Carotid artery plaque progression and cognitive decline: the Tromsø Study 1994-2008

BACKGROUND

Carotid atherosclerosis is a risk factor for stroke and cognitive decline, but knowledge on how progression of carotid atherosclerosis affects cognitive function in stroke-free individuals is scarce.

METHODS

In the population-based Tromsø study, we calculated the change in ultrasound-assessed carotid plaque number and total plaque area from baseline (survey 4) to follow-up 7 years later (survey 5) in 4274 middle-aged stroke-free subjects. Cognitive function was assessed at follow-up by the verbal memory test, the digit-symbol coding test, and the tapping test and repeated after an additional 6 years in a subgroup of 2042 subjects (survey 6). Associations between the average of survey 4 and survey 5 plaque scores and the progression of plaque scores and cognitive test scores were assessed in regression analyses adjusted for baseline age, sex, education, depression, and cardiovascular risk factors.

RESULTS

Progression of total plaque area was associated with lower scores in the digit-symbol coding test (multivariable adjusted standardized β, -0.03; 95% CI, -0.05 to -0.00; P = 0.04) and the tapping test (β, -0.03; 95% CI, -0.06 to -0.00; P = 0.03). Similar results were seen for progression of plaque number. The average plaque scores were associated with lower scores in all cognitive tests (P-values ≤ 0.01). No association was found between plaque scores and cognitive decline.

CONCLUSIONS

The average plaque scores were associated with lower scores in all cognitive tests. Progression of plaque scores was associated with lower scores in the digit-symbol coding test and the tapping test, but not with the verbal memory test or with cognitive decline.

Subclinical carotid atherosclerosis and cognitive function

Carotid artery atherosclerosis is a major risk factor for stroke and subsequent cognitive impairment. Recent studies indicate that carotid atherosclerosis without clinical stroke may also be an independent risk factor for cognitive decline and dementia. Ultrasonography is an easily assessable and non-invasive method to measure different stages of the carotid artery atherosclerotic process and is widely used in clinical assessment as well as in epidemiological and clinical research. We give a brief review of studies that have investigated degrees of the subclinical atherosclerosis in the carotid arteries in relation to cognitive function and dementia, and we discuss several possible mechanisms that could explain the association between atherosclerosis and cognitive impairment.

Incidence and mortality of aneurysmal subarachnoid hemorrhage in two Norwegian cohorts, 1984-2007

OBJECTIVE

The incidence of aneurysmal subarachnoid hemorrhage (aSAH) ranges from 4 to 10 per 100,000 person-years in most countries, and 30-day case fatality is high. The aim of this study was to estimate the incidence and case fatality of aSAH and to assess preictal predictors of survival in 2 large Norwegian population-based cohort studies.

METHODS

A total of 94,976 adults (≥20 years) in the Nord-Trøndelag Health Study and 31,753 participants (aged ≥20 years) in the Tromsø Study were included. During follow-up, aSAHs were identified, incidence rates were estimated, and predictors of survival were assessed using Cox and Poisson regression analysis.

RESULTS

A total of 214 patients with aSAH were identified during 2,077,927 person-years of follow-up from 1984 to 2007. The incidence rate was 10.3 per 100,000 person-years: 13.3 for women and 7.1 for men. The incidence increased by 2% (95% confidence interval [CI] 0-4) per 5-year time period. Case fatality at 3, 7, and 30 days was 20%, 24%, and 36%. Thirty-day case fatality remained stable during follow-up (odds ratio 1.01, 95% CI 0.97-1.06 per year). Never smokers had poorer survival after aSAH than current and former smokers combined (hazard ratio 1.6, 95% CI 0.9-2.9).

CONCLUSIONS

The slight increase in incidence of aSAH over time may be explained by differences in diagnostic procedures. Case fatality remained stable during 23 years of follow-up.

Serum osteoprotegerin is a predictor for incident cardiovascular disease and mortality in a general population: the Tromsø Study

BACKGROUND

Osteoprotegerin (OPG) concentration in serum is associated with the presence and severity of atherosclerosis.

OBJECTIVE

To investigate the association between serum osteoprotegerin and the risk of a future myocardial infarction, ischemic stroke and mortality in a general population.

PATIENTS/METHODS

OPG was measured in serum collected from 6265 subjects recruited from a general population without a prior myocardial infarction and ischemic stroke (the Tromsø Study). Incident myocardial infarction, ischemic stroke and mortality were registered during follow-up. Cox regression models were used to estimate crude and adjusted hazard ratios and 95% confidence intervals (HR; 95% CI).

