Surveillance of the Initiation of, Participation in, and Completion of Cardiac Rehabilitation in Minnesota, 2017-2018

INTRODUCTION

Cardiac rehabilitation (CR) is an evidence-based secondary prevention program designed to improve cardiovascular health after a cardiac event. The objective of our study was to identify gaps in CR use among publicly and privately insured people in Minnesota to assist in developing shared goals among public health, cardiac rehabilitation professionals, and program delivery sites to improve CR delivery.

METHODS

We applied a published claims-based surveillance methodology to the Minnesota All Payer Claims Database to assess eligibility for, initiation of, participation in, and completion of CR by patients with qualifying events in 2017. We stratified results by sociodemographic and geographic factors and qualifying condition and used adjusted prevalence ratios to make statistical comparisons.

RESULTS

Less than half (47.6%) of qualifying patients initiated CR within 1 year of their qualifying event; the rate was higher among men (vs women), adults aged 45 to 64 years (vs ≥65 y), and patients with commercial or Medicaid insurance coverage (vs Medicare). Among those who initiated CR, only 14.0% completed the full series of 36 sessions. Participation in at least 12 sessions and completion of 36 sessions was less likely among adults aged 18 to 64 (vs 65-74 y) and among patients covered by Medicaid (vs Medicare). Patterns of CR initiation, participation, and completion also varied geographically.

CONCLUSION

This analysis expands on previous Medicare fee-for-service population CR surveillance and provides a first detailed look at the CR landscape in Minnesota, renewing attention to CR as a key secondary prevention strategy. Collaboration and sharing with partners has established the Minnesota Department of Health as a valuable partner in driving health system change to improve equitable provision of CR in Minnesota.

Abstract TMP65: The Minnesota Stroke System, 2012-2017: Development and Impact of a Statewide System of Stroke Care

Background: The Minnesota Stroke System is comprised of hospitals able to deliver state-of-the-art stroke treatment. The system is designed to increase access to acute stroke treatment and improve outcomes for stroke patients. Between 2011 and 2013, the Minnesota Department of Health convened health care providers and stroke patient advocates to plan and create the components of a statewide stroke system for Minnesota. To launch the system, the Minnesota legislature gave MDH statutory authorization to designate Acute Stroke Ready Hospitals (ASRHs) and recognize Primary and Comprehensive Stroke Centers certified by national accreditation bodies. The ASRHs meet ten criteria corresponding to the 2013 Brain Attack Coalition recommendations.

Analysis: Stroke patient data are reported to the Minnesota Stroke Registry by hospital-based abstractors. Data are combined for 2012-2013, 2014-2015, and 2016-2017. Performance metric statistics were calculated using SAS (Cary, NC). The resident population living within 30 minutes of designated hospitals was calculated from 2010 US Census Bureau data using ArcGIS 10.3 Network Analyst.

Results: From 2012 to 2017, the number of designated ASRHs increased from zero to 89, out of 111 eligible hospitals. The percentage of residents living within 30 minutes of any designated facility increased from 60% to 90%. The percentage of all stroke patients whose computed tomography image was initiated within 25 minutes of arrival increased from 34.2% to 42.9%. Intravenous thrombolytic therapy increased from 8.8% to 11% of all ischemic stroke patients. Median door-to-imaging time decreased from 40 to 33 minutes. Median door-to-needle time decreased from 56 to 53 minutes. 28.7% of patients in 2012-2013 who received IV tPA were treated within 4.5 hours of time last known well, increasing to 35.6% in 2016-2017.

Conclusions: The Minnesota Stroke System has successfully catalyzed and supported significant improvements in acute stroke treatment in Minnesota.

Blood glucose screening rates among Minnesota adults with hypertension, Behavioral Risk Factor Surveillance System, 2011

Introduction

Many US adults have multiple chronic conditions, and hypertension and diabetes are among the most common dyads. Diabetes and prediabetes prevalence are increasing, and both conditions negatively affect cardiovascular health. Early diagnosis and treatment of diabetes and prediabetes can benefit people with hypertension by preventing cardiovascular complications.

Methods

We analyzed 2011 Minnesota Behavioral Risk Factor Surveillance System data to describe the proportion of adults with hypertension screened for diabetes according to US Preventive Services Task Force Recommendations for blood glucose testing. Covariates associated with lower odds of recent screening among adults without diabetes were determined using weighted logistic regression.

Results

Of Minnesota adults with self-reported hypertension, 19.6% had a diagnosis of diabetes and 10.7% had a diagnosis of prediabetes. Nearly one-third of adults with hypertension without diabetes had not received blood glucose screening in the past 3 years. Factors associated with greater odds of not being screened in multivariable models included being aged 18 to 44 years (adjusted odds ratio [AOR], 1.77; 95% confidence interval [CI], 1.23–2.55); being nonobese, with stronger effects for normal body mass index; having no check-up in the past 2 years (AOR, 2.49; 95% CI, 1.49–4.17); having hypertension treated with medication (AOR, 2.01; 95% CI, 1.49–2.71); and completing less than a college degree (AOR, 1.45; 95% CI, 1.14–1.84). Excluding respondents with prediabetes or those not receiving a check-up did not change the results.

Conclusions

Failure to screen among providers and failure to understand the importance of screening among individuals with hypertension may mean missed opportunities for early detection, clinical management, and prevention of diabetes.

The impact of prolonged lower limb ischemia on amputation, mortality, and functional status: the FRIENDS registry

BACKGROUND

Peripheral artery disease (PAD) is a major cause of cardiovascular ischemic events and amputation. Knowledge gaps exist in defining and measuring key factors that predict these events. The objective of this study was to assess whether duration of limb ischemia would serve as a major predictor of limb and patient survival.

METHODS

The FReedom from Ischemic Events: New Dimensions for Survival (FRIENDS) registry enrolled consecutive patients with limb-threatening peripheral artery disease at a single tertiary care hospital. Demographic information, key clinical care time segments, functional status and use of revascularization, and pharmacotherapy data were collected at baseline, and vascular ischemic events, cardiovascular mortality, and all-cause mortality were recorded at 30 days and 1 year.

RESULTS

A total of 200 patients with median (interquartile range) age of 76 years (65-84 years) were enrolled in the registry. Median duration of limb ischemia was 0.75 days for acute limb ischemia (ALI) and 61 days for chronic critical limb ischemia (CLI). Duration of limb ischemia of <12, 12 to 24, and >24 hours in patients with ALI was associated with much higher rates of first amputation (P = .0002) and worse amputation-free survival (P = .037). No such associations were observed in patients with CLI.

CONCLUSIONS

For individuals with ischemic symptoms <14 days, prolonged limb ischemia is associated with higher 30-day and 1-year amputation, systemic ischemic event rates, and worse amputation-free survival. No such associations are evident for individuals with chronic CLI. These data imply that prompt diagnosis and revascularization might improve outcomes for patients with ALI.

Acute stroke reperfusion therapy trends in the expanded treatment window era

BACKGROUND

The American Heart Association/American Stroke Association (AHA/ASA) recommended an expansion of the time window for acute ischemic stroke (AIS) reperfusion with intravenous (IV) recombinant tissue plasminogen activator (rt-PA) from 3 to 4.5 hours after symptom onset. We examine rates of IV and intra-arterial (IA) reperfusion before and after the recommendations to track guideline adoption in community practice.

METHODS

Patients with AIS in the Paul Coverdell National Acute Stroke Registry spanning years 2007-2012 were identified. Trends in rates of IV rt-PA versus IA therapy were examined. Outcomes included symptomatic intracerebral hemorrhage (sICH), in-hospital mortality, ability to ambulate at discharge, and discharge destination.

RESULTS

From 2007 to 2012, there were 182,235 AIS patients (median age, 72 years; 51.5% women) in the database at the time of analysis. AIS patients receiving IV rt-PA increased significantly from 3.7% in 2007 to 5.1% in 2012 in the ≤3 hours time window and from .2% in 2007 to 1.3% in 2012 in the 3-4.5 hours time window (P < .001 for both). There was also a significant increase in the rate of IA therapy between 2007 and 2012 (P < .001). There was a significant decrease in the rate of sICH among patients who received any reperfusion between 2007 and 2012.

