Nature and human well-being: The olfactory pathway.

The world is undergoing massive atmospheric and ecological change, driving unprecedented challenges to human well-being. Olfaction is a key sensory system through which these impacts occur. The sense of smell influences quality of and satisfaction with life, emotion, emotion regulation, cognitive function, social interactions, dietary choices, stress, and depressive symptoms. Exposures via the olfactory pathway can also lead to (anti-)inflammatory outcomes. Increased understanding is needed regarding the ways in which odorants generated by nature (i.e., natural olfactory environments) affect human well-being. With perspectives from a range of health, social, and natural sciences, we provide an overview of this unique sensory system, four consensus statements regarding olfaction and the environment, and a conceptual framework that integrates the olfactory pathway into an understanding of the effects of natural environments on human well-being. We then discuss how this framework can contribute to better accounting of the impacts of policy and land-use decision-making on natural olfactory environments and, in turn, on planetary health.

Susceptibility to stress and nature exposure: Unveiling differential susceptibility to physical environments; a randomized controlled trial.

BACKGROUND: Emerging epidemiological evidence indicates nature exposure could be associated with greater health benefits among groups in lower versus higher socioeconomic positions. One possible mechanism underpinning this evidence is described by our framework: (susceptibility) adults in low socioeconomic positions face higher exposure to persistent psychosocial stressors in early life, inducing a pro-inflammatory phenotype as a lifelong susceptibility to stress; (differential susceptibility) susceptible adults are more sensitive to the health risks of adverse (stress-promoting) environments, but also to the health benefits of protective (stress-buffering) environments. OBJECTIVE: Experimental investigation of a pro-inflammatory phenotype as a mechanism facilitating greater stress recovery from nature exposure. METHODS: We determined differences in stress recovery (via heart rate variability) caused by exposure to a nature or office virtual reality environment (10 min) after an acute stressor among 64 healthy college-age males with varying levels of susceptibility (socioeconomic status, early life stress, and a pro-inflammatory state [inflammatory reactivity and glucocorticoid resistance to an in vitro bacterial challenge]). RESULTS: Findings for inflammatory reactivity and glucocorticoid resistance were modest but consistently trended towards better recovery in the nature condition. Differences in recovery were not observed for socioeconomic status or early life stress. DISCUSSION: Among healthy college-age males, we observed expected trends according to their differential susceptibility when assessed as inflammatory reactivity and glucocorticoid resistance, suggesting these biological correlates of susceptibility could be more proximal indicators than self-reported assessments of socioeconomic status and early life stress. If future research in more diverse populations aligns with these trends, this could support an alternative conceptualization of susceptibility as increased environmental sensitivity, reflecting heightened responses to adverse, but also protective environments. With this knowledge, future investigators could examine how individual differences in environmental sensitivity could provide an opportunity for those who are the most susceptible to experience the greatest health benefits from nature exposure.

Associations of nature contact with emotional ill-being and well-being: the role of emotion regulation.

Nature contact has associations with emotional ill-being and well-being. However, the mechanisms underlying these associations are not fully understood. We hypothesised that increased adaptive and decreased maladaptive emotion regulation strategies would be a pathway linking nature contact to ill-being and well-being. Using data from a survey of 600 U.S.-based adults administered online in 2022, we conducted structural equation modelling to test our hypotheses. We found that (1) frequency of nature contact was significantly associated with lesser emotional ill-being and greater emotional well-being, (2) effective emotion regulation was significantly associated with lesser emotional ill-being and greater emotional well-being, and (3) the associations of higher frequency of nature contact with these benefits were partly explained via emotion regulation. Moreover, we found a nonlinear relationship for the associations of duration of nature contact with some outcomes, with a rise in benefits up to certain amounts of time, and a levelling off after these points. These findings support and extend previous work that demonstrates that the associations of nature contact with emotional ill-being and well-being may be partly explained by changes in emotion regulation.

Long-Term Impact of Childhood Adversity on the Gut Microbiome of Nursing Students.

