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1.  Correlates and consequences of venous thromboembolism: The Iowa Women’s Health Study Authors 
American journal of public health  2009;100(8):1506-1513.
To document the incidence, case-fatality, and recurrence of venous thromboembolism (VTE) in women, and to explore the relation of demographic, lifestyle, and anthropometric factors to VTE incidence.
In 1986 Iowa women aged 55–69 completed a mailed survey. These data were linked to Medicare data for 1986–2004 (n=40,377) to identify hospitalized VTE cases. Cox regression adjusted for age, education, smoking status, physical activity, and BMI.
2,137 women developed VTE, yielding an incidence rate of 4.04/1,000 person-years. The 28-day case-fatality was 7.7% and the 1-year recurrence, 3.4%. Educational attainment and age-at-menopause were inversely associated with VTE, as was physical activity, prior to BMI adjustment. The risk of secondary (particularly cancer-related) VTE was increased in smokers compared with never smokers. BMI, waist circumference, waist-hip-ratio height, and diabetes were positively associated with VTE risk. Hormone replacement therapy use was associated with increased risk of idiopathic VTE, while parity was unrelated.
VTE is a significant source of morbidity and mortality in older women. Risk was elevated among women who were smokers, physically inactive, overweight, and diabetic, indicating that lifestyle contributes to VTE risk.
PMCID: PMC2901301  PMID: 19910349
2.  Fibroblast Growth Factor‐23 and Incident Coronary Heart Disease, Heart Failure, and Cardiovascular Mortality: The Atherosclerosis Risk In Communities Study 
Fibroblast growth factor‐23 (FGF‐23) is a hormone involved in phosphorous regulation and vitamin D metabolism that may be associated with cardiovascular risk, and it is a potential target for intervention. We tested whether elevated FGF‐23 is associated with incident coronary heart disease, heart failure, and cardiovascular mortality, even at normal kidney function.
Methods and Results
A total of 11 638 Atherosclerosis Risk In Communities study participants, median age 57 at baseline (1990–1992), were followed through 2010. Cox regression was used to evaluate the independent association of baseline serum active FGF‐23 with incident outcomes. Models were adjusted for traditional cardiovascular risk factors and estimated glomerular filtration rate. During a median follow‐up of 18.6 years, 1125 participants developed coronary heart disease, 1515 developed heart failure, and 802 died of cardiovascular causes. For all 3 outcomes, there was a threshold, whereby FGF‐23 was not associated with risk at <40 pg/mL but was positively associated with risk at >40 pg/mL. Compared with those with FGF‐23 <40 pg/mL, those in the highest FGF‐23 category (≥58.8 pg/mL) had a higher risk of incident coronary heart disease (adjusted hazard ratio, 95% CIs: 1.65, 1.40 to 1.94), heart failure (1.75, 1.52 to 2.01), and cardiovascular mortality (1.65, 1.36 to 2.01). Associations were modestly attenuated but remained statistically significant after further adjustment for estimated glomerular filtration rate. In stratified analyses, similar results were observed in African Americans and among persons with normal kidney function.
High levels of serum FGF‐23 were associated with increased risk of coronary heart disease, heart failure, and cardiovascular mortality in this large, biracial, population‐based cohort. This association was independent of traditional cardiovascular risk factors and kidney function.
PMCID: PMC4309096  PMID: 24922628
Atherosclerosis Risk In Communities; cardiovascular mortality; coronary heart disease; epidemiology; fibroblast growth factor 23; heart failure
3.  Relations of the Mediterranean dietary pattern with insulin resistance and diabetes incidence in the Multi-Ethnic Study of Atherosclerosis (MESA) 
The British journal of nutrition  2012;109(8):1490-1497.
Type 2 diabetes is a highly prevalent but preventable disorder. We assessed the association between an a priori Mediterranean diet score (MeDiet) and fasting glucose and insulin at baseline and incident type 2 diabetes after 6-year follow-up in MESA. Dietary intake was measured at baseline by a 127-item food frequency questionnaire in 5,390 men and women aged 45-84 years free of prevalent diabetes and clinical CVD. A MeDiet score was created based on intake of 10 food components: vegetables, whole grains, nuts, legumes, fruits, ratio of monounsaturated to saturated fat, red and processed meat, dairy, fish and alcohol. Multivariable linear and proportional hazard models were used to estimate the association of MeDiet, categorized in quintiles, with baseline insulin and glucose, and incident diabetes, respectively. Models adjusted for demographic, physiologic and behavioral characteristics. After multivariable adjustment, individuals with a higher MeDiet score had lower baseline mean (95% CI) insulin levels [mean Q1: = 5.8 (5.6-6.0) umol/l; mean Q5: = 4.8 (4.6-5.0) umol/l; p-trend= <0.0001]. A higher MeDiet score was also associated with significantly lower glucose levels after basic adjustment, but was attenuated after adjustment for waist circumference. During follow-up, 412 incident diabetes events accrued. MeDiet was not significantly related to risk of incident diabetes (p-trend=0.64). In summary, greater consistency with a Mediterranean-style diet, reflected by a higher a priori Mediterranean diet score, was cross-sectionally associated with lower insulin levels among non-diabetics, and lower blood glucose prior to adjustment for obesity, but not with lower incidence of diabetes.
