Life-style factors and risk for abdominal aortic aneurysm in a cohort of Finnish male smokers

Ultrasonographic Study of the Effects of Essential Hypertension on the Luminal Diameter and Doppler Velocimetric Indices of the Abdominal Aorta in Adults

OBJECTIVE

To investigate the effects of essential hypertension on the luminal diameter (caliber) and Doppler velocimetric indices of the abdominal aorta (AA) in adult patients with systemic hypertension.

MATERIALS AND METHODS

This was a prospective descriptive comparative study of 254 participants (127 with essential hypertension and 127 age/sex-matched controls). Their anthropometric parameters, fasting blood pressure, lipid profile, fasting blood sugar, and triplex sonography of the suprarenal and infrarenal abdominal aorta (Peak systolic velocity, PSV; End-diastolic velocity, EDV; Resistive Index, RI; and luminal diameter) were evaluated.

RESULTS

The mean age of the male subjects was 64.02 ± 10.02 years, while the mean age of the male controls was 63.14 ± 10.52 years (P > 0.05). The mean age of female subjects was 61.23 ± 10.09 years, while the mean age of the female controls was 61.76 ± 10.26 years (P > 0.05). The age group 60 - 69 years had the highest number of subjects and controls. The mean duration of hypertension in the subjects was 12.5 ± 5.2 years. The suprarenal and infrarenal abdominal aortic diameters (AAD) were higher in males than age-matched female counterparts. AAD increased with age mostly in hypertensive male subjects. PSV (in males) and RI (in both sexes) were elevated in hypertensive subjects compared to controls, while EDV (in both sexes) was significantly lower in subjects than controls. Multivariate linear regression showed that age and diastolic blood pressure were significant independent predictors for both suprarenal and infrarenal AADs.

CONCLUSION

Systemic hypertension causes structural and hemodynamic changes in the abdominal aorta which are detectable on triplex sonography.

Association of Abdominal Aortic Aneurysm and Simple Renal Cysts: A Systematic Review and Meta-Analysis

BACKGROUND-OBJECTIVE

Prior studies have suggested a higher prevalence of simple renal cysts (SRC) among patients with aortic disease, including abdominal aortic aneurysms (AAA). Thus, the aim of this study was to systematically review all currently available literature and investigate whether patients with AAA are more likely to have SRC.

METHODS

This study was performed according to the PRISMA guidelines. A meta-analysis was conducted with the use of random effects modeling and the I-square was used to assess heterogeneity. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were synthesized to compare the prevalence of several patients' characteristics between AAA vs. no-AAA cases.

RESULTS

Eleven retrospective studies, 9 comparative (AAA vs. no-AAA groups) and 3 single-arm (AAA group), were included in this meta-analysis, enrolling patients (AAA: N = 2,297 vs. no-AAA: N = 35,873) who underwent computed tomography angiography as part of screening or preoperative evaluation for reasons other than AAA. The cumulative incidence of SRC among patients with AAA and no-AAA was 55% (95% CI: 49%-61%) and 32% (95% CI: 22%-42%) respectively, with a statistically higher odds of SRC among patients with AAA (OR: 3.02; 95% CI: 2.01-4.56; P< 0.001). The difference in SRC prevalence remained statistically significant in a sensitivity analysis, after excluding the study with the largest sample size (OR: 2.71; 95% CI: 1.91-3.84; P< 0.001).

CONCLUSIONS

Our meta-analysis demonstrated a 3-fold increased prevalence of SRC in patients with AAA compared to no-AAA cases, indicating that the pathogenic processes underlying SRC and AAA could share a common pathophysiologic mechanism. Thus, patients with SRC could be considered at high risk for AAA formation, potentially warranting an earlier AAA screening.

Diabetes Mellitus Lowers the Risk of Aortic Dissection: a Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aimed to investigate the association between diabetes mellitus and aortic dissection.

METHODS

The PubMed and Embase databases were searched until December 2019 to identify all articles reporting diabetes mellitus and aortic dissection. The pooled odds ratio and 95% confidence interval were calculated using random-effects model.

RESULTS

A total of 14 articles with 15,794 participants, of which 2133 diabetes mellitus patients, were eligible and included in this meta-analysis. The data suggested that diabetes mellitus decreased the risk of aortic dissection. In the subgroup analysis, this association was significant in worldwide studies except for the Chinese cohort and in studies adjusted for confounding factors. The results were stable after sensitivity analysis and no evidence of publication bias was found among studies.

