Positional cloning of the gene for multiple endocrine neoplasia-type 1

Multiple endocrine neoplasia-type 1 (MEN1) is an autosomal dominant familial cancer syndrome characterized by tumors in parathyroids, enteropancreatic endocrine tissues, and the anterior pituitary. DNA sequencing from a previously identified minimal interval on chromosome 11q13 identified several candidate genes, one of which contained 12 different frameshift, nonsense, missense, and in-frame deletion mutations in 14 probands from 15 families. The MEN1 gene contains 10 exons and encodes a ubiquitously expressed 2.8-kilobase transcript. The predicted 610-amino acid protein product, termed menin, exhibits no apparent similarities to any previously known proteins. The identification of MEN1 will enable improved understanding of the mechanism of endocrine tumorigenesis and should facilitate early diagnosis.

Simple risk model predicts incidence of atrial fibrillation in a racially and geographically diverse population: the CHARGE-AF consortium

BACKGROUND

Tools for the prediction of atrial fibrillation (AF) may identify high-risk individuals more likely to benefit from preventive interventions and serve as a benchmark to test novel putative risk factors.

METHODS AND RESULTS

Individual-level data from 3 large cohorts in the United States (Atherosclerosis Risk in Communities [ARIC] study, the Cardiovascular Health Study [CHS], and the Framingham Heart Study [FHS]), including 18 556 men and women aged 46 to 94 years (19% African Americans, 81% whites) were pooled to derive predictive models for AF using clinical variables. Validation of the derived models was performed in 7672 participants from the Age, Gene and Environment-Reykjavik study (AGES) and the Rotterdam Study (RS). The analysis included 1186 incident AF cases in the derivation cohorts and 585 in the validation cohorts. A simple 5-year predictive model including the variables age, race, height, weight, systolic and diastolic blood pressure, current smoking, use of antihypertensive medication, diabetes, and history of myocardial infarction and heart failure had good discrimination (C-statistic, 0.765; 95% CI, 0.748 to 0.781). Addition of variables from the electrocardiogram did not improve the overall model discrimination (C-statistic, 0.767; 95% CI, 0.750 to 0.783; categorical net reclassification improvement, -0.0032; 95% CI, -0.0178 to 0.0113). In the validation cohorts, discrimination was acceptable (AGES C-statistic, 0.664; 95% CI, 0.632 to 0.697 and RS C-statistic, 0.705; 95% CI, 0.664 to 0.747) and calibration was adequate.

CONCLUSION

A risk model including variables readily available in primary care settings adequately predicted AF in diverse populations from the United States and Europe.

Absolute and attributable risks of atrial fibrillation in relation to optimal and borderline risk factors: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Atrial fibrillation (AF) is an important risk factor for stroke and overall mortality, but information about the preventable burden of AF is lacking. The aim of this study was to determine what proportion of the burden of AF in blacks and whites could theoretically be avoided by the maintenance of an optimal risk profile.

METHODS AND RESULTS

This study included 14 598 middle-aged Atherosclerosis Risk in Communities (ARIC) Study cohort members. Previously established AF risk factors, namely high blood pressure, elevated body mass index, diabetes mellitus, cigarette smoking, and prior cardiac disease, were categorized into optimal, borderline, and elevated levels. On the basis of their risk factor levels, individuals were classified into 1 of these 3 groups. The population-attributable fraction of AF resulting from having a nonoptimal risk profile was estimated separately for black and white men and women. During a mean follow-up of 17.1 years, 1520 cases of incident AF were identified. The age-adjusted incidence rates were highest in white men and lowest in black women (7.45 and 3.67 per 1000 person-years, respectively). The overall prevalence of an optimal risk profile was 5.4% but varied according to race and gender: 10% in white women versus 1.6% in black men. Overall, 56.5% of AF cases could be explained by having ≥ 1 borderline or elevated risk factors, of which elevated blood pressure was the most important contributor.

CONCLUSION

As with other forms of cardiovascular disease, more than half of the AF burden is potentially avoidable through the optimization of cardiovascular risk factors levels.

