Comparison of global estimates of prevalence and risk factors for peripheral artery disease in 2000 and 2010: a systematic review and analysis.

BACKGROUND: Lower extremity peripheral artery disease is the third leading cause of atherosclerotic cardiovascular morbidity, following coronary artery disease and stroke. This study provides the first comparison of the prevalence of peripheral artery disease between high-income countries (HIC) and low-income or middle-income countries (LMIC), establishes the primary risk factors for peripheral artery disease in these settings, and estimates the number of people living with peripheral artery disease regionally and globally. METHODS: We did a systematic review of the literature on the prevalence of peripheral artery disease in which we searched for community-based studies since 1997 that defined peripheral artery disease as an ankle brachial index (ABI) lower than or equal to 0·90. We used epidemiological modelling to define age-specific and sex-specific prevalence rates in HIC and in LMIC and combined them with UN population numbers for 2000 and 2010 to estimate the global prevalence of peripheral artery disease. Within a subset of studies, we did meta-analyses of odds ratios (ORs) associated with 15 putative risk factors for peripheral artery disease to estimate their effect size in HIC and LMIC. We then used the risk factors to predict peripheral artery disease numbers in eight WHO regions (three HIC and five LMIC). FINDINGS: 34 studies satisfied the inclusion criteria, 22 from HIC and 12 from LMIC, including 112,027 participants, of which 9347 had peripheral artery disease. Sex-specific prevalence rates increased with age and were broadly similar in HIC and LMIC and in men and women. The prevalence in HIC at age 45-49 years was 5·28% (95% CI 3·38-8·17%) in women and 5·41% (3·41-8·49%) in men, and at age 85-89 years, it was 18·38% (11·16-28·76%) in women and 18·83% (12·03-28·25%) in men. Prevalence in men was lower in LMIC than in HIC (2·89% [2·04-4·07%] at 45-49 years and 14·94% [9·58-22·56%] at 85-89 years). In LMIC, rates were higher in women than in men, especially at younger ages (6·31% [4·86-8·15%] of women aged 45-49 years). Smoking was an important risk factor in both HIC and LMIC, with meta-OR for current smoking of 2·72 (95% CI 2·39-3·09) in HIC and 1·42 (1·25-1·62) in LMIC, followed by diabetes (1·88 [1·66-2·14] vs 1·47 [1·29-1·68]), hypertension (1·55 [1·42-1·71] vs 1·36 [1·24-1·50]), and hypercholesterolaemia (1·19 [1·07-1·33] vs 1·14 [1·03-1·25]). Globally, 202 million people were living with peripheral artery disease in 2010, 69·7% of them in LMIC, including 54·8 million in southeast Asia and 45·9 million in the western Pacific Region. During the preceding decade the number of individuals with peripheral artery disease increased by 28·7% in LMIC and 13·1% in HIC. INTERPRETATION: In the 21st century, peripheral artery disease has become a global problem. Governments, non-governmental organisations, and the private sector in LMIC need to address the social and economic consequences, and assess the best strategies for optimum treatment and prevention of this disease. FUNDING: Peripheral Arterial Disease Research Coalition (Europe).

Short-term effects of daily aspirin on cancer incidence, mortality, and non-vascular death: analysis of the time course of risks and benefits in 51 randomised controlled trials.

BACKGROUND: Daily aspirin reduces the long-term risk of death due to cancer. However, the short-term effect is less certain, especially in women, effects on cancer incidence are largely unknown, and the time course of risk and benefit in primary prevention is unclear. We studied cancer deaths in all trials of daily aspirin versus control and the time course of effects of low-dose aspirin on cancer incidence and other outcomes in trials in primary prevention. METHODS: We studied individual patient data from randomised trials of daily aspirin versus no aspirin in prevention of vascular events. Death due to cancer, all non-vascular death, vascular death, and all deaths were assessed in all eligible trials. In trials of low-dose aspirin in primary prevention, we also established the time course of effects on incident cancer, major vascular events, and major extracranial bleeds, with stratification by age, sex, and smoking status. RESULTS: Allocation to aspirin reduced cancer deaths (562 vs 664 deaths; odds ratio [OR] 0·85, 95% CI 0·76-0·96, p=0·008; 34 trials, 69,224 participants), particularly from 5 years onwards (92 vs 145; OR 0·63, 95% CI 0·49-0·82, p=0·0005), resulting in fewer non-vascular deaths overall (1021 vs 1173; OR 0·88, 95% CI 0·78-0·96, p=0·003; 51 trials, 77,549 participants). In trials in primary prevention, the reduction in non-vascular deaths accounted for 87 (91%) of 96 deaths prevented. In six trials of daily low-dose aspirin in primary prevention (35,535 participants), aspirin reduced cancer incidence from 3 years onwards (324 vs 421 cases; OR 0·76, 95% CI 0·66-0·88, p=0·0003) in women (132 vs 176; OR 0·75, 95% CI 0·59-0·94, p=0·01) and in men (192 vs 245; OR 0·77, 95% CI 0·63-0·93, p=0·008). The reduced risk of major vascular events on aspirin was initially offset by an increased risk of major bleeding, but effects on both outcomes diminished with increasing follow-up, leaving only the reduced risk of cancer (absolute reduction 3·13 [95% CI 1·44-4·82] per 1000 patients per year) from 3 years onwards. Case-fatality from major extracranial bleeds was also lower on aspirin than on control (8/203 vs 15/132; OR 0·32, 95% CI 0·12-0·83, p=0·009). INTERPRETATION: Alongside the previously reported reduction by aspirin of the long-term risk of cancer death, the short-term reductions in cancer incidence and mortality and the decrease in risk of major extracranial bleeds with extended use, and their low case-fatality, add to the case for daily aspirin in prevention of cancer. FUNDING: None.

