Byoungjun Kim

Global positioning system (GPS) data capture fine-scale spatial and temporal mobility, enabling more precise, individualized assessments of neighborhood exposures than residential-based measures. Despite growing use, there is little consensus on how to define and quantify GPS-based exposures, highlighting the need for theory-informed approaches. This study demonstrates how GPS data can enhance neighborhood exposure assessment, address spatial misclassification, and inform future research on mobility and neighborhood environments. We integrated theoretical frameworks from psychology, sociology, and geography into GPS-based research using data from 2 cohort studies: the Neighborhoods and Networks Study and the Trying to Understand Relationships, Networks and Neighborhoods among Transgender Women of Color Study. The final GPS analytic sample was 649 participants. We constructed GPS-based neighborhood exposure measures, including direct exposure to specific locations and neighborhood psychosocial exposures, and compared these metrics with conventional residential-based measures. We also derived GPS-based mobility measures to characterize individual mobility patterns. Global positioning system-based measures captured higher variability in neighborhood exposures compared with residential-based measures. Global positioning system-derived mobility measures further characterized individual mobility patterns, providing additional context for understanding exposure beyond residential location. Accounting for spatial and temporal dimensions offers a robust foundation for future studies with more precise, spatially relevant health interventions.

Air pollution remains a leading cause of mortality. Few studies have leveraged residential relocation to examine impacts of intra-individual changes in PM2.5 exposure. As the largest integrated health system in the U.S., the Veterans Health Administration (VHA) is an ideal setting to examine relocation-induced changes in air pollution. We constructed a cohort of Veterans who relocated from one ZIP code to another between 2011 and 2017 (n = 762 905). We linked spatially averaged annual PM2.5 estimates to each person based on residential address. We examined relocation-induced PM2.5 changes and post-move mortality in discrete time models, accounting for individual- and area-level confounding variables. We estimated pooled odds ratios over 5 years of follow up and examined effect measure modification by age (<65, 65+), sex, and neighborhood-level poverty. The pooled OR associated with a 2 μg/m3 increase in PM2.5 levels between the origin and destination areas was 1.03 (95% CI = 1.01-1.03). Associations appeared more pronounced among older individuals when assessing potential additive effect measure modification. Examining intra-individual changes in PM2.5 exposure and subsequent health outcomes can elucidate potential impacts of air pollution and pollution reduction policies. Results suggest survival benefits associated with policies that continue to reduce PM2.5 levels.

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Introduction: Effective July 2018, the U.S. Department of Housing and Urban Development issued a rule requiring all public housing authorities to implement smoke-free housing (SFH) policies in their developments. We examined the differential impacts of SFH policy on hospitalizations for myocardial infarction (MI) and stroke among adults aged ≥50 years old living in New York City (NYC) Housing Authority (NYCHA) versus a matched-comparison population in NYC. Aims and Methods: We identified census block groups (CBGs) comprised solely of 100% NYCHA units (N = 160) and compared NYCHA CBGs to a selected subset of CBGs from all CBGs with no NYCHA units (N = 5646). We employed propensity score matching on distributions of key CBG-level sociodemographic and housing covariates. We constructed incident rates per 1000 persons by aggregating 3-month “quarterly” counts of New York State all-payer hospitalization data from October 2015 to December 2022 and dividing by the population aged ≥50 in selected CBGs, ascertained from 2016 American Community Survey 5-year estimates. We selected a difference-in-differences (DID) analytic approach to examine pre- and post-policy differences in incident hospitalizations between the intervention and matched-comparison groups. Results: Matching results indicated a balanced match for all covariates, with standardized mean differences <0.10. In DID analyses, we observed small declines in both MI (DID = −0.26, p = .02) and stroke (DID = −0.28, p = .06) hospitalization rates for NYCHA CBGs compared to non-NYCHA CBGs from pre-to post-54 months’ policy. Conclusions: SFH policies in NYC were associated with small reductions in CVD-related hospitalizations among older adults living in housing subject to the policy. Implications: Housing remains a key focal setting for interventions to reduce SHS exposure and associated morbidities. Ongoing monitoring is warranted to understand the long-term impacts of SFH policies in public housing developments.

