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.

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

BACKGROUND

Nearly half of all Americans have hypertension, and Black adults experience a disproportionate burden. Hypercoagulability may relate to hypertension risk, and higher levels of factor VIII increase thrombosis risk. Black adults have higher factor VIII and more hypertension than other groups. Whether higher factor VIII associates with incident hypertension is unknown.

METHODS

The Biomarkers as Mediators of Racial Disparities in Risk Factors (BioMedioR) study measured certain biomarkers in a sex-race stratified sample of 4,400 REGARDS participants who attended both visits. We included BioMedioR participants, excluding those with prevalent hypertension, missing factor VIII level, or covariates of interest. Modified Poisson regression estimated risk ratios (RR) for incident hypertension by higher log-transformed factor VIII level per SD (SD of log-transformed factor VIII, 0.33). Weighting was applied to take advantage of REGARDS sampling design.

RESULTS

Among the 1,814 participants included (55% female, 24% Black race), median follow-up was 9.5 years and 35% (2,146/6,138) developed hypertension. Black participants had a higher median (IQR) factor VIII level (105.6%; 87.1 to 126.9%) than White participants (95.6%; 79.8% to 115.9%; p<0.001). . The age and sex-adjusted Black-White hypertension RR was 1.45 (95% CI 1.28, 1.63). Higher factor VIII was not associated with more hypertension (final model RR 1.01; 95% CI 0.94, 1.07).

CONCLUSIONS

In a prospective study of Black and White adults without prevalent hypertension, factor VIII was not associated with greater hypertension risk.

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.

Urban-rural differences in hypertension prevalence, blood pressure control, and systolic blood pressure levels

Higher rates of cardiovascular events have been observed among rural residents compared with urban. Hypertension and lack of blood pressure (BP) control are risk factors for cardiovascular events. We compared the prevalence of hypertension and controlled BP, and the distribution of systolic blood pressure (SBP), by urban-rural residence. Participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, a prospective cohort of Black and White adults aged ≥45 years, were categorized as either urban, large rural, or small-isolated rural, by using the Rural-Urban Commuting Area (RUCA) categorization B system. Oucomes were hypertension prevalence (BP ≥ 140/90 mmHg or antihypertensive use), BP control (BP < 140/90 among participants on antihypertensive medication), and the distribution of SBP. Counfounders were age, race, sex, antihypertensive medication use, and US Census Bureau division. The analysis included 26,133 participants (80.3% urban, 11.6% large-rural, 8.2% small-isolated rural). The unadjusted prevalence of hypertension was not different between groups. However, after adjustment, the odds of hypertension was higher among participants in the large rural group (odds ratio [OR] 1.17; 95% confidence interval [CI], 1.08-1.27) and small-isolated rural group (OR 1.19; 95% CI, 1.08-1.30), compared with the urban group. There was no evidence of an adjusted difference in BP control for those taking antihypertensive medications. Adjusted differences in SBP were greater for both rural groups, compared with urban, at the higher percentiles of SBP. Rural residence was associated with a higher adjusted odds of hypertension and higher SBP.

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 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 MP57: Coagulation Factor IX and Incident Diabetes Risk: The REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Introduction: A prothrombotic state is implicated in the vascular complications of type 2 diabetes (DM), and such complications disproportionately affect Black compared to White adults. However, it is not known if this is due to DM or whether coagulation factor levels are related to DM incidence. Higher coagulation factor IX (FIX) was related to increased risk of CHD and stroke among Black but not White participants in the REGARDS cohort. We hypothesized higher FIX antigen would be associated with incident DM risk, with stronger relationships in Black versus White adults.

Methods: REGARDS enrolled 30,239 Black and White adults from across the contiguous US from 2003-2006 with a second in-home visit from 2013-2016. The Biomarkers as MEDiators of Racial Disparities in Risk Factors (BioMedioR) nested cohort study included 4,400 participants who completed both visits, balanced on race and sex. Modified Poisson regression models estimated the RR of incident DM per 1-SD increment log FIX. We tested for a FIX-by-race interaction a priori due to differential associations of FIX with CHD and stroke by race in REGARDS.

