Plasma Metabolites and Life's Simple 7 in REGARDS

BACKGROUND

The American Heart Association's Life's Simple 7 (LS7) is a health metric that captures important factors associated with cardiovascular and cerebrovascular health. Previous studies highlight the potential of plasma metabolites to serve as a marker for lifestyle and health behavior that could be a target for stroke prevention. The objectives of this study were to identify metabolites that were associated with LS7 and incident ischemic stroke and mediate the relationship between the two.

METHODS

Targeted metabolomic profiling of 162 metabolites by liquid chromatography-tandem mass spectrometry was used to identify candidate metabolites in a stroke case-cohort nested within the REGARDS study (Reasons for Geographic and Racial Differences in Stroke). Weighted linear regression and weighted Cox proportional hazard models were used to identify metabolites that were associated with LS7 and incident ischemic stroke, respectively. Effect measures were based on a 1-SD change in metabolite level. Metabolite mediators were examined using inverse odds ratio weighting mediation analysis.

RESULTS

The study comprised 1075 ischemic stroke cases and 968 participants in the random cohort sample. Three out of 162 metabolites were associated with the overall LS7 score including guanosine (β, -0.46 [95% CI, -0.65 to -0.27]; P=2.87×10-6), cotinine (β, -0.49 [95% CI, -0.70 to -0.28]; P=7.74×10-6), and acetylneuraminic acid (β, -0.59 [95% CI, -0.77 to -0.42]; P=4.29×10-11). Guanosine (hazard ratio, 1.47 [95% CI, 1.31-1.65]; P=6.97×10-11), cotinine (hazard ratio, 1.30 [95% CI, 1.16-1.44]; P=2.09×10-6), and acetylneuraminic acid (hazard ratio, 1.29 [95% CI, 1.15-1.45]; P=9.24×10-6) were associated with incident ischemic stroke. The mediation analysis identified guanosine (27% mediation, indirect effect; P=0.002), cotinine (30% mediation, indirect effect; P=0.004), and acetylneurminic acid (22% mediation, indirect effect; P=0.041) partially mediated the relationship between LS7 and ischemic stroke.

CONCLUSIONS

We identified guanosine, cotinine, and acetylneuraminic acid that were associated with LS7, incident ischemic stroke, and mediated the relationship between LS7 and ischemic stroke.

Comparative Discrimination of Life's Simple 7 and Life's Essential 8 to Stratify Cardiovascular Risk: Is the Added Complexity Worth It?

BACKGROUND

Life's Simple 7 (LS7) is an easily calculated and interpreted metric of cardiovascular health based on 7 domains: smoking, diet, physical activity, body mass index, blood pressure, cholesterol, and fasting glucose. The Life's Essential 8 (LE8) metric was subsequently introduced, adding sleep metrics and revisions of the previous 7 domains. Although calculating LE8 requires additional information, we hypothesized that it would be a more reliable index of cardiovascular health.

METHODS

Both the LS7 and LE8 metrics yield scores with higher values indicating lower risk. These were calculated among 11 609 Black and White participants free of baseline cardiovascular disease (CVD) in the Reasons for Geographic and Racial Differences in Stroke study, enrolled in 2003 to 2007, and followed for a median of 13 years. Differences in 10-year risk of incident CVD (coronary heart disease or stroke) were calculated as a function LS7, and LE8 scores were calculated using Kaplan-Meier and proportional hazards analyses. Differences in incident CVD discrimination were quantified by difference in the c-statistic.

RESULTS

For both LS7 and LE8, the 10-year risk was approximately 5% for participants around the 99th percentile of scores, and a 4× higher 20% risk for participants around the first percentile. Comparing LS7 to LE8, 10-year risk was nearly identical for individuals at the same relative position in score distribution. For example, the "cluster" of 2013 participants with an LS7 score of 7 was at the 35.8th percentile in distribution of LS7 scores, and had an estimated 10-year CVD risk of 8.4% (95% CI, 7.2%-9.8%). In a similar location in the LE8 distribution, the 1457 participants with an LE8 score of 60±2.5 at the 39.4th percentile of LE8 scores had a 10-year risk of CVD of 8.5% (95% CI, 7.1%-10.1%), similar to the cluster defined by LS7. The age-race-sex adjusted c-statistic of the LS7 model was 0.691 (95% CI, 0.667-0.705), and 0.695 for LE8 (95% CI, 0.681-0.709) (P for difference, 0.12).

CONCLUSIONS

Both LS7 and LE8 were associated with incident CVD, with discrimination of the 2 indices practically indistinguishable. As a simpler metric, LS7 may be favored for use by the general population and clinicians.

Long-term exposure to air pollution and risk of stroke by ecoregions: The REGARDS study

Several cohort studies have found associations between long-term exposure to air pollution and stroke risk. However, it is unclear whether the surrounding ecology may modify these associations. This study evaluates associations of air pollution with stroke risk by ecoregions, which are areas of similar type, quality, and quantity of environmental resources in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study. We assessed the incidence of stroke in 26,792 participants (45+ yrs) from the REGARDS study, a prospective cohort recruited across the contiguous United States. One-yr and 3-yr means of PM2.5, PM10, O3, NO2, SO2, and CO were estimated at baseline using data from the Center for Air, Climate, & Energy Solution, and assigned to participants at the census block group level. Incident stroke was ascertained through September 30, 2020. Relations of air pollutants with the risk of incident stroke were estimated using Cox proportional hazards models, adjusting for relevant demographics, behavioral risk factors, and neighborhood urbanicity. Models were stratified by EPA designated ecoregions. A 5.4 μg/m3 (interquartile range) increase in 1-yr PM10 was associated with a hazard ratio (95 %CI) for incident stroke of 1.07 (1.003, 1.15) in the overall study population. We did not find evidence of positive associations for PM2.5, O3, NO2, SO2, and CO in the fully adjusted models. In our ecoregion-specific analysis, associations of PM2.5 with stroke were stronger in the Great Plains ecoregion (HR = 1.44) than other ecoregions, while associations for PM10 were strongest in the Eastern Temperate Forests region (HR = 1.15). The associations between long-term exposure to air pollution and risk of stroke varied by ecoregion. Our results suggests that the type, quality, and quantity of the surrounding ecology can modify the effects of air pollution on risk of stroke.

Cytokines, C-Reactive Protein, and Risk of Incident Hypertension in the REGARDS Study

BACKGROUND

Hypertension is a highly prevalent cardiovascular disease risk factor that may be related to inflammation. Whether adverse levels of specific inflammatory cytokines relate to hypertension is unknown. The present study sought to determine whether higher levels of IL (interleukin)-1β, IL-6, TNF (tumor necrosis factor)-α, IFN (interferon)-γ, IL-17A, and CRP (C-reactive protein) are associated with a greater risk of incident hypertension.

METHODS

The REGARDS study (Reasons for Geographic and Racial Difference in Stroke) is a prospective cohort study that recruited 30 239 community-dwelling Black and White adults from the contiguous United States in 2003 to 2007 (visit 1), with follow-up 9 years later in 2013 to 2016 (visit 2). We included participants without prevalent hypertension who attended follow-up 9 years later and had available laboratory measures and covariates of interest. Poisson regression estimated the risk ratio of incident hypertension by level of inflammatory biomarkers.

RESULTS

Among 1866 included participants (mean [SD] aged of 62 [8] years, 25% Black participants, 55% women), 36% developed hypertension. In fully adjusted models comparing the third to first tertile of each biomarker, there was a greater risk of incident hypertension for higher IL-1β among White (1.24 [95% CI, 1.01-1.53]) but not Black participants (1.01 [95% CI, 0.83-1.23]) and higher TNF-α (1.20 [95% CI, 1.02-1.41]) and IFN-γ (1.22 [95% CI, 1.04-1.42]) among all participants. There was no increased risk with IL-6, IL-17A, or CRP.

CONCLUSIONS

Higher levels of IL-1β, TNF-α, and IFN-γ, representing distinct inflammatory pathways, are elevated in advance of hypertension development. Whether modifying these cytokines will reduce incident hypertension is unknown.

Associations between dietary habits, socio-demographics and gut microbial composition in adolescents

The relationship between dietary habits and microbiota composition during adolescence has not been well examined. This is a crucial knowledge gap to fill considering that diet-microbiota interactions influence neurodevelopment, immune system maturation and metabolic regulation. This study examined the associations between diet and the gut microbiota in a school-based sample of 136 adolescents (Mage = 12·1 years; age range 11-13 years; 48 % female; 47 % Black, 38 % non-Hispanic White, 15 % Hispanic or other minorities) from urban, suburban and rural areas in the Southeast USA. Adolescents completed the Rapid Eating Assessment for Participants and provided stool samples for 16S ribosomal RNA gene sequencing. Parents reported their child and family socio-demographic characteristics. The associations between diet and socio-demographics with gut microbiota diversity and abundance were analysed using multivariable regression models. Child race and ethnicity, sex, socio-economic status and geographic locale contributed to variation within microbiota composition (β-diversity). Greater consumption of processed meat was associated with a lower microbial α-diversity after adjusting for socio-demographic variables. Multi-adjusted models showed that frequent consumption of nutrient-poor, energy-dense foods (e.g. sugar-sweetened beverages, fried foods, sweets) was negatively associated with abundances of genera in the family Lachnospiraceae (Anaerostipes, Fusicatenibacter and Roseburia), which are thought to play a beneficial role in host health through their production of short-chain fatty acids (SCFAs). These results provide new insights into the complex relationships among socio-demographic factors, diet and gut microbiota during adolescence. Adolescence may represent a critical window of opportunity to promote healthy eating practices that shape a homoeostatic gut microbiota with life-long benefits.

Changes in Adiposity and Cognitive Function in Older Adults: The REGARDS Study

OBJECTIVES

Adiposity may have a role in the risk of dementia. Fewer studies have focused on the relationship between change in adiposity and cognitive decline. Our study aimed to explore the association between the change in adiposity and cognitive function in Black and White older adults.

METHODS

The participants were 12,204 older adults without cognitive impairment (62.8 ± 8.0 years) in the United States. The percent body mass index change (%BMI change) and percent waist circumference change (%WC change) were measured at 2 in-home visits (first: 2003-2007, second: 2013-2016). Cognitive status was assessed by the Six-Item Screener annually. Memory and executive function were measured by word list learning, MOCA recall and orientation, and letter and animal fluency every 2 years. Logistic regression or linear regression models were used to estimate the relationship between percent change in adiposity and cognitive function.

