Toxic metals and pediatric clinical immune dysfunction: A systematic review of the epidemiological evidence

BACKGROUND

Children are at high risk for exposure to toxic metals and are vulnerable to their effects. Significant research has been conducted evaluating the role of these metals on immune dysfunction, characterized by biologic and clinical outcomes. However, there are inconsistencies in these studies. The objective of the present review is to critically evaluate the existing literature on the association between toxic metals (lead, mercury, arsenic, and cadmium) and pediatric immune dysfunction.

METHODS

Seven databases (PubMed (NLM), Embase (Elsevier), CINAHL (Ebsco), Web of Science (Clarivate Analytics), ProQuest Public Health Database, and ProQuest Environmental Science Collection) were searched following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in February 2024. Rayaan software identified duplicates and screened by title and abstract in a blinded and independent review process. The remaining full texts were reviewed for content and summarized. Exclusions during the title, abstract, and full-text reviews included: 1) not original research, 2) not epidemiology, 3) did not include toxic metals, 4) did not examine an immune health outcome, or 5) not pediatric (>18 years). This systematic review protocol followed the PRISMA guidelines. Rayaan was used to screen records using title and abstract by two blinded and independent reviewers. This process was repeated for full-text article screening selection.

RESULTS

The search criteria produced 7906 search results; 2456 duplicate articles were removed across search engines. In the final review, 79 studies were included which evaluated the association between toxic metals and outcomes indicative of pediatric immune dysregulation.

CONCLUSIONS

The existing literature suggests an association between toxic metals and pediatric immune dysregulation. Given the imminent threat of infectious diseases demonstrated by the recent COVID-19 epidemic in addition to increases in allergic disease, understanding how ubiquitous exposure to these metals in early life can impact immune response, infection risk, and vaccine response is imperative.

Social Support and Depression among Stroke Patients: A Topical Review

Research has shown a protective association between social support and depression, depression among stroke patients, and health impacts of depression. Despite this, not much is known about the effect of social support on depression among stroke patients. This review aims to summarize the current research examining the association between social support and depression among stroke patients. A literature search was performed in PubMed to find original peer-reviewed journal articles from 2016 to 12 March 2023 that examined the association between social support and depression among stroke patients. The search terms were depression and "social support" and stroke, which lead to 172 articles. After abstract review, seven observational studies that studied the target association among stroke patients were selected. One additional study was found using PsycINFO as a complementary source with the same search strategy and criteria. Overall, a negative association was found between social support and depression among stroke patients in eight studies, with more social support leading to lower rates of depression post-stroke. The other study did not find a statistically significant association. Overall, the results of recent studies suggest that social support is negatively associated with depression among stroke patients. In most studies, this association was statistically significant. The findings suggest the importance of improving social support perceived by stroke patients in the prevention of depression after the occurrence of stroke.

The role of intracranial artery calcification (IAC) in stroke subtype and risk of vascular events

OBJECTIVE

To test the hypothesis that intracranial arterial calcification (IAC) is associated with intracranial large artery stenosis (ILAS) and a higher risk of vascular events and mortality.

METHOD

We leveraged data from two cohorts, the New York-Presbyterian Hospital/Columbia University Irving Medical Center Stroke Registry Study (NYP/CUIMC-SRS) and the Northern Manhattan Study (NOMAS) to test our hypotheses. We measured IAC using CT scans of participants in both cohorts and expressed IAC as present (vs not) and in tertiles. For the CUIMC-SRS, demographic, clinical and ILAS status was collected retrospectively. In NOMAS, we used research brain MRI and MRA to define asymptomatic ILAS and covert brain infarcts(CBI). We built models adjusted for demographics and vascular risk factors for cross-sectional and longitudinal analyses.

RESULTS

Cross-sectionally, IAC was associated with ILAS in both cohorts (OR 1.78, 95% CI: 1.16-2.73 for ILAS-related stroke in the NYP/CUIMC-SRS and OR 3.07, 95%CI 1.13-8.35 for ILAS-related covert brain infarcts in NOMAS). In a meta-analysis of both cohorts, IAC in the upper (HR 1.25, 95%CI 1.01-1.55) and middle tertile (HR 1.27, 95%CI 1.01-1.59) was associated with higher mortality compared with participants with no IAC. There were no longitudinal associations between IAC and risk of stroke or other vascular events.

CONCLUSION

In these multiethnic populations, IAC is associated with symptomatic and asymptomatic ILAS as well as higher mortality. IAC may be a useful marker of higher mortality, the role of IAC as an imaging marker of risk of stroke is less certain.

The structural and social determinants of Alzheimer's disease related dementias

INTRODUCTION

The projected growth of Alzheimer's disease (AD) and AD-related dementia (ADRD) cases by midcentury has expanded the research field and impelled new lines of inquiry into structural and social determinants of health (S/SDOH) as fundamental drivers of disparities in AD/ADRD.

METHODS

In this review, we employ Bronfenbrenner's ecological systems theory as a framework to posit how S/SDOH impact AD/ADRD risk and outcomes.

RESULTS

Bronfenbrenner defined the "macrosystem" as the realm of power (structural) systems that drive S/SDOH and that are the root cause of health disparities. These root causes have been discussed little to date in relation to AD/ADRD, and thus, macrosystem influences, such as racism, classism, sexism, and homophobia, are the emphasis in this paper.

DISCUSSION

Under Bronfenbrenner's macrosystem framework, we highlight key quantitative and qualitative studies linking S/SDOH with AD/ADRD, identify scientific gaps in the literature, and propose guidance for future research.

HIGHLIGHTS

Ecological systems theory links structural/social determinants to AD/ADRD. Structural/social determinants accrue and interact over the life course to impact AD/ADRD. Macrosystem is made up of societal norms, beliefs, values, and practices (e.g., laws). Most macro-level determinants have been understudied in the AD/ADRD literature.

Long-term exposure to ambient particulate matter and stroke etiology: Results from the Women's Health Initiative

BACKGROUND

Ambient particulate matter (PM) air pollution is a leading cause of global disability and accounts for an annual 2.9 million deaths globally. PM is established as an important risk factor for cardiovascular disease, however the evidence supporting a link specifically between long-term exposure to ambient PM and incident stroke is less clear. We sought to evaluate the association of long-term exposure to different size fractions of ambient PM with incident stroke (overall and by etiologic subtypes) and cerebrovascular deaths within the Women's Health Initiative, a large prospective study of older women in the US.

METHODS

We studied 155,410 postmenopausal women without previous cerebrovascular disease enrolled into the study between 1993 and 1998, with follow-up through 2010. We assessed geocoded participant address-specific concentrations of ambient PM (fine [PM2.5], respirable [PM10] and coarse [PM10-2.5]), as well as nitrogen dioxide [NO2] using spatiotemporal models. We classified hospitalization events into ischemic, hemorrhagic, or other/unclassified stroke. Cerebrovascular mortality was defined as death from any stroke etiology. We used Cox proportional hazard models to calculate hazard ratios (HR) and 95% confidence intervals (CI), adjusting for individual and neighborhood-level characteristics.

