Samaah Sullivan

Neighborhood environments and obesity among Afro-Caribbean, African American, and Non-Hispanic white adults in the United States: results from the National Survey of American Life.

OBJECTIVE To examine possible associations between perceived neighborhood environments and obesity among a U.S. nationally representative sample of Afro-Caribbean, African American, and Non-Hispanic white adults. METHODS Data was used from the 2001-2003 National Survey of American Life (NSAL). All measures including neighborhood characteristics, height, and weight were self-reported. Multivariate logistic regression was used to compute odds ratios (ORs) of obesity (body mass index (BMI) ≥ 30 kg/m(2)) based on perceived neighborhood physical and social characteristics. RESULTS The odds of obesity were significantly lower for adults who reported involvement in clubs, associations, or help groups (odds ratio (OR): 0.62; 95% confidence interval (CI): 0.44, 0.85) and perceived that they had a park, playground, or open space in their neighborhood (odds ratio (OR): 0.68; 95% confidence interval (CI): 0.47, 0.98). These associations remained significant after adjusting for leisure-time physical activity. Race/ethnicity appeared to modify the association between involvement in clubs, associations, or help groups and obesity. CONCLUSIONS Providing parks, playgrounds, or open space or increasing the perception of those amenities may assist in the prevention of obesity, especially in ethnically diverse neighborhoods in the United States. More research is needed to investigate how perceptions of the neighborhood environment influence obesity and whether perceptions of the neighborhood environment differ between individuals within the same neighborhoods.

Mental Stress–Induced-Myocardial Ischemia in Young Patients With Recent Myocardial Infarction: Sex Differences and Mechanisms

Background: Mental stress-induced myocardial ischemia (MSIMI) is frequent in patients with coronary artery disease and is associated with worse prognosis. Young women with a previous myocardial infarction (MI), a group with unexplained higher mortality than men of comparable age, have shown elevated rates of MSIMI, but the mechanisms are unknown. Methods: We studied 306 patients (150 women and 156 men) ⩽61 years of age who were hospitalized for MI in the previous 8 months and 112 community controls (58 women and 54 men) frequency matched for sex and age to the patients with MI. Endothelium-dependent flow-mediated dilation and microvascular reactivity (reactive hyperemia index) were measured at rest and 30 minutes after mental stress. The digital vasomotor response to mental stress was assessed using peripheral arterial tonometry. Patients received 99mTc-sestamibi myocardial perfusion imaging at rest, with mental (speech task) and conventional (exercise/pharmacological) stress. Results: The mean age of the sample was 50 years (range, 22–61). In the MI group but not among controls, women had a more adverse socioeconomic and psychosocial profile than men. There were no sex differences in cardiovascular risk factors, and among patients with MI, clinical severity tended to be lower in women. Women in both groups showed a higher peripheral arterial tonometry ratio during mental stress but a lower reactive hyperemia index after mental stress, indicating enhanced microvascular dysfunction after stress. There were no sex differences in flow-mediated dilation changes with mental stress. The rate of MSIMI was twice as high in women as in men (22% versus 11%, P=0.009), and ischemia with conventional stress was similarly elevated (31% versus 16%, P=0.002). Psychosocial and clinical risk factors did not explain sex differences in inducible ischemia. Although vascular responses to mental stress (peripheral arterial tonometry ratio and reactive hyperemia index) also did not explain sex differences in MSIMI, they were predictive of MSIMI in women only. Conclusions: Young women after MI have a 2-fold likelihood of developing MSIMI compared with men and a similar increase in conventional stress ischemia. Microvascular dysfunction and peripheral vasoconstriction with mental stress are implicated in MSIMI among women but not among men, perhaps reflecting women’s proclivity toward ischemia because of microcirculatory abnormalities.

