The research team analyzed data from 18,734 responders who both live in New York City and receive care through one of the World Trade Center Health Program Clinical Centers of Excellence. These responders represent a population that experienced an extraordinary confluence of toxic exposures—dust, combustion products, airborne particulates, and a cocktail of known and suspected carcinogens—alongside severe psychological trauma. While decades of prior research have documented elevated rates of respiratory disease, cancer, and mental illness in this group, far less attention had been paid to whether the everyday conditions of their neighborhoods might compound or buffer those effects as responders age.

To answer that question, the researchers linked each responder’s residential address to annual estimates of three environmental factors: air pollution, high ambient temperatures, and neighborhood greenness, the last typically quantified through satellite-derived vegetation indices. This exposure-assessment approach, common in the field of environmental epidemiology, allowed the team to characterize the conditions each participant encountered where they lived year after year, rather than relying on broad regional averages. The researchers then examined whether those exposures were associated with the probability of being classified as frail, and with diagnosed PTSD and depression.

The results were striking in their consistency. Responders living in hotter neighborhoods—areas that experience more extreme heat days, a burden that falls disproportionately on densely built urban districts with impervious surfaces and little tree canopy—showed an elevated risk of frailty, a geriatric syndrome marked by diminished physiological reserve and heightened vulnerability to stressors. Elevated concentrations of air pollution were likewise associated with increased risks of both frailty and adverse mental health outcomes. Frailty itself is increasingly understood as a whole-body phenomenon, involving chronic inflammation, immune dysregulation, and cumulative cellular wear, all of which are plausible biological pathways through which heat and pollution could accelerate aging.

The mental health findings carried equal weight. Higher pollution and heat exposure were associated with increased odds of PTSD and depression, while responders living in greener surroundings—those with more parks, trees, and vegetated land near their homes—showed lower risks of all three conditions. This inverse association with greenness aligns with a substantial body of literature suggesting that access to green space can reduce psychological stress, encourage physical activity, dampen inflammation, and moderate urban heat, though the observational design of the study means that causation cannot be definitively established.

Perhaps the most provocative finding concerned interaction effects. The researchers found that responders who had experienced higher levels of World Trade Center–related chemical and psychological exposure appeared more vulnerable to the effects of environmental stressors in their current neighborhoods. In other words, the disaster and the decades that followed may not be independent chapters in these individuals’ health histories. Instead, responders already carrying the biological imprint of trauma and toxic dust—including altered inflammatory profiles, epigenetic changes, and persistent hypothalamic-pituitary-adrenal axis dysregulation—may enter later life with less reserve to absorb additional environmental insults. Everyday exposures that might be merely uncomfortable for a healthy middle-aged adult could, for these individuals, translate into measurable acceleration of physical decline and psychological deterioration.

“Twenty-five years after 9/11, we are still learning about the factors that influence the health of those who responded to the attacks,” said Helena Furman Krasnov, PhD, postdoctoral researcher at the Icahn School of Medicine and the study’s first author. “Our findings suggest that everyday exposures, including heat, air pollution, and access to green space, may contribute to responders’ long-term physical and psychological well-being. Understanding these factors could help identify new opportunities to support healthy aging in this population.”

The study’s senior and corresponding author, Maayan Yitshak-Sade, MPH, PhD, Associate Professor of Environmental Medicine at Mount Sinai and a member of the Institute for Exposomic Research, framed the work within the broader exposome paradigm—the effort to capture the totality of environmental exposures an individual accumulates over a lifetime. “Our findings suggest that the health consequences of 9/11 may not end with the disaster itself,” she said. “For responders already carrying the biological effects of trauma and toxic exposures, everyday environmental conditions may represent an additional source of stress on the body and mind. These findings highlight the importance of considering where people live, not just what they experienced during the disaster.”

That framing underscores a conceptual shift in disaster medicine. Traditional models tend to treat a catastrophic event as a discrete exposure with a defined aftermath. The Mount Sinai findings instead suggest that disaster-related health effects may unfold across an entire life course, modified by conditions that have no obvious connection to the original event. A responder’s risk of frailty in 2026 may reflect not only the hours spent at Ground Zero, but also the temperature of the summers they have endured since, the particulate matter drifting through their streets, and whether a leafy park sits within walking distance of their apartment.

The study arrives at a moment when urban environmental health has become a pressing policy concern. Extreme heat now kills more Americans annually than any other weather phenomenon, and cities including New York have launched ambitious initiatives to expand tree canopy, create cool corridors, and retrofit public housing with resilient cooling infrastructure. Air pollution, even at levels within regulatory limits, continues to be linked to cardiovascular, respiratory, and neurocognitive harm. If the associations identified in this cohort hold up under further scrutiny, they could strengthen the case for targeted environmental interventions—not as amenities, but as clinical supports for a vulnerable population.