RESULTS

There were 575 myocardial infarctions, 284 ischemic strokes and 824 deaths (146 deaths as a result of ischemic heart disease, 78 deaths because of stroke and 600 deaths due to other causes) in the cohort during a median of 10.6 years of follow-up. Serum OPG (per SD [1.13 ng mL(-1)] increase in OPG) was associated with an increased risk of a myocardial infarction (1.20; 1.11-1.31), ischemic stroke (1.32; 1.18-1.47), total mortality (1.34; 1.26-1.42), death because of ischemic heart disease, (1.35; 1.18-1.54), stroke (1.44; 1.19-1.75) and non-vascular causes (1.31; 1.22-1.41) after adjustment for age, gender, current smoking, systolic blood pressure, body mass index, high density lipoprotein cholesterol, total cholesterol, creatinine, high sensitivity C-reactive protein (CRP) and diabetes mellitus or HbA1c > 6.1%. No association was detected between OPG and incident hemorrhagic stroke (1.02; 0.73-1.43).

CONCLUSIONS

Serum OPG was associated with future risk of myocardial infarction, ischemic stroke, total mortality, mortality of ischemic heart disease, stroke and of non-vascular causes independent of traditional cardiovascular risk factors.

Moderate wine consumption is associated with better cognitive test results: a 7 year follow up of 5033 subjects in the Tromsø Study

BACKGROUND

The impact of moderate alcohol consumption on cognitive function and dementia is unclear. We examined the relationship between consumption of different alcoholic beverages and cognitive function in a large population-based study.

METHODS

Subjects were 5033 stroke-free men and women who participated in a longitudinal population-based study in Tromsø, Norway. Alcohol consumption and other cardiovascular risk factors were measured at baseline and cognitive function was assessed after 7 years follow up with verbal memory test, digit-symbol coding test and tapping test.

RESULTS

Moderate wine consumption was independently associated with better performance on all cognitive tests in both men and women. There was no consistent association between consumption of beer and spirits and cognitive test results. Alcohol abstention was associated with lower cognitive performance in women.

CONCLUSIONS

Light-to-moderate wine consumption was associated with better performance on cognitive tests after 7 years follow up.

Incidence of aneurysmal subarachnoid hemorrhage in Norway, 1999-2007

OBJECTIVE

To investigate changes and regional variations in annual incidence rates of aneurysmal subarachnoid hemorrhage (SAH) in Norway between 1999 and 2007.

METHODS

The authors retrospectively reviewed data from the Norwegian Patient Register for the period 1999-2007.

RESULTS

Crude incidence of aneurysmal SAH was 10.0/100,000 person years [95% CI (confidence interval): 9.7-10.3] and was higher in women (12.0/100,000 person years; 95% CI: 11.5-12.5) than men (8.1/100,000 person years; 95% CI: 7.7-8.4). Decreasing annual incidence rates were observed from 11.1/100,000 person years (95% CI: 10.5-11.6) in the period 1999-2001 to 8.9/100,000 person years (95% CI: 8.4-9.4) in the period 2005-2007 (P for trend <0.001). Regional variations were observed, from 8.4/100,000 person years (95% CI: 7.7-9.00) in the southern region, 10.4/100,000 person years (95% CI: 9.5-11.2) in the central region and 11.9/100,000 person years (95% CI: 10.8-12.9) in the northern region.

CONCLUSIONS

Incidence of aneurysmal SAH in Norway decreased from 1999 to 2007, with significant regional variations indicating an increasing gradient from south to north.

Impact of cardiovascular risk factors on cognitive function: the Tromsø study

BACKGROUND AND PURPOSE

The role of cardiovascular risk factors in the pathogenesis of cognitive impairment and dementia remains still unclear. We examined the impact of cardiovascular risk factors on cognitive function in a large longitudinal population study.

METHODS

Subjects were 5033 stroke-free men and women who participated in a longitudinal population-based study. Cardiovascular risk factors were measured at baseline, and cognitive function was assessed after 7 years of follow-up with verbal memory test, digit-symbol coding test, and tapping test.

RESULTS

Diabetes, systolic blood pressure, and current smoking were independently associated with lower cognitive test results in men and women. Low physical activity was independently associated with lower scores in women. We found no consistent association between total-cholesterol, HDL-cholesterol, coronary heart disease or BMI, and cognitive test results.