Purpose of review: Despite emerging studies on neighborhood-level risk factors for chronic kidney disease (CKD), our understanding of the causal links between neighborhood characteristics and CKD is limited. In particular, there is a gap in identifying modifiable neighborhood factors, such as the built environment, in preventing CKD, that could be targets for feasible place-based interventions. Recent findings: Most published studies on neighborhood factors and CKD have focused on a single social attribute, such as neighborhood disadvantage, while research on the role of the built environment is more nascent. Early studies on this topic have yielded inconsistent results, particularly regarding whether food deserts are an environmental risk factor for CKD onset. International studies have shown that walkable neighborhoods – characterized by features such as urban design, park access, and green spaces – can be protective against both the onset and progression of CKD. However, these findings are inconclusive and understudied in the context of United States, where neighborhood environments differ from those in other countries. Summary: Future research on modifiable neighborhood factors and CKD using advanced study designs and population-representative datasets can yield stronger evidence on potential causal associations and suggest feasible place-based interventions as strategies for preventing CKD. As an example, we demonstrated the potential of electronic health record-based studies to advance research in this area.

Background/Objectives: Socioeconomic hardship during the COVID-19 pandemic was associated with lower vaccine uptake. Since the pandemic has exacerbated socioeconomic challenges faced by sexual and gender minority populations, including employment income loss, housing instability, food insufficiency, and household expense difficulty, this study investigated the disparities in COVID-19 vaccine uptake among these populations. Methods: Using the U.S. Census Bureau Household Pulse Survey, a nationally representative sample of 1,767,966 individuals (6% gay or lesbian, 4.2% bisexual, 1.6% something else, and 90.6% heterosexual respondents), we quantified the COVID-19 vaccine uptakes among sexual and gender minorities, as well as the effect measure modifications by socioeconomic hardships. Results: Despite higher vaccine uptake rates among sexual and gender minorities compared to their heterosexual counterparts, socioeconomic hardships triggered by the pandemic among these populations were associated with decreased vaccine uptake. Importantly, the effect measure modifications by socioeconomic hardships were more pronounced among sexual and gender minority status compared to heterosexual individuals. Conclusions: These results highlight the critical need to address socioeconomic hardships among sexual and gender minorities to enhance vaccine uptake, along with the pre-existing and exacerbated social and economic disadvantages during the COVID-19 pandemic.

Key Points: Older patients with kidney failure who are newly diagnosed with sleep disorders are at higher risk of developing any type of dementia, vascular dementia, and other/mixed types of dementia. For older patients with kidney failure who are diagnosed with obstructive sleep apnea, positive airway pressure therapy is an intervention that is associated with lower dementia risk. Background: Community-dwelling older adults with sleep disorders are at higher risk of developing dementia. Greater than 50% of older patients with kidney failure experience sleep disorders, which may explain their high burden of dementia. Methods: Among 216,158 patients (aged 66 years and older) with kidney failure (United States Renal Data System; 2008–2019), we estimated the risk of dementia (including subtypes) associated with sleep disorders using Cox proportional hazards models with propensity score weighting. We tested whether positive airway pressure (PAP) therapy was associated with reduced dementia risk among patients with obstructive sleep apnea (OSA). Results: 26.3% of patients were diagnosed with sleep disorders; these patients had a higher 5-year unadjusted cumulative incidence for any type of dementia (36.2% versus 32.3%; P < 0.001), vascular dementia (4.4% versus 3.7%; P < 0.001), and other/mixed dementia (29.3% versus 25.8%; P < 0.001). Higher risk of any type of dementia was identified in patients with insomnia (adjusted hazard ratio [aHR], 1.42; 95% confidence interval [CI], 1.34 to 1.51), sleep-related breathing disorders (SRBDs) (aHR, 1.20, 95% CI, 1.17 to 1.23), and other sleep disorders (aHR, 1.24; 95% CI, 1.11 to 1.39). Higher vascular dementia risk was observed in patients with insomnia (aHR, 1.43; 95% CI, 1.19 to 1.73) and SRBDs (aHR, 1.15; 95% CI, 1.07 to 1.24). Patients with SRBDs (aHR, 1.07; 95% CI, 1.00 to 1.15) were at higher risk of Alzheimer disease. Among patients with OSA, PAP therapy was associated with lower risk of any type of dementia (aHR, 0.82; 95% CI, 0.76 to 0.90) and vascular dementia (aHR, 0.65; 95% CI, 0.50 to 0.85). Conclusions: Older patients with kidney failure and sleep disorders are at a higher risk of dementia. Sleep is an important modifiable factor that should be considered for targeted interventions to mitigate dementia risk in patients with kidney failure. For patients with OSA, PAP therapy is associated with lower dementia risk.