Hemodynamic, catecholamine, vasomotor and vascular responses: Determinants of myocardial ischemia during mental stress

AIMS Mental stress-induced myocardial ischemia (MSIMI) in patients with coronary artery disease (CAD) is associated with adverse cardiovascular outcomes. We aim to assess hemodynamic, neuro-hormonal, endothelial, vasomotor and vascular predictors of MSIMI. METHODS AND RESULTS We subjected 660 patients with stable CAD to 99mTc sestamibi myocardial perfusion imaging at rest, with mental (speech task) and with conventional (exercise/pharmacological) stress. Endothelium-dependent flow-mediated dilation (FMD), microvascular reactivity [reactive hyperemia index (RHI)] and arterial stiffness [pulse wave velocity (PWV)] were measured at rest and 30-min after mental stress. The digital microvascular vasomotor response during mental stress was assessed using peripheral arterial tonometry (PAT). A total of 106(16.1%) patients had MSIMI. Mental stress was accompanied by significant increases in rate-pressure-product (heart rate x systolic blood pressure; RPP), epinephrine levels and PWV, and significant decreases in FMD and PAT ratio denoting microvascular constriction. In comparison to those with no MSIMI, patients with MSIMI had higher hemodynamic and digital vasoconstrictive responses (p<0.05 for both), but did not differ in epinephrine, endothelial or macrovascular responses. Only presence of ischemia during conventional stress (OR of 7.1, 95%CI of 4.2, 11.9), high hemodynamic response (OR for RPP response≥vs<ROC cutoff of 1.8, 95%CI of 1.1, 2.8), and high digital vasoconstriction (OR for PAT ratio<vs≥ROC cutoff of 2.1, 95%CI of 1.3, 3.3) were independent predictors of MSIMI. CONCLUSION Ischemia during conventional stress testing and hemodynamic and vasoconstrictive responses to mental stress can help predict subjects with CAD at greater risk of developing MSIMI.

Sex Differences in Hemodynamic and Microvascular Mechanisms of Myocardial Ischemia Induced by Mental Stress

Objective— To investigate sex-specific vascular mechanisms for mental stress-induced myocardial ischemia (MSIMI). Approach and Results— Baseline data from a prospective cohort study of 678 patients with coronary artery disease underwent myocardial perfusion imaging before and during a public speaking stressor. The rate-pressure product response was calculated as the difference between the maximum value during the speech minus the minimum value during rest. Peripheral vasoconstriction by peripheral arterial tonometry was calculated as the ratio of pulse wave amplitude during the speech over the resting baseline; ratios <1 indicate a vasoconstrictive response. MSIMI was defined as percent of left ventricle that was ischemic and as a dichotomous variable. Men (but not women) with MSIMI had a higher rate-pressure product response than those without MSIMI (6500 versus 4800 mm Hg bpm), whereas women (but not men) with MSIMI had a significantly lower peripheral arterial tonometry ratio than those without MSIMI (0.5 versus 0.8). In adjusted linear regression, each 1000-U increase in rate-pressure product response was associated with 0.32% (95% confidence interval, 0.22–0.42) increase in inducible ischemia among men, whereas each 0.10-U decrease in peripheral arterial tonometry ratio was associated with 0.23% (95% confidence interval, 0.11–0.35) increase in inducible myocardial ischemia among women. Results were independent of conventional stress-induced myocardial ischemia. Conclusions— Women and men have distinct cardiovascular reactivity mechanisms for MSIMI. For women, stress-induced peripheral vasoconstriction with mental stress, and not increased hemodynamic workload, is associated with MSIMI, whereas for men, it is the opposite. Future studies should examine these pathways on long-term outcomes.

Associations of neighborhood social environment attributes and physical activity among 9–11 year old children from 12 countries

Abstract We investigated whether associations of neighborhood social environment attributes and physical activity differed among 12 countries and levels of economic development using World Bank classification (low/lower‐middle‐, upper‐middle‐ and high‐ income countries) among 9–11 year old children (N=6161) from the International Study of Childhood Obesity, Lifestyle, and the Environment (ISCOLE). Collective efficacy and perceived crime were obtained via parental/guardian report. Moderate‐to‐vigorous physical activity (MVPA) was assessed with waist‐worn Actigraph accelerometers. Neighborhood environment by country interactions were tested using multi‐level statistical models, adjusted for covariates. Effect estimates were reported by country and pooled estimates calculated across World Bank classifications for economic development using meta‐analyses and forest plots. Associations between social environment attributes and MVPA varied among countries and levels of economic development. Associations were more consistent and in the hypothesized directions among countries with higher levels economic development, but less so among countries with lower levels of economic development.