RESULTS

After 12.7 ± 1.7 years, a greater decrease in %BMI change or %WC change was significantly associated with a higher risk of cognitive impairment. Compared to older adults with -5% ≤ change ≤ 5% from baseline, a significantly higher risk of cognitive impairment and greater loss in memory and executive function were found among those who experienced more than a 10% decline in %BMI change or %WC change. Older adults who experienced a 5%-10% decrease in %BMI change had a higher risk of cognitive impairment and greater loss of memory compared to those with -5% ≤ change ≤ 5%.

DISCUSSION

A greater decrease in %BMI (>5%) and %WC (>10%) change was associated with greater cognitive loss observed over time.

Interleukin-6, Diabetes, and Metabolic Syndrome in a Biracial Cohort: The Reasons for Geographic and Racial Differences in Stroke Cohort

OBJECTIVE

Black Americans have a greater risk of type 2 diabetes than White Americans. The proinflammatory cytokine interleukin-6 (IL-6) is implicated in diabetes pathogenesis, and IL-6 levels are higher in Black individuals. This study investigated associations of IL-6 with incident diabetes and metabolic syndrome in a biracial cohort.

RESEARCH DESIGN AND METHODS

The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study enrolled 30,239 Black and White adults age ≥45 years in 2003-2007, with a follow-up ∼9.5 years later. Baseline plasma IL-6 was measured in 3,399 participants at risk of incident diabetes and 1,871 at risk of metabolic syndrome. Relative risk (RR) by IL-6 was estimated with modified Poisson regression for both groups.

RESULTS

Incident diabetes occurred in 14% and metabolic syndrome in 20%; both rates rose across IL-6 quartiles. There was a three-way interaction of IL-6, race, and central adiposity for incident diabetes (P = 8 × 10-5). In Black participants with and without central adiposity, RRs were 2.02 (95% CI 1.00-4.07) and 1.66 (1.00-2.75) for the fourth compared with first IL-6 quartile, respectively. The corresponding RRs were 1.73 (0.92-3.26) and 2.34 (1.17-4.66) in White participants. The pattern was similar for IL-6 and metabolic syndrome.

CONCLUSIONS

Although IL-6 was higher in Black than in White participants and those with central adiposity, the association of IL-6 with diabetes risk was statistically significant only among White participants without central adiposity. The association with metabolic syndrome risk was similarly stronger in low-risk groups. The results support the concept of interventions to lower inflammation in diabetes prevention, but to reduce race disparities, better biomarkers are needed.

Tubule dysfunction and injury and future risk of sepsis-associated acute kidney injury

BACKGROUND

Novel biomarkers can quantify both kidney tubule function, including proximal tubule reabsorptive (urine α-1 microglobulin (uα1m)) and tubule protein synthesis capacities (urine uromodulin (uUMOD)), and tubular injury (urine neutrophil gelatinase-associated lipocalin (uNGAL)). In a blood pressure trial, we reported that lower reabsorptive and synthetic protein capacity at times of health predicted future risk of acute kidney injury (AKI), but most AKI was related to hemodynamic causes in this trial. Associations between tubular function and injury and future AKI related to other causes is unknown.

MATERIALS AND METHODS

We performed a case-control study in REGARDS, a population-based cohort study, among participants who provided urine at the baseline visit. We matched each septic AKI case by age, sex, race, and time from baseline to hospital admission 1 : 1 to a participant with sepsis who did not develop AKI (controls). Using conditional logistic regression, we evaluated the associations of uα1m, uUMOD, urine ammonium, and uNGAL with septic AKI.

RESULTS

Mean age was 69 ± 8 years, 44% were female, and 39% were Black participants. Median baseline eGFR among cases and controls was 73 (55, 90) and 82 (65, 92) mL/min/1.73m2, and median albuminuria was 19 (8, 87) vs. 9 (5, 22) mg/g, respectively. No independent associations were observed between the tubule function or injury markers and subsequent risk of septic AKI once models were adjusted for baseline albuminuria, estimated glomerular filtration rate, and other risk factors.

CONCLUSION

Among community participants, tubule function and injury markers at times of health were not independently associated with future risk of septic AKI.

Neighborhood Disadvantage and Risk of Heart Failure: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

BACKGROUND

Heart failure (HF) affects >6 million US adults, with recent increases in HF hospitalizations. We aimed to investigate the association between neighborhood disadvantage and incident HF events and potential differences by diabetes status.

METHODS

We included 23 645 participants from the REGARDS study (Reasons for Geographic and Racial Differences in Stroke), a prospective cohort of Black and White adults aged ≥45 years living in the continental United States (baseline 2005-2007). Neighborhood disadvantage was assessed using a Z score of 6 census tract variables (2000 US Census) and categorized as quartiles. Incident HF hospitalizations or HF-related deaths through 2017 were adjudicated. Multivariable-adjusted Cox regression was used to examine the association between neighborhood disadvantage and incident HF. Heterogeneity by diabetes was assessed using an interaction term.

RESULTS

The mean age was 64.4 years, 39.5% were Black adults, 54.9% females, and 18.8% had diabetes. During a median follow-up of 10.7 years, there were 1125 incident HF events with an incidence rate of 3.3 (quartile 1), 4.7 (quartile 2), 5.2 (quartile 3), and 6.0 (quartile 4) per 1000 person-years. Compared to adults living in the most advantaged neighborhoods (quartile 1), those living in neighborhoods in quartiles 2, 3, and 4 (most disadvantaged) had 1.30 (95% CI, 1.06-1.60), 1.36 (95% CI, 1.11-1.66), and 1.45 (95% CI, 1.18-1.79) times greater hazard of incident HF even after accounting for known confounders. This association did not significantly differ by diabetes status (interaction P=0.59). For adults with diabetes, the adjusted incident HF hazards comparing those in quartile 4 versus quartile 1 was 1.34 (95% CI, 0.92-1.96), and it was 1.50 (95% CI, 1.16-1.94) for adults without diabetes.

CONCLUSIONS

In this large contemporaneous prospective cohort, neighborhood disadvantage was associated with an increased risk of incident HF events. This increase in HF risk did not differ by diabetes status. Addressing social, economic, and structural factors at the neighborhood level may impact HF prevention.

A cross-sectional study observing the association of psychosocial stress and dietary intake with gut microbiota genera and alpha diversity among a young adult cohort of black and white women in Birmingham, Alabama

BACKGROUND

The relationships between psychosocial stress and diet with gut microbiota composition and diversity deserve ongoing investigation. The primary aim of this study was to examine the associations of psychosocial stress measures and dietary variables with gut microbiota genera abundance and alpha diversity among young adult, black and white females. The secondary aim was to explore mediators of psychosocial stress and gut microbiota diversity and abundance.

METHODS

Data on 60 females who self-identified as African American (AA; n = 29) or European American (EA; n = 31) aged 21-45 years were included. Cortisol was measured in hair and saliva, and 16S analysis of stool samples were conducted. Discrimination experiences (recent and lifetime), perceived stress, and depression were evaluated based on validated instruments. Spearman correlations were performed to evaluate the influence of psychosocial stressors, cortisol measures, and dietary variables on gut microbiota genus abundance and alpha diversity measured by amplicon sequence variant (ASV) count. Mediation analyses assessed the role of select dietary variables and cortisol measures on the associations between psychosocial stress, Alistipes and Blautia abundance, and ASV count.

RESULTS

AA females were found to have significantly lower ASV count and Blautia abundance. Results for the spearman correlations assessing the influence of psychosocial stress and dietary variables on gut microbiota abundance and ASV count were varied. Finally, diet nor cortisol was found to partially or fully mediate the associations between subjective stress measures, ASV count, and Alistipes and Blautia abundance.

CONCLUSION

In this cross-sectional study, AA females had lower alpha diversity and Blautia abundance compared to EA females. Some psychosocial stressors and dietary variables were found to be correlated with ASV count and few gut microbiota genera. Larger scale studies are needed to explore the relationships among psychosocial stress, diet and the gut microbiome.

Stroke Severity, Caregiver Feedback, and Cognition in the REGARDS-CARES Study

Objective

Cognitive impairment after stroke is common, present up to 60% of survivors. Stroke severity, indicated by both volume and location, is the most consequential predictor of cognitive impairment, with severe strokes predicting higher chances of cognitive impairment. The current investigation examines the associations of two stroke severity ratings and a caregiver-report of post-stroke functioning with longitudinal cognitive outcomes.

Methods

The analysis was conducted on 157 caregivers and stroke survivor dyads who participated in the Caring for Adults Recovering from the Effects of Stroke (CARES) project, an ancillary study of the REasons for Geographic and Racial Differences in Stroke (REGARDS) national cohort study. Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) collected at hospitalization discharge were included as two primary predictors of cognitive impairment. The number of caregiver-reported problems and impairments at nine months following stroke were included as a third predictor. Cognition was assessed using a biennial telephone battery, incorporating multiple cognitive assessments to assess learning, memory, and executive functioning. Longitudinal cognitive scores were analyzed up to five years post-stroke, controlling for baseline (pre-stroke) cognitive scores and demographic variables of each stroke survivor collected at CARES baseline.

Results

Separate mixed models showed significant main effects of GOS (b=0.3280, p=0.0009), mRS (b=-0.2119, p=0.0002), and caregiver-reported impairments (b=-0.0671, p<0.0001) on longitudinal cognitive scores. In a combined model including all three predictors, only caregiver-reported problems significantly predicted cognitive outcomes (b=-0.0480, p<0.0001).

Impact

These findings underscore the importance of incorporating caregivers feedback in understanding cognitive consequences of stroke.

A Segmented Regression Analysis of Household Income and Recurrent Falls Among Adults in a National Cohort Study

Falls can have life-altering consequences for older adults, including extended recovery periods and compromised independence. Higher household income may mitigate the risk of falls by providing financial resources for mobility tools, remediation of environmental hazards, and needed supports, or it may buffer the impact of an initial fall on subsequent risk through improved assistance and care. Household income has not had a consistently observed association with falls in older adults; however, a segmented association may exist such that associations are attenuated above a certain income threshold. In this study, we utilized segmented negative binomial regression analysis to examine the association between household income and recurrent falls among 2,302 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study recruited between 2003 and 2007. Income-fall association segments separated by changes in slope were considered. Model results indicated a 2-segment association between household income and recurrent falls in the past year. In the range below the breakpoint, household income was negatively associated with the rate of recurrent falls across all age groups examined; in a higher income range (from $20,000-$49,999 to ≥$150,000), the association was attenuated (weaker negative trend) or reversed (positive trend). These findings point to potential benefits of ensuring that incomes for lower-income adults exceed the threshold needed to confer a reduced risk of recurrent falls.