Adverse childhood experiences (ACEs) encompass negative, stressful, and potentially traumatic events during childhood, impacting physical and mental health outcomes in adulthood. Limited studies suggest ACEs can have short-term effects on children's gut microbiomes and adult cognitive performance under stress. Nevertheless, the long-term effects of ACEs experienced during adulthood remain unexplored. Thus, this study aimed to assess the long-term effects of ACEs on the gut microbiota of adult nursing students. We employed a multidimensional approach, combining 16S rRNA sequencing, bioinformatics tools, and machine learning to predict functional capabilities. High-ACE individuals had an increased abundance of Butyricimonas spp. and Prevotella spp. and decreased levels of Clostridiales, and Lachnospira spp. Prevotella abundance correlated negatively with L-glutamate and L-glutamine biosynthesis, potentially impacting intestinal tissue integrity. While nursing students with high ACE reported increased depression, evidence for a direct gut microbiota-depression relationship was inconclusive. High-ACE individuals also experienced a higher prevalence of diarrhea. These findings highlight the long-lasting impact of ACEs on the gut microbiota and its functions in adulthood, particularly among nursing students. Further research is warranted to develop targeted interventions and strategies for healthcare professionals, optimizing overall health outcomes.

Neural and peripheral markers of reward during positive social evaluation are associated with less clinician-rated depression symptom severity in adolescence.

Although blunted sensitivity to reward is thought to play a key role in promoting risk for depression, most research on this topic has utilized monetary reward paradigms and focused on currently depressed adults. To address this issue, we analyzed neural reward and ß-endorphin data from the Psychobiology of Stress and Adolescent Depression (PSY SAD) Study, which recruited a well-characterized sample of adolescent girls at high vs. low risk for major depressive disorder (MDD) (N = 52, M age = 14.90, SD = 1.35) based on their mothers' lifetime history of MDD. As hypothesized, greater striatal activity while receiving positive (vs. neutral) social evaluation was associated with lower depression symptom severity as independently assessed by the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS). This association was present for girls at high but not low risk for MDD, suggesting that this neural response may represent a pre-clinical marker of risk for depression. Consistent with these results, higher post-social evaluation levels of a peripheral marker of reward sensitivity, ß-endorphin, were related to lower clinician-rated depression symptom severity. Together, these results indicate that neural and peripheral markers of responsivity to social reward are both related to depression severity, which may have implications for understanding the pathophysiology of depression.

Dissertation Topics in Nursing.

BACKGROUND: Few quantitative studies have documented the types of research topics most commonly employed by nursing PhD students and whether they differ by program delivery (in-person vs. online/hybrid programs). OBJECTIVES: We examined a large set of publicly available PhD dissertation abstracts to (a) describe the relative prevalence of different research topics and methods and (b) test whether the primary topics and methods used differed between online or hybrid and in-person PhD programs. A secondary goal was to introduce the reader to modern text-mining approaches to generate insights from a document corpus. METHODS: Our database consisted of 2,027 dissertation abstracts published between 2015 and 2019. We used a structural topic modeling text-mining approach to explore PhD students' research topics and methods in United States-based doctoral nursing programs. RESULTS: We identified 24 different research topics representing a wide range of research activities. Most of the research topics identified did not differ in prevalence between online/hybrid and in-person programs. However, online/hybrid programs were more likely to engage students in research focused on nursing education, professional development, work environment, simulation, and qualitative analysis. Pediatrics, sleep science, older adults and aging, and chronic disease management were more prevalent topics in in-person-only programs. DISCUSSION: The range of topics identified highlights the breadth of research nursing PhD students' conduct. Both in-person and online/hybrid programs offer a range of research opportunities, although we did observe some differences in topic prevalence. These differences could be due to the nature of some types of research (e.g., research that requires an in-person presence) or differences in research intensity between programs (e.g., amount of grant funding or proximity to a medical center). Future research should explore why research topic prevalence may vary by program delivery. We hope that this text-mining application serves as an illustrative example for researchers considering how to draw inferences from large sets of text documents. We are particularly interested in seeing future work that might combine traditional qualitative approaches and large-scale text mining to leverage the advantages of each.

Psychobiology of Stress and Adolescent Depression (PSY SAD) Study: Protocol overview for an fMRI-based multi-method investigation.

