Association of Left Atrial Enlargement and Atrial Fibrillation With Cognitive Function and Decline: The ARIC-NCS

Background Atrial fibrillation (AF) is associated with cognitive decline. Whether left atrial enlargement (LAE), a critical substrate for AF, is also associated is less well established. Therefore, we assessed the association of LAE and AF with cognitive decline in the ARIC-NCS (Atherosclerosis Risk in Communities Neurocognitive Study). Methods and Results Participants (n=3391; mean age, 75±5 years; 59% women) underwent cognitive tests and 2-dimensional echocardiograms at visit 5 (2011-2013) and follow-up cognitive tests at visit 6 (2016-2017). LAE was defined as left atrium volume index ≥34 mL/m2. AF was ascertained using study ECGs and hospitalization discharge codes. We assessed the association of AF and LAE with (a) cognitive domain scores at visit 5 and (b) cognitive domain score changes between visit 5 and visit 6. At visit 5, compared with the reference group (without AF, normal left atrium), participants with LAE and AF had significantly lower global cognition (Z score, -0.24; 95% CI, -0.38 to -0.10), whereas participants with AF and without LAE and participants with LAE and without AF did not have lower global cognition. In longitudinal analysis, compared with the reference group, participants with AF but without LAE had significantly greater decline in global cognition (Z score, -0.13; 95% CI, -0.21 to -0.06). However, LAE, with or without AF, was not associated with greater cognitive decline. Conclusion Although LAE with AF was significantly associated with lower cognitive function in cross-sectional analysis, LAE, with or without AF, was not associated with greater cognitive decline over 5 years, highlighting the importance of evaluating longitudinal cognitive function. Future studies should have longer follow-up and evaluate left atrium function.

Association of Oral Anticoagulant Type With Risk of Dementia Among Patients With Nonvalvular Atrial Fibrillation

Background

Oral anticoagulants (OACs) in patients with atrial fibrillation (AF), in addition to reducing stroke risk, could also prevent adverse cognitive outcomes. The purpose of this study was to compare the risk of dementia incidence across patients with AF initiating different OACs.

Methods and Results

We identified patients with nonvalvular AF initiating OACs in 2 US healthcare claim databases, MarketScan (2007–2015) and Optum Clinformatics (2009–2015). Dementia, comorbidities, and use of medications were defined on the basis of inpatient and outpatient claims. We performed head‐to‐head comparisons of warfarin, dabigatran, rivaroxaban, and apixaban in propensity score–matched cohorts. We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) of incident dementia for each propensity score–matched cohort and meta‐analyzed database‐specific results. We analyzed 307 099 patients with AF from the MarketScan database and 161 346 from the Optum database, of which 6572 and 4391, respectively, had a diagnosis of incident dementia. The mean follow‐up of each cohort ranged between 0.7 and 2.2 years. Patients initiating direct OACs experienced lower rates of dementia than those initiating warfarin (dabigatran: HR, 0.85; 95% CI, 0.71–1.01; rivaroxaban: HR, 0.85; 95% CI, 0.76–0.94; apixaban: HR, 0.80; 95% CI, 0.65–0.97). There were no differences in rates of dementia comparing direct OAC user groups (dabigatran versus rivaroxaban: HR, 1.02; 95% CI, 0.79–1.32; dabigatran versus apixaban: HR, 0.92; 95% CI, 0.63–1.36; apixaban versus rivaroxaban: HR, 1.01; 95% CI, 0.86–1.19).

Conclusions

Patients with AF initiating direct OACs experienced lower rates of incident dementia than warfarin users. No obvious benefit was observed for any particular direct OAC in relation to dementia rates.

Sequencing Analysis at 8p23 Identifies Multiple Rare Variants in DLC1 Associated with Sleep-Related Oxyhemoglobin Saturation Level

Average arterial oxyhemoglobin saturation during sleep (AvSpO2S) is a clinically relevant measure of physiological stress associated with sleep-disordered breathing, and this measure predicts incident cardiovascular disease and mortality. Using high-depth whole-genome sequencing data from the National Heart, Lung, and Blood Institute (NHLBI) Trans-Omics for Precision Medicine (TOPMed) project and focusing on genes with linkage evidence on chromosome 8p23,1,2 we observed that six coding and 51 noncoding variants in a gene that encodes the GTPase-activating protein (DLC1) are significantly associated with AvSpO2S and replicated in independent subjects. The combined DLC1 association evidence of discovery and replication cohorts reaches genome-wide significance in European Americans (p = 7.9 × 10-7). A risk score for these variants, built on an independent dataset, explains 0.97% of the AvSpO2S variation and contributes to the linkage evidence. The 51 noncoding variants are enriched in regulatory features in a human lung fibroblast cell line and contribute to DLC1 expression variation. Mendelian randomization analysis using these variants indicates a significant causal effect of DLC1 expression in fibroblasts on AvSpO2S. Multiple sources of information, including genetic variants, gene expression, and methylation, consistently suggest that DLC1 is a gene associated with AvSpO2S.