CONCLUSIONS

The result of this meta-analysis indicated that diabetes mellitus was associated with a lower risk of aortic dissection.

Physical activity and the risk of abdominal aortic aneurysm: a systematic review and meta-analysis of prospective studies

The association between physical activity and risk of abdominal aortic aneurysm has been inconsistent with some studies reporting a reduced risk while others have found no association. We conducted a systematic review and meta-analysis of prospective studies to quantify the association. PubMed and Embase databases were searched up to 3 October 2020. Prospective studies were included if they reported adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) of abdominal aortic aneurysm associated with physical activity. Summary RRs (95% CIs) were estimated using a random effects model. Nine prospective studies (2073 cases, 409,732 participants) were included. The summary RR for high vs. low physical activity was 0.70 (95% CI: 0.56-0.87, I2 = 58%) and per 20 metabolic equivalent task (MET)-hours/week increase of activity was 0.84 (95% CI: 0.74-0.95, I2 = 59%, n = 6). Although the test for nonlinearity was not significant (p = 0.09) the association appeared to be stronger when increasing the physical activity level from 0 to around 20-25 MET-hours/week than at higher levels. The current meta-analysis suggest that higher physical activity may reduce the risk of abdominal aortic aneurysm, however, further studies are needed to clarify the dose-response relationship between different subtypes and intensities of activity and abdominal aortic aneurysm risk.

Diabetes, its duration, and the long-term risk of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

We aimed at comprehensively evaluate the independent association of diabetes and its duration with incident abdominal aortic aneurysm (AAA) and aortic diameter.

METHODS AND RESULTS

We prospectively studied incident AAA according to baseline glycemic status (diabetes, prediabetes, normal glycemia) in 13,116 ARIC participants (1990-1992) and the time-varying exposure of duration post incident diabetes in 11,675 participants (1987-1989) using Cox models. Additionally, we cross-sectionally explored ultrasound-based abdominal aortic diameter by glycemic status and cumulative duration of diabetes in 4710 participants (2011-2013) using linear regression models. Over ~20 years of follow-up, diabetes (vs. normal glycemia) at baseline was independently associated with lower AAA risk (489 cases) (hazard ratio: 0.71 [95%CI 0.51-0.99]), especially after 10 years (hazard ratio: 0.58 [0.38-0.87]). Prediabetes did not demonstrate an independent association. The inverse association was more evident with longer duration of diabetes (p for trend = 0.045), with 30-50% lower risk in eight years after diabetes diagnosis. The cross-sectional analysis demonstrated smaller aortic diameters with longer duration of diabetes (e.g., -0.76 mm [-1.24, -0.28] in diabetes with 8-12 years) compared to non-diabetes, whereas prediabetes consistently showed nominally greater diameter.

CONCLUSIONS

Diabetes, especially with longer duration, but not prediabetes, was independently associated with lower risk of AAA and smaller aortic diameter. Our findings suggest that long lasting clinical hyperglycemia plays an important role in the reduced AAA risk, and the reduced aortic diameter may be a structural mechanism behind this paradoxical association.

The association between simple renal cyst and aortic diseases: A systematic review and meta-analysis of observational studies

OBJECTIVE

The objective of this meta-analysis of observational studies was to evaluate the association between simple renal cysts (SRC) and presence of aortic pathology such as aortic aneurysms and dissection.

METHODS

We conducted searches in Ovid MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials from January 1960 to August 2019 to identify observational studies that examined the association between SRCs and any aortic diseases, including aortic aneurysms and dissection. Two reviewers independently extracted the data and assessed the risk of bias. The meta-analysis was performed by STATA 14.1.