Closing the Last Mile Gap in Access to Multimodality Imaging in Rural Settings: Design of the Imaging Core of the Risk Underlying Rural Areas Longitudinal Study

Achieving optimal cardiovascular health in rural populations can be challenging for several reasons including decreased access to care with limited availability of imaging modalities, specialist physicians, and other important health care team members. Therefore, innovative solutions are needed to optimize health care and address cardiovascular health disparities in rural areas. Mobile examination units can bring imaging technology to underserved or remote communities with limited access to health care services. Mobile examination units can be equipped with a wide array of assessment tools and multiple imaging modalities such as computed tomography scanning and echocardiography. The detailed structural assessment of cardiovascular and lung pathology, as well as the detection of extracardiac pathology afforded by computed tomography imaging combined with the functional and hemodynamic assessments acquired by echocardiography, yield deep phenotyping of heart and lung disease for populations historically underrepresented in epidemiological studies. Moreover, by bringing the mobile examination unit to local communities, innovative approaches are now possible including engagement with local professionals to perform these imaging assessments, thereby augmenting local expertise and experience. However, several challenges exist before mobile examination unit-based examinations can be effectively integrated into the rural health care setting including standardizing acquisition protocols, maintaining consistent image quality, and addressing ethical and privacy considerations. Herein, we discuss the potential importance of cardiac multimodality imaging to improve cardiovascular health in rural regions, outline the emerging experience in this field, highlight important current challenges, and offer solutions based on our experience in the RURAL (Risk Underlying Rural Areas Longitudinal) cohort study.

Hepatocyte growth factor and risk of incident stroke in Black and White Americans in the Reasons for Geographic and Racial Differences in Stroke study

Background

Hepatocyte growth factor (HGF) is a cytokine produced in response to endothelial damage. Higher levels correlate with cardiovascular risk factors, including hypertension and diabetes.

Objectives

We hypothesized that HGF is associated with stroke.

Methods

The Reasons for Geographic And Racial Differences in Stroke (REGARDS) study enrolled 30,239 Black and White Americans aged ≥45 years from 2003 to 2007. In this case-cohort study, after 5.5 years of follow-up, circulating baseline HGF was measured in 557 participants with incident ischemic stroke and in a cohort random sample of 964 participants. Hazard ratios (HRs) per SD log-transformed HGF and by HGF quintile were calculated using Cox proportional hazards models adjusting for stroke risk factors and other correlates of HGF. Differences by race and sex were tested using interaction terms.

Results

Median HGF was 295 (IQR, 209-402) pg/mL. HGF was higher with older age, male sex, prevalent cardiovascular disease, smoking, and warfarin use, but did not differ by race. The adjusted HR of incident ischemic stroke per SD higher baseline HGF (145 pg/mL) was 1.30 (CI, 1.00-1.70), with no difference by sex or race. HGF in the highest (>434 pg/mL) vs lowest quintile (<135 pg/mL) was associated with an adjusted HR of incident stroke of 2.12 (CI, 1.31-3.41).

Conclusion

In the REGARDS study, higher HGF was associated with increased risk of incident ischemic stroke in Black and White adults, with a doubling in risk of HGF in the top quintile compared with the lowest quintile after adjusting for other stroke risk factors.

Age and sex differences in the association between neighborhood socioeconomic environment and incident diabetes: Results from the diabetes location, environmental attributes and disparities (LEAD) network

Objective

Worse neighborhood socioeconomic environment (NSEE) may contribute to an increased risk of type 2 diabetes (T2D). We examined whether the relationship between NSEE and T2D differs by sex and age in three study populations.

Research design and methods

We conducted a harmonized analysis using data from three independent longitudinal study samples in the US: 1) the Veteran Administration Diabetes Risk (VADR) cohort, 2) the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort, and 3) a case-control study of Geisinger electronic health records in Pennsylvania. We measured NSEE with a z-score sum of six census tract indicators within strata of community type (higher density urban, lower density urban, suburban/small town, and rural). Community type-stratified models evaluated the likelihood of new diagnoses of T2D in each study sample using restricted cubic splines and quartiles of NSEE.

Results

Across study samples, worse NSEE was associated with higher risk of T2D. We observed significant effect modification by sex and age, though evidence of effect modification varied by site and community type. Largely, stronger associations between worse NSEE and diabetes risk were found among women relative to men and among those less than age 45 in the VADR cohort. Similar modification by age group results were observed in the Geisinger sample in small town/suburban communities only and similar modification by sex was observed in REGARDS in lower density urban communities.

Conclusions

The impact of NSEE on T2D risk may differ for males and females and by age group within different community types.

Strong protective effect of the APOL1 p.N264K variant against G2-associated focal segmental glomerulosclerosis and kidney disease

African Americans have a significantly higher risk of developing chronic kidney disease, especially focal segmental glomerulosclerosis -, than European Americans. Two coding variants (G1 and G2) in the APOL1 gene play a major role in this disparity. While 13% of African Americans carry the high-risk recessive genotypes, only a fraction of these individuals develops FSGS or kidney failure, indicating the involvement of additional disease modifiers. Here, we show that the presence of the APOL1 p.N264K missense variant, when co-inherited with the G2 APOL1 risk allele, substantially reduces the penetrance of the G1G2 and G2G2 high-risk genotypes by rendering these genotypes low-risk. These results align with prior functional evidence showing that the p.N264K variant reduces the toxicity of the APOL1 high-risk alleles. These findings have important implications for our understanding of the mechanisms of APOL1-associated nephropathy, as well as for the clinical management of individuals with high-risk genotypes that include the G2 allele.

Cumulative Experience of Neighborhood Walkability and Change in Weight and Waist Circumference in REGARDS

Neighborhood walkability-features of the built environment that promote pedestrian activity-has been associated with greater physical activity and lower body mass index (BMI; calculated as weight (kg)/height (m)2) among neighborhood residents. However, much of the literature has been cross-sectional and only a few cohort studies have assessed neighborhood features throughout follow-up. Using data from the Reasons for Geographic and Racial Differences in Stroke Study (2003-2016) and a neighborhood walkability index (NWI) measured annually during follow-up, we assessed whether the cumulative experience of neighborhood walkability (NWI-years) predicted BMI and waist circumference after approximately 10 years of follow-up, controlling for these anthropometric measures at enrollment. Analyses were adjusted for individual-level sociodemographic covariates and the cumulative experience of neighborhood poverty rate and neighborhood greenspace coverage. Almost a third (29%) of participants changed address at least once during follow-up. The first change of residence, on average, brought the participants to neighborhoods with higher home values and lower NWI scores than their originating neighborhoods. Compared with those having experienced the lowest quartile of cumulative NWI-years, those who experienced the highest quartile had 0.83 lower BMI (95% confidence interval, -1.5, -0.16) and 1.07-cm smaller waist circumference (95% confidence interval, -1.96, -0.19) at follow-up. These analyses provide additional longitudinal evidence that residential neighborhood features that support pedestrian activity are associated with lower adiposity.

Birth in the U.S. Plantation South and Racial Differences in all-cause mortality in later life

The American South has been characterized as a Stroke Belt due to high cardiovascular mortality. We examine whether mortality rates and race differences in rates reflect birthplace exposure to Jim Crow-era inequalities associated with the Plantation South. The plantation mode of agricultural production was widespread through the 1950s when older adults of today, if exposed, were children. We use proportional hazards models to estimate all-cause mortality in Non-Hispanic Black and White birth cohorts (1920-1954) in a sample (N = 21,941) drawn from REasons for Geographic and Racial Differences in Stroke (REGARDS), a national study designed to investigate Stroke Belt risk. We link REGARDS data to two U.S. Plantation Censuses (1916, 1948) to develop county-level measures that capture the geographic overlap between the Stroke Belt, two subregions of the Plantation South, and a non-Plantation South subregion. Additionally, we examine the life course timing of geographic exposure: at birth, adulthood (survey enrollment baseline), neither, or both portions of life. We find mortality hazard rates higher for Black compared to White participants, regardless of birthplace, and for the southern-born compared to those not southern-born, regardless of race. Race-specific models adjusting for adult Stroke Belt residence find birthplace-mortality associations fully attenuated among White-except in one of two Plantation South subregions-but not among Black participants. Mortality hazard rates are highest among Black and White participants born in this one Plantation South subregion. The Black-White mortality differential is largest in this birthplace subregion as well. In this subregion, the legacy of pre-Civil War plantation production under enslavement was followed by high-productivity plantation farming under the southern Sharecropping System.

Assessing the association between food environment and dietary inflammation by community type: a cross-sectional REGARDS study

BACKGROUND

Communities in the United States (US) exist on a continuum of urbanicity, which may inform how individuals interact with their food environment, and thus modify the relationship between food access and dietary behaviors.

OBJECTIVE

This cross-sectional study aims to examine the modifying effect of community type in the association between the relative availability of food outlets and dietary inflammation across the US.

METHODS

Using baseline data from the REasons for Geographic and Racial Differences in Stroke study (2003-2007), we calculated participants' dietary inflammation score (DIS). Higher DIS indicates greater pro-inflammatory exposure. We defined our exposures as the relative availability of supermarkets and fast-food restaurants (percentage of food outlet type out of all food stores or restaurants, respectively) using street-network buffers around the population-weighted centroid of each participant's census tract. We used 1-, 2-, 6-, and 10-mile (~ 2-, 3-, 10-, and 16 km) buffer sizes for higher density urban, lower density urban, suburban/small town, and rural community types, respectively. Using generalized estimating equations, we estimated the association between relative food outlet availability and DIS, controlling for individual and neighborhood socio-demographics and total food outlets. The percentage of supermarkets and fast-food restaurants were modeled together.

RESULTS

Participants (n = 20,322) were distributed across all community types: higher density urban (16.7%), lower density urban (39.8%), suburban/small town (19.3%), and rural (24.2%). Across all community types, mean DIS was - 0.004 (SD = 2.5; min = - 14.2, max = 9.9). DIS was associated with relative availability of fast-food restaurants, but not supermarkets. Association between fast-food restaurants and DIS varied by community type (P for interaction = 0.02). Increases in the relative availability of fast-food restaurants were associated with higher DIS in suburban/small towns and lower density urban areas (p-values < 0.01); no significant associations were present in higher density urban or rural areas.

CONCLUSIONS

The relative availability of fast-food restaurants was associated with higher DIS among participants residing in suburban/small town and lower density urban community types, suggesting that these communities might benefit most from interventions and policies that either promote restaurant diversity or expand healthier food options.

Retirement and cognitive aging in a racially diverse sample of older Americans

BACKGROUND

Retirement represents a crucial transitional period for many adults with possible consequences for cognitive aging. We examined trajectories of cognitive change before and after retirement in Black and White adults.