Metabolic Syndrome and Risk of Ischemic Stroke in Atrial Fibrillation: ARIC Study

Background and Purpose- Metabolic syndrome (MetS), a prothrombotic state, is associated with an increased risk of atrial fibrillation (AF) and stroke. The CHA2DS2-VASc score does not account for the MetS components of prehypertension, prediabetes mellitus, abdominal obesity, elevated triglycerides, and low HDL (high-density lipoprotein). Data are limited on the association of MetS with stroke in AF, independent of CHA2DS2-VASc variables. Our aim was to identify MetS components associated with ischemic stroke in participants with AF in the ARIC study (Atherosclerosis Risk in Communities). Methods- We included 1172 participants with incident AF within 5 years of measurement of MetS components. MetS was defined by ATP criteria and International Diabetes Federation criteria. Incident ischemic stroke was physician adjudicated. Multivariable Cox proportional hazards regression was used to assess the association of MetS components with stroke. Results- After a median follow-up of 14.8 years, there were 113 ischemic stroke cases. Of the individual MetS components, low HDL was borderline associated with increased stroke risk (hazard ratio, 1.48 [95% CI, 0.99-2.21]) after adjustment for CHA2DS2-VASc variables while the remaining MetS variables were not associated with stroke risk. The presence of ≥3 components of MetS was not significantly associated with ischemic stroke after adjustment for CHA2DS2-VASc variables (hazard ratio, 1.38 [95% CI, 0.91-2.11]). The risk of stroke increased by 13% for each additional component of MetS; however, this association was borderline significant (hazard ratio, 1.13 [95% CI, 0.99-1.28]). Conclusions- The presence of MetS was not significantly associated with ischemic stroke after adjustment for CHA2DS2-VASc variables. Consideration of MetS is unlikely to improve stroke prediction in AF.

Mid-life serum Vitamin D concentrations were associated with incident dementia but not late-life neuropsychological performance in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Activated Vitamin D has anti-inflammatory properties and adequate 25-hydroxyvitamin D [25(OH)D] concentrations may be important for neurocognitive function and protection against neurologic injury. We examined whether mid-life 25(OH) D concentrations were associated with later-life performance on neuropsychological testing, functional ability, depressive symptoms, and incident dementia.

METHODS

We studied 13,039 white and black ARIC participants who had serum 25(OH) D measured mid-life at visit 2 (1990-1992). Over the next ~ 20 years through visit 5 (2011-2013), participants underwent 3 additional in-person visits, annual telephone calls, and hospitalization surveillance. An extensive battery of neuropsychological outcomes were assessed at visit 5 using standardized protocols. Incident dementia was ascertained through a formal algorithm that included data from in-person cognitive testing, telephone interviews, hospital discharge codes, and death certificate codes. Diagnoses of dementia were adjudicated by expert clinician committee. For the primary cognitive analyses, we imputed for missing covariates and outcomes and used linear regression to evaluate non-concurrent cross-sectional associations of mid-life 25(OH) D (visit 2) with late-life neuropsychological outcomes (visit 5). We also used Cox regression models to examine associations of mid-life 25(OH) D and incident dementia.

RESULTS

In mid-life, the mean (SD) age of participants was 57 (6) years, 57% were women, and 24% black. Mean (SD) 25(OH) D was 24.3 (8.6) ng/mL; 33% had deficient (< 20 ng/mL), 44% intermediate (20- < 30 ng/mL), and 23% sufficient (≥30 ng/mL) 25(OH) D concentrations. Association between mid-life 25(OH) D and late-life performance on neuropsychological testing were mostly null. There was no significant association with functional ability or depressive symptoms. Results were similar in a sensitivity analysis using complete-case data (no imputation). However, after a median follow-up of 20 years, low 25(OH) D concentrations were associated with increased risk for incident dementia (p = 0.01 for trend across categories), with HR of 1.26 (95% CI 1.06, 1.49) for participants with deficient 25(OH) D, compared to sufficient concentrations.

CONCLUSION

In this community cohort, mid-life serum 25(OH) D concentrations were associated with incident dementia but not with performance on neuropsychological testing, functional ability, or depressive symptoms, 20 years later. Whether serum 25(OH) D concentrations are causally related to dementia or confounded by poorer health status remains uncertain.

TRIAL REGISTRATION

Registered on clinicaltrials.gov NCT00005131 .

Direct oral anticoagulants and warfarin for venous thromboembolism treatment: Trends from 2012 to 2017

BACKGROUND

Direct oral anticoagulants (DOACs), namely rivaroxaban, apixaban, dabigatran, and edoxaban, are now included together with warfarin as standards of care for the primary treatment of venous thromboembolism (VTE). The extent to which the DOACs have been adopted since receiving US Food and Drug Administration (FDA) approval is unknown.

OBJECTIVE

To document temporal trends in oral anticoagulant (OAC) prescriptions among anticoagulant-naïve patients initiating OACs for VTE primary treatment in the United States and to report participant characteristics by OAC prescribed for the year 2017.