PMCID: PMC4002212  PMID: 22932232
5.  Relation of Lipid Gene Scores to Longitudinal Trends in Lipid Levels and Incidence of Abnormal Lipid Levels Among Individuals of European Ancestry: The Atherosclerosis Risk in Communities (ARIC) Study 
Multiple genetic loci have been associated with blood lipid levels. We tested the hypothesis that people with an unfavorable lipid gene profile would experience a greater increase in lipid levels and a higher incidence of abnormal lipid levels, relative to those with more favorable lipid gene profiles.
Methods and Results
9,328 European-descent individuals in ARIC (ages 45–64 y) were followed for 9 years. Separate gene scores were created for each lipid phenotype based on 95 loci identified in a published GWAS of >100,000 European-descent individuals. Adjusted linear and survival models were used to estimate associations with lipid levels and incidence of lipid-lowering medication or abnormal lipid levels. Age and sex interactions were also explored. The cross-sectional difference (mg/dL) per one standard deviation (SD) was −1.89 for HDL-C, 9.5 for LDL-C, and 22.8 for triglycerides (p<5 × 10−34 for all). Longitudinally, overall triglyceride levels rose over time, and each SD greater triglyceride gene score was associated with an average increase in triglyceride levels of 0.3 mg/dL (p=0.003) over 3-years. The HDL-C, LDL-C and total cholesterol gene scores were not related to change. All lipid gene scores were positively related to incidence of abnormal lipid levels over follow-up (HRs per SD ranged from 1.15–1.36).
Associations of genetic variants with lipid levels over time are complex, with the triglyceride gene score positively related to change in triglycerides levels. Similar longitudinal results were not observed for LDL-C or HDL-C levels. Unfavorable gene scores were nevertheless related to higher incidence of abnormal levels.
PMCID: PMC3288431  PMID: 22057756
lipids; longitudinal trends; gene score; Atherosclerosis Risk in Communities (ARIC)
6.  Invited Commentary: Diet and Risk of Venous Thromboembolism—A Hard Nut to Crack 
American Journal of Epidemiology  2011;175(2):127-130.
Recently, there has been interest in determining whether diet is associated with the risk of venous thromboembolism. The article by Varraso et al. (Am J Epidemiol. 2012;175(2):114–126) published in this issue of the Journal is an important contribution to this literature. In this commentary, the author discusses the findings of Varraso et al. within the context of the existing literature and posits epidemiologic explanations for why investigators might have failed to identify strong associations between diet and venous thromboembolism.
PMCID: PMC4047293  PMID: 22180876
diet; food; pulmonary embolism; venous thrombosis
7.  Longer legs are associated with greater risk of incident venous thromboembolism independent of total body height: The Longitudinal Study of Thromboembolism Etiology (LITE) 
Thrombosis and haemostasis  2011;106(1):113-120.
Several studies have reported that taller individuals are at greater risk of venous thromboembolism (VTE). We hypothesized that longer leg length would be positively associated with incident VTE, and would explain the height association. LITE ascertained VTE in a prospective population-based sample of 21,860 individuals aged 45 and older. Leg length was measured as standing height minus sitting height. Cox regression models were adjusted for age, race, sex, waist circumference, diabetes, and factor VIII. To evaluate whether leg length was associated with VTE risk independent of height we standardized leg length and height per 1 standard deviation (SD), and then included them simultaneously in Cox regression models. A total of 641 incident VTE cases accrued over a median follow-up of 16 yrs. Participants in the highest quintile of leg length were at 59% (95% CI: 22%-108%) greater risk of VTE, relative to the lowest quintile. For height, risk was 45% (12%-88%) greater for those in the highest quintile, compared to the lowest. When leg length and height were modeled simultaneously leg length remained associated with VTE risk (HR per 1 SD: 1.21 (1.04-1.40) while height was unrelated (HR per 1 SD: 1.00 (0.86-1.16). To conclude, participants with longer legs were at greater risk of incident VTE, and leg length explained the relation of height to VTE. It remains to be established whether this finding is due to greater venous surface area, a larger number of venous valves, or greater hydrostatic pressure among individuals with longer legs.
PMCID: PMC3180885  PMID: 21655679
height; leg length; venous thromboembolism; Atherosclerosis Risk in Communities Study (ARIC); Cardiovascular Health Study (CHS)
8.  Social Network, Social Support, and Risk of Incident Stroke: The Atherosclerosis Risk in Communities Study 
Background and Purpose
Having a small social network and lack of social support have been associated with incident coronary heart disease, however epidemiologic evidence for incident stroke is limited. We assessed the longitudinal association of a small social network and lack of social support with risk of incident stroke, and evaluated whether the association was partly mediated by vital exhaustion and inflammation.
