The price of admission: does moving to a low-poverty neighborhood increase discriminatory experiences and influence mental health?

The challenges of quantifying the effects of housing on health using observational data

Housing is an often overlooked yet fundamental social determinant of health. Like other social epidemiology exposures, housing faces a tension between the promise of modern causal inference methods and the messy reality of complex social processes and reliance on observational data. We use examples from over a decade of research to illustrate some of the key challenges in undertaking causally focused healthy housing research and demonstrate approaches that have been applied to address these challenges. We reflect on the improved understanding these approaches have delivered, and the key gaps and next steps in generating the evidence required to act on housing as a social determinant of health.

School racial/ethnic composition, effect modification by caring teacher/staff presence, and mid-/late-life depressive symptoms: findings from the Study of Healthy Aging in African Americans

For Black students in the United States, attending schools with a higher proportion of White students is associated with worse mental and physical health outcomes in adolescence/early adulthood. To our knowledge, no prior studies have evaluated the association between school racial/ethnic composition from kindergarten through grade 12 and later-life mental health. In a cohort of Black adults aged ≥50 years in Northern California who retrospectively reported (2017-2020) school racial/ethnic composition for grades 1, 6, 9, and 12, we assessed the association between attending a school with mostly Black students versus not and mid-/late-life depressive symptoms (8-item Patient-Reported Outcomes Measurement Information System (PROMIS) depression score, standardized to the 2000 US adult population) using age-, sex/gender-, southern US birth-, and parental education-adjusted generalized estimating equations, and assessed effect modification by the presence of a caring teacher/staff member. Levels of later-life depressive symptoms were lower among those who attended schools with mostly Black students in grades 1 and 6 (β = -0.12 [95% CI, -0.23 to 0.00] and β = -0.11 [95% CI, -0.22 to 0.00], respectively). In grade 6, this difference was larger for students without an adult at school who cared about them (β = -0.29 [95% CI, -0.51 to -0.07] vs β = -0.04 [95% CI, -0.17 to 0.09]). Among Black Americans, experiencing early schooling with mostly Black students may have later-life mental health benefits; this protective association appears more important for students without the presence of caring teachers/staff. This article is part of a Special Collection on Mental Health.

Using instrumental variables to address unmeasured confounding in causal mediation analysis

Mediation analysis is a strategy for understanding the mechanisms by which interventions affect later outcomes. However, unobserved confounding concerns may be compounded in mediation analyses, as there may be unobserved exposure-outcome, exposure-mediator, and mediator-outcome confounders. Instrumental variables (IVs) are a popular identification strategy in the presence of unobserved confounding. However, in contrast to the rich literature on the use of IV methods to identify and estimate a total effect of a non-randomized exposure, there has been almost no research into using IV as an identification strategy to identify mediational indirect effects. In response, we define and nonparametrically identify novel estimands-double complier interventional direct and indirect effects-when 2, possibly related, IVs are available, one for the exposure and another for the mediator. We propose nonparametric, robust, efficient estimators for these effects and apply them to a housing voucher experiment.

Opportunities and challenges in using instrumental variables to study causal effects in nonrandomized stress and trauma research

OBJECTIVE

Researchers are often interested in assessing the causal effect of an exposure on an outcome when randomization is not ethical or feasible. Estimating causal effects by controlling for confounders can be unconvincing because important potential confounders remain unmeasured. Study designs leveraging instrumental variables (IVs) offer alternatives to confounder-control methods but are rarely used in stress and trauma research.

METHOD

We review the conceptual foundations and implementation of IV methods. We discuss strengths and limitations of IV approaches, contrasting with confounder-control methods, and illustrate the relevance of IVs for stress and trauma research.

RESULTS

IV approaches leverage an external or exogenous source of variation in the exposure. Instruments are variables that meet three conditions: relevance (variation in the IV is associated with variation in the chance of exposure), exclusion (the IV only affects the outcome through the exposure), and exchangeability (no unmeasured confounding of the IV-outcome relationship). Interpreting estimates from IV analyses requires an additional assumption, such as monotonicity (the instrument does not change the chance of exposure in different directions for any two individuals). Valid IVs circumvent the need to correctly identify, measure, and control for all confounders of the exposure-outcome relationship. The primary challenge is identifying a valid instrument.

CONCLUSIONS

IV approaches have strengths and weaknesses compared with confounder-control approaches. IVs offers a promising complementary study design to improve evidence about the causal effects of exposures on outcomes relevant to stress and trauma. Collaboration with scientists who are experienced with identifying and analyzing IVs will support this work. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Housing mobility protects against alcohol use for children with socioemotional health vulnerabilities: An experimental design

PURPOSE

Neighborhood context may influence alcohol use, but effects may be heterogeneous, and prior evidence is threatened by confounding. We leveraged a housing voucher experiment to test whether housing vouchers' effects on alcohol use differed for families of children with and without socioemotional health or socioeconomic vulnerabilities.

TRIAL DESIGN

In the Moving to Opportunity (MTO) study, low-income families in public housing in five US cities were randomized in 1994 to 1998 to receive one of three treatments: (1) a housing voucher redeemable in a low-poverty neighborhood plus housing counseling, (2) a housing voucher without locational restriction, or (3) no voucher (control). Alcohol use was assessed 10 to 15 years later (2008 to 2010) in youth ages 13 to 20, N = 4600, and their mothers, N = 3200.

METHODS

Using intention-to-treat covariate-adjusted regression models, we interacted MTO treatment with baseline socioemotional health vulnerabilities, testing modifiers of treatment on alcohol use.