METHODS

Longitudinal examination of up to 10 years (mean = 7.1 ± 2.2 years) using data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study-a national, longitudinal study of Black and White adults ≥45 years of age. Data were from 2226 members of the REGARDS study who retired around the time when an occupational ancillary survey was administered. Cognitive function was an average of z-scores for tests of verbal fluency, memory, and global function.

RESULTS

Cognitive functioning was stable before retirement (Estimate = 0.05, p = 0.322), followed by a significant decline after retirement (Estimate = -0.15, p < 0.001). The decline was particularly pronounced in White (Estimate = -0.19, p < 0.001) compared with Black (Estimate = -0.07, p = 0.077) participants, twice as large in men (Estimate = -0.20, p < 0.001) compared with women (Estimate = -0.11, p < 0.001), highest among White men (Estimate = -0.22, p < 0.001) and lowest in Black women (Estimate = -0.04, p = 0.457). Greater post-retirement cognitive decline was also observed among participants who attended college (Estimate = -0.14, p = 0.016). While greater work complexity (Estimate = 0.92, p < 0.05) and higher income (Estimate = 1.03, p < 0.05) were related to better cognitive function at retirement, neither was significantly related to cognitive change after retirement.

CONCLUSION

Cognitive functioning may decline at an accelerated rate immediately post-retirement, more so in White adults and men than Black adults and women. Lifelong structural inequalities including occupational segregation and other social determinants of cognitive health may obscure the role of retirement in cognitive aging.

Strong protective effect of the APOL1 p.N264K variant against G2-associated focal segmental glomerulosclerosis and kidney disease

Black Americans have a significantly higher risk of developing chronic kidney disease (CKD), especially focal segmental glomerulosclerosis (FSGS), than European Americans. Two coding variants (G1 and G2) in the APOL1 gene play a major role in this disparity. While 13% of Black Americans carry the high-risk recessive genotypes, only a fraction of these individuals develops FSGS or kidney failure, indicating the involvement of additional disease modifiers. Here, we show that the presence of the APOL1 p.N264K missense variant, when co-inherited with the G2 APOL1 risk allele, substantially reduces the penetrance of the G1G2 and G2G2 high-risk genotypes by rendering these genotypes low-risk. These results align with prior functional evidence showing that the p.N264K variant reduces the toxicity of the APOL1 high-risk alleles. These findings have important implications for our understanding of the mechanisms of APOL1 -associated nephropathy, as well as for the clinical management of individuals with high-risk genotypes that include the G2 allele.

The association of baseline depressive symptoms and stress on withdrawal in a national longitudinal cohort: the REGARDS study

PURPOSE

To measure the association of baseline psychological symptoms (depressive symptoms and perceived stress) with withdrawal from a cohort study.

METHODS

Depressive symptoms and perceived stress were obtained using validated measures during the baseline computer-assisted telephonic interview for the REasons for Geographic and Racial Differences in Stroke study a national longitudinal cohort (≥45 years, 42% Black, 55% women) recruited between 2003 and 2007. Participants who completed follow-up after September 1, 2019, were considered active. Primary outcome was time to study withdrawal. The association of psychological symptoms and time-to-withdrawal was measured using Cox proportional hazard regression models with incremental adjustments by demographic and clinical factors.

RESULTS

Out of 29,964 participants included in the analysis, 11,111 (37.1%) participants withdrew over the follow-up period (median: 11 years). Compared to participants with low depressive symptoms, those with moderate symptoms had 5% higher risk (aHR= 1.05; 95% CI= 1.00-1.10) and those with high level of depressive had 19% higher risk (aHR= 1.19; 95% CI= 1.11-1.27) of withdrawal in fully adjusted models. No significant association between perceived stress and withdrawal risk was observed.

CONCLUSIONS

Depressive symptoms were significantly associated with withdrawal. Prevalence of depressive symptoms at baseline is an important indicator of participant retention in large prospective cohorts.

Gut microbiota-associated metabolites and risk of ischemic stroke in REGARDS

Several metabolite markers are independently associated with incident ischemic stroke. However, prior studies have not accounted for intercorrelated metabolite networks. We used exploratory factor analysis (EFA) to determine if metabolite factors were associated with incident ischemic stroke. Metabolites (n = 162) were measured in a case-control cohort nested in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, which included 1,075 ischemic stroke cases and 968 random cohort participants. Cox models were adjusted for age, gender, race, and age-race interaction (base model) and further adjusted for the Framingham stroke risk factors (fully adjusted model). EFA identified fifteen metabolite factors, each representing a well-defined metabolic pathway. Of these, factor 3, a gut microbiome metabolism factor, was associated with an increased risk of stroke in the base (hazard ratio per one-unit standard deviation, HR = 1.23; 95%CI = 1.15-1.31; P = 1.98 × 10-10) and fully adjusted models (HR = 1.13; 95%CI = 1.06-1.21; P = 4.49 × 10-4). The highest tertile had a 45% increased risk relative to the lowest (HR = 1.45; 95%CI = 1.25-1.70; P = 2.24 × 10-6). Factor 3 was also associated with the Southern diet pattern, a dietary pattern previously linked to increased stroke risk in REGARDS (β = 0.11; 95%CI = 0.03-0.18; P = 8.75 × 10-3). These findings highlight the role of diet and gut microbial metabolism in relation to incident ischemic stroke.

Risk Factors for Incident CKD in Black and White Americans: The REGARDS Study

RATIONALE & OBJECTIVE

Little information exists on the incidence of and risk factors for chronic kidney disease (CKD) in contemporary US cohorts and whether risk factors differ by race, sex, or region in the United States.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

4,198 Black and 7,799 White participants aged at least 45 years, recruited from 2003 through 2007 across the continental United States, with baseline estimated glomerular filtration rate (eGFR)>60mL/min/1.73m2 and eGFR assessed again approximately 9 years later.

EXPOSURES

Age, sex, race (Black or White), region ("stroke belt" or other), education, income, systolic blood pressure, body mass index, diabetes, coronary heart disease, hyperlipidemia, smoking, and albuminuria.

OUTCOMES

(1) eGFR change and (2) incident CKD defined as eGFR<60mL/min/1.73m2 and≥40% decrease from baseline or kidney failure.

ANALYTICAL APPROACH

Linear regression and modified Poisson regression were used to determine the association of risk factors with eGFR change and incident CKD overall and stratified by race, sex, and region.

RESULTS

Mean age of participants was 63±8 (SD) years, 54% were female, and 35% were Black. After 9.4±1.0 years of follow-up, CKD developed in 9%. In an age-, sex-, and race-adjusted model, Black race (β =-0.13; P<0.001) was associated with higher risk of eGFR change, but this was attenuated in the fully adjusted model (β=0.02; P=0.5). Stroke belt residence was independently associated with eGFR change (β =-0.10; P<0.001) and incident CKD (relative risk, 1.14 [95% CI, 1.01-1.30]). Albuminuria was more strongly associated with eGFR change (β of-0.26 vs-0.17; P=0.01 for interaction) in Black compared with White participants. Results were similar for incident CKD.

LIMITATIONS

Persons of Hispanic ethnicity were excluded; unknown duration and/or severity of risk factors.

CONCLUSIONS

Established CKD risk factors accounted for higher risk of incident CKD in Black versus White individuals. Albuminuria was a stronger risk factor for eGFR decrease and incident CKD in Black compared with White individuals. Living in the US stroke belt is a novel risk factor for CKD.

Alpha globin gene copy number and incident ischemic stroke risk among Black Americans

Introduction

People with African ancestry have greater stroke risk and greater heritability of stroke risk than people of other ancestries. Given the importance of nitric oxide (NO) in stroke, and recent evidence that alpha globin restricts nitric oxide release from vascular endothelial cells, we hypothesized that alpha globin gene (HBA) deletion would be associated with reduced risk of incident ischemic stroke.

Methods

We evaluated 8,947 participants self-reporting African ancestry in the national, prospective Reasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Incident ischemic stroke was defined as non-hemorrhagic stroke with focal neurological deficit lasting ≥ 24 hours confirmed by the medical record or focal or non-focal neurological deficit with positive imaging confirmed with medical records. Genomic DNA was analyzed using droplet digital PCR to determine HBA copy number. Multivariable Cox proportional hazards regression was used to estimate the hazard ratio (HR) of HBA copy number on time to first ischemic stroke.

Results

Four-hundred seventy-nine (5.3%) participants had an incident ischemic stroke over a median (IQR) of 11.0 (5.7, 14.0) years' follow-up. HBA copy number ranged from 2 to 6: 368 (4%) -α/-α, 2,480 (28%) -α/αα, 6,014 (67%) αα/αα, 83 (1%) ααα/αα and 2 (<1%) ααα/ααα. The adjusted HR of ischemic stroke with HBA copy number was 1.04; 95%CI 0.89, 1.21; p = 0.66.

Conclusions

Although a reduction in HBA copy number is expected to increase endothelial nitric oxide signaling in the human vascular endothelium, HBA copy number was not associated with incident ischemic stroke in this large cohort of Black Americans.

Dietary patterns in rural and metropolitan Australia: a cross-sectional study exploring dietary patterns, inflammation and association with cardiovascular disease risk factors

OBJECTIVES

This study sought first to empirically define dietary patterns and to apply the novel Dietary Inflammation Score (DIS) in data from rural and metropolitan populations in Australia, and second to investigate associations with cardiovascular disease (CVD) risk factors.

DESIGN

Cross-sectional study.

SETTING

Rural and metropolitan Australia.

PARTICIPANTS

Adults over the age of 18 years living in rural or metropolitan Australia who participated in the Australian Health survey.

PRIMARY OUTCOMES

A posteriori dietary patterns for participants separated into rural and metropolitan populations using principal component analysis.

SECONDARY OUTCOMES

association of each dietary pattern and DIS with CVD risk factors was explored using logistic regression.

RESULTS

The sample included 713 rural and 1185 metropolitan participants. The rural sample was significantly older (mean age 52.7 compared with 48.6 years) and had a higher prevalence of CVD risk factors. Two primary dietary patterns were derived from each population (four in total), and dietary patterns were different between the rural and metropolitan areas. None of the identified patterns were associated with CVD risk factors in metropolitan or rural areas, aside diet pattern 2 being strongly associated with from self-reported ischaemic heart disease (OR 13.90 95% CI 2.29 to 84.3) in rural areas. There were no significant differences between the DIS and CVD risk factors across the two populations, except for a higher DIS being associated with overweight/obesity in rural areas.

CONCLUSION

Exploration of dietary patterns between rural and metropolitan Australia shows differences between the two populations, possibly reflective of distinct cultures, socioeconomic factors, geography, food access and/or food environments in the different areas. Our study provides evidence that action targeting healthier dietary intakes needs to be tailored to rurality in the Australian context.