Effect of daily aspirin on long-term risk of death due to cancer: analysis of individual patient data from randomised trials.

BACKGROUND: Treatment with daily aspirin for 5 years or longer reduces subsequent risk of colorectal cancer. Several lines of evidence suggest that aspirin might also reduce risk of other cancers, particularly of the gastrointestinal tract, but proof in man is lacking. We studied deaths due to cancer during and after randomised trials of daily aspirin versus control done originally for prevention of vascular events. METHODS: We used individual patient data from all randomised trials of daily aspirin versus no aspirin with mean duration of scheduled trial treatment of 4 years or longer to determine the effect of allocation to aspirin on risk of cancer death in relation to scheduled duration of trial treatment for gastrointestinal and non-gastrointestinal cancers. In three large UK trials, long-term post-trial follow-up of individual patients was obtained from death certificates and cancer registries. RESULTS: In eight eligible trials (25 570 patients, 674 cancer deaths), allocation to aspirin reduced death due to cancer (pooled odds ratio [OR] 0·79, 95% CI 0·68-0·92, p=0·003). On analysis of individual patient data, which were available from seven trials (23 535 patients, 657 cancer deaths), benefit was apparent only after 5 years' follow-up (all cancers, hazard ratio [HR] 0·66, 0·50-0·87; gastrointestinal cancers, 0·46, 0·27-0·77; both p=0·003). The 20-year risk of cancer death (1634 deaths in 12 659 patients in three trials) remained lower in the aspirin groups than in the control groups (all solid cancers, HR 0·80, 0·72-0·88, p<0·0001; gastrointestinal cancers, 0·65, 0·54-0·78, p<0·0001), and benefit increased (interaction p=0·01) with scheduled duration of trial treatment (≥7·5 years: all solid cancers, 0·69, 0·54-0·88, p=0·003; gastrointestinal cancers, 0·41, 0·26-0·66, p=0·0001). The latent period before an effect on deaths was about 5 years for oesophageal, pancreatic, brain, and lung cancer, but was more delayed for stomach, colorectal, and prostate cancer. For lung and oesophageal cancer, benefit was confined to adenocarcinomas, and the overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR 0·66, 0·56-0·77, p<0·0001). Benefit was unrelated to aspirin dose (75 mg upwards), sex, or smoking, but increased with age-the absolute reduction in 20-year risk of cancer death reaching 7·08% (2·42-11·74) at age 65 years and older. INTERPRETATION: Daily aspirin reduced deaths due to several common cancers during and after the trials. Benefit increased with duration of treatment and was consistent across the different study populations. These findings have implications for guidelines on use of aspirin and for understanding of carcinogenesis and its susceptibility to drug intervention. FUNDING: None.

Effect modification by population dietary folate on the association between MTHFR genotype, homocysteine, and stroke risk: a meta-analysis of genetic studies and randomised trials.