Results: Among 3,381 participants without baseline DM (mean age 63 years, 44% Black race, 51% women), 456 (13.5%) developed incident DM over 9.5-years. Adjusting for age, sex, and race, there was a significant difference in the association of FIX with DM by race (p-interaction<0.01). As shown in the Figure, adjusted for age and sex (Model 1), the RR (95% CI) for incident DM was 1.19 (1.05, 1.34) for Black adults and 1.49 (1.23, 1.81) for White adults. Adjusting for clinical risk factors (Model 2) fully attenuated this association for Black adults, and further adjusting for behavioral factors (Model 3) fully attenuated this association for Black and White adults.

Conclusions: Higher FIX levels were associated with incident DM risk. Relationships between FIX and incident DM were stronger for White than Black adults. The FIX-DM association may be due to adverse clinical and behavioral risk factors.

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.

Abstract P623: Long-Term Mortality and Causes of Death After Venous Thromboembolism: The Atherosclerosis Risk in Communities Study

Background: Each year in the U.S, 60,000-100,000 people die of venous thromboembolism (VTE), but little is known about mortality and causes of death over the long-term after VTE.

Hypotheses: VTE, especially cancer-related VTE, is associated with poor long-term survival. Cancer and circulatory diseases are the main causes of death after VTE.

Methods: Atherosclerosis Risk in Communities (ARIC) cohort participants, free of VTE at baseline (n=15,516), were followed (1986-2019) to identify first-time VTE (classified as unprovoked, cancer-provoked, or other-provoked, e.g., after surgery) and deaths. ICD10 codes were used to define cause of death. The proportion who died for each cause of death after first VTE, by type of VTE, was tabulated. Hazard ratios (HRs) of death by type of VTE were estimated with Cox proportional hazards models adjusted for age, race, gender, and pre-baseline cancer. Survival rates were visualized by adjusted survival curves.

Results: Over a maximum follow-up of 33 years, 1,076 participants had first-time VTE; 441 were unprovoked, 271 were cancer-provoked, 364 were other-provoked. Mean age at first VTE was 74. After unprovoked VTE, 37% died of circulatory diseases (excluding VTE) and 13% of cancer. Those values were 35% and 13% for other-provoked VTE. By contrast, for cancer-provoked VTE, 80% died of cancer and 10% of circulatory diseases (excluding VTE). In the Figure , those with VTE had poorer long-term survival than 14,400 participants without VTE, and cancer-provoked VTE had the highest mortality. Overall, the HR of death was 2.75 (95% CI: 2.49-3.05) for those with vs without VTE. Those with cancer-provoked VTE had the highest HR, 10.02 (95% CI 8.81-11.40), but those with unprovoked and other-provoked VTE also had higher mortality than those without VTE.

Conclusions: In this study, long-term survival after VTE was poor. Apart from cancer-provoked VTE, circulatory diseases were the primary causes of death after VTE. Optimizing cardiovascular prevention could improve long-term survival of patients with VTE.

Transitions to Family Caregiving and Latent Variables of Systemic Inflammation Over Time

Circulating levels of inflammatory biomarkers may be influenced by chronic psychological stressors such as those experienced by family caregivers. However, previous studies have found mostly small and inconsistent differences between caregivers and control samples on individual measures of systemic inflammation. Latent variables of inflammation were extracted from six biomarkers collected from two blood samples over 9 years apart for 502 participants in a national cohort study. One-half of these participants transitioned into a sustained family caregiving role between the blood samples. Two latent factors, termed "up-regulation" and "inhibitory feedback," were identified, and the transition to family caregiving was associated with a lower increase over time on the inhibitory feedback factor indexed by interleukin (IL)-2 and IL-10. No caregiving effect was found on the up-regulation factor indexed primarily by IL-6 and C-reactive protein. These findings illustrate the advantages of using latent variable models to study inflammation in response to caregiving stress.

Associations of Telomere Length and Change With Cognitive Decline Were Modified by Sex and Race: The REGARDS Study

INTRODUCTION

We examined the associations of baseline telomere length (TL) and TL change with cognitive function over time in older US adults, as well as differences by sex and race.

METHODS

A total of 1820 cognitively healthy individuals (median baseline age: 63 years) were included. Telomere length was measured using qPCR-based method at baseline and among 614 participants in the follow-up examination 10 years later. Cognitive function was assessed by a four-test battery every 2 years.