The implications also extend well beyond the World Trade Center community. The researchers point out that survivors and responders from other disasters—wildfires that blanket entire regions in smoke and ash, industrial accidents that release toxic plumes, building collapses that bury rescue workers in dust—may face the same dual burden of physical and psychological exposures that continues to shape health long after the initial event. Climate change is intensifying heat waves and wildfire seasons simultaneously, meaning that disaster-affected populations may increasingly find themselves living in precisely the kinds of hostile urban microclimates the study identifies as risky. The framework developed here could inform how health surveillance programs for disaster cohorts are designed, prompting them to collect residential and environmental data alongside clinical outcomes.

The authors are careful to note the study’s observational nature. Associations between neighborhood environment and health can be confounded by socioeconomic status, housing quality, access to care, and the self-selection of healthier individuals into greener, quieter neighborhoods. The investigators controlled for available covariates, and the sheer size of the cohort lends statistical power, but randomized evidence on green space exposure is practically impossible to generate, and residual confounding remains an inherent limitation of the design. Longitudinal follow-up, and ideally natural-experiment analyses—such as the addition of new parks or major infrastructure changes—will be needed to firm up causal inference.

That work is already on the horizon. The team plans to investigate whether beneficial environmental factors, including green space and access to healthy food, can actively reduce the long-term health effects associated with World Trade Center–related exposures—a question that shifts the framing from risk identification to potential intervention. If confirmatory studies support the protective role of greenness, the findings could justify clinical guidance for responders, and potentially for other disaster-exposed populations, that goes beyond medication and monitoring to encompass the places where patients live.

For a population that has already given so much and borne so much, the idea that healing might partly depend on the landscape outside the front door is both sobering and hopeful. It suggests that some of the damage inflicted on September 11, 2001 may not be fixed, but modifiable—and that the next chapter of care for responders could be written not only in clinics, but in city planning offices, park commissions, and the slow, patient work of greening the neighborhoods where aging heroes live out their lives.

Sleep has increasingly been recognized as a pillar of public health, as central to long-term wellbeing as diet or exercise. Chronic short sleep has been tied to obesity, type 2 diabetes, cardiovascular disease, and impaired immune function, while excessively long sleep and prolonged daytime napping have been associated in prior research with inflammation, metabolic disturbance, and elevated mortality risk. Yet the reasons why sleep quality varies so dramatically across communities have remained elusive. Scientists have long observed that residents of disadvantaged neighborhoods sleep worse on average, but identifying the behavioral machinery behind that association has proven difficult. The new study set out to test whether two of the most consequential daily behaviors—moderate-to-vigorous physical activity and sedentary time spent watching television—act as pathways connecting neighborhood conditions to sleep outcomes.

To do so, the research team, led by Kosuke Tamura of the National Institute on Minority Health and Health Disparities, tapped one of the largest prospective cohort studies ever assembled in the United States. Their analytical sample included 233,335 participants from the NIH-AARP Diet and Health Study, a collaboration between the National Institutes of Health and AARP that has followed hundreds of thousands of older American adults for decades. Participants self-reported their nightly sleep duration, allowing the researchers to classify short sleep as less than seven hours, optimal sleep as seven to eight hours, and long sleep as nine or more hours. They also reported how much time they typically spent napping during the day, with long napping defined as an hour or more, and how much time they devoted to moderate-to-vigorous physical activity and television viewing.

Neighborhood socioeconomic status was measured using a standardized index derived from census variables, a composite that captures the economic and social resources of the areas where participants lived. The researchers then applied formal mediation analysis, a statistical technique that partitions the total association between an exposure and an outcome into direct and indirect components. In this case, the question was whether the relationship between lower neighborhood socioeconomic status and poor sleep traveled through physical activity or television viewing. Because conventional confidence intervals can be unreliable in mediation settings, the team used bootstrap-generated bias-corrected confidence intervals, a resampling method that provides more robust estimates of statistical uncertainty. All models were adjusted for age, sex, racial and ethnic group, education, and marital status, helping to isolate the contribution of the neighborhood itself from individual-level characteristics.

The results were consistent and telling. Lower neighborhood socioeconomic status was associated with short sleep, long sleep, and long napping, and both physical activity and television viewing emerged as significant mediators of all three associations. The mediated odds ratios were modest in magnitude—ranging from 1.002 to 1.011 for the physical activity pathway and from 1.003 to 1.033 for the television pathway, all statistically significant at the five percent level—but the sheer scale of the cohort lends the pattern considerable weight. The strongest mediated effect appeared for long napping through television viewing, hinting that sedentary screen time may be an especially important behavioral link between disadvantaged surroundings and disrupted sleep rhythms. The logic of the mechanism is intuitive: residents of lower-income neighborhoods often have fewer safe parks, sidewalks, gyms, and recreational facilities, which discourages physical activity, while the same environments may encourage more time spent indoors in front of the television—a pattern of behavior that, in turn, displaces sleep, fragments rest, and promotes daytime drowsiness.