The Women and Their Children’s Health (WaTCH) study: methods and design of a prospective cohort study in Louisiana to examine the health effects from the BP oil spill

Purpose The Deepwater Horizon Oil Spill is the largest marine oil spill in US history. Few studies have evaluated the potential health effects of this spill on the Gulf Coast community. The Women and Their Children’s Health (WaTCH) study is a prospective cohort designed to investigate the midterm to long-term physical, mental and behavioural health effects of exposure to the oil spill. Participants Women were recruited by telephone from pre-existing lists of individuals and households using an address-based sampling frame between 2012 and 2014. Baseline interviews obtained information on oil spill exposure, demographics, physical and mental health, and health behaviours. Women were also asked to provide a household roster, from which a child between 10 and 17 years was randomly selected and recruited into a child substudy. Telephone respondents were invited to participate in a home visit in which blood samples, anthropometrics and neighbourhood characteristics were measured. A follow-up interview was completed between 2014 and 2016. Findings to date 2852 women completed the baseline interview, 1231 of whom participated in the home visit, and 628 children participated in the child’s health substudy. The follow-up interview successfully reinterviewed 2030 women and 454 children. Future plans WaTCH continues to conduct follow-up surveys, with a third wave of interviews planned in 2017. Also, we are looking to enhance the collection of spatially related environmental data to facilitate assessment of health risks in the study population. In addition, opportunities to participate in behavioural interventions for subsets of the cohort have been initiated. There are ongoing studies that examine the relationship between genetic and immunological markers with mental health.

Myocardial Ischemia and Mobilization of Circulating Progenitor Cells

Background The response of progenitor cells (PCs) to transient myocardial ischemia in patients with coronary artery disease remains unknown. We aimed to investigate the PC response to exercise‐induced myocardial ischemia (ExMI) and compare it to flow mismatch during pharmacological stress testing. Methods and Results A total of 356 patients with stable coronary artery disease underwent 99mTc‐sestamibi myocardial perfusion imaging during exercise (69%) or pharmacological stress (31%). CD34+ and CD34+/chemokine (C‐X‐C motif) receptor 4 PCs were enumerated by flow cytometry. Change in PC count was compared between patients with and without myocardial ischemia using linear regression models. Vascular endothelial growth factor and stromal‐derived factor‐1α were quantified. Mean age was 63±9 years; 76% were men. The incidence of ExMI was 31% and 41% during exercise and pharmacological stress testing, respectively. Patients with ExMI had a significant decrease in CD34+/chemokine (C‐X‐C motif) receptor 4 (−18%, P=0.01) after stress that was inversely correlated with the magnitude of ischemia (r=−0.19, P=0.003). In contrast, patients without ExMI had an increase in CD34+/chemokine (C‐X‐C motif) receptor 4 (14.7%, P=0.02), and those undergoing pharmacological stress had no change. Plasma vascular endothelial growth factor levels increased (15%, P<0.001) in all patients undergoing exercise stress testing regardless of ischemia. However, the change in stromal‐derived factor‐1α level correlated inversely with the change in PC counts in those with ExMI (P=0.03), suggesting a greater decrease in PCs in those with a greater change in stromal‐derived factor‐1α level with exercise. Conclusions ExMI is associated with a significant decrease in circulating levels of CD34+/chemokine (C‐X‐C motif) receptor 4 PCs, likely attributable, at least in part, to stromal‐derived factor‐1α–mediated homing of PCs to the ischemic myocardium. The physiologic consequences of this uptake of PCs and their therapeutic implications need further investigation.

Inflammatory response to mental stress and mental stress induced myocardial ischemia