HRPT2, encoding parafibromin, is mutated in hyperparathyroidism-jaw tumor syndrome

We report here the identification of a gene associated with the hyperparathyroidism-jaw tumor (HPT-JT) syndrome. A single locus associated with HPT-JT (HRPT2) was previously mapped to chromosomal region 1q25-q32. We refined this region to a critical interval of 12 cM by genotyping in 26 affected kindreds. Using a positional candidate approach, we identified thirteen different heterozygous, germline, inactivating mutations in a single gene in fourteen families with HPT-JT. The proposed role of HRPT2 as a tumor suppressor was supported by mutation screening in 48 parathyroid adenomas with cystic features, which identified three somatic inactivating mutations, all located in exon 1. None of these mutations were detected in normal controls, and all were predicted to cause deficient or impaired protein function. HRPT2 is a ubiquitously expressed, evolutionarily conserved gene encoding a predicted protein of 531 amino acids, for which we propose the name parafibromin. Our findings suggest that HRPT2 is a tumor-suppressor gene, the inactivation of which is directly involved in predisposition to HPT-JT and in development of some sporadic parathyroid tumors.

Chronic kidney disease is associated with the incidence of atrial fibrillation: the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Chronic kidney disease is associated with the incidence of cardiovascular disease. Chronic kidney disease may also increase the risk of atrial fibrillation (AF), but existing studies have reported inconsistent results.

METHODS AND RESULTS

We estimated cystatin C-based glomerular filtration rate (eGFR(cys)) and measured urinary albumin-to-creatinine ratio (ACR) in 10 328 men and women free of AF from the Atherosclerosis Risk in Communities (ARIC) Study in 1996 to 1998. Incidence of AF was ascertained through the end of 2007. During a median follow-up of 10.1 years, we identified 788 incident AF cases. Compared with individuals with eGFR(cys) ≥90 mL · min(-1) · 1.73 m(-2), multivariable hazard ratios and 95% confidence intervals (CIs) of AF were 1.3 (95% CI, 1.1 to 1.6), 1.6 (95% CI, 1.3 to 2.1), and 3.2 (95% CI, 2.0 to 5.0; P for trend <0.0001) in those with eGFR(cys) of 60 to 89, 30 to 59, and 15 to 29 mL · min(-1) · 1.73 m(-2), respectively. Similarly, the presence of macroalbuminuria (ACR ≥300 mg/g; hazard ratio, 3.2; 95% CI, 2.3 to 4.5) and microalbuminuria (ACR, 30 to 299 mg/g; hazard ratio, 2.0; 95% CI, 1.6 to 2.4) was associated with higher AF risk compared with those with ACR <30 mg/g. Risk of AF was particularly elevated in those with both low eGFR(cys) and macroalbuminuria (hazard ratio, 13.1; 95% CI, 6.0 to 28.6, comparing individuals with ACR ≥300 mg/g and eGFR(cys) of 15 to 29 mL · min(-1) · 1.73 m(-2) and those with ACR <30 mg/g and eGFR(cys) ≥90 mL · min(-1) · 1.73 m(-2)).

CONCLUSION

In this large population-based study, reduced kidney function and presence of albuminuria were strongly associated with the incidence of AF independently of other risk factors.

Menin interacts with the AP1 transcription factor JunD and represses JunD-activated transcription

MEN1 is a tumor suppressor gene that encodes a 610 amino acid nuclear protein (menin) of previously unknown function. Using a yeast two-hybrid screen with menin as the bait, we have identified the transcription factor JunD as a direct menin-interacting partner. Menin did not interact directly with other Jun and Fos family members. The menin-JunD interaction was confirmed in vitro and in vivo. Menin repressed transcriptional activation mediated by JunD fused to the Gal4 DNA-binding domain from a Gal4 responsive reporter, or by JunD from an AP1-responsive reporter. Several naturally occurring and clustered MEN1 missense mutations disrupted menin interaction with JunD. These observations suggest that menin's tumor suppressor function involves direct binding to JunD and inhibition of JunD activated transcription.

Germline mutations of the MEN1 gene in familial multiple endocrine neoplasia type 1 and related states

Familial multiple endocrine neoplasia type 1 (FMEN1) is an autosomal dominant trait characterized by tumors of the parathyroids, gastro-intestinal endocrine tissue, anterior pituitary and other tissues. We recently cloned the MEN1 gene and confirmed its identity by finding mutations in FMEN1. We have now extended our mutation analysis to 34 more unrelated FMEN1 probands and to two related states, sporadic MEN1 and familial hyperparathyroidism. There was a high prevalence of heterozygous germline MEN1 mutations in sporadic MEN1 (8/11 cases) and in FMEN1 (47/50 probands). One case of sporadic MEN1 was proven to be a new MEN1 mutation. Eight different mutations were observed more than once in FMEN1. Forty different mutations (32 FMEN1 and eight sporadic MEN1) were distributed across the MEN1 gene. Most predicted loss of function of the encoded menin protein, supporting the prediction that MEN1 is a tumor suppressor gene. No MEN1 germline mutation was found in five probands with familial hyperparathyroidism, suggesting that familial hyperparathyroidism often is caused by mutation in another gene or gene(s).

