Diana Younan

University of Southern California | USC · Department of Preventive Medicine

Background: Late-life exposure to ambient air pollution is a modifiable risk factor for dementia, but epidemiological studies have shown inconsistent evidence for cognitive decline. Air quality (AQ) improvement has been associated with improved cardiopulmonary health and decreased mortality, but to the best of our knowledge, no studies have examin...

Exposures to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) have been associated with the emergence of depressive symptoms in older adulthood, although most studies used cross-sectional outcome measures. Elucidating the brain structures mediating the adverse effects can strengthen the causal role between air pollution and increasing dep...

Late-life ambient air pollution is a risk factor for brain aging, but it remains unknown if improved air quality (AQ) lowers dementia risk. We studied a geographically diverse cohort of older women dementia free at baseline in 2008 to 2012 ( n = 2,239, aged 74 to 92). Incident dementia was centrally adjudicated annually. Yearly mean concentrations...

Exposure to air pollution may accelerate brain aging and increase risk of late-life depressive symptoms (DS). Brain structures underlying these associations are unknown. Longitudinal data from 829 community-dwelling women without dementia (baseline age 81.6 ± 3.6 years old) who participated in both the Women’s Health Initiative Memory Study Magneti...

Air pollution exposure is an environmental risk factor in brain aging and may also be associated with late-life depressive symptoms (DS). It is unknown if air quality (AQ) improvement is associated with reductions in DS in later life. Longitudinal data from 917 cognitively intact women with no prior history of depression (baseline age 66.4 ± 1.6 ye...

Air pollution exposure is a novel environmental risk factor in brain aging. It remains unclear whether long‐term exposure in older adulthood is associated with profiles of cognitive performance across multiple domains. Participants included 2,185 women (aged 66‐83 years) without dementia from the Women’s Health Initiative Study of Cognitive Aging....

Air pollution is associated with increased risk of cognitive decline and dementia. However, whether and how air quality (AQ) improvement is associated with better cognitive performance across multiple domains is unknown. Participants included 2,114 women (aged 74‐92 at the enrollment) from the US‐based Women’s Health Initiative Memory Study‐Epidemi...

Late‐life exposure to ambient air pollution is a modifiable risk factor for dementia, but epidemiological studies have shown inconsistent evidence for cognitive decline. Improved air quality (AQ) is associated with decreased mortality and improved respiratory health, but no studies have examined the association with cognitive function. Participants...

Late‐life ambient air pollution is a novel risk factor for brain aging. Air quality improvement has been associated with improved cardiopulmonary health and reduced mortality; however, whether it is associated with reduced dementia risk is unknown. We studied a geographically‐diverse cohort from the Women’s Health Initiative Memory Study‐Epidemiolo...

Background: Elucidating associations between exposures to ambient air pollutants and profiles of cognitive performance may provide insight into neurotoxic effects on the aging brain. Objective: We examined associations between empirically derived profiles of cognitive performance and residential concentrations of particulate matter of aerodynami...

Background: Episodic memory decline varies by age and underlying neuropathology. Whether ambient air pollution contributes to the heterogeneity of episodic memory decline in older populations remains unclear. Objectives: We estimated associations between air pollution exposures and episodic memory decline according to pollutant, exposure time wi...

Background Whether racial/ethnic disparities in Alzheimer’s disease (AD) risk may be explained by ambient fine particles (PM2.5) has not been studied. Methods We conducted a prospective, population-based study on a cohort of Black (n=481) and White (n=6004) older women (aged 65-79) without dementia at enrollment (1995-98). Cox models accounting fo...

The interrelationships among long-term ambient air pollution exposure, emotional distress and cognitive decline in older adulthood remain unclear. Long-term exposure may impact cognitive performance and subsequently impact emotional health. Conversely, exposure may initially be associated with emotional distress followed by declines in cognitive pe...

Background/objectives: Exposure to air pollution may contribute to both increasing depressive symptoms and decreasing episodic memory in older adulthood, but few studies have examined this hypothesis in a longitudinal context. Accordingly, we examined the association between air pollution and changes in depressive symptoms (DS) and episodic memory...

The developmental course of antisocial behavior is often described in terms of qualitatively distinct trajectories. However, the genetic etiology of various trajectories is not well understood. We examined heterogeneity in the development of delinquent and aggressive behavior in 1532 twin youth using four waves of data collection, spanning ages 9–1...

Ambient air pollution, especially fine particulate matter (aerodynamic diameter <2.5 μm; PM2.5), is a novel neurotoxin. Psychosocial stress has been linked to Alzheimer’s disease (AD) and other dementias (ADRD). We test the hypothesis that PM2.5 and psychosocial stress may interact to accelerate brain aging, by investigating their potential joint e...

Late‐life exposure to ambient air pollutants may accelerate episodic memory (EM) declines in older women, but very little is known about the midlife exposure effects. Animal data suggests that hormone therapy (HT) may protect female brain from neurotoxic insult. We examined the EM trajectories associated with air pollutants and whether the associat...

Episodic memory (EM) declines vary by age and underlying neuropathology. Whether exposure to ambient air pollutants contributes to the observed heterogeneity of EM decline in older people is unclear. We examined the associations between exposures and EM trajectories in the US‐based Women’s Health Initiative Memory Study‐Epidemiology of Cognitive He...