METHODS

MarketScan databases for years 2012 through 2017 were used to identify VTE cases and comorbidities using International Classification of Diseases codes and prescriptions for OACs via outpatient pharmaceutical claims data.

RESULTS

The 137 203 VTE cases were on average (± standard deviation) 56.7 ± 16.0 years old and 49.9% female. Warfarin was prescribed to 98.7% of VTE patients receiving an OAC in quarter 1 (January through March) of 2012. By quarter 4 (October through December) of 2017, warfarin was prescribed to 17.5%, while rivaroxaban was prescribed to 42.7%, apixaban to 38.6%, dabigatran to 1.3%, and edoxaban to <0.1%. In 2017, the comorbidity burden was highest among patients prescribed warfarin, intermediate among patients prescribed apixaban, and lowest among patients prescribed rivaroxaban.

CONCLUSIONS

Rivaroxaban and apixaban use to treat VTE has increased dramatically since receiving FDA approval, whereas warfarin use has plummeted. Dabigatran and edoxaban are infrequently prescribed. Given widespread usage of rivaroxaban and apixaban, there is a need for continued monitoring of the comparative effectiveness of these OAC therapies in real-world settings.

Prevalence and Characteristics of Subclinical Atrial Fibrillation in a Community-Dwelling Elderly Population: The ARIC Study

BACKGROUND

The prevalence of subclinical atrial fibrillation (AF) in the elderly general population is unclear. We sought to define the prevalence of subclinical AF in a community-based elderly population and to characterize subclinical AF and the incremental diagnostic yield of 4 versus 2 weeks of continuous ECG monitoring.

METHODS

We conducted a cross-sectional analysis within the community-based multicenter observational ARIC study (Atherosclerosis Risk in Communities) using visit 6 (2016-2017) data. The 2616 ARIC study participants who wore a leadless, ambulatory ECG monitor (Zio XT Patch) for up to 2 weeks were aged 79±5 years, 42% men, and 26% black. In a subset, 386 participants without clinically recognized AF wore the monitor twice, each time for up to 2 weeks. We characterized the prevalence of subclinical AF (ie, AF detected on the Zio XT Patch without clinically recognized AF) over 2 weeks of monitoring and the diagnostic yield of 4 versus 2 weeks of monitoring.

RESULTS

The prevalence of subclinical AF was 2.5%; the prevalence of subclinical AF was 3.3% among white men, 2.5% among white women, 2.1% among black men, and 1.6% among black women. Subclinical AF was mostly intermittent (75%). Among those with intermittent subclinical AF, 91% had AF burden ≤10% during the monitoring period. In a subset of 386 participants without clinical AF, 78% more subclinical AF was detected by 4 weeks versus 2 weeks of ECG monitoring.

CONCLUSIONS

In our study, the prevalence of subclinical AF was lower than previously reported and monitoring beyond 2 weeks provided substantial incremental diagnostic yield. Future studies should focus on individuals with higher risk to increase diagnostic yield and consider continuous monitoring duration longer than 2 weeks.

Joint Associations of Obesity and NT-proBNP With the Incidence of Atrial Fibrillation in the ARIC Study

Background

Circulating NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) levels, a well‐known indicator of atrial wall stress and remodeling, inversely correlate with body mass index. Both are strongly predictive of atrial fibrillation (AF). Their potential interaction in relation to incident AF, however, has not been explored.

Methods and Results

In total, 9556 participants of the ARIC (Atherosclerosis Risk in Communities) study who had 2 measurements of NT‐proBNP and no baseline AF or heart failure were followed from 1996 to 1998 through 2016 for the occurrence of incident AF. Participants were categorized as obese (body mass index ≥30) and nonobese (body mass index <30) and by NT‐proBNP levels (using the median of 68.2 pg/mL as the cutoff). Over a median follow‐up of 18.3 years, we identified 1806 incident cases of AF. Analysis using multivariable Cox regression models showed that obese participants with high NT‐proBNP levels at visit 4 had a higher adjusted risk of incident AF (hazard ratio: 3.64; 95% CI, 3.15–4.22) compared with nonobese individuals with low NT‐proBNP levels. The association of obesity with AF risk was not modified by NT‐proBNP levels (P=0.46 for interaction). Increasing BNP among participants from 1990–1992 to 1996–1998 was associated with increased AF risk. After further adjustment for clinical risk factors and medications, results were similar.

Conclusions

Individuals who had both elevated body mass index and NT‐proBNP and were free of clinically recognized heart failure were at higher risk of AF development. Those who experienced an increase in NT‐proBNP levels between visits 2 and 4 were at higher risk of AF.

Serum 25-Hydroxyvitamin D Concentrations and Incidence of Age-Related Macular Degeneration: The Atherosclerosis Risk in Communities Study

Purpose

To investigate the association between serum 25-hydroxyvitamin D (25[OH]D) concentrations at visit 2 (1990–1992) and the 18-year incidence of age-related macular degeneration (AMD) between visit 3 (1993–1995) and visit 5 (2011–2013).