Variants in ZFHX3 are associated with atrial fibrillation in individuals of European ancestry

We conducted meta-analyses of genome-wide association studies (GWAS) for atrial fibrillation (AF) in participants from five community-based cohorts. Meta-analyses of 896 prevalent (15,768 referents) and 2,517 incident (21,337 referents) AF cases identified a novel locus for AF (ZFHX3, rs2106261, risk ratio [RR]=1.19; P=2.3×10⁻⁷), an association that was replicated in the German AF Network (odds ratio=1.44; P=1.6×10⁻¹¹). Combining the discovery and replication results, rs2106261 was significantly associated with AF (RR=1.25; P=1.8×10⁻¹⁵).

Somatic mutation of the MEN1 gene in parathyroid tumours

Primary hyperparathyroidism is a common disorder with an annual incidence of approximately 0.5 in 1,000 (ref. 1). In more than 95% of cases, the disease is caused by sporadic parathyroid adenoma or sporadic hyperplasia. Some cases are caused by inherited syndromes, such as multiple endocrine neoplasia type 1 (MEN1; ref. 2). In most cases, the molecular basis of parathyroid neoplasia is unknown. Parathyroid adenomas are usually monoclonal, suggesting that one important step in tumour development is a mutation in a progenitor cell. Approximately 30% of sporadic parathyroid tumours show loss of heterozygosity (LOH) for polymorphic markers on 11q13, the site of the MEN1 tumour suppressor gene. This raises the question of whether such sporadic parathyroid tumours are caused by sequential inactivation of both alleles of the MEN1 gene. We recently cloned the MEN1 gene and identified MEN1 germline mutations in fourteen of fifteen kindreds with familial MEN1 (ref. 10). We have studied parathyroid tumours not associated with MEN1 to determine whether somatic mutations in the MEN1 gene are present. Among 33 tumours we found somatic MEN1 gene mutation in 7, while the corresponding MEN1 germline sequence was normal in each patient. All tumours with MEN1 gene mutation showed LOH on 11q13, making the tumour cells hemi- or homozygous for the mutant allele. Thus, somatic MEN1 gene mutation for the mutant allele. Thus, somatic MEN1 gene mutation contributes to tumorigenesis in a substantial number of parathyroid tumours not associated with the MEN1 syndrome.

Antifungal activity of anthraquinone derivatives from Rheum emodi

Rhein, physcion, aloe-emodin and chrysophanol isolated from Rheum emodi rhizomes exhibited antifungal activity against Candida albicans, Cryptococcus neoformans, Trichophyton mentagrophytes and Aspergillus fumigatus (MIC 25-250 microg/ml).

Perceived weight status, overweight diagnosis, and weight control among US adults: the NHANES 2003-2008 Study

OBJECTIVES

To examine the association between perceived overweight status and weight control, discrepancies between perceived and measured weight status, and opportunities for health care professionals (HCPs) to correct weight perception among US adults.

DESIGN

Population-based cross-sectional study.

SUBJECTS

In all, 16,720 non-pregnant adults from the 2003 to 2008 National Health and Nutrition Examination Survey.

RESULTS

Overall, 64% (73% women, 55% men) reported a desire to weigh less and 48% (57% women, 40% men) reported pursuing weight control. Weight control was positively associated with overweight perception (odds ratio (OR) women 3.74; 95% confidence interval (CI) 2.96, 4.73; OR men 2.82; 95% CI 2.11, 3.76) and an HCP diagnosis of overweight/obesity (OR women 2.22; 95% CI 1.69, 2.91; OR men 2.14; 95% CI 1.58, 2.91), independent of measured weight status. A large proportion of overweight individuals (23% women, 48% men) perceived themselves as having the right weight. Also, 74% of overweight and 29% of obese individuals never had an HCP diagnosis of overweight/obesity. Although the majority of overweight/obese individuals (74% women, 60% men) pursued at least one weight management strategy, fewer (39% women, 32% men) pursued both dietary change and physical activity. Among overweight/obese adults, those with an HCP diagnosis of overweight/obesity were more likely to diet (74 versus 52%), exercise (44 versus 34%), or pursue both (41 versus 30%, all P<0.01) than those who remained undiagnosed.