RESULTS

During a median follow-up time of 15 years, participants experienced 4,556 cerebrovascular events. The hazard ratio for all cerebrovascular events was 2.14 (95% CI: 1.87, 2.44) comparing the top versus bottom quartiles of PM2.5. Similarly, there was a statistically significant increase in events comparing the top versus bottom quartiles of PM10 and NO2 (HR: 1.17; 95% CI: 1.03, 1.33 and HR:1.26; 95% CI: 1.12, 1.42). The strength of association did not vary substantially by stroke etiology. There was little evidence of an association between PMcoarse and incident cerebrovascular events.

CONCLUSIONS

Long-term exposure to fine (PM2.5) and respirable (PM10) particulate matter as well as NO2 was associated with a significant increase of cerebrovascular events among postmenopausal women. Strength of the associations were consistent by stroke etiology.

Ambient Air Pollution and Stroke: An Updated Review

Despite recent advances in treatment and prevention, stroke remains a leading cause of morbidity and mortality. There is a critical need to identify novel modifiable risk factors for disease, including environmental agents. A body of evidence has accumulated suggesting that elevated levels of ambient air pollutants may not only trigger cerebrovascular events in susceptible people (short-term exposures) but also increase the risk of future events (long-term average exposures). This review assesses the updated evidence for both short and long-term exposure to ambient air pollution as a risk factor for stroke incidence and outcomes. It discusses the potential pathophysiologic mechanisms and makes recommendations to mitigate exposure on a personal and community level. The evidence indicates that reduction in air pollutant concentrations represent a significant population-level opportunity to reduce risk of cerebrovascular disease.

Linking Air Pollution Exposure to Blood-Based Metabolic Features in a Community-Based Aging Cohort with and without Dementia

BACKGROUND

Long-term exposure to air pollution has been associated with changes in levels of metabolites measured in the peripheral blood. However, most research has been conducted in ethnically homogenous, young or middle-aged populations.

OBJECTIVE

To study the relationship between the plasma metabolome and long-term exposure to three air pollutants: particulate matter (PM) less than 2.5μm in aerodynamic diameter (PM2.5), PM less than 10μm in aerodynamic diameter (PM10), and nitrogen dioxide (NO2) in an ethnically diverse, older population.

METHODS

Plasma metabolomic profiles of 107 participants of the Washington Heights and Inwood Community Aging Project in New York City, collected from 1995-2015, including non-Hispanic white, Caribbean Hispanic, and non-Hispanic Black older adults were used. We estimated the association between each metabolic feature and predicted annual mean exposure to the air pollutants using three approaches: 1) A metabolome wide association study framework; 2) Feature selection using elastic net regression; and 3) A multivariate approach using partial-least squares discriminant analysis.

RESULTS

79 features associated with exposure to PM2.5 but none associated with PM10 or NO2. PM2.5 exposure was associated with altered amino acid metabolism, energy production, and oxidative stress response, pathways also associated with Alzheimer's disease. Three metabolites were associated with PM2.5 exposure through all three approaches: cysteinylglycine disulfide, a diglyceride, and a dicarboxylic acid. The relationship between several features and PM2.5 exposure was modified by diet and metabolic diseases.

CONCLUSIONS

These relationships uncover the mechanisms through which PM2.5 exposure can lead to altered metabolic outcomes in an older population.

The Effect of Breathy Vocal Quality on Speech Intelligibility and Listening Effort in Background Noise

Speech perception is challenging under adverse conditions. However, there is limited evidence regarding how multiple adverse conditions affect speech perception. The present study investigated two conditions that are frequently encountered in real-life communication: background noise and breathy vocal quality. The study first examined the effects of background noise and breathiness on speech perception as measured by intelligibility. Secondly, the study tested the hypothesis that both noise and breathiness affect listening effort, as indicated by linear and nonlinear changes in pupil dilation. Low-context sentences were resynthesized to create three levels of breathiness (original, mild-moderate, and severe). The sentences were presented in a fluctuating nonspeech noise with two signal-to-noise ratios (SNRs) of -5 dB (favorable) and -9 dB (adverse) SNR. Speech intelligibility and pupil dilation data were collected from young listeners with normal hearing thresholds. The results demonstrated that a breathy vocal quality presented in noise negatively affected speech intelligibility, with the degree of breathiness playing a critical role. Listening effort, as measured by the magnitude of pupil dilation, showed significant effects with both severe and mild-moderate breathy voices that were independent of noise level. The findings contributed to the literature by demonstrating the impact of vocal quality on the perception of speech in noise. They also highlighted the complex dynamics between overall task demand and processing resources in understanding the combined impact of multiple adverse conditions.

Interactions between acoustic challenges and processing depth in speech perception as measured by task-evoked pupil response

Speech perception under adverse conditions is a multistage process involving a dynamic interplay among acoustic, cognitive, and linguistic factors. Nevertheless, prior research has primarily focused on factors within this complex system in isolation. The primary goal of the present study was to examine the interaction between processing depth and the acoustic challenge of noise and its effect on processing effort during speech perception in noise. Two tasks were used to represent different depths of processing. The speech recognition task involved repeating back a sentence after auditory presentation (higher-level processing), while the tiredness judgment task entailed a subjective judgment of whether the speaker sounded tired (lower-level processing). The secondary goal of the study was to investigate whether pupil response to alteration of dynamic pitch cues stems from difficult linguistic processing of speech content in noise or a perceptual novelty effect due to the unnatural pitch contours. Task-evoked peak pupil response from two groups of younger adult participants with typical hearing was measured in two experiments. Both tasks (speech recognition and tiredness judgment) were implemented in both experiments, and stimuli were presented with background noise in Experiment 1 and without noise in Experiment 2. Increased peak pupil dilation was associated with deeper processing (i.e., the speech recognition task), particularly in the presence of background noise. Importantly, there is a non-additive interaction between noise and task, as demonstrated by the heightened peak pupil dilation to noise in the speech recognition task as compared to in the tiredness judgment task. Additionally, peak pupil dilation data suggest dynamic pitch alteration induced an increased perceptual novelty effect rather than reflecting effortful linguistic processing of the speech content in noise. These findings extend current theories of speech perception under adverse conditions by demonstrating that the level of processing effort expended by a listener is influenced by the interaction between acoustic challenges and depth of linguistic processing. The study also provides a foundation for future work to investigate the effects of this complex interaction in clinical populations who experience both hearing and cognitive challenges.

Individual and Joint Effects of Influenza-Like Illness and Vaccinations on Stroke in the Young: A Case-Control Study

BACKGROUND:

Influenza-like illness (ILI) is an acute trigger for stroke, although joint effects of vaccinations and ILI have not yet been explored.

METHODS:

Data for our case-control study was obtained from MarketScan Commercial Claims and Encounters between 2008 and 2014. Patients 18 to 65 years old who experienced a stroke were matched on age and admission date to a control, defined as patients with head trauma or ankle sprain at an inpatient or emergency department visit. Exposures were ILI in the prior 30 days, and any type of vaccination during the year prior. Our outcome was ischemic and intracerebral hemorrhagic strokes identified using International Classification of Diseases, Ninth Revision (ICD-9 ) codes. Logistic regression models estimated adjusted odds ratios (aORs) controlling for preventive care visits, diabetes, valvular heart disease, smoking, alcohol abuse, obesity, and hypertension.