RESULTS

In total, 11 observational studies with 19 719 participants were included in this meta-analysis. Compared to individuals without SRCs, patients with SRCs had higher odds of abdominal aortic aneurysm (AAA) (adjusted OR = 2.61, 95% CI 2.34-2.91, P < 0.001, I²   = 0%), ascending thoracic aortic aneurysm (TAA) (adjusted OR = 1.98, 95% CI 1.09-3.63, P = 0.03, I²   = 90.1%), descending TAA (adjusted OR = 3.44, 95% CI, 2.67-4.43, P < 0.001, I²   = 0%), type A aortic dissection (AD) (adjusted OR = 1.98, 95% CI 1.32-2.96, P = 0.001, I²   = 12.9%), and type B AD (adjusted OR = 2.55, 95% CI, 1.31-4.96, P = 0.006, I²   = 76.2%). There was a higher average in the sum of diameter of SRCs among AAA compared to patients without AAA (WMD = 19.80 mm, 95% CI 13.92-25.67, P < 0.001, I²   = 63.8%).

CONCLUSION

SRC is associated with higher odds of aortic diseases including AAA, ascending and descending TAA, type A and type B dissection even after adjusting for confounders.

Correlation of Atherosclerotic Risk Factors with the Size of Abdominal Aortic Aneurysm (AAA)

INTRODUCTION

Abdominal aortic aneurysm represents a local pathological dilatation of the abdominal aorta. It is caused by structural weakness of aortic wall but there are many other risk factors that may positively correlate with incidence of AAA like hypertension, smoking, male gender, older age, family history etc.

AIM

The purpose of the study was to evaluate the correlation of atherosclerotic risk factors and the size of aortic aneurysm in patients that were admitted for the surgical treatment at the Clinic for cardiovascular surgery in Sarajevo during period 2016-2019.

METHODS

The study was designed as a retrospective study with one group of patients that was conducted at the Clinical Center of the University of Sarajevo at the Clinic for Cardiovascular Surgery. It included 150 patients, 126 males and 24 females, all of them with infrarenal localization of AAA. From medical records we have collected relevant anamnestic data (age, gender, positive family history, diabetes mellitus, hypertension, hyperlipidemia, smoking, alcohol consumption and obesity). The size of aneurysm was determined by both ultrasound and CT arteriography. The data are processed in the Statistical Package for Social Sciences Ver. 22.0. The results are tabulated or graphically showed, and level of statistical significance was set at p <0.05.

RESULTS

Total amount of 129 of patients (86%) had hypertension, 57.3% (n=86) of them were smokers, 18.7% (n = 28) were former smokers, and 24% (n = 36) were non-smokers Blood lipid level analysis have shown that 44% (n = 66) of patients were normolipemic, while elevated blood lipid levels were found in 56% (n = 84) of patients. Diabetes mellitus was present in 17.3% (n = 26) of patients, 2.7% (n = 4) of them had an insulin-dependent form, while 14.7% (n = 22) of the analyzed patients had insulin independent DM. Almost half of total number of patients (46%, n = 69) were obese. 19.3% (n = 29) of patients consumed alcohol while the 80.7% (n = 121) denied alcohol consumption. Ratio of males in comparison to females was 5:1. The average age in males was 69.79 ± 8.16 years and 72.13 ± 9.11 years in females. Significant statistical correlation of AAA size and risk of atherosclerosis factor has not been established. We have found that there is a significant positive correlation between size of aneurysm and risk of rupture (p= 0,000<0,05).

CONCLUSION

Although risk factors of atherosclerosis were present, statistically positive correlation was not confirmed between the size of AAA and analyzed risk factors.

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

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

Blood pressure, hypertension and the risk of abdominal aortic aneurysms: a systematic review and meta-analysis of cohort studies

Abdominal aortic aneurysms (AAA) are fatal in 80% of the cases when ruptured. Hypertension has been considered a potential risk factor for AAA; but the findings from prospective cohort studies have not been entirely consistent, nor have they been summarised in a comprehensive meta-analysis. Our aim was to conduct a systematic review and meta-analysis of cohort studies of the association between blood pressure, hypertension and AAA to clarify the strength and shape of these associations. We searched PubMed and Embase databases for relevant cohort studies up to April 30th, 2018. Random-effects models were used to calculate summary relative risks (RRs) and 95% confidence intervals (CIs). The meta-analysis included 21 cohort studies (20 publications) with data on 28,162 cases and 5,440,588 participants. The findings indicate that the RR of AAA in hypertensive patients is 1.66 times (95% CI: 1.49–1.85, I² = 79.3%, n = 13) that of non-hypertensive patients. In addition, there was a 14% (95% CI: 6–23%, I² = 30.5%, n = 6) and a 28% (95% CI: 12–46%, I² = 80.1%, n = 6) increase in the RR of AAA for every 20 mmHg and 10 mmHg increase in systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. The analysis of DBP showed evidence of a strong and highly significant nonlinear dose–response relationship (p < 0.001) with a steeper association from 80 mmHg and above. This meta-analysis suggests that hypertension increases the risk of developing AAA by 66%. Further studies are needed to clarify the underlying mechanism explaining the much stronger association between DBP and AAA than for SBP.