CONCLUSION

HCPs have unused opportunities to motivate their patients to control and possibly lose weight by correcting weight perceptions and offering counseling on healthy weight loss strategies.

Smoking and incidence of atrial fibrillation: results from the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Cigarette smoking increases the risk of coronary heart disease, but whether smoking increases atrial fibrillation (AF) is uncertain.

OBJECTIVE

The purpose of this study was to determine the association of cigarette smoking with incident AF in a population-based cohort of blacks and whites.

METHODS

We determined the risk of incident AF through December 2002 in relation to baseline (1987-1989) smoking status and cigarette-years of smoking in over 15,000 participants of the prospective Atherosclerosis Risk in Communities (ARIC) study.

RESULTS

Over a mean follow-up of 13.1 years, 876 incident AF events were identified. Compared to never smokers, the multivariable-adjusted hazard ratios (HRs) for AF were 1.32 (95% confidence interval [CI] 1.10-1.57) in former smokers, 2.05 (95% CI 1.71-2.47) in current smokers, and 1.58 (95% CI 1.35-1.85) in ever smokers. In the highest tertile of accumulated smoking amount (>675 cigarette-years), the incidence of AF was 2.10 times greater (95% CI 1.74-2.53) than in those who never smoked. Associations were similar by gender, race, type of event (AF and atrial flutter), and when only AF events identified by study exam ECGs were included. Finally, individuals who quit smoking exhibited a trend indicating a slightly lower risk of developing AF (HR 0.88, 95% CI 0.65-1.17) compared to those who continued to smoke.

CONCLUSION

Smoking was associated with the incidence of AF, with more than a two-fold increased risk of AF attributed to current smoking. In addition, a trend toward a lower incidence of AF appeared among smokers who quit compared to continued smokers.

Cytokine dysregulation associated with exam stress in healthy medical students

The mechanisms of stress-related immune alterations have not been fully elucidated. Cell-mediated immune responses as well as antibody and certain cytokines are reported as being suppressed during times of high stress. However, the role of suppression vs dysregulation has not been established in human stress models. The effect of exam stress on regulatory cytokines in 16 healthy medical students was assessed by measuring type-1 (IFN-gamma) and type-2 (IL-10) cytokines from 72-h PHA/PMA-stimulated PBMC 4 weeks before and 48 h after exams. Results demonstrated decreased IFN-gamma accompanied by increased IL-10 during exam stress that resulted in a decreased IFN-gamma:IL-10 ratio. There was a significant correlation between the cytokine response to PHA/PMA and number and subjective adjustment to daily hassles. Additionally, students who reported greater levels of loneliness also reported greater numbers of and poorer subjective adjustment to hassles. The differences were consistent in both males and females but did not correlate with AM cortisol levels. Additionally, when individuals were grouped into high vs low preexam hassle levels, the type-1/type-2 shift in the IFN-gamma:IL-10 ratio occurred in the low hassles group only. These data suggest that psychologically stressful situations shift type-1/type-2 cytokine balance toward type-2 and result in an immune dysregulation rather than overall immunosuppression. This may partially explain the increased incidence of type-2-mediated conditions such as increased viral infections, latent viral expression, allergic/asthmatic reactions, and autoimmunity reported during periods of high stress.

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.

Prediction of incident heart failure in general practice: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

A simple and effective heart failure (HF) risk score would facilitate the primary prevention and early diagnosis of HF in general practice. We examined the external validity of existing HF risk scores, optimized a 10-year HF risk function, and examined the incremental value of several biomarkers, including N-terminal pro-brain natriuretic peptide.

METHODS AND RESULTS

During 15.5 years (210 102 person-years of follow-up), 1487 HF events were recorded among 13 555 members of the biethnic Atherosclerosis Risk in Communities (ARIC) Study cohort. The area under curve from the Framingham-published, Framingham-recalibrated, Health ABC HF recalibrated, and ARIC risk scores were 0.610, 0.762, 0.783, and 0.797, respectively. On addition of N-terminal pro-brain natriuretic peptide, the optimism-corrected area under curve of the ARIC HF risk score increased from 0.773 (95% CI, 0.753-0.787) to 0.805 (95% CI, 0.792-0.820). Inclusion of N-terminal pro-brain natriuretic peptide improved the overall classification of recalibrated Framingham, recalibrated Health ABC, and ARIC risk scores by 18%, 12%, and 13%, respectively. In contrast, cystatin C or high-sensitivity C-reactive protein did not add toward incremental risk prediction.