RESULTS

In multivariable-adjusted linear mixed models, longer baseline TL and smaller attrition/lengthening of TL over time were associated with better Animal Fluency Test score. Longer baseline TL was also linearly associated with better Letter Fluency Test score. The observed associations were consistently more pronounced in women than men and in Black compared to White participants.

DISCUSSION

Telomere length may be a biomarker that predicts long-term verbal fluency and executive function, particularly in women and Black Americans.

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.

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.

Collaborative Cohort of Cohorts for COVID-19 Research (C4R) Study: Study Design

The Collaborative Cohort of Cohorts for COVID-19 Research (C4R) is a national prospective study of adults comprising 14 established US prospective cohort studies. Starting as early as 1971, investigators in the C4R cohort studies have collected data on clinical and subclinical diseases and their risk factors, including behavior, cognition, biomarkers, and social determinants of health. C4R links this pre-coronavirus disease 2019 (COVID-19) phenotyping to information on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and acute and postacute COVID-related illness. C4R is largely population-based, has an age range of 18-108 years, and reflects the racial, ethnic, socioeconomic, and geographic diversity of the United States. C4R ascertains SARS-CoV-2 infection and COVID-19 illness using standardized questionnaires, ascertainment of COVID-related hospitalizations and deaths, and a SARS-CoV-2 serosurvey conducted via dried blood spots. Master protocols leverage existing robust retention rates for telephone and in-person examinations and high-quality event surveillance. Extensive prepandemic data minimize referral, survival, and recall bias. Data are harmonized with research-quality phenotyping unmatched by clinical and survey-based studies; these data will be pooled and shared widely to expedite collaboration and scientific findings. This resource will allow evaluation of risk and resilience factors for COVID-19 severity and outcomes, including postacute sequelae, and assessment of the social and behavioral impact of the pandemic on long-term health trajectories.

Telomere shortening and the transition to family caregiving in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study

Telomere length (TL) is widely studied as a possible biomarker for stress-related cellular aging and decreased longevity. There have been conflicting findings about the relationship between family caregiving stress and TL. Several initial cross-sectional studies have found associations between longer duration of caregiving or perceived stressfulness of caregiving and shortened TL, suggesting that caregiving poses grave risks to health. Previous reviews have suggested the need for longitudinal methods to investigate this topic. This study examined the association between the transition to family caregiving and change in TL across ~9 years. Data was utilized from the Caregiving Transitions Study, an ancillary study to the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. TL was assayed using qPCR and analyzed as the telomere-to-single copy gene ratio for each participant at baseline and follow-up. General linear models examined the association between caregiving status and the change in TL for 208 incident caregivers and 205 controls, as well as associations between perceived stress and TL among caregivers. No association was found between TL change and caregiving (p = 0.494), and fully adjusted models controlling for health and socioeconomic factors did not change the null relationship (p = 0.305). Among caregivers, no association was found between perceived caregiving stress and change in TL (p = 0.336). In contrast to earlier cross-sectional studies, this longitudinal, population-based study did not detect a significant relationship between the transition into a family caregiving role and changes in TL over time. Given the widespread citation of previous findings suggesting that caregiving shortens telomeres and places caregivers at risk of early mortality, these results demonstrate the potential need of a more balanced narrative about caregiving.

Diabetes and acculturation in African immigrants to the United States: analysis of the 2010-2017 National Health Interview Survey (NHIS)