Association of Circulating Metabolites With Racial Disparities in Hypertension and Stroke in the REGARDS Study

BACKGROUND AND OBJECTIVES

In the United States, the risk of stroke is greater among Black compared with that among White individuals. However, the reasons for the difference in stroke incidence are not fully elucidated. We aimed to identify metabolites that account for higher prevalent hypertension and incident ischemic stroke among Black adults.

METHODS

We used a stroke case cohort nested within the REasons for Geographic and Racial Differences in Stroke (REGARDS) study. Targeted metabolomic profiling of 162 plasma metabolites was performed by liquid chromatography-tandem mass spectrometry. We identified metabolites that were associated with prevalent hypertension and incident ischemic stroke and mediated the relationship between hypertension and ischemic stroke by weighted logistic regression, Cox proportional hazard model, and inverse odds ratio weighting mediation analysis.

RESULTS

Incident ischemic stroke cases adjudicated through April 1, 2019 (n = 1,075) were included in the study. The random cohort sample was derived from the full cohort using stratified sampling (n = 968). Among 162 metabolites, gluconic acid was associated with prevalent hypertension in Black adults (odds ratio [OR] 1.86, 95% CI 1.39-2.47, p = 2.58 × 10-5) but not in White adults (OR 1.00, 95% CI 0.80-1.24, p = 0.97; p for interaction = 4.57 × 10-4). Gluconic acid also demonstrated an association with incident ischemic stroke among Black participants (hazard ratio [HR] 1.53, 95% CI 1.28-1.81, p = 1.76 × 10-6) but not White participants (HR 1.16, 95% CI 1.00-1.34, p = 0.057; p for interaction = 0.019). In mediation analysis, gluconic acid mediated 25.4% (95% CI 4.1%-46.8%, p = 0.02) of the association between prevalent hypertension and incident ischemic stroke among Black individuals. Specific socioeconomic factors were linked to elevated gluconic acid level among Black adults in multivariable analysis, including a Southern dietary pattern (β = 0.18, 95% CI 0.08-0.28, p < 0.001), lower educational attainment (β = 0.45, 95% CI 0.19-0.72, p = 0.001), and a lack of exercise (β = 0.26, 95% CI 0.01-0.51, p = 0.045).

DISCUSSION

Gluconic acid is associated with prevalent hypertension and incident ischemic stroke and mediates the relationship between hypertension and ischemic stroke in Black but not White adults. Gluconic acid is a biomarker that is associated with social determinants of health including a Southern diet, low educational attainment, and low physical activity.

Alpha globin gene copy number and incident ischemic stroke risk among Black Americans

Introduction

People with African ancestry have greater stroke risk and greater heritability of stroke risk than people of other ancestries. Given the importance of nitric oxide (NO) in stroke, and recent evidence that alpha globin restricts nitric oxide release from vascular endothelial cells, we hypothesized that alpha globin gene ( HBA) deletion would be associated with reduced risk of incident ischemic stroke.

Methods

We evaluated 8,947 participants self-reporting African ancestry in the national, prospective Reasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Incident ischemic stroke was defined as non-hemorrhagic stroke with focal neurological deficit lasting ≥ 24 hours confirmed by the medical record or focal or non-focal neurological deficit with positive imaging confirmed with medical records. Genomic DNA was analyzed using droplet digital PCR to determine HBA copy number. Multivariable Cox proportional hazards regression was used to estimate the hazard ratio (HR) of HBA copy number on time to first ischemic stroke.

Results

Four-hundred seventy-nine (5.3%) participants had an incident ischemic stroke over a median (IQR) of 11.0 (5.7, 14.0) years' follow-up. HBA copy number ranged from 2 to 6: 368 (4%) -α/-α, 2,480 (28%) -α/αα, 6,014 (67%) αα/αα, 83 (1%) ααα/αα and 2 (<1%) ααα/ααα. The adjusted HR of ischemic stroke with HBA copy number was 1.04; 95%CI 0.89, 1.21; p = 0.66.

Conclusions

Although a reduction in HBA copy number is expected to increase endothelial nitric oxide signaling in the human vascular endothelium, HBA copy number was not associated with incident ischemic stroke in this large cohort of Black Americans.

Dietary Patterns, Apolipoprotein L1 Risk Genotypes, and CKD Outcomes Among Black Adults in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study

Rationale & Objective

Dietary factors may impact inflammation and interferon production, which could influence phenotypic expression of Apolipoprotein1 (APOL1) genotypes. We investigated whether associations of dietary patterns with kidney outcomes differed by APOL1 genotypes.

Study Design

Prospective cohort.

Settings & Participants

5,640 Black participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS).

Exposures

Five dietary patterns derived from food frequency questionnaires: Convenience foods, Southern, Sweets and Fats, Plant-based, and Alcohol/Salads.

Outcomes

Incident chronic kidney disease (CKD), CKD progression, and kidney failure. Incident CKD was defined as a change in estimated glomerular filtration rate (eGFR) to <60 mL/min/1.73 m2 accompanied by a ≥25% decline from baseline eGFR or development of kidney failure among those with baseline eGFR ≥60 mL/1.73 m2 body surface area. CKD progression was defined as a composite of 40% reduction in eGFR from baseline or development of kidney failure in the subset of participants who had serum creatinine levels at baseline and completed a second in-home visit/follow-up visit.

Analytical Approach

We examined associations of dietary pattern quartiles with incident CKD (n=4,188), CKD progression (n=5,640), and kidney failure (n=5,640). We tested for statistical interaction between dietary patterns and APOL1 genotypes for CKD outcomes and explored stratified analyses by APOL1 genotypes.

Results

Among 5,640 Black REGARDS participants, mean age was 64 years (standard deviation = 9), 35% were male, and 682 (12.1%) had high-risk APOL1 genotypes. Highest versus lowest quartiles (Q4 vs Q1) of Southern dietary pattern were associated with higher adjusted odds of CKD progression (OR, 1.28; 95% CI, 1.01-1.63) but not incident CKD (OR, 0.92; 95% CI, 0.74-1.14) or kidney failure (HR, 1.48; 95% CI, 0.90-2.44). No other dietary patterns showed significant associations with CKD. There were no statistically significant interactions between APOL1 genotypes and dietary patterns. Stratified analysis showed no consistent associations across genotypes, although Q3 and Q4 versus Q1 of Plant-based and Southern patterns were associated with lower odds of CKD progression among APOL1 high- but not low-risk genotypes.

Limitations

Included overlapping dietary patterns based on a single time point and multiple testing.

Conclusions

In Black REGARDS participants, Southern dietary pattern was associated with increased risk of CKD progression. Analyses stratified by APOL1 genotypes suggest associations may differ by genetic background, but these findings require confirmation in other cohorts.

Nonalcoholic fatty liver disease and cognitive impairment: A prospective cohort study

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is prevalent and may affect cognitive function. We studied associations of NAFLD with risk of cognitive impairment. Secondarily we evaluated liver biomarkers (alanine aminotransferase (ALT), aspartate aminotransferase (AST), their ratio, and gamma-glutamyl transpeptidase).

METHODS

In a prospective cohort study, the REasons for Geographic and Racial Differences in Stroke, among 30,239 black and white adults aged ≥45,495 cases of incident cognitive impairment were identified over 3.4 years follow up. Cognitive impairment was identified as new impairment in two of three cognitive tests administered every two years during follow up; word list learning and recall, and verbal fluency. 587 controls were selected from an age, race, sex-stratified sample of the cohort. The fatty liver index was used to define baseline NAFLD. Liver biomarkers were measured using baseline blood samples.

RESULTS

NAFLD at baseline was associated with a 2.01-fold increased risk of incident cognitive impairment in a minimally adjusted model (95% CI 1.42, 2.85). The association was largest in those aged 45-65 (p interaction by age = 0.03), with the risk 2.95-fold increased (95% CI 1.05, 8.34) adjusting for cardiovascular, stroke and metabolic risk factors. Liver biomarkers were not associated with cognitive impairment, except AST/ALT >2, with an adjusted OR 1.86 (95% CI 0.81, 4.25) that did not differ by age.

CONCLUSIONS

A laboratory-based estimate of NAFLD was associated with development of cognitive impairment, particularly in mid-life, with a tripling in risk. Given its high prevalence, NAFLD may be a major reversible determinant of cognitive health.

Age-Related Differences in the Role of Risk Factors for Ischemic Stroke

BACKGROUND AND OBJECTIVES

Reports assessing the association of stroke risk factors with incident stroke have generally assumed a uniform magnitude of associations across the age spectrum, an assumption we assess in this report.

METHODS

Participants enrolled 2003-2007 in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort study who were stroke free at baseline were followed for incident stroke. Associations of traditional stroke risk factors with incident stroke were assessed using (1) proportional hazards analysis based on the baseline age of the participant and (2) Poisson regression analysis assessing associations based on the changing age of the participant during their follow-up (age at exposure). In each analysis, age strata were selected to have a similar number of strokes in each stratum, specifically 45-64, 65-73, and 74+ years for the proportional hazards analysis and 45-69, 70-79, and 80+ years for Poisson regression.

RESULTS

A total of 1,405 ischemic stroke events occurred among 28,235 participants over a median follow-up of 11.3 years, with a total of 276,074 person-years exposure. For both analytic approaches, the magnitude of the association with stroke was significantly less at older ages for diabetes (hazard or relative risk decreasing from ≈2.0 in younger strata to ≈1.3 in older strata), heart disease (from ≈2.0 to ≈1.3), and hypertension defined at a threshold of 140/90 mm Hg (from ≈1.80 to ≈1.50); however, there was no age-related difference in the magnitude of the association for smoking, atrial fibrillation, or left ventricular hypertrophy.

DISCUSSION

Hypertension and diabetes are 2 of the more important risk factors for stroke; however, their association with stroke risk appears substantially less at older ages. That the magnitude of the association for smoking, atrial fibrillation, and left ventricular hypertrophy does not decrease with age suggests their relative importance in determining stroke risk likely increases with age.

Abstract 68: Interleukin-6, Diabetes and Metabolic Syndrome in a Biracial Cohort: The Reasons for Geographic and Racial Differences in Stroke (REGARDS)

Background: Type 2 diabetes mellitus (DM) is more common in Black than White adults in the US. The inflammatory cytokine interleukin-6 (IL-6) is implicated in DM pathogenesis and circulates at higher levels in Black people. Metabolic syndrome (MetS), a group of conditions related to insulin resistance, often precedes or coexists with DM. Little evidence is available on associations of IL-6 with these disorders in Black people.