The Atherosclerosis Risk in Communities (ARIC) Study measured social network and social support in 13,686 men and women (mean, 57±5.7 years, 56% female, 24% black; 76% white) without a history of stroke. Social network was assessed by the 10-item Lubben Social Network Scale, and social support by a 16-item Interpersonal Support Evaluation List-Short Form (ISEL-SF).
Over a median follow-up of 18.6-years, 905 incident strokes occurred. Relative to participants with a large social network, those with a small social network had a higher risk of stroke [HR (95% CI): 1.44 (1.02–2.04)] after adjustment for demographics, socioeconomic variables and marital status, behavioral risk factors and major stroke risk factors. Vital exhaustion, but not inflammation, partly mediated the association between a small social network and incident stroke. Social support was unrelated to incident stroke.
In this sample of US community-dwelling men and women, having a small social network was associated with excess risk of incident stroke. As with other cardiovascular conditions, having a small social network may be associated with a modestly increased risk of incident stroke.
PMCID: PMC4201236  PMID: 25139878
Social network; Social support; Stroke; Psychological distress; Inflammation; Epidemiology
9.  Interactions Between Race/Ethnicity and Anthropometry in Risk of Incident Diabetes 
American Journal of Epidemiology  2010;172(2):197-204.
This study examined how adiposity influences racial/ethnic differences in diabetes incidence by exploring whether relations between anthropometric measures and incident diabetes vary by race/ethnicity. Data from the Multi-Ethnic Study of Atherosclerosis initiated in 2000 (n = 5,446 US men and women aged 45–84 years) were analyzed by using proportional hazards and Poisson regression. The diabetes incidence rate was 2/100 person-years (n = 479 cases). Interactions were present between race and anthropometry (P-interaction(race × body mass index) = 0.002). The slope of incident diabetes per anthropometric unit was greatest for Chinese, less for whites and Hispanics, and still less for blacks. For small waist, risk of incident diabetes was <1/100 person-years for all racial/ethnic groups. At intermediate waist levels, Chinese had the highest and whites the lowest rates of incident diabetes. At the respective 95th percentiles of waist circumference, risk of incident diabetes per 100 person-years was 3.9 for Chinese (104 cm), 3.5 for whites (121 cm), 5.0 for blacks (125 cm), and 5.3 for Hispanics (121 cm). Adiposity influenced relative diabetes occurrence across racial/ethnic groups, in that Chinese had a steeper diabetes risk per unit of adiposity. However, the generally low level of adiposity in Chinese led to a relatively low diabetes occurrence.
PMCID: PMC2915488  PMID: 20570825
Asian continental ancestry group; body mass index; diabetes mellitus; waist circumference
10.  Vitamin D and Cognitive Function and Dementia Risk in a Biracial Cohort: the ARIC Brain MRI Study 
Some recent studies in older, largely white populations suggest that vitamin D, measured by 25-hydroxyvitamin D [25(OH)D], is important for cognition, but such results may be affected by reverse-causation. Measuring 25(OH)D in late-middle age before poor cognition affects behavior may provide clearer results.
Prospective cohort analysis of 1,652 participants (52% white; 48% black) in the Atherosclerosis Risk in Communities (ARIC) Brain MRI Study. 25(OH)D was measured from serum collected in 1993–1995. Cognition was measured by the Delayed Word Recall Test (DWRT), the Digit Symbol Substitution Test (DSST), and the Word Fluency Test (WFT). Dementia hospitalization was defined by ICD-9 codes. Adjusted linear, logistic, and Cox proportional hazards models were used.
Mean age of participants was 62 years and 60% were female. Mean 25(OH)D was higher in whites than blacks (25.5 ng/ml versus 17.3 ng/ml, p<0.001). Lower 25(OH)D was not associated with lower baseline scores or with greater DWRT, DSST, or WFT decline (p>0.05). Over a median of 16.6 years, there were 145 incident hospitalized dementia cases. Though not statistically significant, lower levels of 25(OH)D were suggestive of an association with increased dementia risk (HR lowest versus highest race-specific tertile: whites 1.32 [95% CI: 0.69, 2.55]; blacks 1.53 [95% CI: 0.84, 2.79]).
In contrast to prior studies performed in older white populations, our study did not find significant associations between lower levels of 25(OH)D measured in late-middle age black or white participants with lower cognitive test scores at baseline, change in scores over time, or dementia risk.
PMCID: PMC4114998  PMID: 24846449
Vitamin D; Cognition; Dementia; ARIC Study
11.  Peak Thrombin Generation and Subsequent Venous Thromboembolism: The Longitudinal Investigation of Thromboembolism Etiology (LITE) 
Thrombin is an enzyme essential to the acceleration of the coagulation cascade and the conversion of fibrinogen to clottable fibrin.