CONCLUSIONS

The ARIC HF risk score is more parsimonious yet performs slightly better than the extant risk scores in predicting 10-year risk of incident HF. The inclusion of N-terminal pro-brain natriuretic peptide markedly improves HF risk prediction. A simplified risk score restricted to a patient's age, race, sex, and N-terminal pro-brain natriuretic peptide performs comparably to the full score (area under curve, 0.745) and is suitable for automated reporting from laboratory panels and electronic medical records.

The tumor suppressor protein menin interacts with NF-kappaB proteins and inhibits NF-kappaB-mediated transactivation

Multiple endocrine neoplasia type 1 is an autosomal dominant tumor syndrome. Manifestations include neoplasms of the parathyroid glands, enteropancreatic neuroendocrine cells, and the anterior pituitary gland. The MEN1 tumor suppressor gene encodes menin, a 610 amino acid nuclear protein without sequence homology to other proteins. To elucidate menin function, we used immunoprecipitation to identify interacting proteins. The NF-kappaB proteins p50, p52 and p65 were found to interact specifically and directly with menin in vitro and in vivo. The region of NF-kappaB proteins sufficient for binding to menin is the N-terminus. Furthermore, amino acids 305-381 of menin are essential for this binding. Menin represses p65-mediated transcriptional activation on NF-kappaB sites in a dose-dependent and specific manner. Also, PMA (phorbol 12-myristate 13-acetate)-stimulated NF-kappaB activation is suppressed by menin. These observations suggest that menin's ability to interact with NF-kappaB proteins and its modulation of NF-kappaB transactivation contribute to menin's tumor suppressor function.

Trends in Hospitalizations and Survival of Acute Decompensated Heart Failure in Four US Communities (2005-2014): ARIC Study Community Surveillance

BACKGROUND

Community trends of acute decompensated heart failure (ADHF) in diverse populations may differ by race and sex.

METHODS

The ARIC study (Atherosclerosis Risk in Communities) sampled heart failure-related hospitalizations (≥55 years of age) in 4 US communities from 2005 to 2014 using International Classification of Diseases, Ninth Revision, Clinical Modification codes. ADHF hospitalizations were validated by standardized physician review and computer algorithm, yielding 40 173 events after accounting for sampling design (unweighted n=8746).

RESULTS

Of the ADHF hospitalizations, 50% had reduced ejection fraction, and 39% had preserved EF (HFpEF). HF with reduced ejection fraction was more common in black men and white men, whereas HFpEF was most common in white women. Average age-adjusted rates of ADHF were highest in blacks (38.1 per 1000 black men, 30.5 per 1000 black women), with rates differing by HF type and sex. ADHF rates increased over the 10 years (average annual percentage change: black women +4.3%, black men +3.7%, white women +1.9%, white men +2.6%), mostly reflecting more acute HFpEF. Age-adjusted 28-day and 1-year case fatality proportions were ≈10% and 30%, respectively, similar across race-sex groups and HF types. Only blacks showed decreased 1-year mortality over time (average annual percentage change: black women -5.4%, black men -4.6%), with rates differing by HF type (average annual percentage change: black women HFpEF -7.1%, black men HF with reduced ejection fraction -4.7%).

CONCLUSIONS

Between 2005 and 2014, trends in ADHF hospitalizations increased in 4 US communities, primarily driven by acute HFpEF. Survival at 1 year was poor regardless of EF but improved over time for black women and black men.

Type 2 diabetes, glucose homeostasis and incident atrial fibrillation: the Atherosclerosis Risk in Communities study

BACKGROUND

Type 2 diabetes has been inconsistently associated with the risk of atrial fibrillation (AF) in previous studies that have frequently been beset by methodological challenges.

DESIGN

Prospective cohort study.

SETTING

The Atherosclerosis Risk in Communities (ARIC) study.

PARTICIPANTS

Detailed medical histories were obtained from 13 025 participants. Individuals were categorised as having no diabetes, pre-diabetes or diabetes based on the 2010 American Diabetes Association criteria at study baseline (1990-2).

MAIN OUTCOME MEASURES

Diagnoses of incident AF were obtained to the end of 2007. Associations between type 2 diabetes and markers of glucose homeostasis and the incidence of AF were estimated using Cox proportional hazards models after adjusting for possible confounders.