RESULTS:

We identified and matched 24 103 cases 18 to 44 years old and 141 811 45 to 65 years old. Those aged 18 to 44 years had increased stroke risk 30 days after ILI (aOR, 1.68 [95% CI, 1.51–1.86]) and reduced risk with any vaccination in the year prior (aOR, 0.92 [95% CI, 0.87–0.99]). Joint effects indicate that ILI was associated with increased stroke risk among those with (aOR, 1.41 [95% CI, 1.08–1.85]) and without (aOR, 1.73 [95% CI, 1.55–1.94]) vaccinations in the prior year ( P interaction =0.16). Among those aged 45 to 65 years, adjusted analyses indicate increased stroke risk for those with ILI (aOR, 1.32 [95% CI, 1.26–1.38]), although there was no effect of vaccinations (aOR, 1.00 [95% CI, 0.97–1.02]). Joint effects indicate that ILI was not associated with stroke among those with any vaccination (aOR, 1.07 [95% CI, 0.96–1.18]) but was associated with increased risk among those without vaccinations ([aOR, 1.39 [95% CI, 1.32–1.47]; P interaction <0.001).

CONCLUSIONS:

ILI was associated with increased stroke risk in the young and middle-aged, while vaccinations of any type were associated with decreased risk among the young. Joint effects of ILI and vaccinations indicate vaccinations can reduce the effect of ILI on stroke.

Rural-Urban Differences in Diagnosed Cervical Artery Dissection in New York State

BACKGROUND

Cervical artery dissection (CeAD) is a leading cause of stroke in young adults. Incidence estimates may be limited by under- or overdiagnosis.

OBJECTIVE

We aimed to investigate if CeAD diagnosis would be higher in urban centers compared to rural regions of New York State (NYS).

METHODS

For this ecological study, administrative codes were used to identify CeAD discharges in the NYS Statewide Planning and Research Cooperative System (SPARCS) from 2009 to 2014. Rural Urban Commuting Area (RUCA) codes were taken from the US Department of Agriculture and included the classifications metropolitan, micropolitan, small town, and rural. Negative binomial models were used to calculate effect estimates and 95% confidence limits (eβ; 95% CL) for the association between RUCA classification and the number of dissections per ZIP code. Models were further adjusted by population.

RESULTS

Population information was obtained from the US Census Bureau on 1,797 NYS ZIP codes (70.7% of NYS ZIP codes), 826 of which had at least 1 CeAD-related discharge from 2009 to 2014. Nonrural ZIP codes were more likely to report more CeAD cases relative to rural areas even after adjusting for population (metropolitan effect = eβ 5.00; 95% CI: 3.75-6.66; micropolitan effect 3.02; 95% CI: 2.16-4.23; small town effect 2.34; 95% CI: 1.58-3.47).

CONCLUSIONS

CeAD diagnosis correlates with population density as defined by rural-urban status. Our results could be due to underdiagnosis in rural areas or overdiagnosis with increasing urbanicity.

Association Between Hurricane Sandy and Emergency Department Visits in New York City by Age and Cause

The magnitude, timing, and etiology of morbidity associated with tropical cyclones remains incompletely quantified. We examined the relative change in cause-specific emergency department (ED) visits among residents of New York City during and after Hurricane Sandy, a tropical cyclone that affected the northeastern United States in October 2012. We used quasi-Poisson constrained distributed lag models to compare the number of ED visits on and after Hurricane Sandy with all other days, 2005-2014, adjusting for temporal trends. Among residents aged ≥65 years, Hurricane Sandy was associated with a higher rate of ED visits due to injuries and poisoning (relative risk (RR) = 1.19, 95% confidence interval (CI): 1.10, 1.28), respiratory disease (RR = 1.35, 95% CI: 1.21, 1.49), cardiovascular disease (RR = 1.10, 95% CI: 1.02, 1.19), renal disease (RR = 1.44, 95% CI: 1.22, 1.72), and skin and soft tissue infections (RR = 1.20, 95% CI: 1.03, 1.39) in the first week following the storm. Among adults aged 18-64 years, Hurricane Sandy was associated with a higher rate of ED visits for renal disease (RR = 2.15, 95% CI: 1.79, 2.59). Among those aged 0-17 years, the storm was associated with lower rates of ED visits for up to 3 weeks. These results suggest that tropical cyclones might result in increased health-care utilization due to a wide range of causes, particularly among older adults.

Association Between Hurricane Sandy and Emergency Department Visits in New York City by Age and Cause

The magnitude, timing, and etiology of morbidity associated with tropical cyclones remains incompletely quantified. We examined the relative change in cause-specific emergency department (ED) visits among residents of New York City during and after Hurricane Sandy, a tropical cyclone that affected the northeastern United States in October 2012. We used quasi-Poisson constrained distributed lag models to compare the number of ED visits on and after Hurricane Sandy with all other days, 2005-2014, adjusting for temporal trends. Among residents aged ≥65 years, Hurricane Sandy was associated with a higher rate of ED visits due to injuries and poisoning (relative risk (RR) = 1.19, 95% confidence interval (CI): 1.10, 1.28), respiratory disease (RR = 1.35, 95% CI: 1.21, 1.49), cardiovascular disease (RR = 1.10, 95% CI: 1.02, 1.19), renal disease (RR = 1.44, 95% CI: 1.22, 1.72), and skin and soft tissue infections (RR = 1.20, 95% CI: 1.03, 1.39) in the first week following the storm. Among adults aged 18-64 years, Hurricane Sandy was associated with a higher rate of ED visits for renal disease (RR = 2.15, 95% CI: 1.79, 2.59). Among those aged 0-17 years, the storm was associated with lower rates of ED visits for up to 3 weeks. These results suggest that tropical cyclones might result in increased health-care utilization due to a wide range of causes, particularly among older adults.

Risk of stroke and myocardial infarction after influenza-like illness in New York State

Background

Influenza may be associated with increased stroke and myocardial infarction (MI) risk. We hypothesized that risk of stroke and MI after influenza-like illness (ILI) would be higher in patients in New York State. We additionally assessed whether this relationship differed across a series of sociodemographic factors.

Methods

A case-crossover analysis of the 2012–2014 New York Statewide Planning and Research Cooperative System (SPARCS) was used to estimate odds of ischemic stroke and MI after ILI. Each patient’s case window (the time period preceding event) was compared to their control windows (same dates from the previous 2 years) in conditional logistic regression models used to estimate odds ratios and 95% confidence intervals (OR, 95% CI). We varied the case windows from 15 to 365 days preceding event as compared to control windows constructed using the same dates from the previous 2 years. Analyses were stratified by sex, race, and urban-rural status based on residential zip code.

Results

A total of 33,742 patients were identified as having ischemic stroke and 53,094 had MI. ILI events in the 15 days prior were associated with a 39% increase in odds of ischemic stroke (95% CI 1.09–1.77), increasing to an almost 70% increase in odds when looking at ILI events over the last year (95% CI 1.56, 1.83). In contrast, the effect of ILI hospitalization on MI was strongest in the 15 days prior (OR = 1.24, 95% CI 1.06–1.44). The risk of ischemic stroke after ILI was higher among individuals living in rural areas in the 90 days prior to stroke and among men in the year prior to event. In contrast, the association between ILI and MI varied only across race with whites having significantly higher ILI associated MI.