CONCLUSIONS

There was a trend for increased utilization of IV rt-PA in the 0-3 hours and the 3-4.5 hours time windows, which began around the same time as the publication of AHA/ASA recommendations in 2009. This increase was associated with an increase in IA treatment rates along with a decrease in overall sICH rates for patients receiving any reperfusion.

The FReedom from Ischemic Events-New Dimensions for Survival (FRIENDS) registry: design of a prospective cohort study of patients with advanced peripheral artery disease

BACKGROUND

Advanced lower extremity peripheral artery disease (PAD), whether presenting as acute limb ischemia (ALI) or chronic critical limb ischemia (CLI), is associated with high rates of cardiovascular ischemic events, amputation, and death. Past research has focused on strategies of revascularization, but few data are available that prospectively evaluate the impact of key process of care factors (spanning pre-admission, acute hospitalization, and post-discharge) that might contribute to improving short and long-term health outcomes.

METHODS/DESIGN

The FRIENDS registry is designed to prospectively evaluate a range of patient and health system care delivery factors that might serve as future targets for efforts to improve limb and systemic outcomes for patients with ALI or CLI. This hypothesis-driven registry was designed to evaluate the contributions of: (i) pre-hospital limb ischemia symptom duration, (ii) use of leg revascularization strategies, and (iii) use of risk-reduction pharmacotherapies, as pre-specified factors that may affect amputation-free survival. Sequential patients would be included at an index "vascular specialist-defined" ALI or CLI episode, and patients excluded only for non-vascular etiologies of limb threat. Data including baseline demographics, functional status, co-morbidities, pre-hospital time segments, and use of medical therapies; hospital-based use of revascularization strategies, time segments, and pharmacotherapies; and rates of systemic ischemic events (e.g., myocardial infarction, stroke, hospitalization, and death) and limb ischemic events (e.g., hospitalization for revascularization or amputation) will be recorded during a minimum of one year follow-up.

DISCUSSION

The FRIENDS registry is designed to evaluate the potential impact of key factors that may contribute to adverse outcomes for patients with ALI or CLI. Definition of new "health system-based" therapeutic targets could then become the focus of future interventional clinical trials for individuals with advanced PAD.

Utilization of intravenous thrombolysis in 3-4.5 hours: analysis of the Minnesota stroke registry

BACKGROUND

The American Heart Association and the American Stroke Association recommend intravenous (IV) thrombolysis up to 4.5 h from acute ischemic stroke symptom onset based on its proven benefit in improving patient outcomes. We analyzed data from the Minnesota Stroke Registry to assess the rates of IV thrombolytic utilization and the process of care in this expanded window.

METHODS

We identified patients who had received IV recombinant tissue plasminogen activator (rt-PA) at any of the 19 participating hospitals from January 1, 2008 till December 31, 2010. Treatment groups were those actually treated by IV rt-PA in 0-3 h and those treated by IV rt-PA in 3-4.5 h. Duration from symptom onset to arrival in the emergency department (ED) was dichotomized to cohorts of 0-2 and 2-3.5 h. We determined the overall utilization of IV rt-PA in the expanded window and calculated door-to-needle times for the two treatment windows. We also ascertained the rates of symptomatic intracerebral hemorrhage between the two treatment groups.

RESULTS

Out of the total 519 patients who received IV rt-PA for acute ischemic stroke, 433 (83%) were treated within 0-3 h and 86 (17%) within 3-4.5 h. Of all the patients who received IV rt-PA within 3-4.5 h, 45% arrived at the ED within 2 h of symptom onset. Median door-to-needle time for the 0- to 3-hour window was 74.5 min [interquartile range (IQR) 57-90] and 54 min (IQR 43.5-70.5) for the 3- to 4.5-hour window. Based on arrival time to the ED, door-to-needle time of ≤60 min was achieved by only 31% (142/458) of patients who arrived within 0-2 h of their symptom onset compared to 61% (37/61) of those who arrived at the ED within 2-3.5 h of their symptom onset. Fifty-nine (14%) patients in the 0- to 3-hour group and 17 (20%) patients in the 3- to 4.5-hour group received a combination of IV rt-PA and endovascular treatments. Among patients with documented admission National Institutes of Health Stroke Scale scores, the values (median with IQR) were different between the 0- to 3- and the 3- to 4.5-hour group, i.e. 10 (IQR 5-18) and 7 (IQR 4-14), respectively.

CONCLUSION

Patients who received IV rt-PA within the 3- to 4.5-hour window comprised 17% of all IV rt-PA cases treated in the Minnesota Stroke Registry hospitals after the new guidelines recommended a time window expansion. Almost half of these patients would have qualified for treatment within the 0- to 3-hour window as they presented within 0-2 h of symptom onset. Patients arriving 2-3.5 h after symptom onset received thrombolysis on average 20 min faster than patients arriving within 2 h of symptom onset.

Serum and dietary magnesium and incidence of atrial fibrillation in whites and in African Americans--Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Low serum magnesium (Mg) has been associated with an increased risk of cardiovascular disease (CVD), including ventricular arrhythmias, but the association between serum or dietary Mg and atrial fibrillation (AF) has not been investigated.

METHODS AND RESULTS

A total of 14,290 men and women (75% white; 53% female; mean age, 54 years) free of AF at baseline participating in the Atherosclerosis Risk in Communities study in the United States, were studied. Incident AF cases through 2009 were ascertained from electrocardiograms, hospital discharge codes, and death certificates. Multivariate 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 multivariate models, lower serum Mg was associated with higher AF risk: compared to individuals in the middle quintile (≥ 0.80-0.83 mmol/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.

CONCLUSIONS

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.

Impact of an electronic medical record-based clinical decision support tool for dysphagia screening on care quality

BACKGROUND AND PURPOSE

Dysphagia screening (DS) before oral intake in patients with acute stroke is a hospital-level performance measure. We report outcomes of an initiative to improve compliance to this quality measure.

METHODS

The design was a pre- versus postintervention comparison study. The Intervention was an electronic medical record-based clinical DS system embedded within stroke admission orders. The clinical DS was designed to facilitate DS in patients with stroke. The primary outcome was compliance to a process measure in patients with ischemic stroke: performance of a swallow screen before oral intake.

RESULTS

DS measure compliance increased from 36% to 74% (P=0.001). Chart audits found screened patients were more likely to have clinical DS-embedded admission orders initiated or stroke unit admission.

CONCLUSIONS

The electronic medical record offers a ready platform for clinical DS implementation. DS is a difficult performance measure to improve. The described clinical DS has the potential for improving performance on this challenging care quality measure.

The incidence and health economic burden of ischemic amputation in Minnesota, 2005-2008

INTRODUCTION

Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease (PAD), is associated with high rates of myocardial infarction, stroke, and amputation, and has a high health economic cost. The objective of this study was to estimate the incidence of lower limb amputation, the most serious consequence of CLI, and to create a surveillance methodology for the incidence of ischemic amputation in Minnesota.

METHODS

We assessed the incidence of ischemic amputation using all inpatient hospital discharge claims in Minnesota from 2005 through 2008. We identified major and minor ischemic amputations via the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure codes for lower limb amputation not due to trauma or cancer and assessed geographic and demographic differences in the incidence of ischemic amputation.

RESULTS

The age-adjusted annual incidence of lower limb ischemic amputation in Minnesota during the 4-year period was 20.0 per 100,000 (95% confidence interval, 19.4-20.6). Amputations increased significantly with age, were more common in men and in people with diabetes, and were slightly more common in rural residents. The number of amputation-related hospitalizations was steady over 4 years. The median total charge for each amputation was $32,129, and cumulative inpatient hospitalization charges were $56.5 million in 2008.

CONCLUSION

The incidence of ischemic amputation is high and results in major illness and health economic costs. These data represent the first population-based estimate of ischemic amputation at the state level and provide a national model for state-based surveillance.