We evaluated the relation of basal peak thrombin generation to risk of future VTE, and determined whether associations were independent of other coagulation markers.
LITE ascertained VTE in two prospective population-based cohorts: the Atherosclerosis Risk in Communities (ARIC) study and the Cardiovascular Health Study (CHS). Peak thrombin generation was measured on stored plasma in a nested case-control sample (434 cases, 1,004 controls). Logistic regression was used to estimate the relation of peak thrombin generation to VTE, adjusted for age, sex, race, center and BMI. Mediation was evaluated by additionally adjusting for factor VIII and D-dimer.
Relative to the first quartile of peak thrombin generation, the odds ratio (95% CI) of VTE for those above the median was 1.74 (1.28–2.37). The association was modestly attenuated by adjustment for factor VIII and D-dimer 1.47 (1.05–2.05). Associations appeared stronger for idiopathic than for secondary VTE. Elevated peak thrombin generation more than added to the VTE risk associated with Factor V Leiden or low aPTT.
In this prospective study of two independent cohorts, elevated basal peak thrombin generation was associated with subsequent risk of VTE, independent of established VTE risk factors.
PMCID: PMC2763356  PMID: 19656279
Longitudinal Investigation of Thromboembolism Etiology (LITE); thrombin generation; venous thromboembolism
12.  Intracranial hemorrhage mortality in atrial fibrillation patients treated with dabigatran or warfarin 
Background and purpose
In randomized trials, atrial fibrillation (AF) patients receiving dabigatran, a direct oral anticoagulant, had lower risk of intracranial bleeding (ICB) than those on warfarin. However, concerns exist about potential worse outcomes in dabigatran users if bleeding occurs, given the lack of approved reversal agents. Thus, we examined in-hospital mortality in AF patients with ICB being treated with dabigatran vs warfarin in a real-world population in the United States.
We analyzed healthcare utilization claims in the Truven Health Marketscan® Research Databases. The study sample included AF patients admitted to a hospital with a primary diagnosis of ICB. Information on medications, inpatient, and outpatient diagnoses was obtained from available claims. Propensity score-adjusted risk ratios (RR) and 95% confidence intervals (95%CI) of in-hospital mortality comparing current users of dabigatran versus warfarin were estimated using relative risk regression.
Among 2391 AF patients admitted with ICB (2290 on warfarin, 101 on dabigatran), 531 died during their admission. In-hospital mortality was similar in those treated with warfarin (22%) or dabigatran (20%). Compared to warfarin users, the propensity score-adjusted RR (95%CI) of mortality in dabigatran users was 0.93 (0.62, 1.37). Associations were similar across different ICB subtypes (intracerebral hemorrhage, subarachnoid hemorrhage, and subdural hematoma).
In this sample of AF patients on oral anticoagulants with ICB, dabigatran was not associated with higher in-hospital mortality compared to warfarin. Hence, reluctance to use of dabigatran because of a lack of approved reversal agents is not supported by our results.
PMCID: PMC4116615  PMID: 24994722
atrial fibrillation; warfarin; dabigatran; intracranial hemorrhage
13.  Chronic Stress, Depressive Symptoms, Anger, Hostility and Risk of Stroke and Transient Ischemic Attack in the MESA Study 
Background and Purpose
This study investigated chronic stress, depressive symptoms, anger and hostility in relation to incident stroke and transient ischemic attacks (TIA) in middle-aged and older adults.
Data were from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort study of 6,749 adults, ages 45-84 and free of clinical cardiovascular disease at baseline, conducted at 6 U.S. sites. Chronic stress, depressive symptoms, trait anger, and hostility were assessed with standard questionnaires. The primary outcome was clinically adjudicated incident stroke or TIA during a median follow-up of 8.5 years.
Results: 195 incident events (147 strokes; 48 TIA) occurred during follow-up. A gradient of increasing risk was observed for depressive symptoms, chronic stress, and hostility (all p-for-trend ≤0.02) but not for trait anger (p>.10). Hazard ratios (HR) and 95% confidence intervals (CI) indicated significantly elevated risk for the highest-scoring relative to the lowest-scoring group for depressive symptoms [HR=1.86; 95% CI=1.16-2.96], chronic stress [HR=1.59; 95% CI=1.11-2.27], and hostility [HR=2.22; 95% CI=1.29-3.81] adjusting for age, demograhics and site. HR were attenuated but remained significant in risk factor-adjusted models. Associations were similar in models limited to stroke and in secondary analyses utilizing time-varying variables.
Higher levels of stress, hostility and depressive symptoms are associated with significantly increased risk of incident stroke or TIA in middle-aged and older adults. Associations are not explained by known stroke risk factors.
PMCID: PMC4131200  PMID: 25013018
stress; emotions; stroke
14.  Diet and Incident Venous Thromboembolism: The Iowa Women’s Health Study 
American heart journal  2009;157(6):1081-1087.