Diabetes mellitus and the risk of abdominal aortic aneurysm: A systematic review and meta-analysis of prospective studies

BACKGROUND

Diabetes mellitus has been associated with reduced risk of abdominal aortic aneurysm in a number of epidemiological studies, however, until recently little data from prospective studies have been available. We therefore conducted a systematic review and meta-analysis of prospective studies to quantify the association.

MATERIAL AND METHODS

Two investigators searched the PubMed and Embase databases for studies of diabetes and abdominal aortic aneurysm up to May 8th 2018. Prospective studies were included if they reported adjusted relative risk (RR) estimates and 95% confidence intervals (95% CIs) of abdominal aortic aneurysm associated with a diabetes diagnosis. Summary relative risks were estimated by use of a random effects model.

RESULTS

We identified 16 prospective studies with 16,572 cases among 4,563,415 participants that could be included in the meta-analysis. The summary RR for individuals with diabetes compared to individuals without diabetes was 0.58 (95% CI: 0.51-0.66, I² = 40.4%, p_{heterogeneity} = 0.06). The results persisted when stratified by sex, duration of follow-up, and in most of the other subgroup analyses. There was no evidence of publication bias with Egger's test, p = 0.64 or by inspection of the funnel plots.

CONCLUSIONS

These results suggest that individuals with diabetes mellitus are at a reduced risk of abdominal aortic aneurysm, however, whether pharmacological agents for diabetes mellitus explain this observation needs to be clarified in future studies.

Evaluation of the relationship between plasma lipids and abdominal aortic aneurysm: A Mendelian randomization study

Studies have reported that higher circulating levels of total cholesterol (TC), low-density lipoprotein (LDL) cholesterol and lower of high-density lipoprotein (HDL) cholesterol may be associated with increased risk of abdominal aortic aneurysm (AAA). Whether dyslipidemia causes AAA is still unclear and is potentially testable using a Mendelian randomization (MR) approach. We investigated the associations between blood lipids and AAA using two-sample MR analysis with SNP-lipids association estimates from a published genome-wide association study of blood lipids (n = 188,577) and SNP-AAA association estimates from European Americans (EAs) of the Atherosclerosis Risk in Communities (ARIC) study (n = 8,793). We used inverse variance weighted (IVW) MR as the primary method and MR-Egger regression and weighted median MR estimation as sensitivity analyses. Over a median of 22.7 years of follow-up, 338 of 8,793 ARIC participants experienced incident clinical AAA. Using the IVW method, we observed positive associations of plasma LDL cholesterol and TC with the risk of AAA (odds ratio (OR) = 1.55, P = 0.02 for LDL cholesterol and OR = 1.61, P = 0.01 for TC per 1 standard deviation of lipid increment). Using the MR-Egger regression and weighted median methods, we were able to validate the association of AAA risk with TC, although the associations were less consistent for LDL cholesterol due to wider confidence intervals. Triglycerides and HDL cholesterol were not associated with AAA in any of the MR methods. Assuming instrumental variable assumptions are satisfied, our finding suggests that higher plasma TC and LDL cholesterol are causally associated with the increased risk of AAA in EAs.

Alcohol consumption and mortality from aortic disease among Japanese men: The Japan Collaborative Cohort study

BACKGROUND AND AIMS

Only a few population-based prospective studies have examined the association between alcohol consumption and abdominal aortic aneurysm, and the results are inconsistent. Moreover, no evidence exists for aortic dissection. We examined the effect of alcohol consumption on risk of mortality from aortic diseases.

METHODS

A total of 34,720 men from the Japan Collaborative Cohort study, aged 40-79 years, without history of cardiovascular disease and cancer at baseline 1988 and 1990 were followed up until the end of 2009 for their mortality and its underlying cause. Hazard ratios of mortality from aortic diseases were estimated according to alcohol consumption categories of never-drinkers, ex-drinkers, regular drinkers of ≤30 g, and >30 g ethanol per day.