Social relationships with less support are linked to greater risk of developing Alzheimer’s disease (AD) and other dementias. Despite growing evidence of this link, to our knowledge, no studies have examined neuropathological processes through which low social support may affect risk of cognitive impairment. We used data from the Women’s Health Ini...

Objective To examine whether late-life exposure to PM 2.5 (particulate matter with aerodynamic diameters <2.5-µm) contributes to progressive brain atrophy predictive of Alzheimer’s disease (AD) using a community-dwelling cohort of women (aged 70-89) with up to two brain MRI scans (MRI-1: 2005-6; MRI-2: 2010-11). Methods AD pattern similarity (AD-P...

Background: Emerging data suggests PM2.5 (particulate matter with aerodynamic diameter <2.5 μm) may be associated with both earlier declines in episodic memory (EM) and increased depressive symptoms in older adults. Although late-life depressive symptoms are associated with EM, no longitudinal studies have examined the inter-relationship among PM2...

Outdoor air pollution has been recognized as a novel environmental neurotoxin. Studies have begun to use brain Magnetic Resonance Imaging (MRI) to investigate how air pollution may adversely impact developing brains. A systematic review was conducted to evaluate and synthesize the reported evidence from MRI studies on how early-life exposure to out...

Evidence suggests exposure to particulate matter with aerodynamic diameter <2.5 μm (PM2.5) may increase the risk for Alzheimer's disease and related dementias. Whether PM2.5 alters brain structure and accelerates the preclinical neuropsychological processes remains unknown. Early decline of episodic memory is detectable in preclinical Alzheimer's d...

Among older adults, exposure to ambient PM2.5 (particulate matter with aerodynamic diameter <2.5 μm) has been associated with more rapid decline in cognitive performance and greater emotional distress. However, the inter-relationship between PM2.5 exposure, emotional distress, and global cognitive decline is unexamined. We examined whether long-ter...

Objectives: Although several environmental factors contribute to the etiology of late-life depressive symptoms, the role of ambient air pollution has been understudied. Experimental data support the neurotoxicity of airborne particulate matter with aerodynamic diameter of ≤2.5 μm (PM2.5), but it remains unclear whether long-term exposure is associ...

Introduction In a geographically diverse sample of women, we asked whether cognitive reserve (CR) is best viewed as a general or cognitive domain-specific construct and whether some cognitive reserve domains but not others exert protective effects on risk of developing mild cognitive impairment (MCI) or dementia. Methods Estimates of general and d...

The climate-violence relationship has been debated for decades, and yet most of the supportive evidence came from ecological or cross-sectional analyses with very limited long-term exposure data. We conducted an individual-level, longitudinal study to investigate the association between ambient temperature and externalizing behaviors of urban-dwell...

Animal experiments and cross-sectional human studies have linked particulate matter (PM) with increased behavioral problems. We conducted a longitudinal study to examine whether the trajectories of delinquent behavior are affected by PM2.5 (PM with aerodynamic diameter ≤ 2.5 μm) exposures before and during adolescence. We used the parent-reported C...

Mounting evidence indicates that early-life exposure to particulate air pollutants pose threats to children’s cognitive development, but studies about the neurotoxic effects associated with exposures during adolescence remain unclear. We examined whether exposure to ambient fine particles (PM2.5) at residential locations affects intelligence quotie...

Microsoft excel file of IQ scores, PM2.5 and relevant covariates for the 1360 subjects across pre-/early- adolescence and emerging adulthood. (XLS)

Appendix. A. Map of Residential Locations during pre-/early- adolescence and emerging adulthood; B. Temporal-spatial Modeling of PM2.5 Exposure; C. Relevant Covariates; D. Summary Table of Air Pollution and IQ Studies. (PDF)

Plot of regression coefficients and 95% confidence intervals for the associations between PM2.5 (1-, 2- and 3-year preceding test) and subscales of IQ from the final-adjusted model. (TIF)

Population Characteristics at Baseline in Relation to Levels of Performance IQ. (PDF)

Associations between total annual NOx and subscales of IQ. (PDF)

Descriptive statistics of major demographic characteristics, PM2.5 1-year preceding and IQ scores of three sub-cohorts. (PDF)

Population Characteristics at Baseline in Relation to Levels of Verbal IQ. (PDF)

Animal experiments and cross-sectional human studies have linked particulate matter (PM) with increased behavioral problems. We conducted a longitudinal study to examine whether the trajectories of delinquent behavior are affected by PM 2.5 (PM with aerodynamic diameter ≤2.5 m) exposures before and during adolescence. We used the parent-reported Ch...

Mounting evidence indicates that early-life exposure to particulate air pollutants pose threats to children’s cognitive development, but studies about the neurotoxic effects associated with exposures during adolescence remain unclear. We examined whether exposure to ambient fine particles (PM 2.5 ) at residential locations affects intelligence quot...

Objective: Neighborhood greenspace improves mental health of urban-dwelling populations, but its putative neurobehavioral benefits in adolescents remain unclear. We conducted a prospective study on urban-dwelling adolescents to examine the association between greenspace in residential neighborhood and aggressive behaviors. Method: Participants (...