BACKGROUND: The MTHFR 677C→T polymorphism has been associated with raised homocysteine concentration and increased risk of stroke. A previous overview showed that the effects were greatest in regions with low dietary folate consumption, but differentiation between the effect of folate and small-study bias was difficult. A meta-analysis of randomised trials of homocysteine-lowering interventions showed no reduction in coronary heart disease events or stroke, but the trials were generally set in populations with high folate consumption. We aimed to reduce the effect of small-study bias and investigate whether folate status modifies the association between MTHFR 677C→T and stroke in a genetic analysis and meta-analysis of randomised controlled trials. METHODS: We established a collaboration of genetic studies consisting of 237 datasets including 59,995 individuals with data for homocysteine and 20,885 stroke events. We compared the genetic findings with a meta-analysis of 13 randomised trials of homocysteine-lowering treatments and stroke risk (45,549 individuals, 2314 stroke events, 269 transient ischaemic attacks). FINDINGS: The effect of the MTHFR 677C→T variant on homocysteine concentration was larger in low folate regions (Asia; difference between individuals with TT versus CC genotype, 3·12 µmol/L, 95% CI 2·23 to 4·01) than in areas with folate fortification (America, Australia, and New Zealand, high; 0·13 µmol/L, -0·85 to 1·11). The odds ratio (OR) for stroke was also higher in Asia (1·68, 95% CI 1·44 to 1·97) than in America, Australia, and New Zealand, high (1·03, 0·84 to 1·25). Most randomised trials took place in regions with high or increasing population folate concentrations. The summary relative risk (RR) of stroke in trials of homocysteine-lowering interventions (0·94, 95% CI 0·85 to 1·04) was similar to that predicted for the same extent of homocysteine reduction in large genetic studies in populations with similar folate status (predicted RR 1·00, 95% CI 0·90 to 1·11). Although the predicted effect of homocysteine reduction from large genetic studies in low folate regions (Asia) was larger (RR 0·78, 95% CI 0·68 to 0·90), no trial has evaluated the effect of lowering of homocysteine on stroke risk exclusively in a low folate region. INTERPRETATION: In regions with increasing levels or established policies of population folate supplementation, evidence from genetic studies and randomised trials is concordant in suggesting an absence of benefit from lowering of homocysteine for prevention of stroke. Further large-scale genetic studies of the association between MTHFR 677C→T and stroke in low folate settings are needed to distinguish effect modification by folate from small-study bias. If future randomised trials of homocysteine-lowering interventions for stroke prevention are undertaken, they should take place in regions with low folate consumption. FUNDING: Full funding sources listed at end of paper (see Acknowledgments).

The Global Epidemiological Transition in Cardiovascular Diseases: Unrecognised Impact of Endemic Infections on Peripheral Artery Disease.

An epidemiological transition in the prevalence of peripheral artery disease (PAD) is taking place especially in low- and middle-income countries (LMICs) where an ageing population and adoption of western lifestyles are associated with an increase in PAD. We discuss the limited evidence which suggests that infection, potentially mediated by inflammation, may be a risk factor for PAD, and show by means of an ecological analysis that country-level prevalence of the major endemic infections of HIV, tuberculosis and malaria are associated with the prevalence of PAD. While further research is required, we propose that scientists and health authorities pay more attention to the interplay between communicable and non-communicable diseases, and we suggest that limiting the occurrence of endemic infections might have some effect on slowing the epidemiological transition in PAD.

Ankle--brachial index predicts level of, but not change in, cognitive function: the Edinburgh Artery Study at the 15-year follow-up.

The ankle-brachial index (ABI), a marker of generalized atherosclerosis, is related to cognitive impairment in older adults. We investigated whether ABI is associated specifically with age-related cognitive decline. We measured ABI at recruitment and 5 and 12 years later in a sample of individuals aged 55-74 years. Cognition was measured in 717 of these participants 10 years after recruitment and 5 years later. It was found that ABI was associated with the level of cognitive function, even after adjustment for estimated premorbid function and concurrently measured anxiety and depression (standardized coefficient of 0.07), but this was attenuated by anxiety and depression. ABI was not associated with change in cognitive function. In conclusion, over long time periods, low ABI may be associated with reduced cognitive function in older adults, at least partly because the associated poor health creates anxiety and depression.

Aspirin for prevention of cardiovascular events in a general population screened for a low ankle brachial index: a randomized controlled trial.

CONTEXT: A low ankle brachial index (ABI) indicates atherosclerosis and an increased risk of cardiovascular and cerebrovascular events. Screening for a low ABI can identify an asymptomatic higher risk group potentially amenable to preventive treatments. OBJECTIVE: To determine the effectiveness of aspirin in preventing events in people with a low ABI identified on screening the general population. DESIGN, SETTING, AND PARTICIPANTS: The Aspirin for Asymptomatic Atherosclerosis trial was an intention-to-treat double-blind randomized controlled trial conducted from April 1998 to October 2008, involving 28,980 men and women aged 50 to 75 years living in central Scotland, free of clinical cardiovascular disease, recruited from a community health registry, and had an ABI screening test. Of those, 3350 with a low ABI (< or = 0.95) were entered into the trial, which was powered to detect a 25% proportional risk reduction in events. INTERVENTIONS: Once daily 100 mg aspirin (enteric coated) or placebo. MAIN OUTCOME MEASURES: The primary end point was a composite of initial fatal or nonfatal coronary event or stroke or revascularization. Two secondary end points were (1) all initial vascular events defined as a composite of a primary end point event or angina, intermittent claudication, or transient ischemic attack; and (2) all-cause mortality. RESULTS: After a mean (SD) follow-up of 8.2 (1.6) years, 357 participants had a primary end point event (13.5 per 1000 person-years, 95% confidence interval [CI], 12.2-15.0). No statistically significant difference was found between groups (13.7 events per 1000 person-years in the aspirin group vs 13.3 in the placebo group; hazard ratio [HR], 1.03; 95% CI, 0.84-1.27). A vascular event comprising the secondary end point occurred in 578 participants (22.8 per 1000 person-years; 95% CI, 21.0-24.8) and no statistically significant difference between groups (22.8 events per 1000 person-years in the aspirin group vs 22.9 in the placebo group; HR, 1.00; 95% CI, 0.85-1.17). There was no significant difference in all-cause mortality between groups (176 vs 186 deaths, respectively; HR, 0.95; 95% CI, 0.77-1.16). An initial event of major hemorrhage requiring admission to hospital occurred in 34 participants (2.5 per 1000 person-years) in the aspirin group and 20 (1.5 per 1000 person-years) in the placebo group (HR, 1.71; 95% CI, 0.99-2.97). CONCLUSION: Among participants without clinical cardiovascular disease, identified with a low ABI based on screening a general population, the administration of aspirin compared with placebo did not result in a significant reduction in vascular events. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN66587262.

