A
long with such associated symptoms as changes in appetite, sleep, and feelings of worthlessness, depression is characterized by a marked downturn in mood or loss of pleasure that interferes with daily life and normal functioning.
1 Many people, however, have experienced symptoms that mimic or match one or more of these symptoms without having enough of them to have a diagnosable health problem of depression.
2 Epidemiological data show that the prevalence of depressive symptoms is higher in African American women than in white women.
3 Known individual characteristics that place women at risk for depressive symptoms are low income, not working, being unmarried, and low educational attainment.
3,4 Further, there is some evidence from longitudinal studies to suggest that obesity is a stigmatizing attribute that promotes negative stereotyping and produces depressive symptoms.
5In recent years, attention has focused beyond individual characteristics to the effects of neighborhood characteristics (e.g., socioeconomic status [SES], built environment, social environment) on depressive symptoms. Neighborhood conditions may be particularly salient for African American women because they are more likely than white women, for example, to live in disadvantaged neighborhoods or neighborhoods with fewer economic or other resources and more hazards.
6–8 In addition to cardiovascular benefits and reduction in obesity,
9,10 a growing body of evidence from observational and intervention studies suggests that leisure time physical activity may decrease depressive symptoms.
11 It is not yet known, however, if physical activity can offset the negative effects of living in disadvantaged neighborhoods on depressive symptoms among African American women. The purpose of this study was to examine relationships among neighborhood characteristics, adherence to a physical activity intervention, and change over time in depressive symptoms in midlife African American women.
Neighborhood characteristics and depressive symptoms
Two recent reviews of neighborhood characteristics and depressive symptoms or major depression found that most studies have focused on neighborhood SES, with the majority finding associations in the expected direction.
12,13 Fewer studies have examined specific features of the social environment (e.g., social disorder, crime) and especially the physical environment (e.g., vacant lots, abandoned buildings) that may influence depressive symptoms, with most relying on respondents' perceptions (subjective appraisals or understandings) of their environment.
12,13 For example, in a cross-sectional study of African Americans and whites residing in a racially integrated neighborhood, those who perceived more neighborhood problems (e.g., crime, drug, and gang activity; lack of access to healthcare, banking, grocery stores, and transportation; poor street lighting) had higher levels of anxiety, stress, and depression.
14 Likewise, in a sample of African American women living in a low-income, predominantly African American neighborhood in Detroit, perceived neighborhood safety stress was directly and positively associated with depressive symptoms.
15 A longitudinal analysis of persons residing in disadvantaged areas showed baseline perceptions of neighborhood problems, such as vacant housing, burglary, robbery, and vandalism, predicted higher rates of depression at follow-up,
16 although others have found no association.
17,18Among the few studies using objective indicators (empirically observable measures derived from sources independent of respondents' perceptions or self-reports) of neighborhood physical and social environments, crime and deterioration have been among the most commonly studied neighborhood characteristics, with complex results. For example, one recent report found depressive/anxiety disorders were more likely among individuals who both lived in a high crime area and had violence exposure,
19 whereas another suggested crime may indirectly impact depressive symptoms through perceptions of the neighborhood and personal experience with neighborhood violence.
20 There are some conflicting reports related to objective neighborhood deterioration and depressive symptoms. Whereas one study found no association in an African American sample,
17 another study in an African American and white urban sample found fear of crime and social capital mediated the association between residential building deterioration and depressive symptoms.
21 Nonetheless, only a handful of the studies have included substantively equivalent objective and perceived measures of neighborhood characteristics, with even fewer comparing the relative effects of perceived and objectively measured neighborhood characteristics on depressive symptoms.
Physical activity and depressive symptoms
A recent review of physical activity and the likelihood of depression
11 included 9 observational studies with nonclinical community samples
22–30 and 16 interventions with healthy or mildly depressed individuals living in the United States.
31–45 All but 1
23 of the 9 observational studies showed an inverse relationship between physical activity and depressive symptoms, and the positive effects of physical activity persisted after adjusting for differences in individual characteristics, including sociodemographics, selected health behaviors, self-reported physical disorders, and comorbid mental disorders.
24,26,28,29 The only study with a large representative sample of African American women found that women who reported vigorous exercise in both high school and adulthood had the lowest odds of depressive symptoms.
30 Despite evidence showing that perceived lack of neighborhood safety
46–48 and unpleasant aesthetics
49–53 (e.g., deterioration) are barriers to physical activity, only 1 of the 9 observational studies included these neighborhood problems. That study failed to examine the interaction between neighborhood problems and physical activity on depressive symptoms.
29Despite some inconsistencies in the intervention studies, the preponderance of evidence verifies observational findings by suggesting that physical activity can improve depressive symptoms.
11 Nonetheless, the intervention studies have several limitations with respect to understanding relationships between physical activity and improvement of depressive symptoms in African American women. First, either they did not specify race or their participants were predominantly white. As noted by Wise et al.,
30 physical activity may serve as a buffer for African American women against stressful life situations, such as those posed by disadvantaged neighborhoods. Second, only King et al.
40 examined whether there were factors common to tested interventions that might be more sensitive predictors of psychological outcomes than intervention assignment; they found that regardless of intervention type, exercise participation level or adherence was associated with fewer depressive symptoms. Last, none of the intervention studies examined the joint influence of neighborhood characteristics and physical activity on depressive symptoms.
Study hypotheses
We developed a 24-week, home-based, moderate-intensity walking intervention for midlife African American women residing throughout metropolitan Chicago. We compared an enhanced treatment (ET) that included behavioral strategies culturally targeted and tailored to African American women with a minimal treatment (MT) for effects on depressive symptoms. The limitations of prior studies of physical activity interventions and depressive symptoms were addressed by including a socioeconomically diverse sample of African American women and both objective and perceived measures of neighborhood characteristics (deterioration and crime) as predictors of depressive symptoms. In addition, rather than relying solely on treatment group, we examined the influence of adherence to physical activity on depressive symptoms. First, we hypothesized that at the end of 24 weeks, ET women compared with MT women would have greater improvement in their depressive symptoms. We also hypothesized that controlling for individual characteristics, walking adherence at 24 weeks would be associated with lower depressive symptoms, whereas neighborhood deterioration and crime would be associated with higher depressive symptoms. Our third hypothesis was that walking adherence would moderate the effects of neighborhood deterioration and crime on depressive symptoms at 24 weeks.