Methods: REGARDS enrolled 30,239 Black and White adults in 2003-07 and conducted a follow up visit 9.5 years later. Baseline IL-6 was measured in a sample of 4,400 participants (equal by race/sex groups) attending both visits. Modified Poisson regression estimated relative risk (RR) by level of baseline IL-6 for incident DM among those without prevalent DM; similar analyses were conducted for MetS. Inverse odds weighting estimated the percent mediation of the racial disparity in incident DM by IL-6.

Results: Incident DM occurred in 460/3,399 (14%) at risk, and there were 384/1,957 (20%) cases of incident MetS. As shown in the Figure , DM and MetS incidence increased across baseline IL-6 quartiles overall, with a steeper rise and higher incidence among Black than White adults. Adjusting for confounders, the RR of DM for IL-6 in the 4 th vs 1 st quartile was 1.91 (95% CI 1.38-2.65). Higher IL-6 was also associated with MetS (RR 1.65 (95% CI 1.22-2.22)). In adjusted models there were no material differences in these associations by race. The RR of DM in Black compared with White people was 1.90 (95% CI 1.59-2.27); there was no association of race with MetS. IL-6 significantly mediated 13.4% of the racial disparity in DM adjusting for demographic factors.

Conclusions: Higher IL-6 is a risk factor for incident DM and MetS in Black and White adults. The race disparity in DM was partly mediated by IL-6. Interventions to reduce IL-6 may lower risk of DM and MetS and lessen the racial disparity in DM.

Figure: Diabetes and Metabolic Syndrome Incidence (bars) and Relative Risk (95% CI) by Baseline IL-6 Quartile

Abstract P602: Complete Blood Count Analysis in the Risk Underlying Rural Areas Longitudinal (RURAL) Cohort Study With a Point of Care Instrument

Background: The RURAL cohort study is a uniquely designed study using a Mobile Examination Unit (MEU) to study heart and lung disorders in rural counties in the southeastern US. Complete blood counts (CBC) are included in the participant baseline examination. We wanted to use an instrument in the MEU for onsite blood counts and chose the Pixcell Hemoscreen, a point-of-care instrument using a unique technology. Before using the Hemoscreen in the RURAL study, it was necessary to ensure that the CBC results would be comparable to laboratory generated results.

Methods: We compared CBC results from the Hemoscreen to those from the Sysmex XN9000 at the University of Vermont Medical Center. CBC measurements include erythrocyte count (RBC), white blood cell count (WBC), hemoglobin concentration (HGB), hematocrit value (HCT), and platelet count (PLT). Blood from ten volunteers was analyzed on the Hemoscreen and the Sysmex. Statistics included average, standard deviation, and coefficient of variance (CV) for each of the parameters analyzed. Blood from ten volunteers was assayed on both the Hemoscreen and the Sysmex to compare for accuracy. Blood from three volunteers was analyzed ten times on the Hemoscreen to assess variability.

Results: The Hemoscreen and Sysmex reported similar values for WBC, RBC, HCT, HGB and PLT counts, as shown in Figure 1. Between repeat measures conducted on the same sample on the Hemoscreen WBC, RBC, HCT, HGB and PLT showed little variance (%CV = 5.9, 2.7, 2.8, 2.7, and 4.0 respectively).

Conclusions: The Hemoscreen data correlated with data generated in a hospital laboratory on the same samples. Variability between multiple measures of the same samples on the Hemoscreen showed acceptable variance. To date over 730 RURAL participants have been seen and the Hemoscreen has proven to be quick, accurate, and reliable.

Abstract P381: Factor VIII and Incident Hypertension in Black and White Adults: The REasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study

Background: Black adults have a disproportionate hypertension burden. While some excess risk is mediated by diet and sociodemographics factors (e.g., income, education) much remains unexplained. Pro-thrombotic and pro-inflammatory states are associated with hypertension risk; higher coagulation factor VIII (FVIII) is associated with thrombosis, inflammation, and cardiovascular disease. Black adults have higher FVIII than White adults. We sought to estimate incident hypertension risk among Black and White REGARDS adults by FVIII level, and determine if FVIII mediates some of the excess hypertension burden in Black REGARDS participants.

Methods: Hypertension was use of blood pressure (BP)-lowering medications or 140/90 mm Hg BP threshold. We included Black and White participants from REGARDS without Visit 1 (2003-2007) hypertension, and hypertension assessment at visit 2 (2013-2016), and Visit 1 ELISA-measured FVIII. Modified Poisson regression estimated risk ratios (RR) of incident hypertension by FVIII level in models controlling for known confounders, stratified by race given a significant race*FVIII interaction on incident hypertension. Inverse odds ratio weighting estimated % mediation of the Black-White hypertension risk in each model that was due to FVIII.

Results: Among the 1,870 included participants, mean (SD) age was 62 (8), 51% were female and 36% were Black participants. Relative to White participants, Black participants had higher mean FVIII level (114% vs. 103%; P<0.001) and 46% greater hypertension risk (95% CI 30-65%) in the crude model. Higher FVIII did not associate with greater hypertension risk in any model ( Figure ). Factor VIII did not mediate excess burden of hypertension among Black participants in any models.

Conclusions: FVIII was not associated with greater hypertension risk and did not mediate any of the excess burden of incident hypertension seen among Black participants.

Abstract P356: Does Out-Migration Contribute to Poorer Health in Rural Communities? An Investigation Using Mortality in the US

People living in poor rural communities, particularly in the South, live shorter and less healthy lives than those residing elsewhere in the United States. The basis of this very high rural burden of heart, lung, and blood disease, which does not spare any race, is unclear. We hypothesized that a potential contribution to this phenomenon is differential selection of healthy individuals to migrate out of rural communities. We examined how county-level migration patterns relate to county-level mortality with a specific focus on rural counties. We compiled nationally representative county-level data migration data from Internal Revenue Services for years 2011-2019 and mortality data from National Center for Health Statistics at the Centers for Disease Control and Prevention for years 2018-2019. We standardized characteristics to a mean=0 and standard deviation=1 and modeled county-level age-adjusted death rate in 2019 using 2-level hierarchical linear regression. Out- and in-migration in 2019 was not significantly associated with age-adjusted death rate in 2019 after adjustment for social, economic and population factors at the county-level. However, when stratified by 6 categories of urban/rural, greater out-migration in the smallest rural counties (non-core) was associated with higher age-adjusted death rate after adjustment for other county factors [Beta (95% CI); 7.2 (0.11,14.28)] (Table 1). When including lagged out-migration rates for years prior to 2019, previous out-migration was associated with age-adjusted death rate in the second smallest rural county categorization (micropolitan). These findings help to ascertain another component potentially contributing to differentially poorer health in rural communities. Future work at the conference will further evaluate decade trends in migration across the US by county.

Abstract P150: Residential Segregation and Hypertension Risk in Black and White Americans

Introduction: Black adults experience the highest hypertension burden of any American group. Evidence indicates social factors adversely affecting Black people explain some of the excess hypertension burden. It’s unclear whether residential segregation, a key cause of health inequities, has a differential impact on Black and White people.

Hypothesis: The magnitude of the association of residential segregation and risk of incident hypertension will be greater in Black than White people.

Methods: Our sample included 6,143 Black and White REasons for Geographic And Racial Differences in Stroke (REGARDS) study participants without prevalent hypertension (2003-7), and with a follow-up visit 9.3 years later. Baseline county-level segregation was measured with the (1) dissimilarity index (DI, the difference in race distribution of census tracts relative to their county), (2) isolation index (ISI, the degree to which Black people are exposed only to one another in a county), and (3) interaction index (ITI, the degree to which Black people are exposed to White people in a county). Modified Poisson regression estimated the risk ratios (RR) of incident hypertension per SD increment of baseline residential segregation.

Results: The mean (SD) age was 61(8) years for Black people and 62(8) years for White people. Hypertension incidence was 46% for Black people and 33% for White people. There was no

association of any of the three measures of residential segregation (DI, ISI and ITI) with incident hypertension, with RRs all around 1.0 ( Figure ).

Conclusions: Three measures of residential segregation were not associated with incident hypertension risk in Black and White participants of the REGARDS cohort. Findings differ from a previous study that reported that a measure of racial clustering was associated with higher risk of hypertension in Black people. Taken together, findings suggest that, in Black people, different domains of residential segregation capture factors related differently to hypertension development.

Using publicly available data to identify priority communities for a SARS-CoV-2 testing intervention in a southern U.S. state

Background

The U.S. Southeast has a high burden of SARS-CoV-2 infections and COVID-19 disease. We used public data sources and community engagement to prioritize county selections for a precision population health intervention to promote a SARS-CoV-2 testing intervention in rural Alabama during October 2020 and March 2021.

Methods

We modeled factors associated with county-level SARS-CoV-2 percent positivity using covariates thought to associate with SARS-CoV-2 acquisition risk, disease severity, and risk mitigation practices. Descriptive epidemiologic data were presented to scientific and community advisory boards to prioritize counties for a testing intervention.

Results

In October 2020, SARS-CoV-2 percent positivity was not associated with any modeled factors. In March 2021, premature death rate (aRR 1.16, 95% CI 1.07, 1.25), percent Black residents (aRR 1.00, 95% CI 1.00, 1.01), preventable hospitalizations (aRR 1.03, 95% CI 1.00, 1.06), and proportion of smokers (aRR 0.231, 95% CI 0.10, 0.55) were associated with average SARS-CoV-2 percent positivity. We then ranked counties based on percent positivity, case fatality, case rates, and number of testing sites using individual variables and factor scores. Top ranking counties identified through factor analysis and univariate associations were provided to community partners who considered ongoing efforts and strength of community partnerships to promote testing to inform intervention.

Conclusions

The dynamic nature of SARS-CoV-2 proved challenging for a modelling approach to inform a precision population health intervention at the county level. Epidemiological data allowed for engagement of community stakeholders implementing testing. As data sources and analytic capacities expand, engaging communities in data interpretation is vital to address diseases locally.

Abstract 83: Racial Disparities In Gluconic Acid, A Lifestyle-related Biomarker Associated With Stroke In REGARDS

Introduction: In the United States, the risk of stroke is greater among Black compared to White adults. Furthermore, hypertension has a greater impact on stroke risk among Black adults. We hypothesized that race-specific metabolites may account for some of this observed disparity.

Methods: This was a case-cohort study nested in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study. Incident ischemic stroke cases (n=1,075) were compared with a random cohort sample (n=968). Metabolites were measured by liquid chromatography-tandem mass spectrometry. Weighted logistic regression and Cox proportional hazard model were used to identify race-specific metabolites in association with prevalent hypertension and incident stroke respectively. Candidate metabolites were assessed for mediation between hypertension and incident ischemic stroke. Linear regression was used to explore the association of metabolites with lifestyle factors.