RESULTS

Type 2 diabetes was associated with a significant increase in the risk of AF (HR 1.35, 95% CI 1.14 to 1.60) after adjustment for confounders. There was no indication that individuals with pre-diabetes or those with undiagnosed diabetes were at increased risk of AF compared with those without diabetes. A positive linear association was observed between HbA1c and the risk of AF in those with and without diabetes (HR 1.13, 95% CI 1.07 to 1.20) and HR 1.05, 95% CI 0.96 to 1.15 per 1% point increase, respectively). There was no association between fasting glucose or insulin in those without diabetes, but a significant association with fasting glucose was found in those with the condition. The results were similar in white subjects and African-Americans.

CONCLUSIONS

Diabetes, HbA1c level and poor glycaemic control are independently associated with an increased risk of AF, but the underlying mechanisms governing the relationship are unknown and warrant further investigation.

Metabolic syndrome and incidence of atrial fibrillation among blacks and whites in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

The metabolic syndrome (MetSyn) has been implicated in the development of atrial fibrillation (AF); however, knowledge of this association among blacks is limited.

METHODS

We determined the risk of incident AF through December 2005 in relation to baseline (1987-1989) MetSyn status in 15,094 participants of the Atherosclerosis Risk in Communities study.

RESULTS

Over a mean follow-up of 15.4 years, 1,238 incident AF events were identified. The hazard ratio (HR) for AF among individuals with, compared to those without, the MetSyn was 1.67 (95% CI 1.49-1.87), and associations did not differ by race (P for interaction = .73). The population attributable risk of AF from the MetSyn was 22%. The multivariable-adjusted HRs (95% CI) for each MetSyn component were 1.95 (1.72-2.21) (elevated blood pressure), 1.40 (1.23-1.59) (elevated waist circumference), 1.20 (1.06-1.37) (low high-density lipoprotein cholesterol), 1.16 (1.03-1.31) (impaired fasting glucose), and 0.95 (0.84-1.09) (elevated triglycerides). A monotonically increasing risk of AF with increasing number of MetSyn components was observed, with an HR of 4.40 (95% CI 3.25-5.94) for those with all 5 MetSyn components compared to those with 0 components.

CONCLUSION

In this large cohort, the MetSyn and most of its components were associated with a higher risk of AF in both blacks and whites. Given the high prevalence of the MetSyn, strategies to prevent its development or to control individual components may reduce the burden of AF.

Multiple endocrine neoplasia type 1: new clinical and basic findings

Multiple endocrine neoplasia type 1 (MEN1) provides a prime example of how a rare disease can advance our understanding of basic cell biology, neoplasia and common endocrine tumors. MEN1 is expressed mainly as parathyroid, enteropancreatic neuroendocrine, anterior pituitary and foregut carcinoid tumors. It is an autosomal dominant disease caused by mutation of the MEN1 gene. Since its identification, the MEN1 gene has been implicated in many common endocrine and non-endocrine tumors. This is a brief overview of recent scientific advances relating to MEN1, including newly recognized clinical features that are now better characterized by genetic analysis, insights into the function of the MEN1-encoded protein menin, and refined recommendations for mutation testing and tumor screening, which highlight our increasing understanding of this complex syndrome.

B-type natriuretic peptide and C-reactive protein in the prediction of atrial fibrillation risk: the CHARGE-AF Consortium of community-based cohort studies

AIMS

B-type natriuretic peptide (BNP) and C-reactive protein (CRP) predict atrial fibrillation (AF) risk. However, their risk stratification abilities in the broad community remain uncertain. We sought to improve risk stratification for AF using biomarker information.