Depression is a common, often recurrent disorder that causes substantial disease burden worldwide, and this is especially true for women following the pubertal transition. According to the Social Signal Transduction Theory of Depression, stressors involving social stress and rejection, which frequently precipitate major depressive episodes, induce depressive symptoms in vulnerable individuals in part by altering the activity and connectivity of stress-related neural pathways, and by upregulating components of the immune system involved in inflammation. To test this theory, we recruited adolescent females at high and low risk for depression and assessed their psychological, neural, inflammatory, and genomic responses to a brief (10 minute) social stress task, in addition to trait psychological and microbial factors affecting these responses. We then followed these adolescents longitudinally to investigate how their multi-level stress responses at baseline were related to their biological aging at baseline, and psychosocial and clinical functioning over one year. In this protocol paper, we describe the theoretical motivations for conducting this study as well as the sample, study design, procedures, and measures. Ultimately, our aim is to elucidate how social adversity influences the brain and immune system to cause depression, one of the most common and costly of all disorders.

Associations of Residential Brownness and Greenness with Fasting Glucose in Young Healthy Adults Living in the Desert.

Evolutionary psychology theories propose that contact with green, natural environments may benefit physical health, but little comparable evidence exists for brown, natural environments, such as the desert. In this study, we examined the association between "brownness" and "greenness" with fasting glucose among young residents of El Paso, Texas. We defined brownness as the surface not covered by vegetation or impervious land within Euclidian buffers around participants' homes. Fasting glucose along with demographic and behavioral data were obtained from the Nurse Engagement and Wellness Study (n = 517). We found that residential proximity to brownness was not associated with fasting glucose when modeled independently. In contrast, we found that residential greenness was associated with decreased levels of fasting glucose, despite the relatively low levels of greenness within the predominantly desert environment of El Paso. A difference between the top and bottom greenness exposure quartiles within a 250 m buffer was associated with a 3.5 mg/dL decrease in fasting glucose levels (95% confidence interval: -6.2, -0.8). Our results suggest that within the understudied context of the desert, green vegetation may be health promoting to a degree that is similar to other, non-desert locations in the world that have higher baselines levels of green.

Green, Brown, and Gray: Associations between Different Measurements of Land Patterns and Depression among Nursing Students in El Paso, Texas.

BACKGROUND: While greenness has been associated with lower depression, the generalizability of this association in arid landscapes remains undetermined. We assessed the association between depression and residential greenness, but also brownness and grayness among nursing students living in El Paso, Texas (the Chihuahuan desert). METHODS: Depression was measured with the Patient Health Questionnaire-9 scale and greenness with the normalized difference vegetation index across three buffer sizes (i.e., 250, 500, and 1000 m). Using data from the National Land Cover Database, two additional measures of land patterns were analyzed: grayness and brownness. Structural equation models were used to assess the relationships of these land patterns to depression and quantify the indirect effects of peer alienation. RESULTS: After adjusting for individual characteristics, at buffers 250 m, greenness was not associated with a decrease in the Incidence Rate Ratios (IRR) of depression (IRR, 0.51; 95% CI, 0.12-2.10); however, grayness and brownness were respectively associated with increases by 64% (IRR, 1.64; 95% CI, 1.07-2.52) and decreases by 35% (IRR, 0.65; 95% CI, 0.42-0.99). At buffer 250 m, peer alienation explained 17.43% (95% CI, -1.79-36.66) of the association between depression and brownness, suggesting a pathway to depression. CONCLUSIONS: We did not observe an association between depression and residential greenness in El Paso, Texas. However, we did observe a protective association between brownness and depression and an adverse association with grayness. These results have theoretical implications as they were based on commonly used frameworks in this literature, and adverse association of brownness (and the lack of greenness) and depression was expected.

Stress and Health in Nursing Students: The Nurse Engagement and Wellness Study.