Results: A total of 162 plasma metabolites were quantified. Of these, gluconic acid was associated with prevalent hypertension in Black adults (OR=1.86, 95% CI=1.39-2.47, P =2.58x10 -5 ) but not in White adults (OR=1.00, 95% CI=0.80-1.24, P =0.97; P for interaction=4.57x10 -4 ). Gluconic acid was also associated with incident ischemic stroke among Black adults (HR=1.53, 95% CI=1.28-1.81, P =1.76x10 -6 ) but not White adults (HR=1.16, 95% CI=1.00-1.34, P =0.057; P for interaction=0.019). Gluconic acid mediated 25.4% (95% CI=4.1%-46.8%, P =0.02) of the association between hypertension and ischemic stroke among Black adults. Specific lifestyle factors were linked to elevated gluconic acid level among Black adults in multivariable analysis, including a Southern diet (β=0.18, 95% CI=0.08-0.28, P <0.001), lower educational attainment (β=0.45, 95% CI=0.19-0.72, P =0.001), and lack of exercise (β=0.26, 95% CI=0.01-0.51, P =0.045).

Conclusions: Gluconic acid is a lifestyle-related biomarker that is associated with prevalent hypertension, incident ischemic stroke, and mediates the relationship between hypertension and ischemic stroke in Black adults. Key factors linked to gluconic acid include Southern diet, low educational attainment, and low physical activity.

Duration of employment within occupations and incident stroke in a US general population cohort 45 years of age or older (REGARDS study)

BACKGROUND

The work environment can contribute to the risk of cardiovascular diseases (CVD) including stroke. Our objective was to identify occupations with elevated risk of stroke within the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort.

METHODS

We analyzed incident stroke outcomes (ischemic and hemorrhagic strokes) from 2003 to 2020 and employment characteristics of 13,659 adults aged ≥45 years enrolled in a national population-based cohort study. Using a modified Poisson regression approach, we estimated the relative risks (RRs) and the associated 95% confidence intervals (CI) of stroke in relation to years of employment within each occupation coded using the US Census two-digit Standard Occupation Code. Models were adjusted for Framingham Stroke Risk Score, region, race, age, and body mass index. We conducted stratified analysis by sex, employment time period (pre-1975 vs. post-1975), and region.

RESULTS

Workers in the following occupations had a greater risk of stroke with longer duration of employment (per decade): protective service (RR: 2.35, 95% CI: 1.11, 4.97), food preparation and service (RR: 1.51, 95% CI: 1.05, 2.19), and transportation and material moving (RR: 1.30, 95% CI: 1.00, 1.69). The stroke risk in these occupations was disproportionately elevated in men, and differed by region and employment time period.

CONCLUSIONS

Longer employment in protective service, food preparation and serving, and transportation and materials moving occupations may increase the risk of stroke. Surveillance may uncover specific work-related risk factors in these occupations, leading to interventions to reduce the burden of stroke among US workers.

Predictive Accuracy of Stroke Risk Prediction Models Across Black and White Race, Sex, and Age Groups

Importance

Stroke is the fifth-highest cause of death in the US and a leading cause of serious long-term disability with particularly high risk in Black individuals. Quality risk prediction algorithms, free of bias, are key for comprehensive prevention strategies.

Objective

To compare the performance of stroke-specific algorithms with pooled cohort equations developed for atherosclerotic cardiovascular disease for the prediction of new-onset stroke across different subgroups (race, sex, and age) and to determine the added value of novel machine learning techniques.

Design, Setting, and Participants

Retrospective cohort study on combined and harmonized data from Black and White participants of the Framingham Offspring, Atherosclerosis Risk in Communities (ARIC), Multi-Ethnic Study for Atherosclerosis (MESA), and Reasons for Geographical and Racial Differences in Stroke (REGARDS) studies (1983-2019) conducted in the US. The 62 482 participants included at baseline were at least 45 years of age and free of stroke or transient ischemic attack.

Exposures

Published stroke-specific algorithms from Framingham and REGARDS (based on self-reported risk factors) as well as pooled cohort equations for atherosclerotic cardiovascular disease plus 2 newly developed machine learning algorithms.

Main Outcomes and Measures

Models were designed to estimate the 10-year risk of new-onset stroke (ischemic or hemorrhagic). Discrimination concordance index (C index) and calibration ratios of expected vs observed event rates were assessed at 10 years. Analyses were conducted by race, sex, and age groups.

Results

The combined study sample included 62 482 participants (median age, 61 years, 54% women, and 29% Black individuals). Discrimination C indexes were not significantly different for the 2 stroke-specific models (Framingham stroke, 0.72; 95% CI, 0.72-073; REGARDS self-report, 0.73; 95% CI, 0.72-0.74) vs the pooled cohort equations (0.72; 95% CI, 0.71-0.73): differences 0.01 or less (P values >.05) in the combined sample. Significant differences in discrimination were observed by race: the C indexes were 0.76 for all 3 models in White vs 0.69 in Black women (all P values <.001) and between 0.71 and 0.72 in White men and between 0.64 and 0.66 in Black men (all P values ≤.001). When stratified by age, model discrimination was better for younger (<60 years) vs older (≥60 years) adults for both Black and White individuals. The ratios of observed to expected 10-year stroke rates were closest to 1 for the REGARDS self-report model (1.05; 95% CI, 1.00-1.09) and indicated risk overestimation for Framingham stroke (0.86; 95% CI, 0.82-0.89) and pooled cohort equations (0.74; 95% CI, 0.71-0.77). Performance did not significantly improve when novel machine learning algorithms were applied.

Conclusions and Relevance

In this analysis of Black and White individuals without stroke or transient ischemic attack among 4 US cohorts, existing stroke-specific risk prediction models and novel machine learning techniques did not significantly improve discriminative accuracy for new-onset stroke compared with the pooled cohort equations, and the REGARDS self-report model had the best calibration. All algorithms exhibited worse discrimination in Black individuals than in White individuals, indicating the need to expand the pool of risk factors and improve modeling techniques to address observed racial disparities and improve model performance.

D-dimer and the risk of hypertension: The REasons for Geographic And Racial Differences in Stroke Cohort Study

Background

Reasons for increased risk of hypertension in Black compared with White people are only partly understood. D-dimer, a thrombo-inflammatory marker higher in Black individuals, is also higher in people with hypertension. However, the impact of D-dimer on racial disparities in risk of incident hypertension has not been studied.

Objectives

To assess whether D-dimer is associated with the risk of incident hypertension, whether the association between D-dimer and the risk of incident hypertension differs by race, and whether the biology reflected by D-dimer explains racial disparities in the risk of incident hypertension.

Methods

This study included 1867 participants in the REasons for Geographic And Racial Differences in Stroke cohort study without baseline hypertension and with a second visit 9.4 years after baseline. Risk ratios of incident hypertension by baseline D-dimer level were estimated, a D-dimer-by-race interaction was tested, and the mediating effect of D-dimer (which represents underlying biological processes) on the association of race and hypertension risk was assessed.

Results

The risk of incident hypertension was 47% higher in persons in the top quartile than in those in the bottom quartile of D-dimer (risk ratio [RR]: 1.47; 95% CI: 1.23-1.76). The association was partly attenuated after adjusting for sociodemographic and adiposity-related risk factors (RR: 1.22; 95% CI: 1.02-1.47). The association of D-dimer and hypertension did not differ by race, and D-dimer did not attenuate the racial difference in the risk of incident hypertension.

Conclusion

D-dimer concentration reflects pathophysiology related to the development of hypertension. Specific mechanisms require further study and may involve adiposity.

Lipid accumulation product, visceral adiposity index and risk of chronic kidney disease

BACKGROUND

Lipid accumulation product (LAP) and visceral adiposity index (VAI) are novel, non-imaging markers of visceral adiposity that are calculated by using body mass index (BMI), waist circumference (WC) and serum lipid concentrations. We hypothesized that LAP and VAI are more strongly associated with adverse kidney outcomes than BMI and WC.

METHODS

Using data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, we used multivariable logistic regression to evaluate associations of LAP, VAI, BMI and WC with incident chronic kidney disease (CKD), (incident eGFR < 60 ml/min/1.73m2 and > 25% decline).

RESULTS

Among the overall cohort of 27,550 participants, the mean baseline age was 65 years; 54% were women; and 41% were African American. After a median of 9.4 years (IQR 8.6, 9.9) of follow-up, a total of 1127 cases of incident CKD were observed. Each two-fold higher value of VAI (OR 1.12, 95% CI 1.04, 1.20), LAP (OR 1.21, 95% CI 1.13, 1.29), WC (OR 2.10, 95% CI 1.60, 2.76) and BMI (OR: 2.66, 95% CI 1.88, 3.77), was associated with greater odds of incident CKD.

CONCLUSIONS

LAP and VAI as measures of visceral adiposity are associated with higher odds of incident CKD but may not provide information beyond WC and BMI.

Inflammation biomarkers and incident coronary heart disease: the Reasons for Geographic And Racial Differences in Stroke Study

BACKGROUND

Individual inflammation biomarkers are associated with incident coronary heart disease (CHD) events. However, there is limited research on whether the risk for incident CHD is progressively higher with a higher number of inflammation biomarkers in abnormal levels.

METHODS

We used data from 15,758 Reasons for Geographic and Racial Differences in Stroke (REGARDS) study participants aged ≥45 years without a history of CHD at baseline in 2003-2007. Abnormal levels of baseline high-sensitivity C-reactive protein, leukocyte count and serum albumin were defined as ≥3.8 mg/L (3rd tertile), ≥6.3 x 10⁹ cells/L (3rd tertile), and <4.0 g/dL (1st tertile), respectively. The outcome was a composite of incident myocardial infarction or CHD death.

RESULTS

Overall, 38.9% (n = 6,123) had 0, 36.6% (n = 5,774) had 1, 19.8% (n = 3,113) had 2 and 4.7% (n = 748) had 3 biomarkers of inflammation in abnormal levels. Over a median follow-up of 11.4 years, 954 (6.1%) participants had incident CHD. The rate of incident CHD per 1000 person-years for individuals with 0, 1, 2, and 3 biomarkers of inflammation in abnormal levels was 4.4 (95% confidence interval [CI]: 3.9-5.0), 6.3 (95% CI: 5.6-6.9), 8.8 (95% CI: 7.8-9.9), and 10.6 (95% CI: 8.1-13.1), respectively. Multi-variable adjusted hazard ratios for incident CHD associated with 1, 2 and 3 versus no inflammation biomarker in abnormal levels were 1.26 (95% CI: 1.07-1.49), 1.72 (95% CI: 1.43-2.07), and 1.84 (95% CI: 1.37-2.47), respectively (P-trend < .001).