CONCLUSIONS

Diabetes, smoking, hypertension, and low physical activity were associated with lower cognitive test results. The study suggests that these modifiable risk factors should be emphasized in the prevention of cognitive decline.

Relation between serum osteoprotegerin and carotid intima media thickness in a general population - the Tromsø Study

BACKGROUND

 Previous studies have reported conflicting results on the relation between serum osteoprotegerin (OPG) concentration and carotid intima media thickness (CIMT).

PATIENTS/METHODS

 The present study was conducted to investigate the relations between OPG, risk factors for cardiovascular diseases (CVD) and carotid intima media thickness (CIMT) in a large cross-sectional study including 6516 subjects aged 25-85years who participated in a population-based health survey.

RESULTS

 CIMT increased significantly across tertiles of OPG after adjustment for traditional cardiovascular risk factors such as age, gender, smoking, total cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), body mass index (BMI), systolic blood pressure, CVD and diabetes mellitus (P<0.0001). There was a significant interaction between age and OPG (P=0.026). The risk of being in the uppermost quartile of CIMT was reduced (OR 0.52, 95% CI 0.30-0.88) with each standard deviation (SD) higher level of OPG in subjects <45years (n=444), whereas subjects ≥55years of age (n=4884) had an increased risk of being in the uppermost quartile of CIMT (OR 1.19, 95% CI 1.10-1.29) after adjustment for traditional CVD risk factors.

CONCLUSIONS

Age has a differential impact on the association between OPG and CIMT in a general population. The present findings may suggest that increased serum OPG does not promote early atherosclerosis in younger subjects.

Serum osteoprotegerin, sRANKL and carotid plaque formation and growth in a general population--the Tromsø study

SUMMARY BACKGROUND

Intervention studies in animal models suggest that osteoprotegerin (OPG) functions as an inhibitor or marker of atherosclerosis, whereas one prospective epidemiological study in humans indicated that OPG was an independent risk factor for progression of atherosclerosis.

OBJECTIVE

To study the association between serum levels of OPG, soluble RANK ligand (sRANKL) and carotid artery plaque formation and plaque growth.

PATIENTS/METHODS

The prevalence of carotid plaque and plaque area were assessed by ultrasonographic imaging at baseline and after 7 years follow-up in 2191 men and 2329 women who participated in a population-based study.

RESULTS

OPG was significantly associated with atherosclerotic plaque burden and cardiovascular risk factors such as age, body mass index, blood pressure, total cholesterol, HDL cholesterol, HbA1c and fibrinogen at baseline, but not with sRANKL. In subjects without plaque at baseline, OPG predicted plaque formation in crude analysis in both women and men, but not after adjustment for age and other atherosclerotic risk factors. OPG predicted plaque growth in women (+1.8 mm(2), 0.6-3.0) (mean, 95% CI) per 1 SD increase in OPG (P = 0.003), whereas no associations were demonstrated in men (0.1 mm(2) (-1.3-1.4), P = 0.93). Soluble RANKL did not predict plaque formation or plaque growth.

CONCLUSIONS

OPG was an independent predictor of plaque growth in women, but not in men, suggesting gender-specific actions of OPG in plaque growth. OPG was not associated with novel plaque formation.

Mean platelet volume is a risk factor for venous thromboembolism: the Tromsø Study, Tromsø, Norway

BACKGROUND

Platelet size, measured as mean platelet volume (MPV), is associated with platelet reactivity. MPV is increased in acute myocardial infarction, and has been identified as an independent risk factor for future myocardial infarction and stroke.

OBJECTIVES

The purpose of the study was to determine the impact of platelet count and MPV on the incidence of venous thromboembolism (VTE) in a prospective, population-based study.

METHODS

Platelet count, MPV and baseline characteristics were registered in 25 923 subjects aged 25-96 years who participated in the Tromsø Study in 1994-1995. Incident VTE events were registered to the end of follow-up (1 September 2007).