Conclusion

This study highlights risk period differences for acute cardiovascular events after ILI, indicating possible differences in mechanism behind the risk of stroke after ILI compared to the risk of MI. High risk populations for stroke after ILI include men and people living in rural areas, while whites are at high risk for MI after ILI. Future studies are needed to identify ways to mitigate these risks.

Influenza-Like Illness is Associated with Increased Short-Term Risk of Cervical Artery Dissection

INTRODUCTION

Non-traumatic Cervical Artery Dissection (CeAD) is a leading cause of ischemic stroke in the young. Influenza-like illnesses (ILI) trigger ischemic strokes. We hypothesized that influenza and ILI are associated with CeAD.

METHODS

In a case-crossover study within the New York State (NYS) Department of Health Statewide Planning and Research Cooperative System (2006-2014), we used ICD-9 codes to exclude major trauma and to define CeAD, influenza, and the Centers for Disease Control defined ILI. We estimated the association of ILI and influenza with CeAD by comparing their prevalence in intervals immediately prior (0-30,0-90,0-180, and 0-365 days) to CeAD (case period) to their prevalence exactly one and two years earlier (control periods). Conditional logistic regression models generated odds ratios and 95% confidence intervals (OR, 95% CI). Models were adjusted for NYS estimates of influenza prevalence rates.

RESULTS

Our sample included 3,610 cases of CeAD (mean age 52±16 years, 54.7% male, 6.2% Hispanic, 9.9% Black, 68.7% White). During case periods, 7.3% had one or more ILI. ILI was more likely within 90 days of CeAD compared to the same time interval one and two years before (0-15 days: adjusted OR 1.88, 95%CI 1.20-2.94; 0-30 days: adjusted OR 1.74, 95%CI 1.22-2.46; 0-90 days: adjusted OR 1.35, 95%CI 1.00-1.81). Influenza trended with CeAD (adjusted OR 1.86, 95%CI 0.37-9.24), but these results were not statistically significant, due to limited instances of confirmed influenza.

CONCLUSIONS

ILI may increase risk of CeAD for 15 days, and possibly up to three months.

Differences in healthcare visit frequency and type one year prior to stroke among young versus middle-aged adults

Background

The incidence and prevalence of stroke among the young are increasing in the US. Data on healthcare utilization prior to stroke is limited. We hypothesized those < 45 years were less likely than those 45–65 years old to utilize healthcare in the 1 year prior to stroke.

Methods

Patients 18–65 years old who had a stroke between 2008 and 2013 in MarketScan Commercial Claims and Encounters Databases were included. We used descriptive statistics and logistic regression to examine healthcare utilization and risk factors between age groups 18–44 and 45–65 years. Healthcare utilization was categorized by visit type (no visits, inpatient visits only, emergency department visits only, outpatient patient visits only, or a combination of inpatient, outpatient or emergency department visits) during the year prior to stroke hospitalization.

Results

Of those 18–44 years old, 14.1% had no visits in the year prior to stroke compared to 11.2% of individuals aged 45–65 [OR = 1.30 (95% CI 1.25,1.35)]. Patients 18–44 years old had higher odds of having preventive care procedures associated with an outpatient visit and lower odds of having cardiovascular procedures compared to patients aged 45–65 years. Of stroke patients aged 18–45 and 45–65 years, 16.8 and 13.2% respectively had no known risk for stroke.

Conclusions

Patients aged 45–65 were less commonly seeking preventive care and appeared to be seeking care to manage existing conditions more than patients aged 18–44 years. However, as greater than 10% of both age groups had no prior risk, further exploration of potential risk factors is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06064-5.

Seasonality of Influenza-Like-Illness and Acute Cardiovascular Events Are Related Regardless of Vaccine Effectiveness

Background

Influenza has been identified as a trigger for stroke and myocardial infarction (MI) with prior studies demonstrating that influenza vaccination may decrease risk of stroke and MI.

Methods and Results

We used data from the New York Department of Health Statewide Planning and Research Cooperative System to evaluate whether annual variability in influenza vaccination effectiveness (VE) would be associated with cardiovascular events. Daily and monthly counts of outpatient and inpatient visits for influenza‐like illness (ILI), stroke, and MI were identified using International Classification of Diseases, Ninth Revision (ICD‐9) codes; VE data for each year are publicly available. We identified pertinent lags between ILI, stroke, and MI using prewhitening cross‐correlation functions and applied them to autoregressive integrated moving average time series regression models. Time series forecasting systems assessed correlations among ILI, stroke, and MI, and the effect of VE on these relationships. Cross‐correlation functions indicated stroke events increased 1 month after increases in ILI rates; MIs increased immediately. Accounting for seasonality and lag, peaks in ILI rates were significantly related to peaks in stroke (P=0.04) and MI (P=0.01). Time forecasting analyses indicated no relationship between VE and cardiovascular events.

Conclusions

We identified that seasonality of cardiovascular events may be associated with seasonality in ILI, though VE did not modify this relationship.

Association Between Blood Pressure and Later-Life Cognition Among Black and White Individuals

Importance

Black individuals are more likely than white individuals to develop dementia. Whether higher blood pressure (BP) levels in black individuals explain differences between black and white individuals in dementia risk is uncertain.

Objective

To determine whether cumulative BP levels explain racial differences in cognitive decline.

Design, Setting, and Participants

Individual participant data from 5 cohorts (January 1971 to December 2017) were pooled from the Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Cardiovascular Health Study, Framingham Offspring Study, and Northern Manhattan Study. Outcomes were standardized as t scores (mean [SD], 50 [10]); a 1-point difference represented a 0.1-SD difference in cognition. The median (interquartile range) follow-up was 12.4 (5.9-21.0) years. Analysis began September 2018.

Main Outcomes and Measures

The primary outcome was change in global cognition, and secondary outcomes were change in memory and executive function.

Exposures

Race (black vs white).

Results

Among 34 349 participants, 19 378 individuals who were free of stroke and dementia and had longitudinal BP, cognitive, and covariate data were included in the analysis. The mean (SD) age at first cognitive assessment was 59.8 (10.4) years and ranged from 5 to 95 years. Of 19 378 individuals, 10 724 (55.3%) were female and 15 526 (80.1%) were white. Compared with white individuals, black individuals had significantly faster declines in global cognition (-0.03 points per year faster [95% CI, -0.05 to -0.01]; P = .004) and memory (-0.08 points per year faster [95% CI, -0.11 to -0.06]; P < .001) but significantly slower declines in executive function (0.09 points per year slower [95% CI, 0.08-0.10]; P < .001). Time-dependent cumulative mean systolic BP level was associated with significantly faster declines in global cognition (-0.018 points per year faster per each 10-mm Hg increase [95% CI, -0.023 to -0.014]; P < .001), memory (-0.028 points per year faster per each 10-mm Hg increase [95% CI, -0.035 to -0.021]; P < .001), and executive function (-0.01 points per year faster per each 10-mm Hg increase [95% CI, -0.014 to -0.007]; P < .001). After adjusting for cumulative mean systolic BP, differences between black and white individuals in cognitive slopes were attenuated for global cognition (-0.01 points per year [95% CI, -0.03 to 0.01]; P = .56) and memory (-0.06 points per year [95% CI, -0.08 to -0.03]; P < .001) but not executive function (0.10 points per year [95% CI, 0.09-0.11]; P < .001).