CONCLUSIONS

The number of inflammation markers in abnormal levels was associated with increased risk of incident CHD after multi-variable adjustment.

Differences in the Association of Select Dietary Measures With Risk of Incident Type 2 Diabetes

OBJECTIVE

To evaluate associations between a broad range of approaches to classifying diet and incident type 2 diabetes in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study.

RESEARCH DESIGN AND METHODS

This study included 8,750 Black and White adults without diabetes at baseline. Diabetes was defined according to fasting glucose ≥70 mmol/L, random glucose ≥111 mmol/L, or use of diabetes medications. The exposures were diet scores for Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), dietary inflammatory index (DII), dietary inflammation score (DIS), and empirical dietary patterns (plant-based and Southern) determined using data collected with use of the Block98 food-frequency questionnaire. Modified Poisson regression was used to assess association of dietary measures with risk of incident type 2 diabetes, with models adjusted for total energy intake, demographics, lifestyle factors, and waist circumference.

RESULTS

There were 1,026 cases of incident type 2 diabetes during follow-up (11.7%). Adherence to the Southern dietary pattern was most strongly associated with risk of incident type 2 diabetes after adjustment for demographics and lifestyle (quintile [Q]5 vs. lowest Q1: risk ratio [RR] 1.95; 95% CI 1.57, 2.41). Of the diet scores, DIS (Q5 vs. Q1 RR 1.41) and MIND (Q1 vs. Q5 RR 1.33), demonstrated anti-inflammatory diets, had strongest associations with lower diabetes incidence.

CONCLUSIONS

We found associations of several dietary approaches with incident type 2 diabetes. Investigation into mechanisms driving the association with the Southern dietary pattern is warranted. Further research into use of DIS, DII, and MIND diet score should be considered for dietary recommendations for diabetes prevention.

SMOC2 gene interacts with APOL1 in the development of end-stage kidney disease: A genome-wide association study

Background

Some but not all African-Americans (AA) who carry APOL1 nephropathy risk variants (APOL1) develop kidney failure (end-stage kidney disease, ESKD). To identify genetic modifiers, we assessed gene-gene interactions in a large prospective cohort of the REasons for Geographic and Racial Differences in Stroke (REGARDS) study.

Methods

Genotypes from 8,074 AA participants were obtained from Illumina Infinium Multi-Ethnic AMR/AFR Extended BeadChip. We compared 388 incident ESKD cases with 7,686 non-ESKD controls, using a two-locus interaction approach. Logistic regression was used to examine the effect of APOL1 risk status (using recessive and additive models), single nucleotide polymorphism (SNP), and APOL1^*SNP interaction on incident ESKD, adjusting for age, sex, and ancestry. APOL1 ^*SNP interactions that met the threshold of 1.0 × 10^-5 were replicated in the Genetics of Hypertension Associated Treatment (GenHAT) study (626 ESKD cases and 6,165 controls). In a sensitivity analysis, models were additionally adjusted for diabetes status. We conducted additional replication in the BioVU study.

Results

Two APOL1 risk alleles prevalence (recessive model) was similar in the REGARDS and GenHAT studies. Only one APOL1-SNP interaction, for rs7067944 on chromosome 10, ~10 KB from the PCAT5 gene met the genome-wide statistical threshold (P _interaction = 3.4 × 10^-8), but this interaction was not replicated in the GenHAT study. Among other relevant top findings (with P _interaction < 1.0 × 10^-5), a variant (rs2181251) near SMOC2 on chromosome six interacted with APOL1 risk status (additive) on ESKD outcomes (REGARDS study, P _interaction =5.3 × 10^-6) but the association was not replicated (GenHAT study, P _interaction = 0.07, BioVU study, P _interaction = 0.53). The association with the locus near SMOC2 persisted further in stratified analyses. Among those who inherited ≥1 alternate allele of rs2181251, APOL1 was associated with an increased risk of incident ESKD (OR [95%CI] = 2.27[1.53, 3.37]) but APOL1 was not associated with ESKD in the absence of the alternate allele (OR [95%CI] = 1.34[0.96, 1.85]) in the REGARDS study. The associations were consistent after adjusting for diabetes.

Conclusion

In a large genome-wide association study of AAs, a locus SMOC2 exhibited a significant interaction with the APOL1 locus. SMOC2 contributes to the progression of fibrosis after kidney injury and the interaction with APOL1 variants may contribute to an explanation for why only some APOLI high-risk individuals develop ESKD.

Growth hormone concentration and risk of all-cause and cardiovascular mortality: The REasons for Geographic And Racial Disparities in Stroke (REGARDS) study

BACKGROUND AND AIMS

Identifying individuals at elevated risk for mortality, especially from cardiovascular disease, may help guide testing and treatment. Risk factors for mortality differ by sex and race. We investigated the association of growth hormone (GH) with all-cause and cardiovascular mortality in a racially diverse cohort in the United States.

METHODS

Among an age, sex and race stratified subgroup of 1046 Black and White participants from the REasons for Geographic And Racial Disparities in Stroke (REGARDS) study, 881 had GH available; values were log₂ transformed. Associations with all-cause and cardiovascular mortality were assessed in the whole subgroup, and by sex and race, using multivariable Cox-proportional hazard models and C-index.

RESULTS

The mean age was 67.4 years, 51.1% were women, and 50.2% were Black participants. The median GH was 280 (interquartile range 79-838) ng/L. There were 237 deaths and 74 cardiovascular deaths over a mean of 8.0 years. In multivariable Cox analysis, GH was associated with higher risk of all-cause mortality per doubling (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.09-1.25) and cardiovascular mortality (HR 1.21, 95% CI 1.06-1.37). The association did not differ by sex or race (interaction p > 0.05). The addition of GH to a model of clinical variables significantly improved the C-index compared to clinical model alone for all-cause and cardiovascular death.

CONCLUSIONS

Higher fasting GH was associated with higher risk of all-cause and cardiovascular mortality and improved risk prediction, regardless of sex or race.

Abstract P079: Leptin And Risk Of Incident Hypertension In The Reasons For Geographic And Racial Differences In Stroke (REGARDS) Cohort Study

Background: Leptin is an anorexigenic and sympathoexcitatory adipokine strongly associated with obesity and associated with hypertension in animal models. Whether leptin is associated with hypertension incidence independent of obesity is unclear.

Methods: REGARDS recruited 30,239 Black or White adults aged ≥45 years recruited from 48 US contiguous states in 2003-07 with a second visit in 2013-16. Baseline serum leptin was measured by ELISA in a sex- and race-stratified sample of 4,400 REGARDS participants. Modified Poisson regression estimated relative risk (RR) of incident hypertension (140/90 mm Hg threshold or use of antihypertensives) per higher leptin tertile, stratified by a BMI of 30 kg/m 2 , adjusting for known confounders.

Results: Among the 1,834 participants without prevalent hypertension (mean [SD] age 62, 56% women, 25% Black adults), median follow-up was 9 years. Incident hypertension developed in 35%. BMI significantly modified the relationship between leptin and incident hypertension (P-interaction <0.001) such that higher leptin was associated with greater hypertension risk in the crude model among those with BMI <30, but not ≥30, kg/m 2 ( Figure ). This association was fully attenuated when adjusting for waist circumference and BMI.

Conclusions: Leptin is associated with hypertension among normal weight but not obese adults in REGARDS. Adiposity may be on the causal pathway between leptin levels and obesity.

Abstract P078: Excess Risk Of Hypertension Among Black Adults And The Mediating Effects Of Leptin: The Reasons For Geographic And Racial Differences In Stroke (REGARDS) Cohort Study

Background: Leptin is a hypertension-related adipokine. We previously found leptin to associate with greater risk of incident hypertension in non-obese adults. Relative to White adults, Black adults have higher circulating leptin concentration. As such, leptin may be a mediator of the excess burden of incident hypertension among Black adults.

Methods: REGARDS recruited 30,239 Black or White adults aged ≥45 years from 48 US states. Leptin was measured from baseline samples among 4,400 participants who attended 2 visits 9 years apart. Modified Poisson regression estimated the relative risk (RR) of incident hypertension (≥140/90 mmHg or use of antihypertensives) of Black relative to White adults, adjusting for risk factors. Inverse odds ratio weighting estimated the % mediation by leptin of the excess hypertension RR among Black relative to White participants in 1,000 bootstrapped samples.

Results: In 1,834 participants without prevalent hypertension (mean age 62, 56% women, 25% Black adults), incident hypertension developed in 47% of Black & 32% of White participants. The Table presents the RR for incident hypertension among Black relative to White adults. In the crude model, Black adults had a 52% greater risk of incident hypertension and leptin mediated 20% of this disparity. Similar associations were seen when adjusting for demographics, behaviors, and diseases. After adjusting for measures of adiposity, leptin no longer mediated the disparity.

Conclusions: Leptin mediated approximately 20% of the Black-White disparity in hypertension incidence in crude and some adjusted models. These data support that this mediation acts through adiposity.

Enhanced Street Crossing Features are Associated with Higher Post-Stroke Physical Quality of Life

BACKGROUND

Features of the physical environment may affect post-stroke recovery, but empirical evidence is limited. This study examines associations between features of the physical environment and post-stroke physical quality of life (PH-QOL).

METHODS

The study sample included stroke survivors enrolled in the Caring for Adults Recovering from the Effects of Stroke project, a prospective cohort. Features of the physical environment surrounding participants' home addresses were audited using Google Earth. Audits captured information about crossings (e.g. curb-cuts; range 0-4), street segments (e.g. sidewalks; range 0-17.5), and a route (e.g. parks; range 0-27) near participants' home. Summary scores were categorized into tertials representing "few," "some," and "many" pedestrian-friendly features. Post-stroke PH-QOL was measured by the SF-12 (range 0-100) around 6 to 12-, 18-, 27-, and 36-months post-stroke. Linear mixed models were used to estimate PH-QOL over time. Chained multiple imputation was used to account for missing data.

RESULTS

Two hundred and seventy-five participants were eligible, among whom 210 had complete data. Most participants lived in areas with "few" features to promote outdoor mobility. Participants living in environments with "some" crossing features had a 4.90 (95% CI: 2.32, 7.48) higher PH-QOL score across the observation period in comparison to participants living in environments with "few" crossing features. Features of the physical environment along street segments and routes were not associated with post-stroke PH-QOL.

CONCLUSION

Crossing features are associated with post-stroke PH-QOL. Modifying features of the physical environment at nearby crossings, such as curb-cuts, may be a promising strategy for increasing PH-QOL.