RESULTS

During the median 17.9-year follow-up period, 45 men died of aortic dissection and 41 men died of abdominal aortic aneurysm. Light to moderate drinkers of ≤30 g ethanol per day had lower risk of mortality from total aortic disease and aortic dissection compared to never-drinkers. The respective multivariable hazard ratios (95% confidence intervals) were 0.46 (0.28-0.76) for total aortic disease and 0.16 (0.05-0.50) for aortic dissection. Heavy drinkers of >30 g ethanol per day did not have reduced risk of mortality from total aortic disease, albeit had risk variation between aortic dissection and abdominal aortic aneurysm.

CONCLUSIONS

Light to moderate alcohol consumption was associated with reduced mortality from aortic disease among Japanese men.

Meta-analysis of the association between alcohol consumption and abdominal aortic aneurysm

Background

Alcohol is a possible risk factor for abdominal aortic aneurysm (AAA), but evidence from individual studies is weak and inconsistent. Existing narrative reviews suggest the possibility of non-linear associations. The aim here was to quantify any association using a systematic literature review, followed by dose–response meta-analysis of prospective studies.

Methods

MEDLINE, Embase and Web of Science were searched systematically to January 2017 for relevant prospective studies of alcohol consumption and AAA risk. Summary estimates of highest versus lowest levels of consumption, and linear and non-linear dose–response curves were quantified using random-effects models.

Results

Eleven relevant cohorts were identified describing results from 3580 individuals with among 473 092 participants. Data were extracted from ten cohorts for meta-analyses of high versus low levels of alcohol consumption (risk ratio for AAA 0·93, 95 per cent c.i. 0·78 to 1·11; P = 0·4, I2 = 47 per cent). The linear dose–response risk ratio for AAA, derived from 11 cohorts, was 1·00 (0·97 to 1·04) per 8 g alcohol per day (P = 0·9, I2 = 73 per cent). Non-linear dose–response results showed a tick-shaped curve with lower risk up to 2 units/day, but increasing risk beyond that (P = 0·05). The increase in risk beyond 2 units/day was stronger in men than in women.

Conclusion

Although the linear dose–response analysis revealed little evidence of an association between alcohol consumption and AAA risk, a tick-shaped trend in the association was observed. This non-linear dose–response analysis revealed reduced risks for alcohol consumption below 2 units/day, masking increased risks for 2 or more units/day.

Associations of Diabetes and Obesity with Risk of Abdominal Aortic Aneurysm in Men

Background. The associations of diabetes and obesity with the risk of abdominal aortic aneurysm (AAA) are inconclusive in previous studies. Subjects/Methods. We conducted prospective analysis in the Physicians' Health Study. Among 25,554 male physicians aged ≥ 50 years who reported no AAA at baseline, 471 reported a newly diagnosed AAA during a mean of 10.4 years' follow-up. Results. Compared with men who had baseline body mass index (BMI) < 25 kg/m², the multivariable hazard ratio (HR [95% CI]) of newly diagnosed AAA was 1.30 [1.06-1.59] for BMI 25-<30 kg/m² and 1.69 [1.24-2.30] for BMI ≥ 30 kg/m². The risk of diagnosed AAA was significantly higher by 6% with each unit increase in baseline BMI. This association was consistent regardless of the other known AAA risk factors and preexisting vascular diseases. Overall, baseline history of diabetes tended to be associated with a lower risk of diagnosed AAA (HR = 0.79 [0.57-1.11]); this association appeared to vary by follow-up time (HR = 1.56 and 0.63 during ≤ and >2 years' follow-up, resp.). Conclusion. In a large cohort of middle-aged and older men, obesity was associated with a higher risk, while history of diabetes tended to associate with a lower risk of diagnosed AAA, particularly over longer follow-up.

Lifetime Risk and Risk Factors for Abdominal Aortic Aneurysm in a 24-Year Prospective Study: The ARIC Study (Atherosclerosis Risk in Communities)

OBJECTIVE

Abdominal aortic aneurysm (AAA) is an important vascular disease in older adults, but data on lifetime risk of AAA are sparse. We examined lifetime risk of AAA in a community-based cohort and prospectively assessed the association between midlife cardiovascular risk factors and AAAs.