BACKGROUND Mental stress-induced myocardial ischemia (MSIMI) is associated with increased risk of adverse cardiovascular outcomes, yet the underlying mechanisms are not well understood. We measured the inflammatory response to acute laboratory mental stress in patients with coronary artery disease (CAD) and its association with MSIMI. We hypothesized that patients with MSIMI would have a higher inflammatory response to mental stress in comparison to those without ischemia. METHODS Patients with stable CAD underwent 99mTc sestamibi myocardial perfusion imaging during mental stress testing using a public speaking stressor. MSIMI was determined as impaired myocardial perfusion using a 17-segment model. Inflammatory markers including interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), matrix metallopeptidase 9 (MMP-9) and high-sensitivity C reactive protein (hsCRP) were measured at rest and 90 min after mental stress. Results were validated in an independent sample of 228 post-myocardial infarction patients. RESULTS Of 607 patients analyzed in this study, (mean age 63 ± 9 years, 76% male), 99 (16.3%) developed MSIMI. Mental stress resulted in a significant increase in IL-6, MCP-1, and MMP-9 (all p <0.0001), but not hsCRP. However, the changes in these markers were similar in those with and without MSIMI. Neither resting levels of these biomarkers, nor their changes with mental stress were significantly associated with MSIMI. Results in the replication sample were similar. CONCLUSION Mental stress is associated with acute increases in several inflammatory markers. However, neither the baseline inflammatory status nor the magnitude of the inflammatory response to mental stress over 90 min were significantly associated with MSIMI.

Neighborhood Environment Measurements and Anthropometric Indicators of Obesity: Results From the Women and Their Children’s Health (WaTCH) Study

We compared geographic information system (GIS)- and Census-based approaches for measuring the physical and social neighborhood environment at the census tract-level versus an audit approach on associations with body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR). Data were used from the 2012-2014 Women and Their Children’s Health (WaTCH) Study (n = 940). Generalized linear models were used to obtain odds ratios (ORs) for BMI (≥30 kg/m2), WC (>88 cm), and WHR (>0.85). Using an audit approach, more adverse neighborhood characteristics were associated with a higher odds of WC (OR: 1.10; 95% confidence interval [CI]: [1.05, 1.15]) and WHR (OR: 1.09; 95% CI: [1.05, 1.14]) after adjustment for age, race/ethnicity, income, and oil spill exposure. There were no significant associations between GIS- and Census-based measures with obesity in adjusted models. Quality aspects of the neighborhood environment captured by audits at the individual-level may be more relevant to obesity than physical or social aspects at the census tract-level.

Neighborhood social cohesion is associated with lower levels of interleukin-6 in African American women

INTRODUCTION Social cohesion is a positive neighborhood characteristic defined by feelings of connectedness and solidarity within a community. Studies have found significant associations between social cohesion and cardiovascular disease (CVD) risk factors and outcomes. Inflammation is one potential physiological pathway linking social cohesion to CVD development, but few studies have evaluated the relationship between social cohesion and inflammatory biomarkers. Prior research has also established that race and gender can modify the effects of neighborhood features, including social cohesion, on CVD risk factors and outcomes. This study aimed to examine the association between social cohesion and the inflammatory biomarkers interleukin-6 (IL-6) and C-reactive protein (CRP) in a cohort of African American and White women and men. MATERIALS AND METHODS Data from the Morehouse and Emory Team Up to Eliminate Health Disparities (META-Health) Study were used to assess the association between social cohesion and inflammation among African American (n = 203) and White (n = 176) adults from the Atlanta metropolitan area. Social cohesion was measured using the social cohesion subscale from the Neighborhood Health Questionnaire. Inflammatory biomarkers were measured from plasma frozen at -70 °C. Multivariable linear regression analyses were conducted, controlling for demographic, clinical, behavioral, and psychosocial factors sequentially. Interaction by race and gender was also examined. RESULTS In models adjusted for age, race, gender, and education, social cohesion was significantly associated with lower levels of IL-6 (β = -0.06, p = 0.03). There was a significant race × social cohesion interaction (p = 0.04), and a marginally significant gender × race × social cohesion interaction (p = 0.09). In race-stratified models controlling for age, gender, and education, social cohesion was associated with lower IL-6 levels in African Americans (β = -0.11, p = 0.01), but not Whites (β = 0.01, p = 0.91). In fully adjusted race- and gender-stratified models, social cohesion was associated with lower levels of IL-6 in African American women only (β = -0.15, p = 0.003). CRP was not associated with social cohesion in fully adjusted models. CONCLUSION The association between social cohesion and lower levels of IL-6 is modified by gender and race, with the strongest association emerging for African American women. Although the pathways through which social cohesion impacts inflammation remain unclear, it is possible that for African American women social cohesion manifests through neighborhood networks.