Abstract
Access to parks improves overall health outcomes in the general population. Given that HIV infection has become a chronic disease to manage, among populations engaged in medical care, parks may be promoted as physical activity opportunities in order to manage chronic comorbid conditions. We conducted a cross-sectional examination of the relationships between sociodemographic and biomedical characteristics to park proximity among 635 individuals receiving outpatient HIV care. The data collected included HIV-related biomarkers, depression, and diagnoses of other chronic diseases. The total acres of parks an individual is exposed within one-quarter mile from their home were assessed. The cohort included 635 individuals (67% men, 73% black, and 21% white, mean age 42 years). Unemployment was negatively associated with park availability. Park proximity was not associated with depression or HIV biomarkers. As yet, little effort has been committed to promoting park usage as a low-cost, sustainable method to addressing comorbidities among individuals with HIV.
Introduction
There are approximately 1.1 million HIV infections in the United States, with an estimated 56 000 new cases annually. 1 Due to significant medical advancements, HIV is increasingly considered and treated as a chronic medical condition. As individuals with HIV infection are living longer, identifying opportunities to enhance health outcomes and reduce HIV transmission need to be further embedded in comprehensive care practices.
Psychological distress is highly prevalent in populations with HIV infection and has been negatively associated with management of their HIV disease.2,3 Thus, effective treatment of these symptoms has the potential to improve other comorbidities, reduce HIV transmission, and promote overall health.4,5 Physical activity interventions have been shown to improve both management of HIV disease and overall quality of life.6,7
Access to and utilization of green spaces, specifically parks, have been shown to increase physical activity, 8 reduce stress, 9 and improve mood and concentration10,11; reduce heart rate 12 ; and are associated with higher self-reported health. 13 In the present study, we evaluated the hypothesis that proximity to parks is associated with fewer HIV-associated psychological and physical comorbidities. Though the evidence supporting the salutogenic effect of proximity to parks continues to grow, no studies have specifically investigated this effect on populations with a severe chronic disease and associated comorbidities.
Methods
This cross-sectional study analyzed the relationship between symptoms of depression, sociodemographic, and biomedical factors to access to parks in a population with HIV infection. As part of standard-of-care practices, individuals who lived in St Louis city or county and engaged in care at the Washington University HIV Clinic completed an annual behavioral assessment during regular clinic visits in 2008 (n = 635). The interview collected sociodemographic characteristics, smoking status, and symptoms of depression, as measured by the Patient Health Questionnaire 9. 14 Depressive symptoms were dichotomized to having symptoms of major depressive disorder and other depressive disorder or no severe symptoms. HIV viral load was dichotomized to < and ≥400 copies/mL, and CD4 counts were dichotomized to < and ≥200 cells/mm3. As part of these analyses, most recent individual addresses were abstracted from medical records and geocoded to assess geospatial effects of parks on HIV management. There was a 100% match of the participant addresses.
ArcGIS v.10.0 was used to spatially calculate acreage of parks within 0.25 mile of participants’ homes. Park data were obtained from St Louis City and County Departments of Recreation and local councils of government. All park polygons were spatially corrected to the most recently available tax parcel feature class. A review of built environment measures and physical activity found 400 m (one-quarter mile) as the smallest buffer distance consistently used in past research. 15 We selected 10 acres because that is roughly the number of acres per 1000 people. ArcGIS Network Analyst 10.2 (Esri, Redlands, California) was used to calculate access to parks and park acreage by creating a 0.25-mile network buffer following road polylines. If a participant had access to any portion of the park within the 0.25 mile, then the entire park acreage was considered accessible to that individual. We conducted Kruskal-Wallis nonparametric tests to analyze relationships between acreage (by category, none, <10 acres, and ≥10 acres) and sociodemographic factors using SPSS v.19.
Results
The cohort included 635 individuals, of whom 67% were men, 73% were African American, with a mean age of 42 years (standard deviation = 11.0 years). Approximately 27% (n = 172) were employed full time, while 13% (n = 84) were employed part time. More than half of the sample (n = 338; 53%) was unemployed or receiving disability benefits. Just over one-third of the sample had completed high school or equivalent (n = 221; 35%), while 20% (n = 131) had not completed high school and 10% (n = 62) had a bachelor degree. More than half of the cohort (n = 349) reported an annual income of less than US$10 000 and 27% (n = 174) reported an annual salary between US$10 000 and US$30 000. Three-quarters of the sample (n = 461) had a current antiretroviral therapy prescription and 67% (n = 425) had suppressed viral loads at the time (<400 copies/mL). More than one-third of the sample (n = 223) endorsed symptoms of current depressive disorders and 50% (n = 315) were current smokers.
Specific comorbid conditions that could be affected by access to parks and physical activity opportunities were assessed, with 8% (n = 52) having a diagnosis of diabetes mellitus, 34% (n = 215) with hypertension, 35% (n = 224) having any psychiatric diagnosis, and 5% (n = 29) having any malignancy. Current prescriptions for comorbid conditions included statins (9%, n = 55), antihypertensives (21%, n = 135), and antidepressants (24%, n = 155).
Nearly half of the cohort had no access to park space (45%, n = 367); 17% (n = 141) had little access (1-9 acres); and 15% (n =127) had at least 10 acres of accessible park space. Individuals who were employed were more likely to have access to green spaces (P = .041), while no other sociodemographic characteristic was associated with proximity to green spaces (Table 1). Unemployed individuals had the least amount of park acreage within a 0.25-mile radius of their home (P < .05). In analyses to examine associations of higher depression, those unemployed had higher rates of depression (P < .001). County residents, in a more suburban environment, were significantly more likely to live in a home with no park access within 0.25 mile than city residents (P < .001).
Associations between Sociodemographic Characteristics and Park Proximity among Individuals Presenting for HIV Care Who Live in St Louis City and County.
Abbreviation: GED, general equivalency diploma.
Discussion
This study found few significant associations of park space with HIV-related health outcomes. Previously, we identified that lower education attainment, unemployment, and depression were factors that negatively impact HIV-related health outcomes.2,16 We found that these HIV-related health factors were not associated with access to parks, with the exception of lack of employment. Unemployment has been associated with higher rates of depression and poor HIV management previously, which suggests additional efforts among individuals who are unemployed are needed.
Park access has previously been associated with improved outcomes related to circulatory disease, obesity, and psychological distress.17–19 This study did not identify relationships between other comorbidities. However, physical proximity is one factor that influences park usability. Cultural ties, social dynamics, and contextual factors also influence usage decisions and may not be reflected in conventional spatial measurement tools. 20
As studies have found that physical activity will improve HIV-related health outcomes and improve mood,21,22 recommendations that include utilizing existing resources have a great potential to impact health outcomes. HIV care providers can identify local parks for patients to use as a sustainable intervention for reducing depressive symptoms, promoting physical activity and health, and improving HIV-related health outcomes, as well as overall well-being. Low-cost interventions, such as park prescriptions, 23 may relieve psychological stress without the need for additional medication in a population already physiologically and financially inundated with medications. Future studies and intervention development may offer a better understanding of park utilization as a method to improve optimal care and enhance quality of life for individuals with HIV infection.
Footnotes
Authors’ Note
The contents of the article are solely the responsibility of the authors and do not necessarily represent the official view of National Institute on Drug Abuse (NIDA) or National Institutes of Health (NIH).
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This publication was partially supported by grant number R03 DA030875 (PI: Enbal Shacham, PhD) from the National Institute on Drug Abuse.