RESULTS

There were 445 validated incident VTE events (1.6 per 1000 person-years), of which 186 (42%) were unprovoked, during a mean of 10.8 years of follow-up. Subjects with MPV >or= 9.5 fL had a 1.3-fold [95% confidence interval (CI) 1.0-1.7] higher risk of total VTE and a 1.5-fold (95% CI 1.1-2.3) higher risk of unprovoked VTE than subjects with MPV < 8.5 fL in analyses adjusted for age, sex, smoking, body mass index, and platelet count. Increasing MPV was associated with increased risk of total VTE (P for trend = 0.09) and unprovoked VTE (P for trend = 0.03) in analyses adjusted for age and sex. There was no significant association between increasing platelet count and risk of VTE.

CONCLUSIONS

An increasing MPV was identified as a predictor for VTE, in particular VTE of unprovoked origin. The present findings support the concept that platelet reactivity is important in the pathogenesis of VTE.

Ultrasonographic measurements of subclinical carotid atherosclerosis in prediction of ischemic stroke

Carotid intima-media thickness (IMT) and plaque measurements are widely used to quantify atherosclerosis and assess the risk of future stroke, and are used as surrogate endpoints for clinical disease. In recent years, it has become clear that carotid IMT and plaque reflect biologically and genetically different aspects of the atherosclerotic process, and are differentially related to risk factors and cardiovascular disease. Plaques are focal manifestations of atherosclerosis while increased IMT represents mainly hypertensive medial hypertrophy. Several prospective studies have showed that IMT and plaque measurements, such as total plaque area and plaque number, are predictive of future stroke. Plaque echogenicity predicts future stroke independent of plaque size. The contribution of IMT and plaque measurements in individual stroke risk prediction in the general population seems to be limited, but may be useful as a tool for individual stratification of high-risk patients.

Abdominal obesity is essential for the risk of venous thromboembolism in the metabolic syndrome: the Tromsø study

SUMMARY BACKGROUND

The metabolic syndrome is a cluster of cardiovascular risk factors, including abdominal obesity, hypertension, dyslipidemia and insulin resistance, associated with increased risk of cardiovascular diseases and all cause mortality.

OBJECTIVES

The purpose of the study was to assess the impact of the metabolic syndrome, and its individual components, on the risk of venous thromboembolism (VTE) in a prospective population-based study.

METHODS

Individual components of the metabolic syndrome were registered in 6170 subjects aged 25-84 years in the Tromsø Study in 1994-1995, and first ever VTE events were registered until 1 September 2007.

RESULTS

The metabolic syndrome was present in 21.9% (1350 subjects) of the population. There were 194 validated first VTE events (2.92 per 1000 person-years) during a mean of 10.8 years of follow-up. Presence of metabolic syndrome was associated with increased risk of VTE (HR, 1.65; 95% CI, 1.22-2.23) in age- and gender-adjusted analysis. The risk of VTE increased with the number of components in the metabolic syndrome (P < 0.001). Abdominal obesity was the only component significantly associated with VTE in multivariable analysis including age, gender, and the individual components of the syndrome (HR, 2.03; 95% CI, 1.49-2.75). When abdominal obesity was omitted as a diagnostic criterion, none of the other components, alone or in cluster, was associated with increased risk of VTE.

CONCLUSIONS

Our study provides evidence for the metabolic syndrome as a risk factor for TE. Abdominal obesity appeared to be the pivotal risk factor among the individual components of the syndrome.

Family history of myocardial infarction is an independent risk factor for venous thromboembolism: the Tromsø study

BACKGROUND

Recent studies indicate that arterial cardiovascular diseases and venous thromboembolism (VTE) share common risk factors. A family history of myocardial infarction (MI) is a strong and independent risk factor for future MI.

OBJECTIVES

The purpose of the present study was to determine the impact of cardiovascular risk factors, including family history of MI, on the incidence of VTE in a prospective, population-based study.

PATIENTS AND METHODS

Traditional cardiovascular risk factors and family history of MI were registered in 21,330 subjects, aged 25-96 years, enrolled in the Tromsø study in 1994-95. First-lifetime VTE events during follow-up were registered up to 1 September 2007.

RESULTS

There were 327 VTE events (1.40 per 1000 person-years), 138 (42%) unprovoked, during a mean of 10.9 years of follow-up. In age- and gender-adjusted analysis, age [hazard ratio (HR) per decade, 1.97; 95% confidence interval (CI), 1.82-2.12], gender (men vs. women; HR, 1.25; 95% CI, 1.01-1.55), body mass index (BMI; HR per 3 kg m(-2), 1.21; 95% CI, 1.13-1.31), and family history of MI (HR, 1.31; 95% CI, 1.04-1.65) were significantly associated with VTE. Family history of MI remained a significant risk factor for total VTE (HR, 1.27; 95% CI, 1.01-1.60) and unprovoked VTE (HR, 1.46; 95% CI, 1.03-2.07) in multivariable analysis. Blood pressure, total cholesterol, HDL-cholesterol, triglycerides, and smoking were not independently associated with total VTE.