Utility of dysphagia screening results in predicting poststroke pneumonia

BACKGROUND AND PURPOSE

Dysphagia screening before oral intake (DS) is a stroke care quality indicator. The value of DS is unproven. Quality adherence and outcome data from the Paul Coverdell National Acute Stroke Registry were examined to establish value of DS.

METHODS

Adherence to the DS quality indicator was examined in patients with stroke discharged from Paul Coverdell National Acute Stroke Registry hospitals between March 1 and December 31, 2009. Patients were classified as unscreened (US), screened and passed (S/P), and screened and failed. Associations between screening status and pneumonia rate were assessed by logistic regression models after adjustment for selected variables.

RESULTS

A total of 18 017 patients with stroke discharged from 222 hospitals in 6 states were included. A total of 4509 (25%) were US; 8406 (47%) were S/P, and 5099 (28%) were screened and failed. Compared with US patients, screened patients were significantly more impaired. Pneumonia rates were: US 4.2%, S/P 2.0%, and screened and failed 6.8%. After adjustment for demographic and clinical features, US patients were at a higher risk of pneumonia (OR, 2.2; 95% CI, 1.7 to 2.7) compared with S/P patients.

CONCLUSIONS

Data suggest that patients are selectively screened based on stroke severity. Pneumonia rate was higher in US patients compared with S/P patients. Clinical judgment regarding who should be screened is imperfect. S/P patients have a lower pneumonia rate indicating that DS adds accuracy in predicting pneumonia risk. The Joint Commission recently retired DS as a performance indicator for Primary Stroke Center certification. These results suggest the need to implement a DS performance measure for patients with acute stroke.

Serum magnesium and risk of sudden cardiac death in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

We hypothesized that serum magnesium (Mg) is associated with increased risk of sudden cardiac death (SCD).

METHODS

The Atherosclerosis Risk in Communities Study assessed risk factors and levels of serum Mg in a cohort of 45- to 64-year-old subjects in 1987-1989 (n = 14,232). After an average of 12 years of follow-up, we observed 264 cases of SCD, as determined by physician review of all suspected cases. We used proportional hazards regression to evaluate the association of serum Mg with risk of SCD.

RESULTS

Individuals in the highest quartile of serum Mg were at significantly lower risk of SCD in all models. This association persisted after adjustment for potential confounding variables, with an almost 40% reduced risk of SCD (hazard ratio 0.62, 95% CI 0.42-0.93) in quartile 4 versus 1 of serum Mg observed in the fully adjusted model.

CONCLUSIONS

This study suggests that low levels of serum Mg may be an important predictor of SCD. Further research into the effectiveness of Mg supplementation for those considered to be at high risk for SCD is warranted.

Serum and dietary magnesium and risk of ischemic stroke: the Atherosclerosis Risk in Communities Study

The authors sought to examine the relation between serum or dietary magnesium and the incidence of ischemic stroke among blacks and whites. Between 1987 and 1989, 14,221 men and women aged 45-64 years took part in the first examination of the Atherosclerosis Risk in Communities Study cohort. The incidence of stroke was ascertained from hospital records. Higher serum magnesium levels were associated with lower prevalence of hypertension and diabetes mellitus at baseline. During the 15-year follow-up, 577 ischemic strokes occurred. Serum magnesium was inversely associated with ischemic stroke incidence. The age-, sex-, and race-adjusted rate ratios of ischemic stroke for those with serum magnesium levels of <or=1.5, 1.6, 1.7, and >or=1.8 mEq/L were 1.0, 0.78 (95% confidence interval (CI): 0.62, 0.96), 0.70 (95% CI: 0.56, 0.88), and 0.75 (95% CI: 0.59, 0.95) (P(trend) = 0.005). After adjustment for hypertension and diabetes, the rate ratios were attenuated to nonsignificant levels. Dietary magnesium intake was marginally inversely associated with the incidence of ischemic stroke (P(trend) = 0.09). Low serum magnesium levels could be associated with increased risk of ischemic stroke, in part, via effects on hypertension and diabetes.

Suggestion for linkage of chromosome 1p35.2 and 3q28 to plasma adiponectin concentrations in the GOLDN Study

BACKGROUND

Adiponectin is inversely associated with obesity, insulin resistance, and atherosclerosis, but little is known about the genetic pathways that regulate the plasma level of this protein. To find novel genes that influence circulating levels of adiponectin, a genome-wide linkage scan was performed on plasma adiponectin concentrations before and after 3 weeks of treatment with fenofibrate (160 mg daily) in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study. We studied Caucasian individuals (n = 1121) from 190 families in Utah and Minnesota. Of these, 859 individuals from 175 families had both baseline and post-fenofibrate treatment measurements for adiponectin. Plasma adiponectin concentrations were measured with an ELISA assay. All participants were typed for microsatellite markers included in the Marshfield Mammalian Genotyping Service marker set 12, which includes 407 markers spaced at approximately 10 cM regions across the genome. Variance components analysis was used to estimate heritability and to perform genome-wide scans. Adiponectin was adjusted for age, sex, and field center. Additional models also included BMI adjustment.

RESULTS

Baseline and post-fenofibrate adiponectin measurements were highly correlated (r = 0.95). Suggestive (LOD > 2) peaks were found on chromosomes 1p35.2 and 3q28 (near the location of the adiponectin gene).

CONCLUSION

Two candidate genes, IL22RA1 and IL28RA, lie under the chromosome 1 peak; further analyses are needed to identify the specific genetic variants in this region that influence circulating adiponectin concentrations.

Metabolic syndrome and risk of venous thromboembolism: Longitudinal Investigation of Thromboembolism Etiology

SUMMARY BACKGROUND

In a recent case-control study, the odds of metabolic syndrome (MetSyn) among deep vein thrombosis cases were almost twice those among controls. We tested the hypothesis that the incidence of non-cancer-related venous thromboembolism (VTE) is higher among adults with MetSyn and further, that associations are stronger for idiopathic than secondary VTE.

METHODS

A total of 20 374 middle-aged and elderly adults were followed for over 12 years for incident VTE in the Longitudinal Investigation of Thromboembolism Etiology (LITE). All hospitalizations were identified and VTEs validated by chart review. Baseline MetSyn was defined using ATP III guidelines, including >or=3 of the following components: abdominal obesity, elevated blood pressure, low HDL-cholesterol, high triglycerides and high glucose. Because sex modified the relation between MetSyn and VTE (p(interaction) = 0.001), proportional hazards regression analyses were stratified by sex to assess the associations of MetSyn and its components with risk of incident non-cancer-related VTE, adjusting for potential confounders.

RESULTS

Incident VTE (n = 358) included 196 idiopathic events. Baseline MetSyn was associated with risk of total VTE (hazard ratio (HR) = 1.84, 95% CI = 1.30, 2.59) and idiopathic VTE (HR = 1.59, 95% CI = 1.02, 2.47) among men, but not women. The association was largely attributable to abdominal obesity (HR of VTE = 2.10, 95% CI = 1.51, 2.93, in men; HR of VTE = 1.70, 95% CI = 1.24, 2.34, in women), with no additional contribution by the other MetSyn components.

CONCLUSION

Although abdominal obesity was associated with increased risk of VTE in both men and women, MetSyn and its other components do not seem important in VTE etiology.

ADIPOQ polymorphisms, monounsaturated fatty acids, and obesity risk: the GOLDN study

Serum adiponectin levels have been positively associated with insulin sensitivity and are decreased in type 2 diabetes (T2D) and obesity. Genetic and environmental factors influence serum adiponectin and may contribute to risk of metabolic syndrome and T2D. Therefore, we investigated the effect of ADIPOQ single-nucleotide polymorphisms (SNPs), -11377C>G and -11391G>A, on metabolic-related traits, and their modulation by dietary fat in white Americans. Data were collected from 1,083 subjects participating in the Genetics of Lipid Lowering Drugs and Diet Network study. Mean serum adiponectin concentration was higher for carriers of the -11391A allele (P = 0.001) but lower for the -11377G allele carriers (P = 0.017). Moreover, we found a significant association with obesity traits for the -11391G>A SNP. Carriers of the -11391A allele had significantly lower weight (P = 0.029), BMI (P = 0.019), waist (P = 0.003), and hip circumferences (P = 0.004) compared to noncarriers. Interestingly, the associations of the -11391G>A with BMI and obesity risk were modified by monounsaturated fatty acids (MUFAs) intake (P-interaction = 0.021 and 0.034 for BMI and obesity risk, respectively). In subjects with MUFA intake above the median (> or =13% of energy intake), -11391A carriers had lower BMI (27.1 kg/m(2) for GA+AA vs. 29.1 kg/m(2) for GG, P = 0.002) and decreased obesity risk (odds ratio for -11391A = 0.52, 95% confidence interval (CI); 0.28-0.96; P = 0.031). However, we did not detect genotype-related differences for BMI or obesity in subjects with MUFA intake <13%. Our findings support a significant association between the -11391G>A SNPs and obesity-related traits and the potential to moderate such effects using dietary modification.