Conclusions and Relevance

These results suggest that black individuals' higher cumulative BP levels may contribute to racial differences in later-life cognitive decline.

Long-term exposure to air pollution and trajectories of cognitive decline among older adults

OBJECTIVE

To evaluate the association between long-term exposure to ambient air pollution and cognitive decline in older adults residing in an urban area.

METHODS

Data for this study were obtained from 2 prospective cohorts of residents in the northern Manhattan area of New York City: the Washington Heights-Inwood Community Aging Project (WHICAP) and the Northern Manhattan Study (NOMAS). Participants of both cohorts received in-depth neuropsychological testing at enrollment and during follow-up. In each cohort, we used inverse probability weighted linear mixed models to evaluate the cross-sectional and longitudinal associations between markers of average residential ambient air pollution (nitrogen dioxide [NO2], fine particulate matter [PM2.5], and respirable particulate matter [PM10]) levels in the year prior to enrollment and measures of global and domain-specific cognition, adjusting for sociodemographic factors, temporal trends, and censoring.

RESULTS

Among 5,330 participants in WHICAP, an increase in NO2 was associated with a 0.22 SD lower global cognitive score at enrollment (95% confidence interval [CI], -0.30, -0.14) and 0.06 SD (95% CI, -0.08, -0.04) more rapid decline in cognitive scores between visits. Results were similar for PM2.5 and PM10 and across functional cognitive domains. We found no evidence of an association between pollution and cognitive function in NOMAS.

CONCLUSION

WHICAP participants living in areas with higher levels of ambient air pollutants have lower cognitive scores at enrollment and more rapid rates of cognitive decline over time. In NOMAS, a smaller cohort with fewer repeat measurements, we found no statistically significant associations. These results add to the evidence regarding the adverse effect of air pollution on cognitive aging and brain health.

Long-term exposure to ambient air pollution, APOE-ε4 status, and cognitive decline in a cohort of older adults in northern Manhattan

BACKGROUND

There is mounting evidence that long-term exposure to air pollution is related to accelerated cognitive decline in aging populations. Factors that influence individual susceptibility remain largely unknown, but may involve the apolipoprotein E genotype E4 (APOE-ε4) allele.

OBJECTIVES

We assessed whether the association between long-term exposure to ambient air pollution and cognitive decline differed by APOE-ε4 status and cognitive risk factors.

METHODS

The Washington Heights Inwood Community Aging Project (WHICAP) is a prospective study of aging and dementia. Neuropsychological testing and medical examinations occur every 18-24 months. We used mixed-effects models to evaluate whether the association between markers of ambient air pollution (nitrogen dioxide [NO2]), fine [PM2.5], and coarse [PM10] particulate matter) and the rate of decline in global and domain-specific cognition differed across strata defined by APOE-ε4 genotypes and cognitive risk factors, adjusting for sociodemographic factors and temporal trends.

RESULTS

Among 4821 participants with an average of 6 years follow-up, higher concentrations of ambient air pollution were associated with more rapid cognitive decline. This association was more pronounced among APOE-ε4 carriers (p < 0.001). A one interquartile range increase in NO2 was associated with an additional decline of 0.09 standard deviations (SD) (95%CI -0.1, -0.06) in global cognition across biennial visits among APOE-ε4 positive individuals and a 0.07 SD (95%CI -0.09, -0.05) decline among APOE-ε4 negative individuals. Results for PM2.5, PM10 and cognitive domains were similar. The association between air pollutants and rate of cognitive decline also varied across strata of race-ethnicity with the association strongest among White non-Hispanic participants.

CONCLUSIONS

These results add to the body of evidence on the adverse impact of ambient air pollution on cognitive aging and brain health and provide new insights into the genetic and behavioral factors that may impact individual susceptibility.

Childhood adversities and prior involvement with child protective services

Objectives

We aimed to determine the relation between childhood adversities and prior involvement with Child Protective Services (CPS) history among children presenting for evaluation at a Child Advocacy Center.

Study design

The study evaluated children presenting to a Child Advocacy Center (CAC) from 2009 to 2014. A five-item child adversity measure, based on mother's report, was characterized into a scale of none, one, or two or more adversities. Caseworkers at the CAC assessed whether families had a prior history of involvement with CPS.

Results

Among the 727 children included in the analyses, 43% had a prior history of involvement with CPS. Twenty-six percent of the children experienced one childhood adversity while 29% experienced two or more. In regression analyses adjusting for socio-demographics, experiencing one (Prevalence Ratio (PR) 1.25 95%CI 1.0-1.5) or two or more adversities (PR1.67 95%CI 1.4, 2.0) was associated with higher prevalence of CPS history compared to those who reported none.

Conclusions

Childhood adversities are associated with prior contact with CPS, suggesting there are missed opportunities to provide services to high-risk families. CACs may be in a unique position to advocate for families and prevent further victimization of children.

Geographic Analysis of Mobile Stroke Unit Treatment in a Dense Urban Area: The New York City METRONOME Registry

Background Mobile stroke units (MSUs) reduce time to intravenous thrombolysis in acute ischemic stroke. Whether this advantage exists in densely populated urban areas with many proximate hospitals is unclear. Methods and Results We evaluated patients from the METRONOME (Metropolitan New York Mobile Stroke) registry with suspected acute ischemic stroke who were transported by a bi-institutional MSU operating in Manhattan, New York, from October 2016 to September 2017. The comparison group included patients transported to our hospitals via conventional ambulance for acute ischemic stroke during the same hours of MSU operation (Monday to Friday, 9 am to 5 pm). Our exposure was MSU care, and our primary outcome was dispatch-to-thrombolysis time. We estimated mean differences in the primary outcome between both groups, adjusting for clinical, demographic, and geographic factors, including numbers of nearby designated stroke centers and population density. We identified 66 patients treated or transported by MSU and 19 patients transported by conventional ambulance. Patients receiving MSU care had significantly shorter dispatch-to-thrombolysis time than patients receiving conventional care (mean: 61.2 versus 91.6 minutes; P=0.001). Compared with patients receiving conventional care, patients receiving MSU care were significantly more likely to be picked up closer to a higher mean number of designated stroke centers in a 2.0-mile radius (4.8 versus 2.7, P=0.002). In multivariable analysis, MSU care was associated with a mean decrease in dispatch-to-thrombolysis time of 29.7 minutes (95% CI, 6.9-52.5) compared with conventional care. Conclusions In a densely populated urban area with a high number of intermediary stroke centers, MSU care was associated with substantially quicker time to thrombolysis compared with conventional ambulance care.

