Neighborhood effects on primary care access in Los Angeles

Abstract

Individual health outcomes differ greatly between neighborhoods, and recent research has begun to examine how neighborhood environment affects individual health. A common hypothesis is that the inequitable distribution of healthcare resources limits access to health care for individuals in disadvantaged neighborhoods, causing poorer long-term health. Yet, research has not examined if neighborhood environment actually affects an individual's ability to access primary care. Data from the Los Angeles Family and Neighborhood Survey suggests there is significant variation between neighborhoods in an individual's ability to access primary care. This neighborhood-level effect is not explained by the composition of individuals living in the neighborhood. Four mechanisms through which neighborhood environment could affect an individual's ability to access primary care are examined: (1) neighborhood information networks, (2) neighborhood health behavior norms, (3) neighborhood social capital and (4) neighborhood healthcare resources. Social capital and healthcare resources significantly predict an individual's primary care access. Since differences in primary care access may explain individual-level health disparities between neighborhoods, policies designed to improve primary care access must account for both individual and neighborhood effects.

Introduction

Individuals who live in poorer and more disadvantaged neighborhoods have inferior health outcomes (Acevedo-Garcia, 2000; Pickett & Pearl, 2001; Robert, 1999). Several reviews of studies using multilevel analysis have concluded that neighborhood socioeconomic status (SES) has an independent effect on a wide variety of individual health outcomes even when controlling for individual SES and other individual characteristics (Ellen, Mijanovich, & Dillman, 2001; Pickett & Pearl, 2001; Robert, 1999). However, the mechanisms linking neighborhood environment to individual health are not well understood. Differences between neighborhoods in the availability of structural resources, including healthcare, have led researchers to hypothesize one mechanism is decreased access to and use of health care (Macintyre, Ellaway, & Cummins, 2002). This paper examines whether restricted primary care access is one plausible mechanism explaining the disparities in individual health between neighborhoods.

Primary care is defined as care that gives patients entry into the healthcare system, coordinates healthcare services for patients, provides care to the same patient over time, is comprehensive (i.e. curative and preventive) and takes into account the patient's societal context outside the healthcare system (Macinko, Starfield, & Shi, 2003). This integration of curative and preventive healthcare over time improves individual and population health (Macinko et al., 2003; Shi, 1994) by helping patients prevent and control illnesses (Blumenthal, Mort, & Edwards, 1995). Macinko et al. (2003) compared mortality rates between countries with similar SES and found countries with stronger primary care systems have lower all-cause and all-cause preventable mortality.

Furthermore, studies have found access to primary care can attenuate the negative effects of lower SES and income inequality on health (Casanova and Starfield, 1995; Shi, Starfield, Kennedy, & Kawachi, 1999; Shi, Starfield, Politzer, & Regan, 2002). Casanova and Starfield (1995) link SES, primary care and preventable hospitalizations. While children from different social classes in the United States have different rates of preventable hospitalizations, they argue these differences are not observed in Spain where all children have a regular source of care (RSOC). Similarly, Shi et al. (1999) found that although income inequality between states significantly predicted all-cause mortality, once models controlled for primary care physician supply, income inequality was not a significant predictor of all-cause mortality.

Past research has largely focused on individual characteristics that predict primary care access and utilization. The Anderson Behavioral Model of Health Service Use traditionally predicts healthcare use based on predisposing, enabling and need factors. Predisposing factors influence an individual's inclination to utilize health care, such as health beliefs. Enabling factors help individuals access care, such as having insurance coverage to help pay for care. These factors must be present for use to take place. Need factors reflect individuals’ perception of how important it is to access care based on their health status. All three factors are essential in explaining healthcare utilization (Andersen, 1995; Gross, 1972).

Yet, recent research argues an individual's ability to access healthcare is independently affected by where he or she lives. Characteristics of an individual's Metropolitan Statistical Area (MSA) were found to affect his or her healthcare access, even when controlling for differences in the composition of individuals living in these MSAs (Brown et al., 2004; Cunningham & Kemper, 1998). Brown et al. (2004) used the 1995 and 1996 National Health Interview Survey and found significant variation across MSAs in the odds of whether low-income adults visited a physician in the last year. Cunningham and Kemper (1998) found over a two-fold difference in the proportion of the uninsured who reported having difficulty accessing healthcare among MSAs included in the Community Tracking Study. These studies selected MSAs with populations of at least 330,000 and 200,000, respectively. Clearly, MSAs are much larger than an individual's actual neighborhood, and researchers have not examined if neighborhood environment independently affects healthcare access using a more precise geographic definition of neighborhood, such as census tracts. Census tracts have a moderate population size (approximately 5500) and lack man-made or natural cross-cutting boundaries (e.g. freeways) (Sastry, Ghosh-Dastidar, Adams, & Pebley, 2003).