Variation in ANGPTL4 and risk of coronary heart disease: the Atherosclerosis Risk in Communities Study

An E40K loss-of-function variant in the ANGPTL4 gene is associated with substantially reduced plasma triglyceride levels in white persons, but its association with cardiovascular disease occurrence has not been reported. The prospective, population-based Atherosclerosis Risk in Communities Study measured the E40K ANGPTL4 variant in approximately 10000 white participants and determined its association with coronary heart disease (CHD) incidence (n = 1318 events) between 1987-1989 and 2004. Compared with noncarriers, carriers of 1 or 2 copies of the 40K variant (3.8% frequency) had a 19-mg/dL lower age- and sex-adjusted mean triglyceride level, 5-mg/dL lower low-density lipoprotein cholesterol, and 4-mg/dL higher high-density lipoprotein cholesterol. The age-, sex-, and field center-adjusted hazard ratio of CHD was 0.63 (95% confidence interval, 0.45-0.89). Adjustment for nonlipid confounding factors did not change this hazard ratio appreciably. Carriers also appeared to have reduced risk of incident stroke, prevalent peripheral artery disease, and carotid atherosclerosis; but these associations were based on few events among 40K carriers and were not statistically significant. In conclusion, in this prospective study, the 40K variant of ANGPTL4 appeared to confer reduced genetic risk for CHD.

Variation in TCF7L2 and increased risk of colon cancer: the Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

The purpose of this study was to determine whether a variation in the transcription factor 7-like 2 (TCF7L2) gene, which influences diabetes risk, is associated with incidence of cancers.

RESEARCH DESIGN AND METHODS

We related diabetes and TCF7L2 variation with occurrence of several common cancers in a prospective cohort study of 13,117 middle-aged adults initially free of cancer in 1987-1989. We assessed five single nucleotide polymorphisms (SNPs) in TCF7L2 including the putative SNP (rs7903146) for diabetes. We identified incident cancers through 2000 via cancer registries, supplemented by hospital records.

RESULTS

Diabetes was associated marginally inversely with incidence of prostate cancer but not with incidence of colorectal, colon, lung, or breast cancer. The T allele of rs7903146 (frequency 30%) was associated with increased risk of colorectal cancer and, more specifically, colon cancer, with adjusted hazard ratios (95% CI) of 1.0 for CC, 1.25 (0.85-1.83) for CT, and 2.15 (1.27-3.64) for TT genotypes (P(trend) = 0.009). TCF7L2 variation also was associated with lung cancer incidence in whites but not blacks, but residual confounding by smoking may be present.

CONCLUSIONS

Subjects who were initially cancer-free and carrying certain genetic variants of TCF7L2, most notably the T allele of rs7903146, have an increased risk of colon cancer. This association appears to be an independent gene effect not explained by diabetes. Because the T allele of rs7903146 is common, if a causal link is established, this variant could account for a sizable proportion ( approximately 17% here) of cases of colon cancer in the general population.

Association of common C-reactive protein (CRP) gene polymorphisms with baseline plasma CRP levels and fenofibrate response: the GOLDN study

OBJECTIVE

C-reactive protein (CRP) is an inflammatory marker that contributes to the prediction of cardiovascular disease. We investigated the influences of CRP polymorphisms on baseline CRP levels and fenofibrate-induced CRP changes in subjects with the metabolic syndrome.

RESEARCH DESIGN AND METHODS

We examined the association of CRP single nucleotide polymorphisms (SNPs) (m772A>G, m301G>A >T, i178T>A, 3u1273C>T, and 3u2131C>T) with baseline plasma CRP levels among 1,123 white U.S. participants in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study and the modulating effect of these SNPs on CRP response to a 3-week fenofibrate treatment among 290 participants with the metabolic syndrome.

RESULTS

There were strong associations of m301G>A>T (rs3091244; P = 0.003), i178T>A (rs1417938; P = 0.001), 3u1273C>T (rs1130864; P = 0.001), and 3u2131C>T (rs1205; P < 0.001) with baseline CRP levels. Moreover, among subjects with the metabolic syndrome, fenofibrate induced the greatest reduction in CRP levels for TT subjects of the i178T>A compared with TA and AA subjects (-30 for TT, -19 for TA, and -11% for AA; P = 0.004). Similarly, for the m301G>A>T, major allele carriers displayed maximal reduction of CRP over noncarriers (-20 for GG, -15 for GA and GT, and -0.3% for TA and AA; P = 0.020).

CONCLUSIONS

Our results demonstrate that common genetic variants within the CRP gene affect baseline CRP levels and further modulate CRP response in subjects with the metabolic syndrome treated with fenofibrate. This knowledge could contribute to a better prediction of therapeutic success.

The effect of IL6-174C/G polymorphism on postprandial triglyceride metabolism in the GOLDN studyboxs

Chronically elevated interleukin-6 (IL-6) affects lipid and lipoprotein metabolism. Individuals genetically predisposed to higher IL-6 secretion may be at risk of dyslipidemia, especially during the postprandial phase. We investigated the effect of genetic variants at the IL6 locus on postprandial lipemia in US Whites participating in the Genetics of Lipid Lowering Drugs and Diet Network study. Subjects were given a single fat load composed of 3% of calories as protein, 14% as carbohydrate, and 83% as fat. Blood was drawn at 0 h, 3.5 h, and 6 h to determine plasma triglyceride (TG), TG-rich lipoprotein (TRL) and lipoprotein particle size. Homozygotes (GG) and heterozygotes (CG) of the -174C/G variant displayed higher plasma IL-6 concentrations compared with major allele homozygotes (CC) (P = 0.029). GG and CG subjects showed higher fasting plasma TG (P = 0.025), VLDL (P = 0.04), and large VLDL (P = 0.02) concentrations than did CC subjects. Moreover, GG and CG subjects experienced greater postprandial response of TG (P = 0.006) and TRL, including chylomicrons (P = 0.005), total VLDL (P = 0.029), and large VLDL (P = 0.017) than did CC subjects. These results suggest that the functional polymorphism -174C>G at the IL6 locus determines the difference in both fasting and postprandial TG metabolism. This phenomenon could be responsible for the observed association of this genetic variant with cardiovascular disease risk.

Variation in PCSK9, low LDL cholesterol, and risk of peripheral arterial disease

BACKGROUND

We hypothesized that variants in PCSK9 that lower LDL cholesterol levels are associated with reduced prevalence and incidence of peripheral artery disease (PAD).

METHODS

The Atherosclerosis Risk in Communities (ARIC) Study assessed risk factors and PCSK9 variants Y142X and C679X (relevant to blacks) and R46L (relevant to whites) in a cohort of 45-64-year olds in 1987-1989 (n=13,634). Prevalent PAD (n=619 cases) was defined by an ankle-brachial index <0.9 or a history of leg claudication. Incident PAD (n=895) was identified from 1987 to 1998 by the same PAD criteria or a PAD hospitalization.

RESULTS

As expected, greater LDL cholesterol was a risk factor for prevalent and incident PAD. 2.4% of blacks and 3.1% of whites were carriers of one of the race-specific PCSK9 variants. Carriers had lower prevalence of PAD compared with non-carriers (2.3% vs. 4.6%). The corresponding age- and sex-adjusted odds ratio of PAD was 0.47 (95% confidence interval, 0.24-0.92). In contrast with the cross-sectional findings, there was no association between PCSK9 variants and incident PAD (age- and sex-adjusted hazard ratio, 1.09 (95% confidence interval, 0.76-1.57)).