Little is known about the role of diet in the development of venous thromboembolism (VTE). We explored the prospective relation of dietary patterns, food groups, and nutrients to incident VTE in older women.
In 1986, Iowa women aged 55–69 completed a mailed survey, including a 127-item food frequency questionnaire. These data were linked to Medicare data from 1986–2004, and International Classification of Disease discharge codes were used to identify hospitalized VTE cases. Cox regression analyses evaluated relations of 2 principal components-derived dietary patterns, 11 food groups, and 6 nutrients to VTE, adjusted for age, education, smoking status, physical activity, and energy intake.
Over 19 years of follow-up 1,950 of the 37,393 women developed VTE. Women consuming alcohol daily were at 26% (95% CI: 11%–38%) lower risk of VTE, as compared to nonconsumers. All alcoholic beverages types were in the direction of lower risk, however only beer and liquor were statistically significant. After basic adjustments coffee was inversely related to VTE, and diet soda and fish positively related. However, these associations were confounded, and became nonsignificant after adjustment for body mass index and diabetes. No associations were observed with consumption of ‘Western’ or ‘Prudent’ dietary patterns, fruit, vegetables, dairy, meat, refined grains, whole grains, regular soda, vitamins E, B6, B12, folate, omega-3 fatty acids, or saturated fat.
In this cohort of older women, greater intake of alcohol was associated with a lower risk of incident VTE. No other independent associations were seen between diet and VTE.
PMCID: PMC2689927  PMID: 19464420
Venous thromboembolism; Diet; Alcohol; Iowa Women’s Health Study; Medicare
15.  Associations of Acculturation and Socioeconomic Status with Subclinical CVD in the MultiEthnic Study of Atherosclerosis 
American journal of public health  2008;98(11):1963-1970.
To assess whether markers of acculturation (birthplace, number of U.S. generations) and socioeconomic status (SES) are associated with carotid artery plaque, internal carotid intima-media thickness (IMT), and albuminuria, in four racial/ethnic groups.
Using Multi-Ethnic Study of Atherosclerosis data (n = 6,716; age: 45-84) and race-specific binomial regression models, we computed prevalence ratios, adjusted for demographics and traditional cardiovascular risk factors.
The adjusted U.S. to foreign-born prevalence ratio (99% CI) for carotid plaque was 1.20 (0.97, 1.39) in Whites, 1.91 (0.94, 2.94) in Chinese, 1.62 (1.28, 2.06) in Blacks, and 1.23 (1.15, 1.31) in Hispanics. Greater carotid plaque prevalence was also found among Whites, Blacks, and Hispanics with more generations of US residence (p<0.001). Lower educational attainment and/or income were associated with greater carotid plaque prevalence in Whites and Blacks. Similar associations were observed with IMT. There was also some evidence of an inverse association between albuminuria and SES, in Whites and Hispanics.
Greater U.S. acculturation and lower SES were associated with a higher prevalence of carotid plaque and IMT, while little association was found with albuminuria.
PMCID: PMC2575668  PMID: 18511718
16.  Smoking Behavior and Lung Cancer in a Biracial Cohort 
In the U.S., the incidence of lung cancer varies by race, with rates being highest among black men. There are marked differences in smoking behavior between blacks and whites, but little is known regarding how these differences contribute to the racial disparities in lung cancer.
To compare the lung cancer risk associated with smoking in 14,610 blacks and whites in the prospective cohort Atherosclerosis Risk in Communities study.
Smoking characteristics were ascertained at baseline and three follow-up visits in 1990–1992, 1993–1995, and 1996–1998 (response rates were 93%, 86%, and 80%, respectively), as well as from annual telephone interviews. Data were analyzed in the fall of 2012. Multivariable-adjusted proportional hazards models were used to calculate hazard ratios and 95% CIs for lung cancer.
Over 20 years of follow-up (1987–2006), 470 incident cases of lung cancer occurred. Lung cancer incident rates were highest in black men and lowest in black women. However, there was no evidence to support racial differences in the associations of smoking status, intensity, or age at initiation with lung cancer risk (all pinteraction≥0.25). The hazard ratio for those who started smoking at age ≤12 versus >22 years was 3.03 (95% CI=1.62, 5.67). Prolonged smoking cessation (≥10 years) was associated with a decrease in lung cancer risk, with equivalent benefits in whites and blacks, 84% and 74%, respectively (pinteraction=0.25).
Smoking confers similar lung cancer risk in blacks and whites.
PMCID: PMC4030495  PMID: 24842739
17.  Impact of Atrial Fibrillation on Healthcare Utilization in the Community: The Atherosclerosis Risk in Communities Study 
Atrial fibrillation (AF) is associated with increased risk of hospitalization. Little is known about the impact of AF on utilization of noninpatient health care or about sex or race differences in AF‐related utilization. We examined rates of inpatient and outpatient utilization by AF status in the Atherosclerosis Risk in Communities study.