Global and regional prevalence, burden, and risk factors for carotid atherosclerosis: a systematic review, meta-analysis, and modelling study.

BACKGROUND: Estimation of the epidemiological burden of carotid atherosclerosis can serve as a basis for prevention and management of cardiovascular disease. We aimed to provide the first estimation on the prevalence, number of cases, and risk factors for carotid atherosclerosis in the general population globally and regionally. METHODS: In this systematic review, meta-analysis, and modelling study, we searched PubMed, MEDLINE, Embase, Global Health, and China National Knowledge Infrastructure for articles published from database inception until May 7, 2019, with no language restrictions, for population-based studies that quantified prevalence of carotid atherosclerosis by means of increased carotid intima-media thickness, carotid plaque, and carotid stenosis. Studies were eligible if they included bilaterally scanned carotid arteries using ultrasonography and defined increased carotid intima-media thickness as a thickness of 1·0 mm or more, carotid plaque as a focal carotid intima-media thickness of 1·5 mm or more encroaching into the lumen or at least 0·5 mm or 50% compared with the surrounding carotid intima-media thickness values, and carotid stenosis as 50% or more stenosis. Studies were excluded if the sample was not representative of the general population. We also included studies identified in our previous systematic review and meta-analysis of the prevalence of carotid atherosclerosis in China. We estimated age-specific and sex-specific prevalences of increased carotid intima-media thickness, carotid plaque, and carotid stenosis. We used UN population data to generate the number of people affected in 2000, 2015, and 2020. We did random-effects meta-analyses to assess the effects of risk factors for increased carotid intima-media thickness and carotid plaque. We derived regional numbers of people living with increased carotid intima-media thickness and carotid plaque in 2015 using a risk factors-based model by WHO region. All analyses were done in populations aged 30-79 years due to availability of data. This systematic review and meta-analysis is registered online on PROSPERO, CRD42019134709. FINDINGS: We identified 8632 articles through our database search, of which 515 were eligible for full-text review, including 37 articles from our previous study, and 59 articles were eligible for inclusion in our systematic review and meta-analysis. Overall, in people aged 30-79 years in 2020, the global prevalence of increased carotid intima-media thickness is estimated to be 27·6% (95% CI 16·9-41·3), equivalent to 1066·70 million affected people and a percentage change of 57·46% from 2000; of carotid plaque is estimated to be 21·1% (13·2-31·5), equivalent to 815·76 million affected people and a percentage change of 58·97% from 2000; and carotid stenosis is estimated to be 1·5% (1·1-2·1), equivalent to 57·79 million affected people and a percentage change of 59·13% from 2000. The prevalence of increased carotid intima-media thickness, carotid plaque, and carotid stenosis increased consistently with age and was higher in men than in women. Current smoking, diabetes, and hypertension were common risk factors for increased carotid intima-media thickness and carotid plaque. In 2015, the Western Pacific region had the largest share of global cases of increased carotid intima-media thickness (317·62 million [33·36%] of 952·13 million affected people) and carotid plaque (240·77 million [33·20%] of 725·25 million), whereas the African region had the smallest share of cases of increased carotid intima-media thickness (59·08 million [6·21%]) and the Eastern Mediterranean region had the smallest share of carotid plaque cases (44·59 million [6·15%]). INTERPRETATION: A substantial global burden of carotid atherosclerosis exists. Effective strategies are needed for primary prevention and management of carotid atherosclerosis. High-quality epidemiological investigations on carotid atherosclerosis are needed to better address the global burden of carotid atherosclerosis at finer levels. FUNDING: None.

Intelligence and persisting with medication for two years: Analysis in a randomised controlled trial.

The study examined whether verbal intelligence is associated with persisting to take medication for up to two years. The design is a prospective follow-up of compliance with taking medication in high-risk individuals participating in a randomised, placebo-controlled trial set in Central Scotland. Participants were 1993 people aged between 50 and 77 years with an ankle brachial index

Global, regional, and national prevalence and risk factors for peripheral artery disease in 2015: an updated systematic review and analysis.