RESULTS

We found treatment effect modification by socioemotional factors. For youth, MTO voucher treatment, compared with controls, reduced the odds of ever drinking alcohol if youth had behavior problems (OR = 0.26, 95% CI [0.09, 0.72]) or problems at school (OR = 0.46, [0.26, 0.82]). MTO low-poverty treatment (vs. controls) also reduced the number of drinks if their health required special medicine/equipment (OR = 0.50 [0.32, 0.80]). Yet treatment effects were nonsignificant among youth without socioemotional vulnerabilities. Among mothers of children with learning problems, MTO voucher treatment (vs. controls) reduced past-month drinking (OR = 0.69 [0.47, 0.99]), but was harmful otherwise (OR = 1.22 [0.99, 1.45]).

CONCLUSIONS

For low-income adolescents with special needs/socioemotional problems, housing vouchers protect against alcohol use.

Perceived Discrimination, Nativity, and Cognitive Performance in a Multi-ethnic Study of Older Adults: Findings from the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

BACKGROUND

Despite growing research on the association between discrimination and disparities in cognitive aging, an evidence gap remains on how the association varies by racial/ethnic group. This study evaluates the associations of experiences of discrimination with cognitive function and whether these associations varied by race/ethnicity and nativity.

METHODS

Using the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) cohort (N=1,712) with approximately equal groups of Black, White, Latino, and Asian community-dwelling older adults aged 65 years and older, we evaluated the associations between self-reported experiences of everyday and major lifetime discrimination with overall cognitive performance and domain-specific cognition (verbal episodic memory, semantic memory and executive functioning) across race/ethnicity and nativity. Linear regression models examined the cross-sectional association between self-reported experiences of everyday and major lifetime discrimination with z-standardized coefficients for cognition. We tested for effect modification by race and nativity. All models controlled for age, sex and education.

RESULTS

Among KHANDLE participants (mean age: 76 years; standard deviation: 6.8), everyday discrimination was not associated with cognitive scores. Major lifetime discrimination was associated with better average cognitive scores among Black participants but not among other racial/ethnic groups. Major lifetime discrimination was associated with better average cognitive scores among US-born but not among non-US born individuals.

CONCLUSION

Our findings do not imply that discrimination improves cognition, but rather suggest that future research should include more detailed measures on discrimination and unfair treatment that could help disentangle the extent to which relationships are causal or reflect some other underlying factor.

The Compounded Burden of Poverty on Mental Health for People with Disabilities

Using 2008-2017 National Health Interview Survey data (N = 127,973), we investigated the relationship between income and psychological distress, measured by the Kessler 6 (K6) Scale (range 0-24), net of education, employment, and other sociodemographic characteristics. Regression models allowed the association to differ by disability status and number of disabilities. Lower income predicted higher psychological distress for those with and without disabilities. However, the adverse association was stronger among people with disabilities. Compared to those with incomes at least four times the poverty threshold, poor individuals with disabilities scored 2.81 (95% CI = 2.55,3.67) points higher on the K6 Scale versus 0.58 (95% CI = 0.48,0.69) points higher for those without disabilities. Differences in associations by number of disabilities were not statistically significant. Nonetheless, those with multiple disabilities were still at increased risk of distress because they were disproportionately poor. People with disabilities who are poor are particularly disadvantaged and should be prioritized in outreach efforts.

Helped into Harm: Mediation of a Housing Voucher Intervention on Mental Health and Substance Use in Boys

BACKGROUND

Interventions can have harmful effects among subgroups they intend to help. The Moving To Opportunity experiment, in which families were randomized to receive a Section 8 housing voucher, was one example. Voucher receipt generally resulted in better long-term mental health and lower substance use and risk behavior outcomes among adolescent girls, but resulted in worse outcomes among adolescent boys. Reasons for this discrepancy and the unintended harmful health effects for boys are unclear. We used mediation analysis to estimate processes through which voucher receipt was hypothesized to affect adolescent mental health and substance use.

METHODS

We used longitudinal data (10-15 years) on boys enrolled in Moving To Opportunity. We estimated interventional (also known as stochastic) indirect effects of voucher receipt on mental health and substance use outcomes through mediators capturing aspects of the school environment, neighborhood poverty, and instability of the social environment. We also estimated interventional direct effects not operating through these mediators. We used a robust, efficient, nonparametric substitution estimator in the targeted minimum loss-based framework.

RESULTS

Housing voucher receipt increased long-term risk of any diagnostic statistical manual disorder, any mood disorder, any externalizing disorder, and cigarette smoking among boys. The majority (between 69% and 90%) of the total negative long-term effects could be explained by indirect effects through the mediators considered.

CONCLUSIONS

This evidence suggests that, even though the intervention had the desired effects on neighborhood poverty and the school environment, these "positives" ultimately negatively impacted the long-term mental health and behaviors of boys.

Neighborhoods, psychological distress, and the quest for causality

Neighborhood characteristics have been associated with psychological distress, but it is uncertain whether these associations are causal. The current article reviews data from interventions and quasi-experimental studies that have addressed the question of causality of neighborhood associations. Overall, data from neighborhood interventions, longitudinal studies, and twin studies have provided only limited and inconsistent evidence to support causal interpretation of neighborhood associations with psychological distress: very few findings have been replicated across different samples, and many associations have been observed only with some of the multiple measures included the studies. Studies that examine the effects of neighborhood change on people's wellbeing are needed to improve causal inference and policy relevance of neighborhood studies.