Objective: This study sought to assess the association between unidimensional acculturation and diabetes, and analyze mediating pathways of the association in African immigrants to the United States (U.S.).Hypothesis: Acculturation would be positively associated with diabetes and that BMI (Body mass index), physical activity, and psychological distress would mediate this association.Methods: An analysis of cross-sectional data from the 2010-2017 National Health Interview Surveys was performed. Adults aged ≥ 18 years who were born in Africa (African immigrants) and residing in the U.S. were considered. The outcome was self-reported diabetes, and acculturation was defined by percent of life spent in the U.S. and citizenship. Multivariable logistic regression analysis was used to assess the association between acculturation and diabetes, and mediation analysis was used to examine the mediating effects of BMI, physical activity, and psychological distress on this association.Results: The analytic sample included 1648 African immigrants with mean (SD) age of 41.3 ± 0.45 years; 56.4% male. Additionally, 46% had ≥ college education, and 21.4% lived below the poverty threshold. About two-thirds were overweight/obese. Less than 50% exercised at adequate levels of physical activity levels. A small percentage (1.8%) reported psychological distress. The prevalence of self-reported diabetes was 6.1%, and 76.5% reported being acculturated. In the multivariate logistic regression analysis, higher levels of acculturation were associated with higher odds of diabetes diagnosis (Odds Ratio (OR) = 2.2; 95% CI = 1.1-4.4). Although BMI mediated the association between acculturation and diabetes (ZMediation = 2.11, p = 0.036), only 18.9% of the total effect of acculturation on diabetes was explained by BMI.Conclusions: Acculturation increased the odds of diabetes diagnosis, and BMI mediated the association. Thus, tailoring culturally-appropriate interventions to control BMI may contribute to preventing diabetes within African immigrant communities to the U.S.

Health care experiences during the COVID-19 pandemic by race and social determinants of health among adults age ≥ 58 years in the REGARDS study

BACKGROUND

Understanding health care experiences during the COVID-19 pandemic may provide insights into patient needs and inform policy. The objective of this study was to describe health care experiences by race and social determinants of health.

METHODS

We conducted a telephone survey (July 6, 2020-September 4, 2021) among 9492 Black and White participants in the longitudinal REasons for Geographic And Racial Differences in Stroke cohort study, age 58-105 years, from the continental United States. Among participants with symptoms of COVID-19, outcomes were: 1. Sought care or advice for the illness; 2. Received a SARS-CoV-2 test for the illness; and 3. Tested positive. Among participants without symptoms of COVID-19, outcomes were: 1. Wanted a test; 2. Wanted and received a test; 3. Did not want but received a test; and 4. Tested positive. We examined these outcomes overall and in subgroups defined by race, household income, marital status, education, area-level poverty, rural residence, Medicaid expansion, public health infrastructure ranking, and residential segregation.

RESULTS

The average age of participants was 76.8 years, 36% were Black, and 57% were female. Among participants with COVID-19 symptoms (n = 697), 74% sought care or advice for the illness, 50% received a SARS-CoV-2 test, and 25% had a positive test (50% of those tested). Among participants without potential COVID-19 symptoms (n = 8795), 29% wanted a SARS-CoV-2 test, 22% wanted and received a test, 8% did not want but received a test, and 1% tested positive; a greater percentage of participants who were Black compared to White wanted (38% vs 23%, p < 0.001) and received tests (30% vs 18%, p < 0.001) and tested positive (1.4% vs 0.8%, p = 0.005).

CONCLUSIONS

In this national study of older US adults, many participants with potential COVID-19 symptoms and asymptomatic participants who desired testing did not receive COVID-19 testing.

Thrombo-inflammatory biomarkers and D-dimer in a biracial cohort study

BACKGROUND

Higher D-dimer is a risk factor for cardiovascular diseases and venous thromboembolism. In the general population, D-dimer and other thrombo-inflammatory biomarkers are higher among Black individuals, who also have higher risk of these conditions compared to White people.

OBJECTIVE

To assess whether Black individuals have an exaggerated correlation between D-dimer and thrombo-inflammatory biomarkers characteristic of cardiovascular diseases.

METHODS

Linear regression was used to assess correlations of 11 thrombo-inflammatory biomarkers with D-dimer in a cross-sectional study of 1068 participants of the biracial Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort.

RESULTS

Adverse levels of most biomarkers, especially fibrinogen, factor VIII, C-reactive protein, N-terminal pro-B-type natriuretic peptide, and interleukin (IL)-6, were associated with higher D-dimer. Several associations with D-dimer differed significantly by race. For example, the association of factor VIII with D-dimer was more than twice as large in Black compared to White participants. Specifically, D-dimer was 26% higher per standard deviation (SD) higher factor VIII in Black adults and was only 11% higher per SD higher factor VIII in White adults. In Black but not White adults, higher IL-10 and soluble CD14 were associated with higher D-dimer.