CONCLUSIONS

Family history of MI is a risk factor for both MI and VTE, and provides further evidence of a link between venous and arterial thrombosis.

[Risk factors for cerebral stroke]

BACKGROUND

Stroke is a heterogenic group of disorders. Cerebral infarction is the largest group (80-85%) and is followed by primary intracerebral hemorrhage and subarachnoid hemorrhage. This article gives a review of risk factors for cerebral stroke, with an emphasis on cerebral infarction.

MATERIAL AND METHODS

The article is based on literature identified through Medline, with emphasis on prospective, population-based studies.

RESULTS AND INTERPRETATION

Genetic studies of the Icelandic population have shown associations between single genes and common types of stroke, but it remains to be seen whether the results can be replicated in other populations. High blood pressure and cigarette smoking are the most important modifiable risk factors for stroke. Serum cholesterol is positively associated with cerebral infarction, but not with intracerebral hemorrhage. Diabetes, atrial fibrillation and carotid stenosis are important predictors of cerebral infarcts, especially in the elderly. Cohort studies and randomized trials have shown that hormone replacement therapy in women increases the risk of stroke, while modern oral contraceptives do not represent a risk factor for stroke in young women. There is a clear social gradient in stroke occurrence, with a higher incidence in lower social classes.

Endothelial dysfunction and systemic inflammation in persons with echolucent carotid plaques

Echolucent carotid plaques are associated with high risk for future ischemic cerebrovascular events independent of the degree of stenosis. Elevated levels of markers of systemic inflammation and endothelial dysfunction are predictors for future myocardial infarction and stroke. The present study was undertaken to investigate the relations between plaque morphology, endothelial dysfunction assessed by tissue-plasminogen activator antigen (t-PA ag) and vonWillebrand factor (vWF), and systemic inflammation in persons with carotid stenosis. We conducted a crosssectional study including 133 persons with carotid stenosis and 138 controls without stenosis recruited from the populationbased Tromsø Study. High-resolution B-mode and colour Doppler/pulsed-wave Doppler ultrasonography of both carotid arteries was performed, and plaque morphology in terms of echogenicity was assessed. Persons with carotid stenosis had significantly higher plasma t-PA and vWF concentrations than controls. There was a significant inverse relationship between t-PA ag and plaque echogenicity (p = 0.034). The increased plasma t-PA ag in persons with carotid stenosis was not associated with increased plasminogen activator inhibitor-I (PAI-1). Persons with echolucent carotid plaques had higher degree of systemic inflammation, and plasma t-PA and vWF concentration increased significantly across quartiles of WBC, fibrinogen, and hs-CRP. Our findings may suggest that plasma t-PA may be superior to vWF as a marker for endothelial dysfunction due to its ability to discriminate between various plaque echogenicity, and that the predictive role of t-PA ag in cardiovascular disease is independent of inhibited fibrinolysis.

Carotid plaque echogenicity and risk of nonvertebral fractures in women: a longitudinal population-based study

Atherosclerosis and osteoporosis appear to be related, but prospective studies on the relationship are sparse. In order to examine whether carotid artery plaques with different morphology predict nonvertebral fractures, we followed 2,733 women, aged 55-74 years (75% of the eligible population in Tromsø, Norway), for 6 years. At baseline, plaque morphology in terms of ultrasound echogenicity was categorized into three groups, ranging from low echogenicity (echolucent plaques with a high content of soft tissue) to strong echogenicity (echogenic plaques with a high content of dense fibrous tissue and calcified material). We found that the age-adjusted relative risk (RR) of fracture was significantly higher among women with echogenic plaques than among women without plaques: 1.7 (95% confidence interval [CI] 1.0-2.7). After adjustment for bone mineral density at baseline in addition to age, the RR was 1.6 (95% CI 1.0-2.6), and further adjustments for body mass index, body height, high-density lipoprotein cholesterol, smoking status, and muscle strength did not influence the association. Subjects with other plaque types were not at an increased risk compared to subjects without plaques: RR < or = 1.1, after multiple adjustments. We conclude that in the general population elderly women with echogenic carotid plaques are at higher risk of nonvertebral fractures than women without plaques.