Methods

This prospective analysis was conducted in a subset of participants (n = 1225) from the Atherosclerosis Risk in Communities Study. We evaluated the incidence of any, early, and late AMD from visit 3 to 5. The 25(OH)D concentrations were assessed in 2012–2013 by using stored serum from visit 2. Retinal fundus photographs taken at both visits were graded side by side to determine the incidence of AMD. Logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for incident AMD outcomes during 18 years of follow-up (1993–1995 to 2011–2013) by tertile of 25(OH)D adjusted for age, race, and smoking status. P for linear trend was estimated by using continuous 25(OH)D concentrations. Sensitivity analyses applied inverse probability weights to account for selection to have eye photographs, death, and loss to follow-up.

Results

There was a decreased odds of any incident AMD (n = 139) and large, soft drusen (n = 80) in 25(OH)D tertile 3 versus 1, with OR (95% CI) = 0.57 (0.36–0.90), P trend = 0.11 and with 0.52 (0.28–0.93), P trend = 0.18, respectively. Applying sampling weights attenuated these results to 0.66 (0.38–1.16), P trend = 0.32 (any incident AMD) and 0.54 (0.27–1.09), P trend = 0.36 (large, soft drusen), respectively, suggesting these associations may be biased by loss to follow-up and sampling for retinal photographs at visit 5. No statistically significant results were observed with pigmentary abnormalities (n = 46) or incident late AMD (n = 26).

Conclusions

High 25(OH)D concentrations, approximately >70 nM, may be associated with decreased odds of incident early AMD.

Provider Specialty, Anticoagulation, and Stroke Risk in Patients With Atrial Fibrillation and Cancer

BACKGROUND

It is unknown whether early cardiology involvement shortly after atrial fibrillation (AF) diagnosis is associated with favorable outcomes in AF patients who have cancer.

OBJECTIVES

The purpose of this study was to examine the relationship between early cardiology involvement after AF diagnosis in patients with history of cancer.

METHODS

This study examined associations of early cardiology involvement with oral anticoagulation use, stroke, and bleeding among nonvalvular AF patients (n = 388,045; mean age 68 ± 15 years; 59% male) with a history of cancer (past or active) from the MarketScan database (2009 to 2014). International Classification of Disease-9th Revision-Clinical Modification codes in any position were used to identify cancer diagnosis prior to AF diagnosis. Provider specialty and filled anticoagulant prescriptions 3 months prior to and 6 months after AF diagnosis were obtained. Poisson regression models were used to compute the probability of an oral anticoagulant prescription fill, and Cox regression was used to estimate the risks of stroke and major bleeding.

RESULTS

A total of 64,016 (17%) AF patients had a history of cancer. Cardiology involvement was less likely to occur among patients with a history of cancer than those without (relative risk [RR]: 0.92 [95% confidence interval (CI): 0.91 to 0.93]). Patients with history of cancer were less likely to fill prescriptions for anticoagulants (RR: 0.89 [95% CI: 0.88 to 0.90]) than those without cancer, and similar results were observed across cancer types. Patients with cancer were more likely to fill prescriptions for anticoagulants (RR: 1.48 [95% CI: 1.45 to 1.52]) if seen by a cardiologist. A reduced risk of stroke (hazard ratio: 0.89 [95% CI: 0.81 to 0.99]) was observed among all cancer patients who were seen by a cardiology provider, without an increased risk of bleeding (hazard ratio: 1.04 [95% CI: 0.95 to 1.13]). Similar results were observed when the analysis was stratified by active versus remote history of cancer.

CONCLUSIONS

Although AF patients with cancer were less likely to see a cardiologist, or fill anticoagulant prescriptions, cardiology involvement was associated with increased anticoagulant prescription fills and favorable AF-related outcomes in AF patients with cancer.

Sex and racial differences in cardiovascular disease risk in patients with atrial fibrillation

BACKGROUND

Outcomes among atrial fibrillation (AF) patients may differ according to race/ethnicity and sex due to differences in biology, the prevalence of cardiovascular risk factors, and the use and effectiveness of AF treatments. We aimed to characterize patterns of cardiovascular risk across subgroups of AF patients by sex and race/ethnicity, since doing so may provide opportunities to identify interventions. We also evaluated whether these patterns changed over time.

METHODS

We utilized administrative claims data from the Optum Clinformatics® Datamart database from 2009 to 2015. Patients with AF with ≥6 months of enrollment prior to the first non-valvular AF diagnosis were included in the analysis. Final analysis utilized Cox proportional hazard models to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cardiovascular outcomes stratified by sex and race/ethnicity. An additional analysis stratified outcomes by calendar year of AF diagnosis to evaluate changes in outcomes over time.

RESULTS

In a cohort of 380,636 AF patients, women had a higher risk of ischemic stroke [HR (95% CI): 1.25 (1.19, 1.31)] and lower risk of heart failure and myocardial infarction [HR (95% CI): 0.91 (0.88, 0.94) and 0.81 (0.77, 0.86), respectively)] compared to men. Black patients had elevated risk across all endpoints compared to whites, while Hispanics and Asian Americans showed no significant differences in any outcome compared to white patients. These sex and race/ethnic differences did not change over time.