BACKGROUND: Peripheral artery disease is a major cardiovascular disease that affected 202 million people worldwide in 2010. In the past decade, new epidemiological data on peripheral artery disease have emerged, enabling us to provide updated estimates of the prevalence and risk factors for peripheral artery disease globally and regionally and, for the first time, nationally. METHODS: For this systematic review and analysis, we did a comprehensive literature search for studies reporting on the prevalence of peripheral artery disease in the general population that were published between Jan 1, 2011, and April 30, 2019, in PubMed, MEDLINE, Embase, the Global Health database, CINAHL, the Global Health Library, the Allied and Complementary Medicine Database, and ProQuest Dissertations and Theses Global. We also included the Global Peripheral Artery Disease Study of 2013 and the China Peripheral Artery Disease Study as sources. Peripheral artery disease had to be defined as an ankle-brachial index lower than or equal to 0·90. With a purpose-built data collection form, data on study characteristics, sample characteristics, prevalence, and risk factors were abstracted from all the included studies identified from the sources. Age-specific and sex-specific prevalence of peripheral artery disease was estimated in both high-income countries (HICs) and low-income and middle-income countries (LMICs). We also did random-effects meta-analyses to pool the odds ratios of 30 risk factors for peripheral artery disease in HICs and LMICs. UN population data were used to generate the number of people affected by the disease in 2015. Finally, we derived the regional and national numbers of people with peripheral artery disease on the basis of a risk factor-based model. FINDINGS: We included 118 articles for systematic review and analysis. The prevalence of peripheral artery disease increased consistently with age. At younger ages, prevalence was slightly higher in LMICs than HICs (4·32%, 95% CI 3·01-6·29, vs 3·54%, 1·17-10·24, at 40-44 years), but the increase with age was greater in HICs than LMICs, leading to a higher prevalence in HICs than LMICs at older ages (21·24%, 15·22-28·90, vs 12·04%, 8·67-16·60, at 80-84 years). In HICs, prevalence was slightly higher in women than in men up to age 75 years (eg, 7·81%, 3·97-14·77, vs 6·60%, 3·74-11·38, at 55-59 years), whereas in LMICs little difference was found between women and men (eg, 6·40%, 5·06-8·05, vs 6·37%, 4·74-8·49, at 55-59 years). Overall, the global prevalence of peripheral artery disease in people aged 25 years and older was 5·56%, 3·79-8·55, and the prevalence estimate was higher in HICs than that in LMICs (7·37%, 4·35-13·66, vs 5·09%, 3·64-7·24). Smoking, diabetes, hypertension, and hypercholesterolaemia were major risk factors for peripheral artery disease. Globally, a total of 236·62 million people aged 25 years and older were living with peripheral artery disease in 2015, among whom 72·91% were in LMICs. The Western Pacific Region had the most peripheral artery disease cases (74·08 million), whereas the Eastern Mediterranean Region had the least (14·67 million). More than two thirds of the global peripheral artery disease cases were concentrated in 15 individual countries in 2015. INTERPRETATION: Peripheral artery disease continues to become an increasingly serious public health problem, especially in LMICs. With the demographic trend towards ageing and projected rise in important risk factors, a larger burden of peripheral artery disease is to be expected in the foreseeable future. FUNDING: None.

Relative value of inflammatory, hemostatic, and rheological factors for incident myocardial infarction and stroke: the Edinburgh Artery Study.

BACKGROUND: The aim of our present study was to compare the association of a wide range of 17 biomarkers of inflammation, hemostasis, and blood rheology with incident heart disease and stroke after accounting for an indicator of subclinical atherosclerotic disease and traditional risk factors and also to determine their incremental predictive ability. METHODS AND RESULTS: We used data from the Edinburgh Artery Study, a population cohort study started in 1987 that comprised 1592 men and women aged 55 to 74 years. Subjects were followed for a mean of 17 years, and 416 of them suffered at least 1 cardiovascular event. In analyses adjusted for cardiovascular risk factors and history of cardiovascular disease (CVD): C-reactive protein, interleukin-6, fibrinogen, fibrin D-dimer, tissue plasminogen activator (t-PA), leukocyte elastase, and lipoprotein(a) (all P<0.01), as well as von Willebrand factor and plasma viscosity (both P<0.05), had significant hazard ratios for incident CVD. Further adjustment for a measure of subclinical atherosclerosis (ankle brachial index) had little impact on these associations. The hazard ratios (95% CI) for incident CVD between top and bottom tertiles in the latter analysis were 1.78 (1.30 to 2.45) for C-reactive protein, 1.85 (1.33 to 2.58) for interleukin-6, and 1.76 (1.35 to 2.31) for fibrinogen. Single biomarkers provided little additional discrimination of incident CVD to that obtained from cardiovascular risk factors and the ankle brachial index. An incremental score of multiple markers [interleukin-6, t-PA, intercellular adhesion molecule 1, and lipoprotein(a)] provided some added discrimination. CONCLUSIONS: Several "novel" risk factors predicted CVD after adjustments for conventional risk factors and also for a measure of asymptomatic disease. However, their incremental predictive ability was modest and their clinical utility remains uncertain.