Methods and Results
Participants with incident AF enrolled in fee‐for‐service Medicare for at least 12 continuous months between 1991 and 2009 (n=932) were matched on age, sex, race and field center with up to 3 participants without AF (n=2729). Healthcare utilization was ascertained from Medicare claims and classified by primary International Classification of Diseases, ninth revision code. The average annual numbers of days hospitalized were 13.2 (95% CI 11.6 to 15.0) and 2.8 (95% CI 2.5 to 3.1) for those with and without AF, respectively. The corresponding numbers of annual outpatient claims were 53.3 (95% CI 50.5 to 56.3) and 22.9 (95% CI 22.1 to 23.8) for those with and without AF, respectively. Most utilization among AF patients was attributable to non‐AF conditions. The adjusted rate ratio for annual days hospitalized for other cardiovascular disease–related reasons was 4.58 (95% CI: 3.41 to 6.16) for those with AF versus those without AF. The association between AF and healthcare utilization was similar among men and women and among white and black participants.
Participants with AF had considerably greater healthcare utilization, and the difference in utilization for other cardiovascular disease–related reasons was substantial. In addition to rate or rhythm treatment, AF management should focus on the accompanying cardiovascular comorbidities.
PMCID: PMC4338687  PMID: 25359400
atrial fibrillation; epidemiology; health care; health disparities
18.  Serum and dietary magnesium and the incidence of atrial fibrillation in whites and African Americans: the Atherosclerosis Risk in Communities (ARIC) Study 
Low serum magnesium (Mg) has been associated with an increased risk of cardiovascular disease (CVD), including ventricular arrhythmias. However, the association between serum or dietary Mg and AF has not been investigated.
Methods and Results
We studied 14,290 men and women (75% white, 53% women, mean age 54) free of AF at baseline participating in the Atherosclerosis Risk in Communities study in the United States. Incident AF cases through 2009 were ascertained from electrocardiograms, hospital discharge codes, and death certificates. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for AF associated with serum and dietary Mg quintiles. Over a median follow-up time of 20.6 years, 1,755 incident AF cases were identified. In multivariable models, lower serum Mg was associated with higher AF risk: compared to individuals in the middle quintile (≥1.60–1.65 mEq/L), the HR (95% CI) of AF in quintiles 1, 2, 4, and 5 were 1.34 (1.16–1.54), 0.99 (0.85–1.16), 1.04 (0.90–1.22), and 1.06 (0.91–1.23), respectively. There was no evidence of significant interactions between serum Mg and sex or race. No association between dietary Mg and AF risk was observed.
Lower serum Mg was associated with a higher AF risk, and this association was not different between whites and African Americans. Dietary Mg was not associated with AF risk.
PMCID: PMC4228988  PMID: 23047297
atrial fibrillation; serum magnesium; dietary magnesium
19.  Vitamin D and Subclinical Cerebrovascular Disease 
JAMA neurology  2014;71(7):863-871.
Vitamin D deficiency has been associated with hypertension, diabetes mellitus, and incident stroke. Little is known about the association between vitamin D and subclinical cerebrovascular disease.
To examine the relationship of 25-hydroxyvitamin D (25[OH]D) levels with cerebrovascular abnormalities as assessed on brain magnetic resonance imaging (MRI) among participants of the Atherosclerosis Risk in Communities (ARIC) Brain MRI study.
Participants were white and black adults aged 55 to 72 years with no history of clinical stroke who underwent a cerebral MRI at ARIC visit 3 (n = 1622) and a second cerebral MRI approximately 10 years later (n = 888).
The 25(OH)D level was measured by mass spectrometry at visit 3, with levels adjusted for calendar month and categorized using race-specific quartiles.
The cross-sectional and prospective associations of 25(OH)D levels with white matter hyperintensities (WMHs) and MRI-defined infarcts were investigated using multivariable regression models.
The mean age of the participants was 62 years, 59.6% were women, and 48.6% were black. Lower 25(OH)D levels were not significantly associated with WMH score of severity, prevalent high-grade WMH score (≥3), or prevalent infarcts in cross-sectional, multivariable-adjusted models (all P > .05). Similarly, no significant prospective associations were found for lower 25(OH)D levels with change in WMH volume, incident high WMH score (≥3), or incident infarcts on the follow-up MRI, which occurred approximately 10 years later.
A single measure of 25(OH)D was not cross-sectionally associated with WMH grade or prevalent subclinical infarcts and was not prospectively associated with WMH progression or subclinical brain infarcts seen on serial cerebral MRIs obtained approximately 10 years apart. These findings do not support optimizing vitamin D levels for brain health.
PMCID: PMC4218739  PMID: 24861877
20.  Circulating Fibroblast Growth Factor‐23 and the Incidence of Atrial Fibrillation: The Atherosclerosis Risk in Communities Study 
Increased concentrations of circulating fibroblast growth factor 23 (FGF‐23) have been associated with higher risk of cardiovascular disease. The association between FGF‐23 and the risk of atrial fibrillation (AF), a common arrhythmia, is less defined. Thus, we explored whether FGF‐23 concentration was associated with AF incidence in a large community‐based cohort.