CONCLUSIONS

We found sex and race/ethnic differences in risk of cardiovascular outcomes among AF patients, without evidence of improvement over time.

Association of Midlife to Late-Life Blood Pressure Patterns With Incident Dementia

Importance

The association between late-life blood pressure (BP) and cognition may depend on the presence and chronicity of past hypertension. Late-life declines in blood pressure following prolonged hypertension may be associated with poor cognitive outcomes.

Objective

To examine the association of midlife to late-life BP patterns with subsequent dementia, mild cognitive impairment, and cognitive decline.

Design, Setting, and Participants

The Atherosclerosis Risk in Communities prospective population-based cohort study enrolled 4761 participants during midlife (visit 1, 1987-1989) and followed-up over 6 visits through 2016-2017 (visit 6). BP was examined over 24 years at 5 in-person visits between visits 1 and 5 (2011-2013). During visits 5 and 6, participants underwent detailed neurocognitive evaluation. The setting was 4 US communities: Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and Minneapolis, Minnesota. Follow-up ended on December 31, 2017.

Exposures

Five groups based on longitudinal patterns of normotension, hypertension (>140/90 mm Hg), and hypotension (<90/60 mm Hg) at visits 1 to 5.

Main Outcomes and Measures

Primary outcome was dementia onset after visit 5, based on Ascertain Dementia-8 informant questionnaires, Six-Item Screener telephone assessments, hospital discharge and death certificate codes, and the visit 6 neurocognitive evaluation. Secondary outcome was mild cognitive impairment at visit 6, based on the neurocognitive evaluation.

Results

Among 4761 participants (2821 [59%] women; 979 [21%] black race; visit 5 mean [SD] age, 75 [5] years; visit 1 mean age range, 44-66 years; visit 5 mean age range, 66-90 years), there were 516 (11%) incident dementia cases between visits 5 and 6. The dementia incidence rate for participants with normotension in midlife (n = 833) and late life was 1.31 (95% CI, 1.00-1.72 per 100 person-years); for midlife normotension and late-life hypertension (n = 1559), 1.99 (95% CI, 1.69-2.32 per 100 person-years); for midlife and late-life hypertension (n = 1030), 2.83 (95% CI, 2.40-3.35 per 100 person-years); for midlife normotension and late-life hypotension (n = 927), 2.07 (95% CI, 1.68-2.54 per 100 person-years); and for midlife hypertension and late-life hypotension (n = 389), 4.26 (95% CI, 3.40-5.32 per 100 person-years). Participants in the midlife and late-life hypertension group (hazard ratio [HR], 1.49 [95% CI, 1.06-2.08]) and in the midlife hypertension and late-life hypotension group (HR, 1.62 [95% CI, 1.11-2.37]) had significantly increased risk of subsequent dementia compared with those who remained normotensive. Irrespective of late-life BP, sustained hypertension in midlife was associated with dementia risk (HR, 1.41 [95% CI, 1.17-1.71]). Compared with those who were normotensive in midlife and late life, only participants with midlife hypertension and late-life hypotension had higher risk of mild cognitive impairment (37 affected individuals (odds ratio, 1.65 [95% CI, 1.01-2.69]). There was no significant association of BP patterns with late-life cognitive change.

Conclusions and Relevance

In this community-based cohort with long-term follow-up, sustained hypertension in midlife to late life and a pattern of midlife hypertension and late-life hypotension, compared with midlife and late-life normal BP, were associated with increased risk for subsequent dementia.

Association Between Thyroid Dysfunction and Incident Dementia in the Atherosclerosis Risk in Communities Neurocognitive Study

BACKGROUND

Abnormal thyroid hormone levels (high or low) and autoimmunity from autoimmune thyroid disease (AITD) may increase dementia risk.

METHODS

We examined the associations of thyroid dysfunction or possible AITD in 1990 - 1992 with dementia through 2017 in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. Thyroid dysfunction (subclinical and overt hypo- or hyperthyroidism and euthyroidism) was categorized from serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) cut-points and AITD from anti-thyroid peroxidase (anti-TPO) antibody positivity. Dementia was identified primarily based on cognitive test performance, neuropsychological examinations and clinician review of suspected cases. Additional cases of dementia were ascertained through telephone interviews or relevant hospital and death certificate codes. Cox regression with multivariable adjustment was used for analysis.

RESULTS

After exclusions for missing data, 12,481 participants were included in the analysis (mean index exam age 57 ± 5.7 (44% male, 25% black)), and 2,235 incident dementia cases were identified. AITD was not significantly associated with dementia. Subclinical hypothyroidism was associated with a lower risk of dementia (hazard ratio (HR) (95% confidence interval (CI)): 0.74 (0.60 - 0.92)), while overt hyperthyroidism was associated with a higher risk of dementia (HR (95% CI): 1.40 (1.02 - 1.92)) compared to euthyroid participants. Participants with serum FT4 concentrations above the 95th percentile were at an increased risk of dementia compared to those in the middle 90% of FT4 (HR (95% CI): 1.23 (1.02 - 1.48)).

