incorporating neighborhood context into the study of health outcomes jennifer f. culhane, mph, phd...

Incorporating neighborhood context into the study of

health outcomes

Jennifer F. Culhane, MPH, PhDDrexel University College of Medicine

Department Of Obstetrics and Gynecology

OUTLINE• How are neighborhoods defined?

• How are neighborhoods characterized and what are sources of neighborhood data?

• How can neighborhood conditions affect health?

• What is the scientific evidence in support of this idea?

• What are the major challenges in this field?

Neighborhood Definitions• Administrative units

– blocks– block groups - counties– census tracts - states

• Political units- wards - State Senatorial Districts- City Counsel Districts - State Rep. Districts

• Service Districts- health districts - fire battalion boundaries- police districts - school boundaries- recreation districts - postal zip codes

• Self-defined neighborhood boundaries - shared environment - natural boundaries

Census Tract verses Block Group

Police Districts

Recreation Districts

School District Boundaries

Characterize NeighborhoodsWhat Types of Data Do You Need?Endogenous data: aggregates of individual characteristics, e.g.,

poverty rate, percent married, percent female headed households, percent unemployed – indirect measures

Direct measures: measure of the built environment like

“walkability”

Sources of Neighborhood-level Data

• Administrative and public health data at the address level

• Census data at the block, block group, and census tract level

• Proprietary data

• Primary data collection

Sources of Data

Direct Mechanisms• Community Social Environment

Social relationships transmit informationNeighborhood cohesionsocial controlShared cultural norms and valuesCivic participation demand servicesAccess to education and employment

• Community ServiceGrocery storesRecreational opportunitiesHealth care facilitiesRetail stores

• Physical EnvironmentToxicantsNoisePoor housing

Indirect Mechanisms

• Chronic StressSelye, 1956 “General Adaptive Response”

Alarm, resistance, exhaustion. Repeated cycles lead to cumulative damage to organism.

McEwen & Stellar, 1993—Allostatic Load The cost of maintaining stability through change

• Mental HealthNegative EmotionsDepressionAnger/hostility

How Does Neighborhood StressGet Under Your Skin?

Biological Mediatorsto Stressful Exposures

Conceptual Framework

Neighborhood Effects: Evidence

Community context consistently has a“modest association” with numerous healthoutcomes.

25 studies reviewedDeveloped countriesIndividual-level attributes controlled for23/25 had significant neighborhood effects

Reviewed in Pickett & Pearl, J. Epidemiol Community Health, 2001; 55

Neighborhood-Level Effects have been found in:

• All cause mortality• Chronic disease among adults• Self-rated health• Long-term disability• Cardiovascular symptoms or disease• Respiratory function• Health Behaviors (i.e.,-smoking, sexual practices)• Domestic Violence• Low birth weight and preterm birth

Neighborhood Effects Vary…

• In nature and intensity at different life stages

• By gender

• By age

• By family structure

• By individual-level attributes

What are the Challenges?1. What is the theory linking contextual variable and

outcome of interest?2. What is context?

– Geographic? Work, Religious affiliations, Clubs, Social Networks ?

3. What contextual-level variables should be measured?4. What is the spatial range of a contextual variable?5. What statistical techniques should be employed?6. Limitations of a cross-sectional design-when to measure

context?7. What individual-level characteristics need to be

controlled for? endogeniety vs. over control

Over Control vs. Endogeneity

Social Conditions as Fundamental Cause

Endogeneity

Endogeneity vs. Over control• Smoking may be the proximal cause but

neighborhood distress may be the “true” distal cause.

• Or, for some reason, people who smoke are “selected” into neighborhood #1 thus neighborhood characteristics have no ‘true’ association to risk of low birth weight

Endogeneity vs. Over Control

• The “selection” or “confounding” issue is the key problem in observational studies of neighborhood effects.

• Epidemiology has attempted to account for this by adjusting for numerous individual-level attributes- confounding.

• The “nagging” problem is that these individual-level attributes may be mediators and not confounders.

Ana V. Dies Roux, Social Science & Medicine 58 (2004) 1953-1960

Individual and Neighborhood Effects

Neighborhood A Neighborhood B

Individual and Neighborhood Effects

Neighborhood ANeighborhood B

Individual Attribute

Protection

Individual and Neighborhood Effects

Neighborhood ANeighborhood B

Individual Attribute

Protection

Neighborhood Characteristic

Protection

Key Messages

• Neighborhoods can be defined in many ways• The definition of ‘neighborhood’ must be

appropriate for the research question• Many different types of data can be used to

characterize neighborhoods• There are plausible direct and indirect pathways

by which neighborhood conditions can affect health

Key Messages

• There are numerous challenges in studying the effect of neighborhood conditions on health

• In the arena of reproductive outcomes neighborhood conditions may be a fruitful avenue for explaining the race/ethnic difference in preterm birth