The Edinburgh Type 2 Diabetes Study: study protocol.

BACKGROUND: Risk factors underlying the development and progression of some of the less well-recognised complications of type 2 diabetes, including cognitive impairment and non-alcoholic fatty liver disease, are poorly understood. The Edinburgh Type 2 Diabetes Study was established in 2006 in order to investigate the role of potential risk factors in these complications, as well as to further investigate mechanisms underlying the development and progression of micro and macrovascular disease in type 2 diabetes. METHODS AND DESIGN: The study is designed as a prospective cohort study. Participants recruited at baseline (2006-2007) constitute 1066 men and women aged 60 to 75 years with established type 2 diabetes, living in the Lothian region of central Scotland. Subjects underwent detailed cognitive and physical examination, the latter including measures of micro- and macro-vascular disease, glycaemic control, body fat composition and plasma inflammatory markers, cortisol, lipids and liver function tests. Participants were re-examined after one year with hepatic ultrasonography and additional measures of vascular disease. This paper reports the methods of recruitment to the study and examinations performed at baseline and one year. Follow-up cognitive, vascular and liver assessments are scheduled for 2010-2011 when subjects will have been in the study for 4 years. DISCUSSION: This study will provide a wealth of epidemiological and biomarker data that should be invaluable in the identification of potentially modifiable, causal risk factors for diabetes-related cognitive impairment, liver dysfunction and vascular disease, which can be targeted for the development of preventive and therapeutic interventions.

Cardiovascular diseases and decline in cognitive function in an elderly community population: the Edinburgh Artery Study.

OBJECTIVE: To investigate cognitive performance and 4-year change in cognitive function in relation to different clinical manifestations of atherosclerotic disease in an elderly community population. METHODS: The Edinburgh Artery Study is a population cohort study of men and women who were recruited to a baseline survey in 1987 and 1988. From the time of study entry, the participants have been invited to two follow-up clinical examinations and continuously monitored for major fatal and nonfatal vascular events. All alive and eligible subjects were invited for cognitive testing in two study years when the mean age of the sample was 73.1 (standard deviation = 5.0) years. A follow-up cognitive assessment was performed in 2002 and 2003 on 452 survivors. RESULTS: In multivariate analyses controlling for demographic characteristics, depression, and major atherosclerotic risk factors, stroke was associated with a significantly worse performance on tests of verbal memory (p = .02) and letter fluency (p = .002). In addition, stroke was related to a significantly steeper 4-year decline in verbal memory performance (p = .04). Among the subjects who had not had an overt stroke, those with symptomatic peripheral arterial disease experienced a significantly greater 4-year decline in verbal memory functioning (p = .04). CONCLUSIONS: In older people, stroke is associated with both worse performance on cognitive tests and progressive verbal memory decline. Elderly individuals with vascular diseases other than stroke may also be vulnerable to a greater decline in verbal memory function. A relationship between vascular diseases and verbal memory decline may exist independently of depressed mood and major atherosclerotic risk factors.

Ankle brachial index and intima media thickness predict cardiovascular events similarly and increased prediction when combined.

OBJECTIVE: To compare the predictive value of the ankle brachial index (ABI) and carotid intima media thickness (IMT) for cardiovascular events. STUDY DESIGN AND SETTING: Population-based cohort study. New cardiovascular events (myocardial infarction [MI], stroke, angina, and intermittent claudication) were ascertained over a 12-year period in 1,007 men and women aged 60-79 and free of MI or stroke. RESULTS: The positive and negative predictive values for an ABIor=0.9mm and for both tests abnormal were not substantially different. However, event rates in subjects with one test normal were increased when the alternate test proved positive (in people with a normal ABI test, 20.8% with an abnormal IMT developed MI/stroke compared with only 10.3% with a normal IMT). The area under the receiver operator curves (AUC) increased significantly between a model containing only age and sex (AUC 0.60, 95% confidence interval [CI] 0.55, 0.65) and that with either ABI (AUC 0.63, 95% CI 0.58, 0.69, P=0.002) or IMT (AUC 0.62, 95% CI 0.57, 0.67, P=0.005) added. The AUC increased further when both tests were added simultaneously (AUC 0.65, 95% CI 0.60, 0.70, P<0.001). CONCLUSION: The ability of the ABI to predict cardiovascular disease was similar to that of the IMT. Combination of the two tests may be advantageous when the second test is applied to people with a negative first test and/or when the results are used as continuous variables.

Cognitive decline and markers of inflammation and hemostasis: the Edinburgh Artery Study.