CONCLUSIONS

Our study provides mixed evidence that variation in PCSK9 may contribute to genetic risk of PAD.

The genetic architecture of fasting plasma triglyceride response to fenofibrate treatment

Metabolic response to the triglyceride (TG)-lowering drug, fenofibrate, is shaped by interactions between genetic and environmental factors, yet knowledge regarding the genetic determinants of this response is primarily limited to single-gene effects. Since very low-density lipoprotein (VLDL) is the central carrier of fasting TG, identifying factors that affect both total TG and VLDL-TG response to fenofibrate is critical for predicting individual fenofibrate response. As part of the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study, 688 individuals from 161 families were genotyped for 91 single-nucleotide polymorphisms (SNPs) in 25 genes known to be involved in lipoprotein metabolism. Using generalized estimating equations to control for family structure, we performed linear modeling to investigate whether single SNPs, single covariates, SNP-SNP interactions, and/or SNP-covariate interactions had a significant association with the change in total fasting TG and fasting VLDL-TG after 3 weeks of fenofibrate treatment. A 10-iteration fourfold cross-validation procedure was used to validate significant associations and quantify their predictive abilities. More than one-third of the significant, cross-validated SNP-SNP interactions predicting each outcome involved just five SNPs, showing that these SNPs are of key importance to fenofibrate response. Multiple variable models constructed using the top-ranked SNP--covariate interactions explained 11.9% more variation in the change in TG and 7.8% more variation in the change in VLDL than baseline TG alone. These results yield insight into the complex biology of fenofibrate response, which can be used to target fenofibrate therapy to individuals who are most likely to benefit from the drug.

Stroke Prevention: The Best Outcome after a Transient Ischemic Attack. Results from the Minnesota Stroke Registry and Opportunities to Improve Care

A transient ischemic attack (TIA) is an opportunity for stroke prevention. We examined the care of 708 TIA patients entered into the Minnesota Stroke Registry (MSR) and analyzed the extent to which they were discharged on appropriate guideline-recommended secondary prevention treatments. We calculated the overall number of strokes prevented by multiple risk factor modifying treatments. Of the 708 TIA patients, 533 (75%) were discharged on antihypertensive treatment. Of 208 patients with an LDL-Cholesterol greater than 100 mg/dl, 131 (63%) patients were prescribed lipid-lowering medications. Anticoagulation treatment was prescribed in 76% (82 of 108) of patients diagnosed with atrial fibrillation during hospitalization. Anti-thrombotic therapy was prescribed in 94% (563 of 600) TIA patients without atrial fibrillation. We estimated that 104 strokes will be prevented over 5 years due to combining multiple treatments assuming a baseline stroke risk of 60% in atrial fibrillation patients and 17% in non-atrial fibrillation patients over 5 years.

Thrombolytic Treatment After Acute Ischemic Stroke Results from the Minnesota Stroke Registry and Opportunities to Improve Care

BACKGROUND: We used data from the Minnesota Stroke Registry to examine rates of intravenous thrombolytic therapy in acute ischemic stroke and identifed opportunities to improve the utilization of this treatment. METHODS: We analyzed a total of 1010 acute ischemic stroke patients who had been entered into the registry by 13 participating hospitals during the first three quarters of the 2008 calendar year. RESULTS: Of the 1010 patients only 121 (12%) came within 2 hours of symptom onset. Intravenous recombinant tissue plasminogen activator (rt-PA) was administered to 32/55 (58%) of the patients who arrived within 2 hours of symptom onset and met eligibility criteria for this treatment. The remaining 66 patients had a documented reason for non-treatment. The most common reason (22/66) for non-treatment was rapid resolution of symptoms or mild stroke. Out of those 22 patients, 20 were ambulating independently prior to admission and only 9/20 (45%) ambulated independently at discharge. CONCLUSION: Further community education on the need for immediate medical attention after stroke is needed. Patients appropriately excluded from rt-PA treatment due to mild deficits or rapidly improving symptoms seem to have poor discharge outcomes. This subgroup of patients will have to be studied further, preferably in the context of a clinical trial.

Erythrocyte fatty acid composition and the metabolic syndrome: a National Heart, Lung, and Blood Institute GOLDN study

BACKGROUND

Different fatty acids may vary in their effect on the metabolic syndrome (MetS). We tested whether fatty acid classes measured in erythrocytes are associated with the MetS or its components.

METHODS

Included were men [n = 497; mean (SD) age, 49 (16) years] and women [n = 539; age, 48 (16) years] from 187 families in a National Heart, Lung, and Blood Institute (NHLBI) family study of the Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) conducted in Utah and Minnesota. We used gas chromatography to measure erythrocyte fatty acids and obtained data on potential confounding variables from interviewer-administered questionnaires.

RESULTS

The prevalence of the MetS as defined by the updated Adult Treatment Panel III criteria was 36.8% in Utah and 39.6% in Minnesota (P >0.05). In a multivariate model that included 4 fatty acid classes, covariates, and pedigree as a random effect, the odds ratios (95% confidence interval) for the MetS in the 1st, 2nd, 3rd, and 4th quartile of polyunsaturated fatty acids were 1.00, 0.72 (0.47-1.10), 0.67 (0.43-1.05), and 0.39 (0.24-0.64), respectively (P for trend = 0.0002). For the corresponding quartiles of saturated fatty acids, the odds ratios were 1.00, 1.19 (0.77-1.84), 1.48 (0.94-2.34), and 1.63 (1.01-2.63), respectively (P for trend = 0.03). Unlike n6 fatty acids, which showed an inverse association (P <0.05) with MetS, n3, trans, and monounsaturated fatty acids were not associated with the MetS (P >0.05). We observed significant correlations (P <0.05) between fatty acid classes, insulin, and components of the MetS.

CONCLUSIONS

Polyunsaturated fats are inversely associated with the MetS, whereas saturated fatty acids are positively associated with the MetS, probably through their effect on lipids, adiposity, insulin, and blood pressure.

Interleukin1beta genetic polymorphisms interact with polyunsaturated fatty acids to modulate risk of the metabolic syndrome

Chronic inflammation has been identified as an important component of the metabolic syndrome (MetS). Therefore, environmental and genetic factors contributing to the variation of inflammatory responses could affect individuals' susceptibility to MetS. We investigated the association between common IL1beta genetic polymorphisms, inflammation, and the MetS, and the modulation of diet-related variables (i.e., erythrocyte membrane fatty acid composition) in a white U.S. population. IL1beta single nucleotide polymorphisms (SNP) (-1473G > C, -511G > A, -31T > C, 3966C > T, 6054G > A), clinical and biochemical measurements were characterized in a total of 1120 subjects (540 males and 580 females) participating in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study. The 6054 G > A SNP was significantly associated with plasma C-reactive protein (P = 0.054), adiponectin (P = 0.021), and the prevalence of MetS (P = 0.004). Moreover, there was a significant interaction between the 6054G > A SNP and erythrocyte membrane (n-3) PUFA (P = 0.019). Among subjects with low (n-3) PUFA content (below the median), the 6054 G allele was associated with increased risk of the MetS (OR = 3.29, 95%CI = 1.49-7.26 for GG and OR = 1.95, 95%CI = 0.85-4.46 for GA, P < 0.001) compared with the AA genotype, but there were no significant genotype associations among subjects with high (n-3) PUFA content (above the median). Further analyses supported a significant haplotype global effect on the MetS (P = 0.017) among subjects with low (n-3) PUFA content. These results suggested that IL1beta genetic variants were associated with measures of chronic inflammation and the MetS risk, and that genetic influences were more evident among subjects with low (n-3) PUFA intake.

The -256T>C polymorphism in the apolipoprotein A-II gene promoter is associated with body mass index and food intake in the genetics of lipid lowering drugs and diet network study

BACKGROUND

Apolipoprotein A-II (APOA2) plays an ambiguous role in lipid metabolism, obesity, and atherosclerosis.