Reduced neuropsychological test performance in asymptomatic carotid stenosis: The Tromso Study

OBJECTIVE

To assess the relationship between asymptomatic carotid stenosis, neuropsychological test performance, and silent MRI lesions.

METHODS

Performance on several neuropsychological tests was compared in 189 subjects with ultrasound-assessed carotid stenosis and 201 control subjects without carotid stenosis, recruited from a population health study. Subjects with a previous history of stroke were excluded. The test battery included tests of attention, psychomotor speed, memory, language, speed of information processing, motor functioning, intelligence, and depression. Sagittal T1-weighted and axial and coronal T2-weighted spin echo MRI was performed, and presence of MRI lesions (white matter hyperintensities, lacunar and cortical infarcts) was recorded.

RESULTS

Subjects with carotid stenosis had significantly lower levels of performance in tests of attention, psychomotor speed, memory, and motor functioning, independent of MRI lesions. There were no significant differences in tests of speed of information processing, word association, or depression. Cortical infarcts and white matter hyperintensities were equally distributed among persons with and without carotid stenosis. Lacunar infarcts were more frequent in the stenosis group (p = 0.03).

CONCLUSIONS

Carotid stenosis was associated with poorer neuropsychological performance. This could not be explained by a higher proportion of silent MRI lesions in persons with asymptomatic carotid stenosis, making it less likely that the cognitive impairment was caused by silent emboli.

Prevalence of and risk factors associated with carotid artery stenosis: the Tromsø Study

BACKGROUND AND PURPOSE

To assess prevalence, distribution, ultrasound characteristics and determinants of carotid artery stenosis in a large, population-based study of both women and men.

METHODS

A total of 6,727 persons aged 25-84 years were screened for extracranial stenosis with Duplex ultrasound of the right carotid artery. Risk factors were compared in 225 persons with stenosis and 5,514 persons without.

RESULTS

The prevalence of carotid stenosis was higher in men than in women, where 3.8% (95% CI, 3.2-4.6%) had carotid stenosis, compared to 2.7% (95% CI, 2.2-3.3%) in women (p = 0.001). The prevalence gradually increased by age in both genders. Cholesterol, HDL cholesterol, fibrinogen, systolic blood pressure levels and current smoking were independently associated with carotid artery stenosis in both women and men. The presence of carotid stenosis was significantly associated with a history of cerebrovascular disease, coronary heart disease and peripheral artery disease. For each 10% increase in the degree of carotid stenosis, the risk of having had a cerebrovascular event increased by 26%.

CONCLUSIONS

The prevalence of carotid stenosis in the general population, as measured by ultrasound, is low. Age, male gender, smoking, total cholesterol, HDL cholesterol (inverse), fibrinogen and systolic blood pressure are all independent predictors of carotid artery stenosis.

Low levels of high-density lipoprotein cholesterol are associated with echolucent carotid artery plaques: the tromsø study

BACKGROUND AND PURPOSE

Ultrasound-assessed plaque morphology is an independent predictor of ischemic stroke. The purpose of this population-based cross-sectional nested case-control study was to examine the risk factors associated with carotid plaque morphology.

METHODS

Ultrasonography of the right carotid artery was conducted on 6727 participants in a population health survey (response rate 79%). Plaque echogenicity, defined as reflectance of the emitted ultrasound signal, was scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Information on cardiovascular risk factors in all 216 participants who had carotid stenosis and in 223 control subjects matched by age and sex who did not have carotid stenosis was obtained from measurements of blood pressure, weight, height, and nonfasting blood samples and from a self-administered questionnaire.

RESULTS

In both univariate and multivariate analyses, low levels of HDL cholesterol and increasing degree of stenosis were independently associated with an increased risk of having an echolucent plaque. For 1-SD increase in HDL cholesterol, the adjusted odds of being in a lower plaque echogenicity category decreased by approximately 30% (OR 0.69, 95% CI 0.52 to 0.93).

CONCLUSIONS

These findings indicate that low levels of HDL cholesterol are associated with an increased risk of having echolucent, rupture-prone atherosclerotic plaques.

Echolucent plaques are associated with high risk of ischemic cerebrovascular events in carotid stenosis: the tromsø study

BACKGROUND

The purpose of the study was to assess in a prospective design whether plaque morphology is associated with risk of ischemic stroke and other cerebrovascular events in subjects with carotid stenosis.