OBJECTIVES: To determine whether circulating markers of activated inflammation and hemostasis are associated with cognitive decline in older people. DESIGN: Prospective cohort study (Edinburgh Artery Study). SETTING: Eleven general practices in Edinburgh, Scotland. PARTICIPANTS: A sample of 452 men and women followed for 16 years. MEASUREMENTS: Biomarker data were collected in 1987/88, and cognitive assessment was first conducted in 1998/99, when the mean age of the sample +/- standard deviation was 73.1+/-5.0), and subsequently in 2002/03. Information was obtained on verbal declarative memory (Wechsler Logical Memory Test (LMT)), nonverbal reasoning (Raven's Standard Progressive Matrices), verbal fluency (Verbal Fluency Test), information processing speed (Wechsler Digit Symbol Test), and a general cognitive factor representing the variance common to the individual test scores. RESULTS: In age-adjusted analyses, plasma fibrinogen, interleukin-6 (IL-6), and intercellular adhesion molecule 1 (ICAM-1) were negatively associated with performance on all cognitive measures in 2002/03 except the LMT (correlation coefficients from -0.10 to -0.24). In multivariate analyses controlling for demographic characteristics, depression, and cardiovascular morbidity and risk factors, fibrinogen independently predicted 4-year decline in nonverbal reasoning (P<.05). Also, when cognitive change was estimated from peak prior level, IL-6 turned out to be inversely related to decline in information processing speed (P<.05). Similarly, ICAM-1 was associated with a greater decline in general cognitive ability (P<.05) and nonverbal ability (P<.05). CONCLUSION: Systemic markers of inflammation and hemostasis are associated with a progressive decline in general and specific cognitive abilities in older people, independent of major vascular comorbidity.

Low ankle-brachial pressure index predicts increased risk of cardiovascular disease independent of the metabolic syndrome and conventional cardiovascular risk factors in the Edinburgh Artery Study.

OBJECTIVE: To investigate whether a low ankle-brachial pressure index (ABI) predicts increased risk of cardiovascular disease (CVD) independent of the metabolic syndrome and conventional cardiovascular risk factors. RESEARCH DESIGN AND METHODS: The Edinburgh Artery Study is a population-based cohort study in which subjects were followed up until their death or for approximately 15 years. Low ABI at baseline was defined as <0.9; subjects with ABI >1.4 (n = 13) were excluded from the analyses. We used a modified version of the definition of the metabolic syndrome published in the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults, replacing waist circumference criteria with BMI criteria. Data on relevant parameters were available for 1,467 men and women ages 55-74 years at baseline. Cox proportional hazards models were used to study cardiovascular morbidity and mortality before and after adjusting for potential confounding factors. RESULTS: We determined that 25% of the study population had the metabolic syndrome and that a low ABI was more prevalent among people with than without the metabolic syndrome (24 vs. 15%; P < 0.001). During the follow-up period, there were 226 deaths from CVD and 462 nonfatal cardiovascular events. The hazard ratio (95% CI) for low ABI after adjusting for age, sex, baseline CVD, diabetes, smoking status, LDL cholesterol, and metabolic syndrome was 1.5 (1.1-2.1) for CVD mortality and 1.5 (1.2-1.8) for all CVD outcomes. CONCLUSIONS: Low ABI is associated with increased risk of CVD independent of the metabolic syndrome and other major CVD risk factors.

C-reactive protein, interleukin-6, and soluble adhesion molecules as predictors of progressive peripheral atherosclerosis in the general population: Edinburgh Artery Study.

BACKGROUND: The relationship between levels of circulating inflammatory markers and risk of progressive atherosclerosis is relatively undetermined. We therefore studied inflammatory markers as predictors of peripheral atherosclerotic progression, measured by the ankle-brachial index (ABI) at 3 consecutive time points over 12 years. METHODS AND RESULTS: The Edinburgh Artery Study is a population cohort study of 1592 men and women aged 55 to 74 years. C-reactive protein (CRP), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin were measured at baseline. Valid ABI measurements were obtained on 1582, 1081, and 813 participants at baseline and 5-year and 12-year follow-up examinations, respectively. At baseline, a significant trend was found between higher plasma levels of CRP (P< or =0.05) and increasing severity of peripheral arterial disease (PAD), after adjustment for baseline cardiovascular risk factors. IL-6 at baseline (P< or =0.001) was associated with progressive atherosclerosis at 5 years (ABI change from baseline), and CRP (P< or =0.01), IL-6 (P< or =0.001), and ICAM-1 (P< or =0.01) were associated with changes at 12 years, independently of baseline ABI, cardiovascular risk factors, and baseline cardiovascular disease. Only IL-6 independently predicted ABI change at 5 years (P< or =0.01) and 12 years (P< or =0.05) in analyses of all inflammatory markers simultaneously and adjusted for baseline ABI, cardiovascular risk factors, and cardiovascular disease at baseline. CONCLUSIONS: These findings suggest that CRP, IL-6, and ICAM-1 are molecular markers associated with atherosclerosis and its progression. IL-6 showed more consistent results and stronger independent predictive value than other inflammatory markers.

Ankle brachial index as a predictor of cognitive impairment in the general population: ten-year follow-up of the Edinburgh Artery Study.