METHODS

We studied the association between a functional APOA2 promoter polymorphism (-265T>C) and plasma lipids (fasting and postprandial), anthropometric variables, and food intake in 514 men and 564 women who participated in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study. We obtained fasting and postprandial (after consuming a high-fat meal) measures. We measured lipoprotein particle concentrations by proton nuclear magnetic resonance spectroscopy and estimated dietary intake by use of a validated questionnaire.

RESULTS

We observed recessive effects for this polymorphism that were homogeneous by sex. Individuals homozygous for the -265C allele had statistically higher body mass index (BMI) than did carriers of the T allele. Consistently, after multivariate adjustment, the odds ratio for obesity in CC individuals compared with T allele carriers was 1.70 (95% CI 1.02-2.80, P = 0.039). Interestingly, total energy intake in CC individuals was statistically higher [mean (SE) 9371 (497) vs 8456 (413) kJ/d, P = 0.005] than in T allele carriers. Likewise, total fat and protein intakes (expressed in grams per day) were statistically higher in CC individuals (P = 0.002 and P = 0.005, respectively). After adjustment for energy, percentage of carbohydrate intake was statistically lower in CC individuals. These associations remained statistically significant even after adjustment for BMI. We found no associations with fasting lipids and only some associations with HDL subfraction distribution in the postprandial state.

CONCLUSIONS

The -265T>C polymorphism is consistently associated with food consumption and obesity, suggesting a new role for APOA2 in regulating dietary intake.

Fenofibrate effect on triglyceride and postprandial response of apolipoprotein A5 variants: the GOLDN study

OBJECTIVE

Apolipoprotein A5 (APOA5) is a key determinant of plasma triglyceride (TG) concentrations. Genetic variation at the APOA5 locus could be responsible for some of the observed differences in response to fenofibrate therapy.

METHODS AND RESULTS

We examined the association between tag SNPs (-1131T>C and 56C>G) at APOA5 and TG and HDL-C response to fenofibrate and a postprandial lipid challenge in 791 men and women participating in the GOLDN study. After 3-week drug treatment, APOA5 56G carriers displayed significant decrease in TG (P=0.006), and increase in HDL-C (P=0.002) levels relative to their basal values in the fasting state when compared with noncarriers (a TG reduction of -35.8+/-2.8% versus -27.9+/-0.9% and a HDL-C increase of 11.8+/-1.3% versus 6.9+/-0.5%, respectively). In the postprandial lipemia after a fat load, the 56G carriers showed a significant decrease in the area under curve for TG and increase for HDL-C than the noncarriers. These diverse beneficial responses of 56G carriers to fenofibrate were further characterized by a higher increase in large LDL-C concentrations and LDL size. On the other hand, subjects with different APOA5-1131T>C genotypes showed no significant response to fenofibrate intervention.

CONCLUSION

This study suggests that the APOA5 56G carriers benefited more from the fenofibrate treatment than noncarriers in lowering plasma TG and increasing HDL-C levels.

Effect of influenza vaccine on markers of inflammation and lipid profile

Despite wide use of the influenza vaccine, relatively little is known about its effect on the measurement of inflammatory markers. Because inflammatory markers such as C-reactive protein (CRP) are increasingly being used in conjunction with lipids for the clinical assessment of cardiovascular disease and in epidemiologic studies, we evaluated the effect of influenza vaccination on markers of inflammation and plasma lipid concentrations. We drew blood from 22 healthy individuals 1 to 6 hours before they were given an influenza vaccination and 1, 3, and 7 days after the vaccination. Plasma CRP, interleukin (IL)-6, monocyte chemotactic protein 1, tumor necrosis factor alpha, IL-2 soluble receptor alpha, and serum amyloid A were measured, and differences in mean concentrations of absolute and normalized values on days 1, 3, and 7 were compared with mean baseline values. There was a significant increase in mean IL-6 (P < .01 absolute values, P < .001 normalized values) on day 1 after receiving the influenza vaccine. The mean increases in normalized high sensitivity CRP values were significant on day 1 (P < .01) and day 3 (P = .05), whereas the mean increase in normalized serum amyloid A was significant only on day 1 (P < .05). No significant changes were seen in mean concentrations of IL-2 soluble receptor alpha, monocyte chemotactic protein-1, or tumor necrosis factor-alpha. Of the lipids, significant decreases in mean concentrations of normalized triglyceride values were seen on days 1 (P < .05), 3 (P < .001), and 7 (P < .05) after vaccination. Our findings show that the influenza vaccination causes transient changes in select markers of inflammation and lipids. Consequently, clinical and epidemiologic interpretation of the biomarkers affected should take into account the possible effects of influenza vaccination.

Evidence for a gene influencing fasting LDL cholesterol and triglyceride levels on chromosome 21q

High levels of low-density lipoprotein (LDL) cholesterol, low levels of high-density lipoprotein (HDL) cholesterol, and high levels of triglycerides (TG) are strong predictors of cardiovascular disease risk. Motivated by previous evidence for pleiotropy between cholesterol and TG levels, we conducted bivariate linkage analysis of LDL cholesterol and TG concentration among participants of the Hypertension Genetic Epidemiolgy Network (HyperGEN), one of four networks in the NHLBI sponsored Family Blood Pressure Program Project. All available hypertensive siblings and their first-degree relatives were recruited. Both phenotypes were similarly adjusted for ethnicity, study center, sex, age, age-by-sex interactions, smoking, alcohol consumption, hormone use, diabetes medication use, and waist circumference. Variance component linkage analysis was performed as implemented in SOLAR, using ethnicity-specific marker allele frequencies derived from founders and multipoint IBDs calculated in MERLIN. A maximum genome-wide empirical LOD score of 3.9 was detected on chromosome 21 at 54cM, between markers D21S2055 and D21S1446. This signal overlaps with suggestive and/or significant linkages for total cholesterol, LDL cholesterol, and apolipoprotein B in three other studies and is suggestive of one or more genes on chromosome 21q jointly regulating LDL cholesterol and TG concentration.

Comparison of ultracentrifugation and nuclear magnetic resonance spectroscopy in the quantification of triglyceride-rich lipoproteins after an oral fat load

BACKGROUND

The measurement of triglyceride (TG)-rich particles after an oral fat challenge has been used to provide a measure of risk for coronary artery disease independent of the fasting plasma triglyceride concentration. The analytical "gold standard" for measuring TG-rich lipoproteins uses density gradient ultracentrifugation; however, this technique is labor-intensive. Because of our need to perform numerous postprandial analyses of TG-rich lipoproteins for a large interventional study (Genetics of Lipid Lowering Drugs and Diet Network), we evaluated the use of nuclear magnetic resonance (NMR) spectroscopy for measuring TG-rich particles.

METHODS

EDTA-blood samples were obtained 0, 3.5, 6, and 8 h after ingestion of an oral fat meal (89% of calories from fat) in 20 apparently healthy individuals. The plasma TG concentrations of chylomicron and chylomicron remnant/VLDL fractions were analyzed by ultracentrifugation and NMR spectroscopy.

RESULTS

Comparison of all values (n = 78) by ultracentrifugation (x) and NMR (y) produced a linear regression equation of y = 0.979x - 0.035 mmol/L (R(2) = 0.90) for chylomicrons and y = 1.398x + 0.067 mmol/L (R(2) = 0.96) for the fraction containing chylomicron remnants and VLDL. Postprandial response of chylomicrons and chylomicron remnant/VLDL was similar, with maximum response occurring between 3.5 to 6 h regardless of method of measurement.

CONCLUSION

Chylomicron and chylomicron remnant/VLDL fraction measurements obtained by NMR have a high degree of correlation with results produced by ultracentrifugation. NMR may therefore be suitable as an alternative method for the measurement of postprandial TG-rich lipoproteins in individuals consuming a high-fat meal.

Influence of apolipoprotein E, smoking, and alcohol intake on carotid atherosclerosis: National Heart, Lung, and Blood Institute Family Heart Study

BACKGROUND AND PURPOSE

Apolipoprotein E (apoE) isoforms and lifestyle factors play an important role in the development of coronary heart disease. The association of apoE and carotid atherosclerosis remains controversial.