METHODS AND RESULTS

We ascertained AF incidence in 18 556 Whites and African Americans from the Atherosclerosis Risk in Communities Study (ARIC, n=10 675), Cardiovascular Health Study (CHS, n = 5043), and Framingham Heart Study (FHS, n = 2838), followed for 5 years (prediction horizon). We added BNP (ARIC/CHS: N-terminal pro-B-type natriuretic peptide; FHS: BNP), CRP, or both to a previously reported AF risk score, and assessed model calibration and predictive ability [C-statistic, integrated discrimination improvement (IDI), and net reclassification improvement (NRI)]. We replicated models in two independent European cohorts: Age, Gene/Environment Susceptibility Reykjavik Study (AGES), n = 4467; Rotterdam Study (RS), n = 3203. B-type natriuretic peptide and CRP were significantly associated with AF incidence (n = 1186): hazard ratio per 1-SD ln-transformed biomarker 1.66 [95% confidence interval (CI), 1.56-1.76], P < 0.0001 and 1.18 (95% CI, 1.11-1.25), P < 0.0001, respectively. Model calibration was sufficient (BNP, χ(2) = 17.0; CRP, χ(2) = 10.5; BNP and CRP, χ(2) = 13.1). B-type natriuretic peptide improved the C-statistic from 0.765 to 0.790, yielded an IDI of 0.027 (95% CI, 0.022-0.032), a relative IDI of 41.5%, and a continuous NRI of 0.389 (95% CI, 0.322-0.455). The predictive ability of CRP was limited (C-statistic increment 0.003). B-type natriuretic peptide consistently improved prediction in AGES and RS.

CONCLUSION

B-type natriuretic peptide, not CRP, substantially improved AF risk prediction beyond clinical factors in an independently replicated, heterogeneous population. B-type natriuretic peptide may serve as a benchmark to evaluate novel putative AF risk biomarkers.

Racial Differences in Atrial Fibrillation-Related Cardiovascular Disease and Mortality: The Atherosclerosis Risk in Communities (ARIC) Study

IMPORTANCE

The adverse outcomes associated with atrial fibrillation (AF) have been studied in predominantly white cohorts. Racial differences in outcomes associated with AF merit continued investigation.

OBJECTIVE

To evaluate the race-specific associations of AF with stroke, heart failure, coronary heart disease (CHD), and all-cause mortality in a community-based cohort.

DESIGN, SETTING, AND PARTICIPANTS

The Atherosclerosis Risk in Communities (ARIC) Study is a prospective, observational cohort. From 1987 through 1989, the ARIC Study enrolled 15 792 men and women and conducted 4 follow-up examinations (2011-2013) with active surveillance for vital status and hospitalizations. Race was determined by self-report and categorized as white, black, or other.

MAIN OUTCOMES AND MEASURES

Atrial fibrillation (adjudicated using electrocardiograms, hospital discharge codes, and death certificates), stroke, heart failure, CHD, and mortality.

RESULTS

After exclusions, 15 080 participants (mean [SD] age, 54.2 [5.8] years; 8290 women [55.5%]; 3831 black individuals [25.4%]) were included in this analysis. During a mean (SD) follow-up of 20.6 (6.2) years, there were 2348 cases of incident AF. The incident rates of AF per 1000 person-years were 8.1 (95% CI, 7.7-8.5) in white individuals and 5.8 (95% CI, 5.2-6.3) in black individuals. The rates of stroke, heart failure, CHD, and mortality were higher in black individuals with AF than white individuals with AF. The association of AF with these outcomes, estimated with rate differences (rate of the end point in those with AF minus the rate in those without AF per 1000 person-years), also differed by race. The rate difference for stroke in individuals with AF was 10.2 (95% CI, 6.6-13.9) in white individuals and 21.4 (95% CI, 10.2-32.6) in black individuals. For heart failure and CHD, the rate differences were 1.5- to 2.0-fold higher in black individuals than white individuals. White individuals with AF had a rate difference of 55.9 (95% CI, 48.1-63.7) for mortality compared with black individuals, who had a rate difference of 106.0 (95% CI, 86.0-125.9).

CONCLUSIONS AND RELEVANCE

In the prospective ARIC Study, the outcome of AF on the rates of stroke, heart failure, CHD, and mortality was considerably larger in black individuals than white individuals. These results indicate the vulnerability and increased risk in black individuals with AF. Continued investigation of racial differences in AF and its related adverse outcomes are essential to identify and mitigate racial disparities in the treatment of AF.

Physical activity, obesity, weight change, and risk of atrial fibrillation: the Atherosclerosis Risk in Communities study

BACKGROUND

Physical activity (PA) has previously been suggested to attenuate the risk of atrial fibrillation (AF) conferred by excess body weight and weight gain. We prospectively examined the relationship between body size, weight change, and level of PA in a biracial cohort of middle-aged men and women.