Perhaps the most striking aspect of the study, however, was its exploratory examination of racial and ethnic differences. When the researchers stratified their mediation analyses by group, the pathways diverged in revealing ways. Among White adults, lower neighborhood socioeconomic status was associated with short sleep, long sleep, and long napping, mediated through both physical activity and television viewing—the full pattern seen in the overall sample. Among Black adults, the associations were narrower: lower neighborhood socioeconomic status related to long sleep through television viewing, and to long napping through both physical activity and television viewing. Among Hispanic adults, lower neighborhood socioeconomic status was linked to long sleep, mediated through physical activity, while among adults in other racial and ethnic groups, the association appeared only for long napping, mediated through television viewing. These subgroup findings, which the authors describe cautiously as suggestive rather than definitive, underscore that the same neighborhood disadvantage can translate into different behavioral and sleep consequences depending on the population and its social context.

The authors emphasize that the study is cross-sectional, meaning that neighborhood characteristics, behaviors, and sleep were all measured at the same point in time. That design limits causal inference: it is possible, for instance, that poor sleep reduces energy for physical activity or increases time spent passively watching television, rather than the reverse. Self-reported sleep and activity measures also introduce the possibility of misclassification, since people are notoriously imprecise at estimating their own habits. The cohort, moreover, consists predominantly of older adults, and sleep architecture and activity patterns change with age, so the findings may not generalize to younger populations. Residual confounding—by shift work, chronic illness, caregiving responsibilities, or unmeasured neighborhood features such as noise, light pollution, and crime—cannot be ruled out entirely, even with the study’s careful statistical adjustments.

Even so, the scale and consistency of the results make a compelling case that neighborhood disadvantage operates on sleep through modifiable daily behaviors. If the pathways identified here hold up in longitudinal and interventional research, they point to concrete targets for public health action. Investments in safe recreational infrastructure, walkable streets, and community exercise programs could raise physical activity levels in disadvantaged areas, while initiatives to reduce sedentary screen time—particularly prolonged evening television viewing—might simultaneously protect sleep. The authors conclude that efforts to improve lower socioeconomic status neighborhoods in ways that encourage physical activity and reduce sedentary time are warranted to improve sleep health, framing sleep not as a private matter of personal discipline but as an environmental outcome that communities can shape.

The broader significance of the work lies in its reframing of sleep inequality. For years, public health campaigns have urged individuals to sleep more and sit less, as if behavior occurred in a vacuum. This study, leveraging one of the largest cohorts in American epidemiology, demonstrates that the places people live exert a measurable pull on the routines that govern rest. The behavioral chain from neighborhood to activity to sleep offers a mechanism, and mechanisms are the raw material of policy. As cities grapple with entrenched disparities in chronic disease, the humble hours of sleep—and the neighborhood conditions that quietly erode them—may deserve a far more prominent place on the agenda.

Beyond its behavioral findings, the study contributes to a growing literature on social determinants of sleep by treating neighborhood socioeconomic status as an exposure in its own right, distinct from individual income or education. The standardized index drawn from census variables reflects shared community resources rather than personal finances, aligning the work with a broader research movement that examines place-based influences on cardiometabolic and behavioral health.

The use of the NIH-AARP cohort also situates the results within a particularly valuable data resource, one that has enabled investigators to examine how lifestyle and environmental factors relate to disease outcomes across very large samples of older adults. The intramural support from the National Institute on Minority Health and Health Disparities and the National Heart, Lung, and Blood Institute reflects federal interest in understanding how structural conditions shape health behaviors. As an open-access publication, the article allows other researchers to scrutinize the mediation methods and subgroup analyses in full.

Subject of Research: How neighborhood socioeconomic status influences sleep health through physical activity and television viewing in a large U.S. cohort.

Article Title: The association between lower neighborhood socioeconomic status and sleep health mediated by physical activity and TV viewing: Findings from a large U.S. cohort

Article References: Tamura, K., Xiao, Q., Moniruzzaman, M., Deng, Y., Liao, L. M., Jones, R. R., & Powell-Wiley, T. M. (2026). The association between lower neighborhood socioeconomic status and sleep health mediated by physical activity and TV viewing: Findings from a large U.S. cohort. Journal of Activity, Sedentary and Sleep Behaviors. https://doi.org/10.1186/s44167-026-00114-1

Image Credits: AI Generated

DOI: 10.1186/s44167-026-00114-1

Keywords: neighborhood socioeconomic status, sleep health, physical activity, television viewing, sedentary behavior, daytime napping, health disparities, NIH-AARP Diet and Health Study, mediation analysis, racial and ethnic differences, association, between