METHODS

We investigated the relation of apoE, cigarette smoking, alcohol drinking, and their interaction with carotid atherosclerosis on 544 individuals free of coronary heart disease in the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Atherosclerotic lesions of the carotid arteries were detected through high-resolution ultrasound.

RESULTS

Subjects in the apoE4 group had lower blood pressure, lower high-density lipoprotein cholesterol, and higher low-density lipoprotein cholesterol. In a multivariate logistic regression model, apoE isoforms and alcohol consumption were not significantly associated with the prevalence odds of carotid atherosclerosis (P=0.94 and 0.98, respectively, for trend). In contrast, compared with those who never smoked, the prevalence odds ratios for carotid atherosclerosis were 1.7 [95% confidence interval (CI),1.1 to 2.7], 2.8 (95% CI, 1.2 to 6.2), and 1.9 (95% CI, 0.7 to 5.5) for former smokers, current smokers of 1 to 20 cigarettes per day, and current smokers of >20 cigarettes day, respectively (P=0.0018 for trend). We did not find evidence of an interaction between apoE and alcohol consumption. Our data suggested a synergistic effect between the apoE allele epsilon(4) and smoking on carotid atherosclerosis: odds ratios were 1.7 (95% CI, 0.8 to 3.6) for smoking alone, 1.0 (95% CI, 0.6 to 1.8) for epsilon4 alone, and 3.7 (95% CI, 1.1 to 3.6) for the joint presence of the apoE allele epsilon4 and smoking.

CONCLUSIONS

Smoking but not alcohol consumption or ApoE is associated with an increased odds of carotid atherosclerosis. Our data suggest a synergistic effect between the apoE allele epsilon4 and smoking on carotid atherosclerosis.

Genome-wide linkage analysis of lipids in the Hypertension Genetic Epidemiology Network (HyperGEN) Blood Pressure Study

Full genome scans were performed for quantitative lipid measurements in 622 African American and 649 white sibling pairs not taking lipid-lowering medications who were ascertained through the Hypertension Genetic Epidemiology Network (HyperGEN) of the National Heart, Lung, and Blood Institute (NHLBI) Family Blood Pressure Program. Genotypes for 391 markers spaced roughly equally throughout the genome were typed by the NHLBI Mammalian Genotyping Service. Each of the phenotypes was adjusted for covariates within sex and race and then subjected to variance components linkage analysis, which was performed separately within race by using race-specific marker allele frequencies from additional random samples. The highest lod score detected was 2.77 for logarithmically transformed triglyceride (TG) on chromosome 20 (at 28.6 cM) in the African American sibling pairs. The highest score detected in the white sibling pairs was 2.74 for high density lipoprotein cholesterol on chromosome 5 (at 48.2 cM). Although no scores >3.0 were obtained, positive scores were found in several regions that have been reported in other genome scans in the literature. For example, a score of 1.91 for TG was found on chromosome 15 (at 28.8 cM) in white sibling pairs. This score overlaps the positive findings for TG in 2 other genome scans.

Genome scan for quantitative trait loci linked to high-density lipoprotein cholesterol: The NHLBI Family Heart Study

We conducted a genome-wide linkage scan for quantitative trait loci influencing total HDL-cholesterol (HDL-C) concentration in a sample of 1027 whites from 101 families participating in the NHLBI Family Heart Study. To maximize the relative contribution of genetic components of variance to the total variance of HDL-C, the HDL-C phenotype was adjusted for age, age(2), body mass index, and Family Heart Study field center, and standardized HDL-C residuals were created separately for men and women. All analyses were completed by the variance components method, as implemented in the program GENEHUNTER using 383 anonymous markers typed at the NHLBI Mammalian Genotyping Service in Marshfield, Wis. Evidence for linkage of residual HDL-C was detected near marker D5S1470 at location 39.9 cM from the p-terminal of chromosome 5 (LOD=3.64). Suggestive linkage was detected near marker D13S1493 at location 27.5 cM on chromosome 13 (LOD=2.36). We conclude that at least 1 genomic region is likely to harbor a gene that influences interindividual variation in HDL cholesterol.

Association of C-reactive protein with markers of prevalent atherosclerotic disease

Recent prospective studies have demonstrated that elevated C-reactive protein (CRP) is a marker of increased risk of atherothrombotic clinical events. We examined in a large, cross-sectional family-based study (n = 875 men, 948 women) whether serum CRP was associated with prevalent coronary heart disease (CHD), the ankle/brachial blood pressure index, or carotid intima-media thickness, an indicator of subclinical atherosclerosis as assessed by B-mode ultrasound. CRP was associated with many other cardiovascular risk factors, particularly markers of obesity and insulin resistance, markers of inflammation and acute phase reaction, and hormone replacement therapy. Adjusted for age and family type, there was a weak positive association of CRP with carotid intima-media thickness in both genders and with prevalent CHD in women. However, adjustment for other risk factors completely eliminated the associations. For example, among women, the risk factor-adjusted mean values of intima-media thickness across quartiles of CRP were 0.76, 0.74, 0.75, and 0.76 mm (p >0.5). In men there was a weak inverse association between CRP and ankle/brachial blood pressure index, independent of other risk factors, but no such association in women. Our findings indicate that CRP is not strongly and independently associated with prevalent atherosclerosis. Because CRP has been associated with clinical events, it could be that elevated CRP may be a stronger marker of thrombotic risk than of the degree of atherosclerosis.

Association of nonsteroidal anti-inflammatory drugs and aspirin with cognitive performance in middle-aged adults

OBJECTIVES

To assess the cross-sectional association of regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin with cognitive function in 13,153 individuals, aged 48-67 years, participating in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

Regular use of NSAIDs or aspirin was analyzed in relation to the results of three cognitive tests, the Delayed Word Recall Test, the WAIS-R Digit Symbol Subtest, and the Word Fluency Test.

RESULTS

After adjustment for covariates previously found to be associated with cognition in this sample, we found a weak negative association between current use of aspirin and poor Word Recall [OR = 0.84 (95% confidence interval: 0.68-1.04)] and poor Word Fluency [OR = 0.85 (0.70-1.03)]. We found no association between current use of aspirin and Digit Symbol score, nor did we find current NSAID use to be significantly associated with any of the cognitive tests.

CONCLUSIONS

This study suggests a modest association, at best, between NSAIDs or aspirin and better cognitive function.

Dietary antioxidant intake and cognitive performance in middle-aged adults. The Atherosclerosis Risk in Communities (ARIC) Study investigators

OBJECTIVE

To assess the cross-sectional association of dietary and supplemental antioxidant (carotenoids, vitamins C and E) intake with cognitive function in 12 187 individuals, aged 48-67 years, participating in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

Dietary intake of antioxidant vitamins, as assessed by a food frequency questionnaire, and use of supplements were analysed in relation to the results of three cognitive tests, the delayed word recall test, the Wechsler adult intelligence scale, revised (WAIS-R) digit symbol subtest and the word fluency test.

RESULTS

After adjustment for covariates previously found to be associated with cognition in this sample, we found no consistent associations between dietary antioxidant vitamin intake or supplement use and any of the cognitive tests.

CONCLUSIONS

This study suggests little, if any, association between antioxidant vitamin intake and better cognitive function in middle-aged adults.

Effect of pulsed Nd:YAG laser radiation on action potential conduction in isolated mammalian spinal nerves

BACKGROUND AND OBJECTIVE

Dental lasers are claimed to produce analgesia, but the mechanisms and extent of any effects are uncertain. This study investigated the effects of lasing on nerve conduction in isolated nerves.

STUDY DESIGN/MATERIALS AND METHODS

Pulsed Nd:YAG laser energy was applied to spinal nerves in vitro and effects were measured as attenuation of the compound action potential (CAP) evoked by electrical stimulation.

RESULTS

Lasing for 1 minute at 0.3-3.0 W caused a dose-dependent attenuation of all components of the CAP (P < 0.03). With 0.3-1.0 W power, the CAP recovered to > 95% of the control levels 7 minutes after lasing; recovery was incomplete after lasing at > 2.0 W.