Methods and Results
We studied 12 349 men and women enrolled in the Atherosclerosis Risk in Communities (ARIC) study, without prevalent AF at baseline in 1990–1992. Serum intact FGF‐23 concentration was measured with the Kainos 2‐site ELISA. Incident AF through 2010 was ascertained from study ECGs and hospital discharge codes. Cox proportional hazards models adjusted for potential confounding factors, including kidney function, were used to estimate the association between FGF‐23 and AF risk. We identified 1572 AF events during a mean follow‐up of 17 years. In multivariable analysis, a difference of 1 SD (16 pg/mL) in baseline FGF‐23 was not associated with the risk of AF (hazard ratio [HR], 1.04; 95% confidence interval [CI], 0.99, 1.09). Results were similar when FGF‐23 was modeled in quartiles (HR, 1.09; 95% CI, 0.94, 1.26, comparing extreme quartiles). Reduced kidney function was associated with increased AF risk across quartiles of FGF‐23 levels.
In this large community‐based cohort, baseline FGF‐23 levels were not associated with AF risk independently of kidney function. Our results do not support a major role for FGF‐23 as a risk factor for AF or as a mediator of the association between chronic kidney disease and AF.
PMCID: PMC4323781  PMID: 25237047
atrial fibrillation; epidemiology; kidney; risk factors
21.  Obstructive Sleep Apnea and Progression of Coronary Artery Calcium: The Multi‐Ethnic Study of Atherosclerosis Study 
Obstructive sleep apnea (OSA) is a common condition associated with cardiovascular disease. Its potential effect on progression of subclinical atherosclerosis is not well understood. We tested the hypothesis that self‐reported OSA is associated with progression of coronary artery calcium (CAC). We also evaluated whether traditional cardiovascular risk factors accounted for the association.
Methods and Results
In the Multi‐Ethnic Study of Atherosclerosis (MESA) prospective cohort, we studied 2603 participants who at baseline (2002–2004) completed a sleep questionnaire and underwent coronary computed tomography (CT) and, then 8 years later (2010–2011), a repeat coronary CT. Participants were categorized by symptoms of habitual snoring or reported physician diagnosis of OSA. At baseline, 102 (3.9%) reported diagnosed OSA; 666 (25.6%) reported diagnosed habitual snoring; and 1835 (70.5%) reported neither habitual snoring nor OSA (“normal”). At baseline, CAC prevalence was highest among those with OSA but similar for those with and without habitual snoring. During 8 years of follow‐up, greater progression of CAC was observed among those with OSA versus normal (mean increase of 204.2 versus 135.5 Agatston units; P=0.01), after accounting for demographics, behaviors, and body habitus. Modest attenuation was observed after adjustment for cardiovascular risk factors (188.7 versus 138.8; P=0.06). CAC progression among habitual snorers was similar to that observed in the normal group.
OSA was associated with CAC score progression after adjustment for demographics, behaviors, and body mass index. However, the association was not significant after accounting for cardiovascular risk factors, which may mediate the association between OSA and CAC.
PMCID: PMC4323795  PMID: 25261530
coronary artery calcium; obstructive sleep apnea; snoring; subclinical atherosclerosis risk factor
22.  Racial and Regional Differences in Venous Thromboembolism in the United States in Three Cohorts 
Circulation  2014;129(14):1502-1509.
Blacks are thought to have a higher risk of venous thromboembolism (VTE) than whites however prior studies are limited to administrative databases that lack specific information on VTE risk factors or have limited geographic scope.
Methods and Results
We ascertained VTE from three prospective studies; the Atherosclerosis Risk in Communities study (ARIC), the Cardiovascular Health Study (CHS), and the REasons for Geographic and Racial Differences in Stroke study (REGARDS). We tested the association of race with VTE using Cox proportional hazard models adjusted for VTE risk factors. Over 438,090 person-years, 916 incident VTE events (302 in blacks) occurred in 51,149 individuals (17,318 blacks) followed. In risk factor-adjusted models, blacks had a higher rate of VTE than whites in CHS (HR 1.81; 95% CI 1.20, 2.73) but not ARIC (HR 1.21; 95% CI 0.96, 1.54). In REGARDS, there was a significant region by race interaction (p = 0.01); blacks in the southeast had a significantly higher rate of VTE than blacks in the rest of the US (HR 1.63; 95% CI 1.08, 2.48) which was not seen in whites (HR 0.83; 95% CI 0.61, 1.14).
The association of race with VTE differed in each cohort, which may reflect the different time periods of the studies and/or different regional rates of VTE. Further study of environmental and genetic risk factors for VTE are needed to determine which underlie racial and perhaps regional differences in VTE.