BACKGROUND: Evidence suggests that behavioral, social, and environmental factors may modify the effects of life stress on health and performance of new nurses as they transition to hospitals. OBJECTIVES: The aim of this study was to describe the methods of a project designed to investigate the role of social, behavioral, and environmental factors in modifying the adverse effects of stress on new nurses and to discuss demographic, health, and life stress characteristics of the cohort at baseline. METHODS: A prospective cohort design was used to conduct a comprehensive assessment of health endpoints, life stress, behaviors, personal traits, social factors, indicators of engagement and performance, and environmental exposures in nursing students. Adjusted odds ratios and analyses of covariance were used to examine associations between these factors at baseline. RESULTS: Health indicators in the cohort were comparable or better than in the broader United States population, and lifetime stress exposure was lower than among students from other majors. Exposure to more lifetime stressors was associated with greater risk for various health conditions, including hypertension, diabetes, and depression. Conversely, better social, environmental, behavioral, and personal profiles were associated with protective effects for the same health conditions. DISCUSSION: These data comprehensively summarize the lives of predominately Hispanic nursing students and highlight risk and resilience factors associated with their health and well-being. The findings are timely, as the nursing field diversifies in preparation to care for a diverse and aging population. Comprehensively assessing stress-health relationships among student nurses ought to inform the policies, practices, and curricula of nursing schools to better prepare nurses to thrive in the often-strenuous healthcare environment.

The value of using seasonality and meteorological variables to model intra-urban PM2.5 variation.

A yearlong air monitoring campaign was conducted to assess the impact of local temperature, relative humidity, and wind speed on the temporal and spatial variability of PM2.5 in El Paso, Texas. Monitoring was conducted at four sites purposely selected to capture the local traffic variability. Effects of meteorological events on seasonal PM2.5 variability were identified. For instance, in winter low-wind and low-temperature conditions were associated with high PM2.5 events that contributed to elevated seasonal PM2.5 levels. Similarly, in spring, high PM2.5 events were associated with high-wind and low-relative humidity conditions. Correlation coefficients between meteorological variables and PM2.5 fluctuated drastically across seasons. Specifically, it was observed that for most sites correlations between PM2.5 and meteorological variables either changed from positive to negative or dissolved depending on the season. Overall, the results suggest that mixed effects analysis with season and site as fixed factors and meteorological variables as covariates could increase the explanatory value of LUR models for PM2.5.

Early life stress, air pollution, inflammation, and disease: An integrative review and immunologic model of social-environmental adversity and lifespan health.

Socially disadvantaged individuals are at greater risk for simultaneously being exposed to adverse social and environmental conditions. Although the mechanisms underlying joint effects remain unclear, one hypothesis is that toxic social and environmental exposures have synergistic effects on inflammatory processes that underlie the development of chronic diseases, including cardiovascular disease, diabetes, depression, and certain types of cancer. In the present review, we examine how exposure to two risk factors that commonly occur with social disadvantage-early life stress and air pollution-affect health. Specifically, we identify neuroimmunologic pathways that could link early life stress, inflammation, air pollution, and poor health, and use this information to propose an integrated, multi-level model that describes how these factors may interact and cause health disparity across individuals based on social disadvantage. This model highlights the importance of interdisciplinary research considering multiple exposures across domains and the potential for synergistic, cross-domain effects on health, and may help identify factors that could potentially be targeted to reduce disease risk and improve lifespan health.

An Integrated Socio-Environmental Model of Health and Well-Being: a Conceptual Framework Exploring the Joint Contribution of Environmental and Social Exposures to Health and Disease Over the Life Span.

PURPOSE OF THE REVIEW: Environmental and social determinants of health often co-occur, particularly among socially disadvantaged populations, yet because they are usually studied separately, their joint effects on health are likely underestimated. Building on converging bodies of literature, we delineate a conceptual framework to address these issues. RECENT FINDINGS: Previous models provided a foundation for study in this area, and generated research pointing to additional important issues. These include a stronger focus on biobehavioral pathways, both positive and adverse health outcomes, and intergenerational effects. To accommodate the expanded set of issues, we put forward the Integrated Socio-Environmental Model of Health and Well-Being (ISEM), which examines how social and environmental factors combine and potentially interact, via multi-factorial pathways, to affect health and well-being over the life span. We then provide applied examples including the study of how food environments affect dietary behavior. The ISEM provides a comprehensive, theoretically informed framework to guide future research on the joint contribution of social and environmental factors to health and well-being across the life span.