CONCLUSION

Isolated nerves were remarkably tolerant of lasing. The degree of nerve conduction block increased with laser power. The data indicate that lasing could diminish sensations, including pain, mediated by peripheral nerves in soft tissues.

Relationship of serum and dietary magnesium to incident hypertension: the Atherosclerosis Risk in Communities (ARIC) Study

PURPOSE

To examine the relationship of serum and dietary magnesium (Mg) with incident hypertension. The setting was the Atherosclerosis Risk in Communities (ARIC) Study, which included a biracial cohort, aged 45-64 years, from four U.S. communities.

METHODS

This analysis included 7731 participants (4190 women and 3541 men) free of hypertension at baseline and followed six years. Fasting serum Mg was measured, and usual dietary intake was assessed with a food frequency questionnaire.

RESULTS

After adjustment for age, race, and a number of other risk factors, the odds of incident hypertension across ascending quartiles of serum Mg were 1.0, 0.79, 0.85, and 0.70 in women (p trend = 0.01) and 1.0, 0.87, 0.87, and 0.82 in men (p trend = 0.16). We found no association between dietary Mg intake and incident hypertension. These associations were attenuated after the addition of baseline systolic blood pressure to the models.

CONCLUSIONS

This study suggests that low Mg may play a modest role in the development of hypertension.

Action potential conduction block of nerves in vitro by potassium citrate, potassium tartrate and potassium oxalate

OBJECTIVES

Potassium salts in desensitising formulations are believed to act by blocking nerve conduction. The aim of this study was to assess the ability of some organic potassium salts to block action potential conduction and to compare their effects with potassium chloride and potassium nitrate.

MATERIALS AND METHOD

Potassium citrate, oxalate or tartrate were added to Krebs' solutions to raise the potassium concentration to 8-64 mM. The test solutions were applied to rat spinal nerves in a bath while monitoring the compound action potentials evoked by electrical stimulation.

RESULTS

All potassium salts attenuated the compound action potential in a dose-dependent manner. There were no significant differences between the effects of potassium tartrate and potassium citrate solutions (p>0.1) which caused significantly greater compound action potential attenuation than the same concentrations of potassium oxalate (p<0.05). On the basis of the potassium ion concentration required to cause 50% attenuation of the compound nerve action potential, the relative potencies of the potassium salts were: citrate = tartrate> oxalate>chloride =nitrate.

CONCLUSION

Potassium citrate and potassium tartrate were more effective than other potassium salts in blocking nerve conduction and may be more effective dentinal desensitising agents.

Plasma fibrinogen and incident hypertension in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Several cross-sectional studies have reported a positive association between plasma fibrinogen levels and prevalent hypertension. Other studies have reported a positive association between hypertension and whole-blood or plasma viscosity, to which fibrinogen contributes. To our knowledge, there has been no prospective study of fibrinogen and incident hypertension.

SUBJECTS AND METHODS

We measured plasma fibrinogen levels in a population-based cohort study of middle-aged adults and related it to the occurrence of incident hypertension (systolic blood pressure > or = 140 mmHg or diastolic blood pressure > or = 90 mmHg or use of antihypertensive medication) over 6 years.

RESULTS

There was a moderately strong positive association between fibrinogen levels and prevalent hypertension in both men and women, with the odds of hypertension elevated by 50% for the highest fibrinogen quartile versus the lowest. Among 7884 participants at risk, 1609 developed hypertension over 6 years. Adjusted for age, race, field center and baseline systolic blood pressure, the odds ratio of incident hypertension in relation to fibrinogen quartiles was 1.0, 1.07, 1.21 and 1.43 in men (P= 0.003 for trend) and 1.0, 0.92, 0.99 and 0.99 in women (P= 0.89 for trend). After adjustment for other risk factors, the odds ratios were 1.0, 1.03, 1.15 and 1.29 (P= 0.045 for trend) in men and remained nonsignificant in women.

CONCLUSIONS

Despite a moderately strong positive association between fibrinogen levels and prevalent hypertension in both sexes, there was only a weak positive association between fibrinogen levels and incident hypertension in men and no association in women. Whether an elevated fibrinogen level is a risk factor for, or a consequence of, hypertension remains unclear.

Effects of pulsed Nd:YAG laser radiation on action potential conduction in nerve fibres inside teeth in vitro

OBJECTIVE

This study aimed to simulate the effects of lasing dentine on pulpal nerve function.

METHODS

Rat spinal nerve roots were threaded through the prepared pulp canal of a 10 mm long tooth root segment which was mounted in a perspex bath. The protruding ends of the nerve were placed on platinum wire electrodes used to elicit and to record compound nerve action potentials (CAPs). Laser energy (average power = 0.3-3.0 W) was applied to the surface of the root segment using a pulsed Nd:YAG dental laser (dLase 300).

RESULTS

With the laser probe tip placed in static contact with the tooth surface, the nerve CAP was irreversibly abolished within 60 s of lasing at 1.0-3.0 W power. When the laser tip was moved to and fro over the root surface in a scanning mode, similar levels of radiation produced less marked effects. In the latter mode, CAP attenuation increased with increasing power and duration of lasing. After 60 s lasing at 0.3 W, the CAP size was 95% (+/- 5, S.D.) of the prelasing controls value; with 2.0 W the CAP was reduced to 54% (+/- 33). The CAP recovered to 90% of control levels after lasing at powers up to 1.5 W, but reached only 72% of control values after lasing at 2.0 W power.

CONCLUSIONS

Laser radiation applied to dentine caused a dose-dependent block of action potential conduction in nerve fibres in the underlying pulp chamber.

Effects of potassium ions on action potential conduction in A- and C-fibers of rat spinal nerves

Potassium ions in dentifrices for treating 'hypersensitive' dentin are believed to act directly on intradental nerves by raising extracellular potassium ion concentration ([K+]o) sufficiently to prevent action potential generation by axonal accommodation. However, the [K+]o necessary to block nerve conduction is not precisely known, nor is it certain that K+ can diffuse from a dentifrice in sufficient amounts to inactivate intradental nerves. To establish more accurately the [K+]o required to block nerve conduction under controlled conditions, we studied the effects of increased [K+]o on the sizes of compound action potentials (CAP) recorded from rat spinal nerves in vitro. [K+]o was increased by the addition of either KCl or KNO3 to Krebs' solutions applied to the central portion of the nerves. CAP attenuation increased in a dose-dependent manner as [K+]o was raised in the 8 to 64 mmol/L range, and complete block was generally produced with solutions containing at least 32 mmol/L K+. CAP attenuation was reversible, and recovery times increased with increasing [K+]o. The effects of KCl and KNO3 solutions were the same for all [K+]o tested. Half-maximal (50%) reduction in the A beta-fiber component of the CAP occurred with 17.4 mmol/L K+, and with 17.8 mmol/L and 19.3 mmol/L K+, respectively, for the A delta- and C-fiber components. Control experiments with glucose and choline chloride confirmed that the conduction block observed with increased [K+]o was not due to increased solution osmolarity or ionic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors affecting nerve excitability and conduction as a basis for desensitizing dentine

Nerve excitability is principally determined by the state of membrane sodium channels, which can be influenced by factors such as drugs or the ionic composition of the extracellular fluids. The excitability of isolated nerves is increased by lowered extracellular calcium and hydrogen ion concentrations, and similar effects are seen on intradental nerve excitability. This is of interest as some agents used to desensitize hypersensitive dentine are believed to act by reducing intradental nerve excitability. A variety of ions, including potassium and divalent cations, have been shown to reduce intradental nerve excitability when applied in relatively high concentrations to dentine close to the pulp. However, these conditions do not mimic the clinical situation, where agents are applied to outer dentine, up to 2 mm from the pulp. Also, when agents are applied to dentine it is difficult to quantify the precise changes in extracellular fluid composition, and there is the additional complication of possible interactions between the agents and dentine. These problems can be minimized by using isolated nerves, which allow better control over the conditions and ionic concentrations necessary to achieve nerve conduction block. Such methods can provide a convenient way to screen potential desensitizing agents before evaluation in vivo or in clinical trials.