PMCID: PMC4098668  PMID: 24508826
Venous Thrombosis; Epidemiology; Race
23.  Lipoprotein-associated phospholipase A2 and venous thromboembolism: a prospective study 
Thrombosis research  2013;132(1):44-46.
Plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammatory marker associated positively with atherothrombotic risk. Whether Lp-PLA2 is related to risk of venous thromboembolism (VTE) is incompletely studied.
We assessed Lp-PLA2 activity in 10,687 Atherosclerosis Risk in Communities (ARIC) Study participants and followed them a median of 8.3 years (from 1996–98 through 2005) for VTE occurrence (n = 226).
There was no significant association between baseline Lp-PLA2 quartiles and risk of VTE, neither overall nor stratified as provoked or unprovoked. Adjusted for other risk factors, the hazard ratios (95% confidence interval) of total VTE across quartiles of Lp-PLA2 were 1.0 (reference), 0.95 (0.64, 1.42), 1.03 (0.69, 1.56), and 1.26 (0.83, 1.91). In the subset of participants with LDL-cholesterol ≥ 130 mg/dL, hazard ratios of total VTE were 1.00, 1.39 (0.44, 4.44), 2.45 (0.84, 7.11), and 2.84 (0.99, 8.14).
Our study does not support the overall hypothesis that elevated Lp-PLA2 contributes to VTE occurrence in the general population. However, in the presence of high LDL-cholesterol there was some evidence that Lp-PLA2 may increase VTE risk.
PMCID: PMC3742644  PMID: 23746626
lipoprotein-associated phospholipase A2; prospective study; pulmonary embolism; venous thromboembolism
24.  Statin Therapy and Levels of Hemostatic Factors in a Healthy Population: the Multi-Ethnic Study of Atherosclerosis 
HMG CoA reductase inhibitors (statins) reduce risk of venous thromboembolism (VTE) in healthy people. Statins reduce levels of inflammation biomarkers, however the mechanism for reduction in VTE risk is unknown. In a large cohort of healthy people, we studied associations of statin use with plasma hemostatic factors related to VTE risk.
Cross-sectional analyses were performed in the Multi-Ethnic Study of Atherosclerosis (MESA), a cohort study of 6814 healthy men and women age 45–84, free of clinical cardiovascular disease at baseline; 1001 were using statins at baseline. Twenty-three warfarin users were excluded. Age, race, and sex-adjusted mean hemostatic factor levels were compared between statin users and nonusers, and multivariable linear regression models were used to assess associations of statin use with hemostasis factors, adjusted for age, race/ethnicity, education, income, hormone replacement therapy (in women), and major cardiovascular risk factors.
Participants using statins had lower adjusted levels of D-dimer (−9%), C-reactive protein (−21%) and factor VIII (−3%) than non-users (p<0.05). Homocysteine and von Willebrand factor were non-significantly lower with statin use. Higher fibrinogen (2%) and PAI-1 (22%) levels were observed among statin users than nonusers (p<0.05). Further adjustment for LDL and triglyceride levels did not attenuate the observed differences in these factors by statin use.
Findings of lower D-dimer, factor VIII and C-reactive protein levels with statin use suggest hypotheses for mechanisms whereby statins might lower VTE risk. A prospective study or clinical trial linking these biochemical differences to VTE outcomes in statin users and nonusers is warranted.
PMCID: PMC3702638  PMID: 23565981
statins; thrombosis; risk factor; blood coagulation; inflammation; fibrinolysis
25.  Physical Activity and Cardiovascular Disease in African Americans in ARIC 
Although there is substantial evidence that physical activity reduces a person's risk of cardiovascular disease (CVD), few of these studies have included African Americans. The studies that have included African Americans offer inconclusive evidence on the association and none studied heart failure separately. We used data from the Atherosclerosis Risk in Communities study cohort to examine, in African Americans, the association of physical activity with the incidence of CVD and its major components – stroke, heart failure, and coronary heart disease.
Participants aged 45 to 64 years (3,707 African Americans and, for comparison, 10,018 Caucasians) had physical activity assessed via questionnaire in 1987 and were followed for incident CVD (n=1,039) through 2008.
After adjustment for potential confounders, physical activity was inversely related to CVD, heart failure, and coronary heart disease incidence in both races (p-values for trend <.0001), and with stroke in African Americans. Hazard ratios (95% confidence intervals) for CVD for each higher physical activity category were similar by race: 1.0, 0.65 (0.56, 0.75), and 0.59 (0.49, 0.71) for African Americans and 1.0, 0.74 (0.66, 0.83), and 0.67 (0.59, 0.75) for Caucasians (p-value for interaction = 0.38).
Our findings reinforce recommendations that regular physical activity is important for CVD risk reduction in African Americans as well as Caucasians and support the idea that some physical activity is better than none.
PMCID: PMC3622814  PMID: 23247714
exercise; stroke; coronary heart disease; heart failure; race

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