Infections Increase the Risk of 30-Day Readmissions Among Stroke Survivors

Background and Purpose- Hospitals are increasingly using 30-day readmission (30dRA) to define the quality of care and reimbursement. We hypothesized that common infections occurring during the stroke stay are associated with 30dRA. Methods- We conducted a weighted analysis of the federally managed 2013 National Readmission Database to assess the relationship between infection during a stroke hospitalization and 30dRA among ischemic stroke survivors. Ischemic stroke, common infections (defined as sepsis, pneumonia, and urinary tract infection), and comorbidities were identified using International Classification of Diseases Ninth Revision ( ICD-9) diagnosis codes, and intravenous tPA (tissue-type plasminogen activator) or intra-arterial therapy was identified using ICD-9 procedure codes. Survey design logistic regression models were fit to estimate crude and adjusted odds ratios and 95% CI for the association between infections and 30dRA. Results- Among 319 317 ischemic stroke patients, 12.1% were readmitted within 30 days, and 29% had an infection during their index hospitalization. Patients with infection during their stroke admission had a 21% higher odds of being readmitted than patients without any type of infection (adjusted odds ratio, 1.21; 95% CI, 1.16-1.26). The association between infection and unplanned readmission was similar with an increased odds of unplanned readmission (adjusted odds ratio, 1.23; 95% CI, 1.18-1.29). When assessing specific types of infections, only urinary tract infections were associated with 30dRA in adjusted models (odds ratio, 1.10; 95% CI, 1.04-1.16). Conclusions- In a nationally representative cohort, patients who had a common infection during their stroke hospitalization were at increased odds of being readmitted. Patients with infection may benefit from earlier poststroke follow-up or closer monitoring.

"Weekend Effect" on 30-Day Readmissions among Stroke Survivors: An Analysis of the National Readmission Database

Background and Purpose

Previous studies suggested that quality of care may be lower on weekends than during the week. We hypothesized that, among patients hospitalized for an index ischemic stroke, those admitted on weekends would have a higher risk of 30-day readmission than those admitted on weekdays.

Methods

We utilized the 2013 Nationwide Readmission Database, which includes data on US inpatient admissions from the Agency for Healthcare Research and Quality Healthcare Utilization Project. The database includes a nationally representative weighted probability sample of inpatient hospitalizations regardless of insurance status. Patients with primary acute ischemic stroke were identified using previously validated ICD-9-CM diagnosis codes. We conducted a weighted analysis using survey design logistic regression models to estimate crude and adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association between weekend admission and 30-day readmission in ischemic stroke patients.

Results

Among 319,317 patients admitted for ischemic stroke, 12.1% were readmitted within 30 days. Those with 30-day readmissions had an average of 8 chronic conditions, and all cardiovascular-related comorbidities increased the risk of 30-day readmissions. Ischemic stroke patients admitted on weekends had odds of 30-day readmission similar to patients admitted on weekdays (OR 1.02; 95% CI 0.98–1.06). Weekend admission also did not affect readmission at 7 or 60 days.

Conclusions

We found no association between weekend admission and 30-day readmissions, providing indirect evidence of homogeneity in the quality of care delivered during week day and weekend admissions.

Abstract WMP49: Influenza-Like Illness May Trigger Cervical Artery Dissection

Background and Purpose: Non-traumatic Cervical Artery Dissection (CeAD) is a leading cause of ischemic stroke in patients 15 to 45 years old. Influenza-like illnesses (ILI) have been found to trigger ischemic stroke, but ILI has not been investigated in relation to CeAD. We hypothesized that ILI and influenza would be associated with CeAD.

Methods: We used a case-crossover design among patients > 18 years old at time of first non-traumatic CeAD within the New York State (NYS) Department of Health Statewide Planning and Research Cooperative System (2006-2014). We used ICD-9 codes to define CeAD (443.21, 443.24) excluding individuals with major trauma (integer values 800-804 and 850-854), confirmed influenza (480, 487.0, 487.1, 487.8), and a broader influenza definition endorsed by the CDC for ILI surveillance. We compared ILI and influenza in sequential, mutually exclusive intervals preceding CeAD (0-15, 16-30, 31-90, 91-180, and 181-365 days prior to CeAD: case period) and overlapping intervals (0-30, 0-90, 0-180, and 0-365 days prior to CeAD: alternate case period) to ILI and influenza exactly one and two years earlier (control periods). Conditional logistic regression models were used to calculate odds ratios and 95% confidence intervals (OR, 95% CI) before and after adjusting for annual NYS population estimates of influenza prevalence rate.

Results: Our final sample included 3,861 cases of CeAD (mean age 52±16 and 55.5% of male). We found 1,736 instances of ILI and 113 of influenza during the 3 years preceding CeAD. Patients were more likely to have ILI within 30 days of CeAD compared to the same time one and two years before (0-15 days: adjusted OR 1.53, 95% CI 1.02 - 2.30; 0-30 days: adjusted OR 1.60, 95% CI 1.14 - 2.23). ILI during later overlapping or sequential intervals was not associated with CeAD in adjusted models. Influenza was associated with CeAD between 31 and 90 days after CeAD, but this effect was no longer significant after adjusting for prevalence rate of influenza, perhaps due the small number of patients with confirmed influenza.

Conclusions: ILI may increase risk of CeAD for up to one month. Further research on mechanisms by which ILI and influenza may trigger dissection are warranted.

Regional Subclinical Cerebrovascular Disease Is Associated with Balance in an Elderly Multi-Ethnic Population

INTRODUCTION

White matter hyperintensity volume (WMHV) and subclinical brain infarcts (SBI) are associated with impaired mobility, but less is known about the association of WMHV in specific brain regions. We hypothesized that anterior WMHV would be associated with lower scores on the Short Physical Performance Battery (SPPB), a well-validated mobility scale.

METHODS

The SPPB was measured a median of 5 years after enrollment into the Northern Manhattan MRI sub study. Volumetric distributions for WMHV in 14 brain regions as a proportion of total cranial volume were determined. Multi-variable linear regression was performed to examine the association of SBI and regional log-WMHV with the SPPB score.

RESULTS

Among 668 participants with SPPB measurements (mean 74 ± 9 years, 37% male and 70% Hispanic), the mean SPPB score was 8.2 ± 2.9. Total (beta = -0.3 per SD, p = 0.001), anterior periventricular (beta = -0.4 per SD, p = 0.001), parietal (beta = -0.2 per SD, p = 0.02) and frontal (beta = -0.3 per SD, p = 0.002) WMHVs were associated with SPPB; other WMHV and SBI were not associated with the SPPB.

CONCLUSIONS

WMHV, especially in the anterior -cerebral regions, is associated with a lower SPPB. Prevention of subclinical cerebrovascular disease is a potential target to prevent physical decline in the elderly.

Infections and Risk of Peripartum Stroke During Delivery Admissions

BACKGROUND AND PURPOSE

Peripartum strokes during delivery admissions are rare but have high maternal morbidity. Infections have been proposed as a possible stroke trigger. We hypothesized that women who had infections diagnosed at the time of delivery admission would have higher risk of stroke during their delivery hospitalization.

METHODS

We conducted a case-control study using state inpatient administrative databases for California (2007-2011), Florida (2009-2011), and New York (2009-2011). Women whose admission included a vaginal or cesarean delivery, with a new diagnosis of stroke during the admission, were considered cases and were randomly matched to 3 in-state controls by age/admission year and presence and severity of hypertensive disorders of pregnancy. The primary exposure of interest was infection of any type present on admission. Secondary exposures included race/ethnicity, payer status, delivery method, and known vascular risk factors such as chronic hypertension, diabetes mellitus, smoking, alcohol abuse, hypercoagulable states, coagulopathies, and renal disease. We used multivariable conditional logistic regression to estimate the odds ratios and 95% confidence intervals for the association of infections and known vascular risk factors with stroke risk.