This paper finds that neighborhood (defined as census tract) environment affects an individual's primary care access. It then examines potential mechanisms between neighborhood environment and individual primary care access by examining the effects of neighborhood information networks, health behavior norms, social capital and healthcare resources on primary care access.

Strong neighborhood information networks may encourage individuals to use primary care because individuals often seek advice from peers before seeking out preventive healthcare (Earp et al., 2002; Levy-Storms & Wallace, 2003). Levy-Storms and Wallace (2003) examined the effect of informal health communication networks on mammogram use among Samoan women in Los Angeles. Women who were the most central in these networks were significantly more likely to plan to have a mammogram and to have had a recent mammogram compared to women who were outside of these networks. Individuals living in neighborhoods with strong information networks may get advice on how to access primary care from their neighbors (Ellen et al., 2001) encouraging primary care use.

The decision to use primary healthcare (especially preventive services) can be viewed as a health-seeking behavior, similar in some ways to other health-related behaviors, such as the decision not to smoke. Social norms or the shared attitude about the importance of health-seeking behaviors differ between neighborhoods, and individuals often behave in concordance with the social norms of their environment (Curry et al., 1993; Ellen et al., 2001). Thus, if an individual lives in a neighborhood with social norms that encourage practicing healthy behaviors, he or she may be more likely to obtain primary care.

Social capital results from aspects of the social structure that provide resources to individuals and facilitate collective action. It can be conceptualized into two components: (1) cognitive and (2) structural (Kawachi & Berkman, 2000; Subramanian, Kim, & Kawachi, 2002). The cognitive component assesses individuals’ perceptions of the level of interpersonal trust, sharing and reciprocity in the community (Subramanian et al., 2002). Sampson (2003) argues this cognitive component can be viewed as collective efficacy, or the expectation that community members will act collectively for the common good, securing needed social goods. Thus, collective efficacy may help keep the healthcare system accountable to the community (Hendryx, Ahern, Lovrich, & McCurdy, 2002; Steinberg & Baxter, 1998). Steinberg and Baxter (1998) conducted a qualitative case study of 12 MSAs in the Community Tracking Study. MSAs where residents shared common values toward healthcare were more effective at holding the local healthcare system accountable to the needs of residents, such as protecting access to care among vulnerable populations. Individuals in communities with greater community social trust, civic engagement and self-esteem have more trust in their physicians (Ahern & Hendryx, 2003), which may lead to increased healthcare utilization. Neighborhood social capital may also increase individual self-esteem (Kawachi & Berkman, 2000) and in turn affect the importance people place on protecting their health and their likelihood of seeking primary care.

The structural component of social capital includes the extent and intensity of associational links (e.g. density of civic associations) (Subramanian et al., 2002). Individuals living in neighborhoods with well-established structural aspects of social capital may also have more social interaction. This could lead to direct functional support that increases primary care access. For example, neighbors could provide child care while an individual goes to the doctor. Thus, neighborhood social capital may increase primary care access through collective efficacy, psychosocial effects and direct functional support.

Finally, neighborhoods differ in their supply of healthcare resources. Areas with greater wealth have more healthcare resources (Jiang & Begun, 2002). The types of industries in a community affect healthcare resources since certain types of employers are more likely to provide private health insurance coverage, which has higher reimbursement rates than public insurance (Brown, Ponce, & Rice, 2001; Cunningham & Ginsburg, 2001; Komaromy, Lurie, & Bindman, 1995). Thus, the spatial distribution of healthcare resources is far from equitable with severely disadvantaged neighborhoods, such as inner cities, having fewer healthcare resources (Fossett, Perloff, Kletke, & Peterson, 1992; Grumbach, Coffman, Young, Vranizan, & Blick, 1998). Also, populations with a greater percentage of the very young or elderly may demand more healthcare since these ages have greater healthcare needs, bringing more providers to an area (Cunningham & Kemper, 1998; Jiang & Begun, 2002). Individuals living in neighborhoods with greater healthcare resources may be more likely to use primary care due to shorter travel distances required to see a provider (Gross, 1972) and greater provider choice.

This study examines if the above neighborhood characteristics influence an individual's primary care access. Individuals living in a neighborhood with stronger information networks, stronger social norms against negative health behaviors, greater social capital and more healthcare resources are hypothesized to have better primary care access.