CONCLUSIONS

Subclinical hypothyroidism was associated with reduced risk of dementia, whereas overt hyperthyroidism, particularly very elevated FT4, was associated with increased risk of dementia. The association between subclinical hypothyroidism and reduced risk of dementia cannot be explained, but may have been an artifact due to change. By extrapolation, effective treatment of overt hyperthyroidism may modestly reduce dementia risk in older adults.

Prospective Association of Serum and Dietary Magnesium with Colorectal Cancer Incidence

BACKGROUND

Laboratory and epidemiologic research suggests a protective role of magnesium in colorectal cancer development. We estimated the associations of serum and dietary magnesium with colorectal cancer incidence in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS

Serum magnesium concentration was measured in blood collected twice (1987-1989 and 1990-1992) and averaged. Dietary magnesium was assessed by food-frequency questionnaire administered twice (1987-1989 and 1993-1995) and averaged. For both dietary and serum magnesium, the averaged measures were categorized into quintiles for analysis. Analyses included 315 colorectal cancer cases among 13,009 participants for serum magnesium (followed for a median of 20.4 years), and 256 cases among 10,971 participants for dietary magnesium (followed for a median of 17.5 years). Cox proportional hazards regression was used to calculate multivariable-adjusted HRs and 95% confidence intervals (CI).

RESULTS

Multivariable-adjusted HRs (95% CI) of colorectal cancer for the highest four quintiles compared with the first quintile of serum magnesium were as follows: Q2: 0.70 (0.49-0.99); Q3: 0.68 (0.47-1.00); Q4: 0.87 (0.62-1.21); and Q5: 0.79 (0.57-1.11; P trend = 0.04). An inverse association was present in females (HR for Q5 vs. Q1: 0.59, 95% CI: 0.36-0.98, P trend = 0.01), but not males (HR for Q5 vs. Q1: 1.10, 95% CI: 0.67-1.79, P trend = 0.92; P interaction = 0.34). Dietary magnesium was not statistically significantly associated with colorectal cancer risk.

CONCLUSIONS

Our study found a higher risk of colorectal cancer with lower serum magnesium among females, but not males.

IMPACT

If our findings are confirmed, maintaining adequate serum magnesium levels may be important for colorectal cancer prevention.

Association between greater leg length and increased incidence of colorectal cancer: the atherosclerosis risk in communities (ARIC) study

PURPOSE

Previous studies have reported that taller people have an increased risk of colorectal cancer (CRC). We examined the association of two height components-leg length and sitting height-with CRC risk in 14,532 individuals aged 45-64 years in the Atherosclerosis Risk in Communities study.

METHODS

Anthropometrics were measured at baseline (1987-1989). Incident CRC cases (n = 382) were ascertained from 1987 to 2012. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios for CRC and colon cancer across quintiles of sex-specific leg length and sitting height.

RESULTS

The highest (versus the lowest) quintile of leg length was associated with a 36% greater CRC risk (p-trend = 0.04), and 51% greater colon cancer risk (p-trend = 0.01). For the top four quintiles combined, risk was increased by 34% for CRC and by 45% for colon cancer versus the lowest quintile. Total height and sitting height were not significantly associated with CRC or colon cancer risk. A small number of cases (n = 57) limited our ability to conduct subgroup analyses for rectal cancer.

CONCLUSIONS

A positive association of leg length with CRC and colon cancer risk suggests that biological mechanisms leading to greater leg length during puberty may explain the association between taller height and CRC.

Reasons for Differences in the Incidence of Venous Thromboembolism in Black Versus White Americans

INTRODUCTION

Venous thromboembolism incidence rates are 30%-100% higher in US blacks than whites. We examined the degree to which differences in the frequencies of socioeconomic, lifestyle, medical risk factors, and genetic variants explain the excess venous thromboembolism risk in blacks and whether some risk factors are more strongly associated with venous thromboembolism in blacks compared with whites.

METHODS

We measured venous thromboembolism risk factors in black and white participants of the Atherosclerosis Risk in Communities study in 1987-1989 and followed them prospectively through 2015 for venous thromboembolism incidence.

RESULTS

Over a mean of 22 years, we identified 332 venous thromboembolisms in blacks and 578 in whites, yielding 65% higher crude incidence rates per 1000 person-years in blacks. The age and sex-adjusted hazard ratio (95% confidence interval) of venous thromboembolism for blacks compared with whites was 2.04 (1.76, 2.37) for follow-up >10 years and was attenuated to 1.14 (0.89, 1.46) when adjusted for baseline confounders or mediators of the race association, which tended to be more common in blacks. For example, adjustment for just baseline weight, family income, and concentration of plasma factor VIII reduced the regression coefficient for race by 75%. There were no significant (P <0.05) 2-way multiplicative interactions of race with any risk factor, except with a 5-single nucleotide polymorphism (5-SNP) genetic risk score (a weaker venous thromboembolism risk factor in blacks) and with hospitalization for heart failure (a stronger venous thromboembolism risk factor in blacks).