CONCLUSIONS

Findings suggest that D-dimer might relate to Black/White differences in cardiovascular diseases and venous thromboembolism because it is a marker of amplified thrombo-inflammatory response in Black people. Better understanding of contributors to higher D-dimer in the general population is needed.

Rural/urban differences in the prevalence of stroke risk factors: A cross-sectional analysis from the REGARDS study

PURPOSE

We previously described the magnitude of rural-urban differences in the prevalence of stroke risk factors and stroke mortality. In this report, we sought to extend the understanding of rural-urban differences in the prevalence of stroke risk factors by using an enhanced definition of rural-urban status and assessing the impact of neighborhood socioeconomic status (nSES) on risk factor differences.

METHODS

This analysis included 28,242 participants without a history of stroke from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Participants were categorized into the 6-level ordinal National Center for Health Statistics Urban-Rural Classification Scheme. The prevalence of stroke risk factors (hypertension, diabetes, smoking, atrial fibrillation, left ventricular hypertrophy, and heart disease) was assessed across the rural-urban scale with adjustment for demographic characteristics and further adjustment for nSES score.

FINDINGS

Hypertension, diabetes, and heart disease were more prevalent in rural than urban regions. Higher odds were observed for these risk factors in the most rural compared to the most urban areas (odds ratios [95% CI]: 1.25 [1.11-1.42] for hypertension, 1.15 [0.99-1.33] for diabetes, and 1.19 [1.02-1.39] for heart disease). Adjustment for nSES score partially attenuated the odds of hypertension and heart disease with rurality, completely attenuated the odds of diabetes, and unmasked an association of current smoking.

CONCLUSIONS

Some of the higher stroke mortality in rural areas may be due to the higher burden of stroke risk factors in rural areas. Lower nSES contributed most notably to rural-urban differences for diabetes and smoking.

Collaborative Cohort of Cohorts for COVID-19 Research (C4R) Study: Study Design

The Collaborative Cohort of Cohorts for COVID-19 Research (C4R) is a national prospective study of adults at risk for coronavirus disease 2019 (COVID-19) comprising 14 established United States (US) prospective cohort studies. For decades, C4R cohorts have collected extensive data on clinical and subclinical diseases and their risk factors, including behavior, cognition, biomarkers, and social determinants of health. C4R will link this pre-COVID phenotyping to information on SARS-CoV-2 infection and acute and post-acute COVID-related illness. C4R is largely population-based, has an age range of 18-108 years, and broadly reflects the racial, ethnic, socioeconomic, and geographic diversity of the US. C4R is ascertaining severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 illness using standardized questionnaires, ascertainment of COVID-related hospitalizations and deaths, and a SARS-CoV-2 serosurvey via dried blood spots. Master protocols leverage existing robust retention rates for telephone and in-person examinations, and high-quality events surveillance. Extensive pre-pandemic data minimize referral, survival, and recall bias. Data are being harmonized with research-quality phenotyping unmatched by clinical and survey-based studies; these will be pooled and shared widely to expedite collaboration and scientific findings. This unique resource will allow evaluation of risk and resilience factors for COVID-19 severity and outcomes, including post-acute sequelae, and assessment of the social and behavioral impact of the pandemic on long-term trajectories of health and aging.

Identifying Genetic and Biological Determinants of Race-Ethnic Disparities in Stroke in the United States

In the United States, causes of racial differences in stroke and its risk factors remain only partly understood, and there is a long-standing disparity in stroke incidence and mortality impacting Black Americans. Only half of the excess risk of stroke in the United States Black population is explained by traditional risk factors, suggesting potential effects of other factors including genetic and biological characteristics. Here, we nonsystematically reviewed candidate laboratory biomarkers for stroke and their relationships to racial disparities in stroke. Current evidence indicates that IL-6 (interleukin-6), a proinflammatory cytokine, mediates racial disparities in stroke through its association with traditional risk factors. Only one reviewed biomarker, Lp(a) (lipoprotein[a]), is a race-specific risk factor for stroke. Lp(a) is highly genetically determined and levels are substantially higher in Black than White people; clinical and pharmaceutical ramifications for stroke prevention remain uncertain. Other studied stroke risk biomarkers did not explain racial differences in stroke. More research on Lp(a) and other biological and genetic risk factors is needed to understand and mitigate racial disparities in stroke.