RESULTS

A total of 455 cases (mean age, 29.8), of whom 195 (42.9%) had hypertensive disorders of pregnancy, were matched with 1365 controls. Infection of any type present on admission increased the odds of stroke diagnosis during the admission (adjusted odds ratio, 1.74; 95% confidence interval, 1.29-2.35). Risk was higher for genitourinary infections (adjusted odds ratio, 2.56; 95% confidence interval, 1.25-5.24) and sepsis (adjusted odds ratio, 10.4; 95% confidence interval, 2.15-20.0). The association between infection and stroke during delivery admission did not differ by the presence of hypertensive disorders of pregnancy.

CONCLUSIONS

Infections present on admission increased stroke risk during delivery admissions in women with and without hypertensive disorders of pregnancy. The results were driven by genitourinary infections and sepsis. Infections may be an underrecognized precipitant of peripartum stroke.

Influenza-like illness as a trigger for ischemic stroke

Objective

We hypothesized that ILI is associated with risk of incident stroke, and that the risk would be highest closest in time to the event.

Methods

This case‐crossover analysis utilized data obtained from the California State Inpatient Database of the Healthcare Cost and Utilization Project (HCUP). The outcome of interest was ischemic stroke. Exposure was defined as a visit to the emergency department or hospitalization for influenza‐like illness (ILI) 365, 180, 90, 30, or 15 days before stroke (risk period) or similar time intervals exactly 1 or 2 years before stroke (control period). Conditional logistic regression was used to calculate the odds ratio and 95% confidence interval (OR, 95% CI).

Results

In 2009, 36,975 hospitalized ischemic strokes met inclusion criteria, and of these strokes, 554 (1.5%) had at least 1 episode of ILI in the 365‐day risk period prior to their stroke. Using non‐overlapping time intervals from ILI to stroke, the odds of ischemic stroke was greatest in the first 15 days post ILI (OR: 2.88, 95% CI: 1.86–4.47). The strength of the relationship decreased as the time from ILI increased, and was no longer significant after 60 days. There was a significant interaction (P = 0.017) with age and ILI; the odds of stroke associated increased 7% with each 10‐year decrease in age (OR per 10‐year age decrease 1.07, 95% CI: 1.03–1.35).

Interpretation

We found that ILI increases short‐term risk of stroke, particularly in people under the age of 45, and therefore may be considered to act as a trigger for stroke.

Residential Proximity to Major Roadways and Risk of Incident Ischemic Stroke in NOMAS (The Northern Manhattan Study)

BACKGROUND AND PURPOSE

The evidence supporting the deleterious cardiovascular health effects of living near a major roadway is growing, although this association is not universal. In primary analyses, we hypothesized that residential proximity to a major roadway would be associated with incident ischemic stroke and that cardiovascular risk factors would modify that association.

METHODS

NOMAS (The Northern Manhattan Study) is an ongoing, population-based cohort study designed to measure cardiovascular risk factors, stroke incidence, and other outcomes in a multiethnic urban population. Recruitment occurred from 1993 to 2001 and participants are followed-up annually by telephone. Residential addresses at baseline were geocoded and Euclidean distance to nearest major roadway was estimated and categorized as in prior studies. We used Cox proportional hazard models to calculate hazard ratios and 95% confidence intervals for the association of this distance to incidence of stroke and other outcomes, adjusting for sociodemographic and cardiovascular risk factors, year at baseline, and neighborhood socioeconomic status. We assessed whether these associations varied by age, sex, smoking status, diabetes mellitus, and hypertension.

RESULTS

During a median follow-up period of 15 years (n=3287), 11% of participants were diagnosed with ischemic stroke. Participants living <100 m from a roadway had a 42% (95% confidence interval, 1.01-2.02) higher rate of ischemic stroke versus those living >400 m away. This association was more pronounced among noncurrent smokers (hazard ratio, 1.54; 95% confidence interval, 1.05-2.26) and not evident among smokers (hazard ratio, 0.69; 95% confidence interval, 0.23-2.06). There was no clear pattern of association between proximity to major roadways and other cardiovascular events including myocardial infarction, all-cause death, or vascular death.

CONCLUSIONS

In this urban multiethnic cohort, we found evidence supporting that within-city variation in residential proximity to major roadway is associated with higher risk of ischemic stroke. An individual's smoking history modified this association, with the association remaining only among participants not currently smokers.

Effects of the New York State Concussion Management and Awareness Act ("Lystedt Law") on Concussion-Related Emergency Health Care Utilization Among Adolescents, 2005-2015

BACKGROUND

All states have enacted legislation addressing the management of sports-related concussions (SRCs) in adolescent athletes. The effect of these laws on health care utilization is uncertain. Hypothesis/Purpose: The purpose was to evaluate the effects of New York's 2011 Concussion Management and Awareness Act ("Lystedt Law") on emergency department (ED) concussion health care visits (EDCHVs) and brain imaging utilization. It was hypothesized that New York concussion legislation would have a significant temporal effect on EDCHVs.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Using the New York State Department of Health Statewide Planning and Research Cooperative System (SPARCS) database, trends in EDCHVs from 2005 to 2015 were identified among 12- to 18-year-old patients, comprising 5,740,403 total ED visits.

RESULTS

Overall, 208,024 EDCHVs, including 54,669 for an SRC, occurred during the study period. EDCHVs increased from 13,664 (2.74% of all ED visits) in 2005 to a peak of 21,374 (4.26%) in 2013, with greatest relative increases from 2008 to 2013. SRCs followed a similar trend: 3213 (0.64%) in 2005 to a peak of 6197 (1.24%) in 2013. Brain imaging utilization decreased by 5.3% for EDCHVs and 15.4% for SRCs (all comparisons year-by-year and for trends; P < .001).

CONCLUSION

The period of greatest increases in EDCHVs and decreases in brain imaging utilization for SRCs preceded New York concussion legislation by several years, suggesting a minimal direct effect on emergency care-seeking behavior for concussions. Instead, increased public awareness of SRCs and imaging guidelines may have driven EDCHV trends and imaging practices.

Physical Inactivity Predicts Slow Gait Speed in an Elderly Multi-Ethnic Cohort Study: The Northern Manhattan Study

INTRODUCTION

Gait speed is associated with multiple adverse outcomes of aging. We hypothesized that physical inactivity would be prospectively inversely associated with gait speed independently of white matter hyperintensity volume and silent brain infarcts on MRI.

METHODS

Participants in the Northern Manhattan Study MRI sub-study had physical activity assessed when they were enrolled into the study. A mean of 5 years after the MRI, participants had gait speed measured via a timed 5-meter walk test. Physical inactivity was defined as reporting no leisure-time physical activity. Multi-variable logistic and quantile regression was performed to examine the associations between physical inactivity and future gait speed adjusted for confounders.