CONCLUSION

The higher incidence rate of venous thromboembolism in blacks than whites was mostly explained by blacks having higher frequencies of venous thromboembolism risk factors.

A prospective study of migraine history and venous thromboembolism in older adults

BACKGROUND

Limited evidence suggests that migraine might be a risk factor for venous thromboembolism (VTE). We conducted an epidemiologic study to assess whether migraine history is associated prospectively with VTE or cross sectionally with hemostatic risk markers for VTE.

METHODS

In a population-based US cohort, 11 985 participants free of VTE reported headache symptoms in 1993-1995. We classified participants as having either migraines with or without aura, severe nonmigraine headaches, or no severe headaches. We followed them through 2015 for incident VTE verified by medical records.

RESULTS

Participants' mean age at baseline was 60 years (SD: 6). Eleven percent were classified as having a migraine history (932 without aura and 396 with aura). Over a mean of 18 years and 211 913 person-years at risk, 688 participants developed VTE. Participants with a migraine history had no greater risk of VTE compared with those free of severe headache (adjusted hazard ratio [HR]: 1.06, 95% confidence interval [CI]: 0.82-1.36). Those with migraine history with aura had an HR of 1.25 (95% CI: 0.85-1.85). Self-reported physician diagnosis of migraine carried an HR of 1.22 (0.96-1.55). At baseline, those with a history of migraine, furthermore, did not have a higher frequency of elevated hemostatic risk factors or a higher genetic risk score for VTE.

CONCLUSION

This study does not support the hypothesis that migraine history is an important risk factor for VTE in older adults.

Obstructive Sleep Apnea and Structural/Functional Properties of the Thoracic Ascending Aorta: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Structural and functional properties of the proximal thoracic aorta have important implications in clinical and subclinical cardiovascular disease (CVD). We examined whether obstructive sleep apnea (OSA) is associated with proximal aortic size and aortic stiffness in a multi-ethnic community-based cohort.

METHODS

The sample included the Multi-Ethnic Study of Atherosclerosis (MESA) Sleep Ancillary study participants without known CVD who underwent cardiac magnetic resonance imaging. The main exposure variable was OSA severity based on the polysomnography-derived apnea hypopnea index (AHI; normal, AHI <5/h; mild, 5≤ AHI <15/h; moderate to severe, AHI ≥15/h). The study outcomes were ascending aortic diameter (AoD, cm), aortic pulse wave velocity (AoPWV, m/s), and ascending aortic distensibility (AAD, %/mm Hg). Analyses were performed in the overall sample and in sex-specific strata, adjusted for multiple potential confounders.

RESULTS

The 708 participants were 55.9% female and on average 68 years old (54-93 years). There was a significant trend (p < 0.0001) of greater mean (SD) AoD across the three OSA groups: normal (n = 87), 3.13 cm (0.35); mild (n = 215), 3.25 (0.34); moderate to severe (n = 406), 3.37 (0.36). In adjusted analysis, participants with moderate to severe OSA had a greater mean AoD compared with the normal group: adjusted mean difference (95% CI), 0.12 cm (0.05, 0.20), p = 0.002. This AoD gradient was observed in women but not in men (p for interaction = 0.02). No differences were found in AoPWV or AAD among the OSA groups.

CONCLUSION

In a diverse community-based cohort, moderate to severe OSA (vs. no OSA) was associated with a larger ascending AoD in women.

Restless legs syndrome and periodic limb movements during sleep in the Multi-Ethnic Study of Atherosclerosis

Study Objectives

To investigate the prevalence of concurrent periodic limb movements during sleep (PLMS) and restless leg syndrome (RLS), as well as the prevalence of PLMS and RLS separately. Additionally, we document these prevalences by age, race/ethnicity, sex, and obesity status.

Methods

Cross-sectional data from 2041 Multi-Ethnic Study of Atherosclerosis (MESA) Sleep ancillary study participants were used. PLMS (>15 periodic limb movements per hour of sleep) was measured by polysomnography. RLS symptoms were assessed using the 2009 International Restless Legs Syndrome Study Group clinical criteria.

Results

The prevalence of RLS with PLMS was 6.7%, RLS alone 16.1%, and PLMS alone 21.2%. RLS with PLMS was prevalent in 7.0% of whites, 4.9% of blacks, 10.1% of Hispanics, and 3.3% of Chinese-Americans. In adjusted models, odds of RLS with PLMS was higher for those older than 67 years versus those younger (odds ratio [OR] [95% confidence interval [CI]] = 1.62 [1.09-2.40]). Relative to white participants, the prevalence of RLS with PLMS tended to be lower among blacks (0.56 [0.32-0.96]). The prevalence of concurrent RLS and PLMS did not statistically differ by sex or obesity status. RLS alone was more common in women.

Conclusions

Approximately 7% of our sample had RLS with PLMS ("electro-clinical RLS"). This condition was more common among older individuals, did not vary by sex, and was less common among blacks. The findings provide some of the first information about the prevalence of concurrent RLS and PLMS in a community-based sample and show distinct sex and race associations for RLS versus electro-clinical RLS.