OBJECTIVES: To determine whether the ankle brachial index (ABI, a marker of generalized atherosclerosis) is associated with cognitive impairment after 10 years in older people. DESIGN: Cohort study (Edinburgh Artery Study). SETTING: Eleven general practices in Edinburgh, Scotland. PARTICIPANTS: Seven hundred seventeen men and women aged 55 to 74 from the general population, followed for 10 years. MEASUREMENTS: ABI measured at baseline and major cognitive functions (including premorbid function using the National Adult Reading Test, NART) tested after 10 years. RESULTS: After adjustment for age and sex, a low ABI was associated with lower scoring (bottom tertile vs top tertile) on Raven's Matrices (odds ratio (OR)=1.6, 95% confidence interval (CI) =1.0-2.6), Verbal Fluency (OR =1.8, 95% CI =1.1-3.0), and Digit Symbol Test (OR =2.3, 95% CI =1.3-4.2), suggesting that the ABI is predictive of poorer performance in nonverbal reasoning, verbal fluency, and information processing speed. The association between ABI and the Digit Symbol Test remained significant after further adjustment for premorbid cognitive function (tested using the NART), suggesting that the ABI is also predictive of decline in information processing speed (from premorbid ability to that measured here in older age). CONCLUSION: The ABI may be useful in identifying older individuals at higher risk of cognitive impairment. In the future, preventive measures developed to target individuals with a low ABI should consider measures to reduce vascular-related cognitive decline as well as cardiovascular events, in an effort to reduce the incidence and consequences of subsequent cognitive impairment and dementia.

Inter-arm blood pressure difference and mortality: a cohort study in an asymptomatic primary care population at elevated cardiovascular risk.

BACKGROUND: Differences in blood pressure between arms are associated with increased cardiovascular mortality in cohorts with established vascular disease or substantially elevated cardiovascular risk. AIM: To explore the association of inter-arm difference (IAD) with mortality in a community-dwelling cohort that is free of cardiovascular disease. DESIGN AND SETTING: Cohort analysis of a randomised controlled trial in central Scotland, from April 1998 to October 2008. METHOD: Volunteers from Lanarkshire, Glasgow, and Edinburgh, free of pre-existing vascular disease and with an ankle-brachial index ≤0.95, had systolic blood pressure measured in both arms at recruitment. Inter-arm blood pressure differences were calculated and examined for cross-sectional associations and differences in prospective survival. Outcome measures were cardiovascular events and all-cause mortality during mean follow-up of 8.2 years. RESULTS: Based on a single pair of measurements, 60% of 3350 participants had a systolic IAD ≥5 mmHg and 38% ≥10 mmHg. An IAD ≥5 mmHg was associated with increased cardiovascular mortality (adjusted hazard ratio [HR] 1.91, 95% confidence interval [CI] = 1.19 to 3.07) and all-cause mortality (adjusted HR 1.44, 95% CI = 1.15 to 1.79). Within the subgroup of 764 participants who had hypertension, IADs of ≥5 mmHg or ≥10 mmHg were associated with both cardiovascular mortality (adjusted HR 2.63, 95% CI = 0.97 to 7.02, and adjusted HR 2.96, 95% CI = 1.27 to 6.88, respectively) and all-cause mortality (adjusted HR 1.67, 95% CI = 1.05 to 2.66, and adjusted HR 1.63, 95% CI = 1.06 to 2.50, respectively). IADs ≥15 mmHg were not associated with survival differences in this population. CONCLUSION: Systolic IADs in blood pressure are associated with increased risk of cardiovascular events, including mortality, in a large cohort of people free of pre-existing vascular disease.

Abdominal aortic aneurysm expansion: risk factors and time intervals for surveillance.

BACKGROUND: Intervention to reduce abdominal aortic aneurysm (AAA) expansion and optimization of screening intervals would improve current surveillance programs. The aim of this study was to characterize AAA growth in a national cohort of patients with AAA both overall and by cardiovascular risk factors. METHODS AND RESULTS: In this study, 1743 patients were monitored for changes in AAA diameter by ultrasonography over a mean follow-up of 1.9 years. Mean initial AAA diameter and growth rate were 43 mm (range 28 to 85 mm) and 2.6 mm/year (95% range, -1.0 to 6.1 mm/year), respectively. Baseline diameter was strongly associated with growth, suggesting that AAA growth accelerates as the aneurysm enlarges. AAA growth rate was lower in those with low ankle/brachial pressure index and diabetes but higher for current smokers (all P<0.001). No other factor (including lipids and blood pressure) was associated with AAA growth. Intervals of 36, 24, 12, and 3 months for aneurysms of 35, 40, 45, and 50 mm, respectively, would restrict the probability of breaching the 55-mm limit at rescreening to below 1%. CONCLUSIONS: Annual, or less frequent, surveillance intervals are safe for all AAAs < or =45 mm in diameter. Smoking increases AAA growth, but atherosclerosis plays a minor role.