RESULTS

Among 711 participants with MRI and gait speed measures (62% women, 71% Hispanic, mean age 74.1 ± 8.4), the mean gait speed was 1.02 ± 0.26 m/s. Physical inactivity was associated with a greater odds of gait speed in the lowest quartile (<0.85 m/s, adjusted OR 1.90, 95% CI 1.17-3.08), and in quantile regression with 0.06 m/s slower gait speed at the lowest 20 percentile (p = 0.005).

CONCLUSIONS

Physical inactivity is associated with slower gait speed independently of osteoarthritis, grip strength, and subclinical ischemic brain injury. Modifying sedentary behavior poses a target for interventions aimed at reducing decline in mobility.

Long-Term Exposure to Ambient Air Pollution and Subclinical Cerebrovascular Disease in NOMAS (the Northern Manhattan Study)

BACKGROUND AND PURPOSE

Long-term exposure to ambient air pollution is associated with higher risk of cardiovascular disease and stroke. We hypothesized that long-term exposure to air pollution would be associated with magnetic resonance imaging markers of subclinical cerebrovascular disease.

METHODS

Participants were 1075 stroke-free individuals aged ≥50 years drawn from the magnetic resonance imaging subcohort of the Northern Manhattan Study who had lived at the same residence for at least 2 years before magnetic resonance imaging. Cross-sectional associations between ambient air pollution and subclinical cerebrovascular disease were analyzed.

RESULTS

We found an association between distance to roadway, a proxy for residential exposure to traffic pollution, and white matter hyperintensity volume; however, after adjusting for risk factors, this relationship was no longer present. All other associations between pollutant measures and white matter hyperintensity volume were null. There was no clear association between exposure to air pollutants and subclinical brain infarcts or total cerebral brain volume.

CONCLUSIONS

We found no evidence that long-term exposure to ambient air pollution is independently associated with subclinical cerebrovascular disease in an urban population-based cohort.

Leisure-Time Physical Activity and Cardiovascular Mortality in an Elderly Population in Northern Manhattan: A Prospective Cohort Study

BACKGROUND

Previous studies of exercise have focused on measuring physical activity in totality using summary statistics such as metabolic equivalent score for total intensity or total energy count.

OBJECTIVE

We aimed to examine the multidimensionality of leisure-time physical activity (LTPA) and to identify the specific LTPA components that were associated with cardiovascular mortality in the elderly.

DESIGN AND PARTICIPANTS

The Northern Manhattan Study (NOMAS) is a multiethnic prospective cohort of elderly stroke-free individuals consisting of a total of 3298 participants recruited between 1993 and 2001, with a median follow-up of 17 years.

MAIN MEASURES

Physical activity questionnaire data were available in 3293 NOMAS participants, who were categorized into subgroups with similar exercise patterns by model-based cluster analysis. Three subgroup-defining LTPA features were identified and were considered as primary exposures in Cox proportional hazard models: frequency of activity, number of activity types (variety), and energy-to-duration ratio (EDR). We considered cardiovascular mortality and non-cardiovascular mortality as outcomes in Cox cause-specific proportional hazard models, and all-cause mortality as outcome in Cox models.

KEY RESULTS

A high activity frequency was associated with reduced cardiovascular mortality (hazard ratio, HR = 0.93, P = 0.03), but demonstrated no effect on non-cardiovascular death. A high EDR was associated with increased risk of cardiovascular death (HR = 1.30, P = 0.01). A high number of activity types was beneficial in reducing all-cause mortality (HR = 0.87, P = 0.01).

CONCLUSIONS

Exercise frequency was protective against cardiovascular mortality, and a high variety of activity was protective against all-cause mortality. The performance of frequent and varied non-intense exercise in an elderly population such as ours is achievable and can reduce the risk of death.

Abstract WP184: Differential Risk of Embolic Stroke Among Stroke Free Community Dwellers With Distinct Categories of Subcortical Infarct

Introduction: Cortically-based subclinical infarcts are considered risks for embolic stroke, but few studies have stratified subcortical SBI by penetrating versus medullary artery location. We hypothesized that subclinical medullary infarcts are due to small emboli and are predictors of embolic stroke.

Methods: Stroke-free participants in the Northern Manhattan Study underwent a brain MRI to assess for subclinical biomarkers of vascular disease. Subcortical brain infarcts were defined voids >3mm on axial T1 and FLAIR images, with perilesional FLAIR hyperintensities referred to as pathology-informed subclinical brain infarcts (PI-SBI). Each subcortical PI-SBI was rated as penetrating or medullary by two vascular neurologists blinded to stroke subtypes. Participants were followed prospectively for incident stroke. Two vascular neurologists ascertained ischemic stroke subtypes independent of brain MRI imaging at baseline. Embolic stroke required a cardiac source or based on a superficial location. Cox proportional risk models generated hazard ratios and 95% confidence intervals (HR, 95% CI) adjusting for age, sex, ethnicity and traditional vascular risk.

Results: The sample included 1290 NOMAS participants (mean age 71±9 years, 60% women, 66% Hispanic, 75% with hypertension) who were followed on average 9±3 years. At baseline, 19% of participants had PI-SBI (11% medullary artery, 7% penetrating artery and 3% cortical). During follow up, 80 participants (6.2%) had stroke (3.6% embolic, 2.4% due to intracranial artery disease (i.e. small and large), and 0.2% other subtypes). In a fully adjusted model, medullary artery (2.04, 1.00-4.14) and not penetrating artery PI-SBI (1.64, 0.99-2.70) predicted risk of embolic stroke. Distal field PI-SBI (i.e. cortical + medullary artery) were even more robust predictors of embolic stroke (2.17, 1.11-4.25). Penetrating artery (1.98, 1.09-3.61) and not medullary artery PI-SBI (HR 1.03, 0.34-3.06) predicted risk of intracranial artery stroke.

Conclusions: Subtyping PI-SBI by location and plausible mechanisms may help with risk stratification for clinical trials testing stroke prevention strategies. Our data suggest not all subcortical infarcts are due to small vessel disease.

The Massachusetts Emergency Medical Service Stroke Quality Improvement Collaborative, 2009-2012

INTRODUCTION

Quality improvement collaboratives are a popular model used to address gaps between evidence-based practice and patient care. Little is known about use of such collaboratives in emergency medical services, particularly for improving prehospital stroke care. To determine the feasibility of using this approach to improve prehospital stroke care, we conducted a pilot study of the Emergency Medical Services Stroke Quality Improvement Collaborative.

METHODS

Seventeen Massachusetts emergency medical service agencies participated in the quality improvement collaborative pilot project. We identified 5 prehospital stroke performance measures to assess the quality of prehospital care, guide collaborative activities, and monitor change in performance over time. During learning sessions, participants were trained in quality improvement and performance measurement, analyzed performance measure results, and shared successes and challenges. Focus groups were conducted to understand participants' experiences with the collaborative.

RESULTS

Participating emergency medical service agencies collected stroke performance measures on 3,009 stroke patients during the pilot study. Adherence to 4 of 5 performance measures increased significantly over time. Participants acknowledged that the collaborative provided them with an efficient and effective framework for stroke quality improvement and peer-learning opportunities.

CONCLUSION

As evidenced in Massachusetts, quality improvement collaboratives can be an effective tool to improve prehospital stroke care. The data collected, improvements made, participation of emergency medical service agencies, and positive experiences within the collaborative support the continued use of this approach.