Impaired Lung Function, Lung Disease, and Risk of Incident Dementia

Rationale: Growing evidence suggests that compromised lung health may be linked to dementia and worsening cognitive ability. Objectives: To test the hypothesis that impaired lung function or lung disease in midlife is associated with greater risk of incident dementia and mild cognitive impairment (MCI) later in life. Methods: A total of 14,184 Atherosclerosis Risk in Communities study participants who underwent spirometry and were asked about lung health (1987-1989) were followed. Dementia and MCI were defined by hospitalization diagnosis codes (1987-2013) in the whole cohort and with adjudication among 42% who attended a comprehensive neurocognitive examination (2011-2013). Measurements and Main Results: In analysis using adjudicated outcomes, odds of dementia or MCI were higher among participants with restrictive (multivariable-adjusted odds ratio, 1.58; 95% confidence interval, 1.14-2.19) and obstructive lung disease (multivariable-adjusted odds ratio, 1.33; 95% confidence interval, 1.07-1.64), compared with those without disease or respiratory symptoms. Associations were similar in analyses restricted to nonsmokers, and present for both Alzheimer's disease-related dementia and cerebrovascular etiologies. Low FEV1% predicted and FVC% predicted were also associated with increased dementia risk. Conclusions: Midlife lung disease and reduced lung function were associated with modestly increased odds of dementia and MCI later in life. Magnitudes of association were more pronounced for restrictive impairment than for obstructive lung disease. These associations were present in smokers and nonsmokers. If the observed associations are causal, policy and public health efforts to reduce smoking and improve air quality may have the added benefit of preventing the development of dementia and MCI.

Association of Life's Simple 7 with reduced clinically manifest abdominal aortic aneurysm: The ARIC study

To optimize cardiovascular health, the American Heart Association (AHA) has recommended 'Life's Simple 7 (LS7)'. We tested the hypothesis that greater adherence to the LS7 cardiovascular risk metric is associated with reduced risk of developing abdominal aortic aneurysm (AAA). A total of 14,375 black and white participants aged 45-64 years at the baseline visit of the Atherosclerosis Risk in Communities (ARIC) study cohort were included in this analysis. A 14-point summary score for LS7 was calculated, and participants were classified as having poor (0-4), average (5-9), or ideal (10-14) cardiovascular health. We also counted the number of ideal components. Poisson regression was used to calculate incidence rates for AAA, and Cox regression to calculate hazard ratios adjusted for age, race, sex, and socioeconomic status. Over 25 years of follow-up, we identified 545 clinically manifest AAA events. Incident rates per 1000 person-years declined markedly across LS7 categories: 3.4 for the 'poor' category, 2.2 for 'average', and 0.9 for 'ideal'. Compared to individuals in the 'poor' LS7 category, individuals in the 'average' category had a 52% lower AAA risk (95% CI: 37% to 63%) and those in the 'ideal' category had an 80% lower risk (95% CI: 72% to 86%). For every additional ideal component, there was a 28% lower risk of AAA (95% CI: 23% to 33%). Greater adherence to the AHA's LS7 cardiovascular risk metric is associated with a reduced risk of clinically manifest AAA. These findings support the recommendation to follow LS7 for primary prevention of AAA.

Association of Antidepressant Medication Type With the Incidence of Cardiovascular Disease in the ARIC Study

Background

The association of antidepressant medication type with the risk of cardiovascular disease (CVD) is unclear. We hypothesized that selective serotonin reuptake inhibitors (SSRIs) are associated with lower risks of CVD events relative to tricyclics and other non‐SSRI antidepressants.

Methods and Results

We studied 2027 participants from the ARIC (Atherosclerosis Risk in Communities) study (mean age 63±10 years; 29% men; 78% white) treated with antidepressants at some time between 1987 and 2013. Antidepressant usage was confirmed by participants bringing pill bottles to study visits. CVD events in the study sample were identified, including atrial fibrillation, heart failure, myocardial infarction, and ischemic stroke. Hazard ratios were used to compare CVD events adjusted for sociodemographic and clinical risk factors in SSRIs users (47%) versus non‐SSRI users. Participants were followed from antidepressant initiation up to 2016 for a median of 13.5 years. We identified 332 atrial fibrillation, 365 heart failure, 174 myocardial infarction and 119 ischemic stroke events. CVD risk was similar for SSRIs and non‐SSRI antidepressant users (hazard ratio, 1.10; 95% CI, 0.86–1.41 for atrial fibrillation; hazard ratio, 0.98; 95% CI, 0.77–1.25 for heart failure; hazard ratio, 0.91; 95% CI, 0.64–1.29 for myocardial infarction; and hazard ratio, 1.07; 95% CI, 0.70–1.63 for ischemic stroke).

Conclusions

SSRI use was not associated with reduced risk of incident CVD compared with non‐SSRI antidepressant use. These results do not provide evidence supporting the use of SSRIs compared with tricyclics and other non‐SSRI antidepressants in relation to CVD risk.