METHODS AND RESULTS

Baseline characteristics on risk factor levels were obtained on 14 219 participants from the Atherosclerosis Risk in Communities Study. AF incidence was ascertained from 1987 to 2009. Adjusted Cox proportional hazards models were used to estimate the associations between body mass index, waist circumference, relative weight change, and PA level with incident AF. During follow-up, there were 1775 cases of incident AF. Body mass index and waist circumference were positively associated with AF as was weight loss/gain of >5% initial body weight. An ideal level of PA had a small protective effect on AF risk and partially attenuated the risk of AF associated with excess weight in men but not women: compared with men with a normal body mass index, the risk of AF in obese men with an ideal, intermediate, and poor level of PA at baseline was increased by 37%, 129%, and 156% (Pinteraction=0.04). During follow-up, PA did not modify the association between weight gain and risk of AF.

CONCLUSIONS

Obesity and extreme weight change are risk factors for incident AF, whereas being physically active is associated with a small reduction in risk. In men only, being physically active offset some, but not all, of the risk incurred with excess body weight.

Blood lipid levels, lipid-lowering medications, and the incidence of atrial fibrillation: the atherosclerosis risk in communities study

BACKGROUND

Several cardiovascular risk factors have been associated with the risk of atrial fibrillation (AF). Limited and inconsistent evidence exists on the association of blood lipid levels and lipid-lowering medication use with AF risk.

METHODS AND RESULTS

We analyzed 13 969 participants (25% African American, 45% men) free of AF at baseline from the Atherosclerosis Risk in Communities study. Fasting high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides, and total cholesterol were measured at baseline (1987-1989) and each of 3 follow-up visits. The incidence of AF was ascertained through 2007. The association of the use of statins and other lipid-lowering medications with AF was estimated in 13 044 Atherosclerosis Risk in Communities participants attending visit 2 (1990-1992), adjusting for covariates from the previous visit. During a median follow-up of 18.7 years, there were 1433 incident AF cases. Multivariable hazard ratios (HRs) and 95% CIs of AF associated with a 1-SD increase in lipid levels were as follows: HDLc, 0.97 (0.91-1.04); LDLc, 0.90 (0.85-0.96); total cholesterol, 0.89 (0.84-0.95); and triglycerides, 1.00 (0.96-1.04). Participants taking lipid-lowering medications had an adjusted HR (95% CI) of AF of 0.96 (0.82-1.13) compared with those not taking medications, whereas those taking statins had an adjusted HR of 0.91 (0.66-1.25) compared with those taking other lipid-lowering medications.

CONCLUSIONS

Higher levels of LDLc and total cholesterol were associated with a lower incidence of AF. However, HDLc and triglycerides were not independently associated with AF incidence. No association was found between the use of lipid-lowering medications and incident AF.

Global Electric Heterogeneity Risk Score for Prediction of Sudden Cardiac Death in the General Population: The Atherosclerosis Risk in Communities (ARIC) and Cardiovascular Health (CHS) Studies

BACKGROUND

Asymptomatic individuals account for the majority of sudden cardiac deaths (SCDs). Development of effective, low-cost, and noninvasive SCD risk stratification tools is necessary.

METHODS AND RESULTS

Participants from the Atherosclerosis Risk in Communities study and Cardiovascular Health Study (n=20 177; age, 59.3±10.1 years; age range, 44-100 years; 56% female; 77% white) were followed up for 14.0 years (median). Five ECG markers of global electric heterogeneity (GEH; sum absolute QRST integral, spatial QRST angle, spatial ventricular gradient [SVG] magnitude, SVG elevation, and SVG azimuth) were measured on standard 12-lead ECGs. Cox proportional hazards and competing risks models evaluated associations between GEH electrocardiographic parameters and SCD. An SCD competing risks score was derived from demographics, comorbidities, and GEH parameters. SCD incidence was 1.86 per 1000 person-years. After multivariable adjustment, baseline GEH parameters and large increases in GEH parameters over time were independently associated with SCD. Final SCD risk scores included age, sex, race, diabetes mellitus, hypertension, coronary heart disease, stroke, and GEH parameters as continuous variables. When GEH parameters were added to clinical/demographic factors, the C statistic increased from 0.777 to 0.790 (P=0.008), the risk score classified 10-year SCD risk as high (>5%) in 7.2% of participants, 10% of SCD victims were appropriately reclassified into a high-risk category, and only 1.4% of SCD victims were inappropriately reclassified from high to intermediate risk. The net reclassification index was 18.3%.

CONCLUSIONS

Abnormal electrophysiological substrate quantified by GEH parameters is independently associated with SCD in the general population. The addition of GEH parameters to clinical characteristics improves SCD risk prediction.