Despite well-studied associations of state firearm laws with lower state- and county-level firearm homicide, there is a shortage of studies investigating differences in the effects of distinct state firearm law categories on various cities within the same state using identical methods. We examined associations of 5 categories of state firearm laws—pertaining to buyers, dealers, domestic violence, gun type/trafficking, and possession—with city-level firearm homicide, and then tested differential associations by city characteristics. City-level panel data on firearm homicide cases of 78 major cities from 2010 to 2020 was assessed from the Centers for Disease Control and Prevention’s National Vital Statistics System. We modeled log-transformed firearm homicide rates as a function of firearm law scores, city, state, and year fixed effects, along with time-varying city-level confounders. We considered effect measure modification by poverty, unemployment, vacant housing, and income inequality. A one z-score increase in state gun type/trafficking, possession, and dealer law scores was associated with 25% (95% confidence interval [CI]:−0.37,−0.1), 19% (95% CI:−0.29,−0.07), and 17% (95% CI:−0.28, −0.4) lower firearm homicide rates, respectively. Protective associations were less pronounced in cities with high unemployment and high housing vacancy, but more pronounced in cities with high income inequality. In large US cities, state-level gun type/trafficking, possession, and dealer laws were associated with lower firearm homicide rates, but buyers and domestic violence laws were not. State firearm laws may have differential effects on firearm homicides based on city characteristics, and city-wide policies to enhance socioeconomic drivers may add benefits of firearm laws.

Black sexually minoritized men (BSMM) are the most likely to acquire HIV in Chicago- a racially segregated city where their daily travel may confer different HIV-related risks. From survey and GPS data among participants of the Neighbourhoods and Networks Cohort Study, we examined spatial (proportion of total activity space away from home), temporal (proportion of total GPS points away from home), and motivation-specific (discordance between residential and frequented sex or socializing neighbourhoods) dimensions of mobility. To identify potential drivers of BSMM’s risk, we then examined associations between mobility and sexual behaviours known to cause HIV transmission: condomless anal sex, condomless anal sex with a casual partner, transactional sex, group sex, and sex-drug use. Multivariable logistic regression models assessed associations. Of 269 cisgender BSMM, most were 20-29 years old, identified as gay, and lowincome. On average, 96.9% (Standard Deviation: 3.7%) of participants’ activity space and 53.9% (Standard Deviation: 38.1%) of participants’ GPS points occurred outside their 800m home network buffer. After covariate adjustment, those who reported sex away from home were twice as likely to report condomless sex (Odds Ratio: 2.02, [95% Confidence Interval (CI): 1.08, 3.78]). Those who reported socializing away from home were four times more likely to have condomless sex with a casual partner (Odds Ratio: 4.16 [CI: 0.99, 29.0]). BSMM are on the move in Chicago, but only motivation-specific mobility may increase HIV transmission risk. Multidimensional investigations of mobility can inform place-based strategies for HIV service delivery.