

No 1 —

Yes 1.16 (0.82, 1.65) 0.3

Connectivity index

1.46–1.74 1 —

1.75–1.80 0.74 (0.50, 1.10) 0.1

1.81–1.99 0.64 (0.44, 0.93) 0.0

Public park density

0.01–4.14 1 —

4.53–7.98 1.42 (1.02, 1.98) 0.0

8.11–35.21 1.06 (0.74, 1.53) 0.7

TransMilenio stationsb

Zero 1 —

One or more 0.75 (0.52, 1.08) 0.1

ENVIRONMENTAL PERCEPTIONS

How safe from traffic do you feelcrossing the streets?

Very unsafe, unsafe, neither 1 —

Very safe, safe 1.50 (1.11, 2.03) 0.0

How satisfied are you with thequality and maintenance ofthe sidewalks?

Very dissatisfied,dissatisfied, neither 1 —

Satisfied, very satisfied 0.82 (0.61, 1.12) 0.2

ote: Buffer of 500 m around the neighborhoods. n�1886; number odjusted by gender, age groups, education level, limitation to engagCiclovía�program in which 121 km of the main avenues of the city arand holidays and opened solely for pedestrians and cyclistsTransMilenio�mass transportation system in BogotáOR, prevalence OR

rian safety. This is particularly important in Bogotá, a

une 2010

which has a high preva-lence of traffıc accidentsinvolving older adultpedestrians in the ma-jority of cases.39

Several study strengthscan be mentioned. Theuse of GIS allowed us tohave objective and robustmeasures of the builtenvironment. The inclu-sion of environmentalperceptions complemen-ted and enriched the anal-yses presented in the cur-rent study. The samplingdesign allowed for com-parison among variousurban attributes of geo-graphicareasfromvariousSES levels, which im-proved the external va-lidity of the study. Fi-nally, the current studyconceived a new defıni-tion of neighborhoodthat may reflect moreclosely the perceptionsthat older adults have oftheir micro-territories.A limitation of the cur-

rent study is its cross-sectional nature, makingit impossible to deter-mine the temporality ofthe observed associa-tions. In addition, be-cause walking levels inthe current studywerede-termined through a self-report instrument, there isa probability of overesti-mation, as documented inseveral studies.40–42 Fi-nally, the possibility ofself-selection cannot

e excluded as people may select their residential areasased on environmental attributes linked with physicalctivity. However, the average time of residency in theurrent study was 24.5 years, and some of the urbanhanges that have occurred in the city and that weressessed in this study were more recent. In addition, in

inutes during a usual

Having walked>150 minutes/

week p-value

1 —

0.80 (0.55, 1.16) 0.254

1 —

1.29 (0.97, 1.73) 0.079

1 —

0.79 (0.58, 1.09) 0.163

0.90 (0.67, 1.23) 0.540

1 —

1.08 (0.81, 1.43) 0.574

0.95 (0.70, 1.29) 0.757

1 —

0.78 (0.59, 1.04) 0.101

1 —

1.19 (0.97, 1.47) 0.088

1 —

0.95 (0.76, 1.19) 0.712

graphic areas�50. Models werehysical activity, slope, and SES.ed to motor vehicles on Sundays

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598 Gómez et al / Am J Prev Med 2010;38(6):592–599

elow the poverty line, it is likely that the reasons forelecting residential areas may have to do more withconomic factors rather than environmentalttributes.To the authors’ knowledge, this is the fırst published

tudy exploring the links between perceived and objectivendicators of the built environment and walking patternsmong the elderly population in a Latin American city.he particular characteristics of the city, including theow proportion of sprawling areas, the high level of com-actness of urban forms, the unplanned and disorganizedrbanization processes that occurred in large parts of theity, as well as other cultural and social aspects, constituteactors that may help explain some of the results from theresent study and that are worth further exploration.

his research was supported by a grant from the Depar-amento Administrativo de Ciencia, Tecnología e Inno-ación, COLCIENCIAS. Many individuals contributedo this research, and their assistance is acknowledged. Inarticular, we thank Janeth Mosquera for the culturaldaptation of the self-report instruments.No fınancial disclosures were reported by the authorsf this paper.

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Did you know?According to the 2008 Journal Citation Reports®, published by Thomson Reuters, the

2008 impact factor for the American Journal of Preventive Medicine is 3.766.