METHODS AND RESULTS

A total of 223 subjects with carotid stenosis (123 with 35% to 49% degree of stenosis, 100 with 50% to 99% stenosis) and 215 control subjects matched by age and sex who participated in a population health survey at baseline were followed up for 3 years. Plaque echogenicity was assessed by ultrasound at baseline and scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Forty-four subjects experienced >/=1 ischemic cerebrovascular events in the follow-up period. Plaque echogenicity, degree of stenosis, and white blood cell count were independent predictors of cerebrovascular events. The unadjusted relative risk for cerebrovascular events was 13.0 (95% CI 4.5 to 37.4) in subjects with echolucent plaques and 3.7 (95% CI 0.7 to 18.2) in subjects with echogenic plaques when subjects without stenosis were used as the reference. The adjusted relative risk for cerebrovascular events in subjects with echolucent plaques was 4.6 (95% CI 1.1 to 18.9), and there was a significant linear trend (P=0.015) for higher risk with increasing plaque echolucency. The adjusted relative risk for a 10% increase in the degree of stenosis was 1.2 (95% CI 1.04 to 1.4).

CONCLUSIONS

Subjects with echolucent atherosclerotic plaques have increased risk of ischemic cerebrovascular events independent of degree of stenosis and cardiovascular risk factors. Subjects at high risk for ischemic vascular events may be identified by ultrasound assessment of plaque morphology.

The uncemented fully textured Lord hip prosthesis: a 10- to 15-year followup study

One hundred fourteen total hip arthroplasties in 110 patients performed between 1979 and 1983 using the Lord femoral component were analyzed. Nine femoral revisions were performed within 13 years after surgery (two because of infection). Excluding infections there was a 94% 13-year survival according to a Kaplan-Meier analysis. Subsidence was seen in five hips (five patients), but only one needed revision surgery. Seventy-six hips (73 patients) had a radiographic followup of 10 years or more and were analyzed in detail. Changes in cortical thickness, density, and formation of spotwelds continued beyond 5 years after surgery, meaning the remodeling of periprosthetic bone continued beyond that time. Osteolysis on the femoral side was seen in seven hips, always in the proximal part of the femur, apparently as a continuation of the joint space. No remote focal osteolysis was seen. Elderly patients, women, and patients with a pedestal were overrepresented among individuals with many spotwelds. For the clinical outcome the Merle d'Aubigne and Postel score as modified by Charnley was used. Among 69 hips (66 patients) with a mean followup of 153 months 96% (66 hips) had a pain score equal to or greater than 4 and 74% (51 hips) had a score of 5 or 6. The Lord femoral component gave surprisingly good clinical long term results despite the bone remodeling (stress shielding), which in some cases was pronounced. The most obvious disadvantage with this design appears to be the difficulties associated with its removal when indicated.

Prediction of mortality by ultrasound screening of a general population for carotid stenosis: the Tromsø Study

BACKGROUND AND PURPOSE

The extensive use of ultrasound examination of carotid arteries has revealed stenosis in many asymptomatic subjects, and clinical studies have shown that carotid stenosis is a risk factor for cardiovascular disease and death. However, information on stenosis as detected in a general population and its relation to mortality is scarce. The purpose of this population-based study was to assess whether carotid stenosis is a predictor of death.

METHODS

In 1994 to 1995, 248 subjects with suspected carotid stenosis were identified among 6727 men and women 25 to 84 years of age who were examined with ultrasound. These subjects and 496 age- and sex-matched control subjects were followed up for 4.2 years, and the number and causes of deaths were registered.

RESULTS

The unadjusted relative risk for death was 2.72 (95% CI, 1.57 to 4.75) for subjects with stenosis compared with control subjects. Adjusting for cardiovascular risk factors increased the relative risk to 3.47 (95% CI, 1.47 to 8.19). The adjusted relative risk in persons with stenosis and no cardiovascular disease or diabetes was 5.66 (95% CI, 1.53 to 20.90), which was higher than in subjects with stenosis and self-reported disease (1.79; 95% CI, 0.75 to 4.27). There was a dose-response relationship between degree of stenosis and risk of death (P=0.002 for linear trend). Carotid stenosis was a stronger predictor of death than self-reported cardiovascular disease or diabetes.

CONCLUSIONS

Carotid stenosis is a strong and independent predictor of death.