APPROACH AND RESULTS

In ARIC study (Atherosclerosis Risk in Communities), 15 792 participants were recruited at visit 1 in 1987 to 1989 and followed up through 2013. Longitudinal smoking status was defined using smoking behavior ascertained from visit 1 (1987-1989) to visit 4 (1996-1998). We followed up participants for incident, clinical AAAs using hospital discharge diagnoses, Medicare outpatient diagnoses, or death certificates through 2011 and identified 590 incident AAAs. An abdominal ultrasound was conducted in 2011 to 2013 in 5911 surviving participants, and 75 asymptomatic AAAs were identified. We estimated the lifetime risk of AAA from the index age 45 years through 85 years of age. At age 45, the lifetime risk for AAA was 5.6% (95% confidence interval, 4.8-6.1) and was higher in men (8.2%) and current smokers (10.5%). Smokers who quit smoking between visit 1 and visit 4 had a 29% lower AAA lifetime risk compared with continuous smokers but had a higher risk than pre-visit 1 quitters. The lifetime risk of rupture or medical intervention was 1.6% (95% confidence interval, 1.2-1.8). Smoking, white race, male sex, greater height, and greater low-density lipoprotein or total cholesterol were associated with an increased risk of clinical AAA and asymptomatic AAA.

CONCLUSIONS

At least 1 in 9 middle-aged current smokers developed AAA in their lifetime. Smoking cessation reduced the lifetime risk of AAA.

Association of diabetes mellitus with presence, expansion, and rupture of abdominal aortic aneurysm: "Curiouser and curiouser!" cried ALICE

Both coronary artery and peripheral artery disease are representative atherosclerotic diseases that are positively associated with presence of abdominal aortic aneurysm (AAA). Diabetes mellitus, which is one of major risk factors of coronary artery and peripheral artery diseases, however, has been curiously suggested to be negatively associated with AAA, despite the positive associations of coronary artery and peripheral artery diseases with presence of AAA. In the present article, we overviewed epidemiologic evidence (meta-analyses) regarding the associations of diabetes mellitus with presence, expansion, and rupture of AAA through a systematic literature search. Our exhaustive search identified seven meta-analyses. Main results of almost all meta-analyses (except for the two earliest ones) apparently found that diabetes mellitus is negatively associated with presence, expansion, and rupture of AAA.

No association between glucose at age 30 and aortic diameter at age 65 in men: a population-based study

OBJECTIVES

Impaired glucose metabolism and diabetes mellitus has been linked to a decreased risk for abdominal aortic aneurysm development in men. We evaluated potential relationships between blood glucose levels in 1722 men with mean age 34 years and their aortic diameter measured by ultrasound at age 65 years.

DESIGN

Prospective cohort study.

RESULTS

Mean follow-up between baseline glucose investigation and aortic ultrasound was 32.8 ± 1.8 years. There was no correlation between baseline blood glucose and later aortic diameter (r = 0.035, p = 0.146), whereas a weak correlation between body mass index (BMI) and aortic diameter was observed (r = 0.097 p < 0.001). In a partial correlation between aortic diameter and glucose levels adjusted for BMI, the correlation did not change (r = 0.011, p = 0.66). Neither were there any significant differences in mean aortic diameter between men belonging to different quartiles of baseline blood glucose levels (19.5, 19.1, 19.6 and 19.7 mm, p = 0.18).

CONCLUSION

Fasting blood glucose in 33-year-old men was not associated with their aortic diameter at age 65 years. Potential pathophysiological processes linking disturbed glucose metabolism to a decreased risk for development of abdominal aortic aneurysm in men are therefore probably not relevant until later in life.

Abdominal aortic aneurysms and diabetes mellitus

There is accumulating evidence that risk profiles differ between coronary artery disease and abdominal aortic aneurysms (AAAs). However, diabetes mellitus (DM) appears to be negatively associated with AAA formation. The underlying mechanisms for this negative relationship are far from defined, but may include: increased arterial wall matrix formation via advanced glycation end products; suppression of plasmin and reduction of levels and activity of matrix metalloproteinases (MMP)-2 and 9; diminished aortic wall macrophage infiltration, elastolysis and neovascularization. In addition, the effect of pharmacological agents used for the treatment of patients with DM on AAA formation has been studied with rather controversial results. Statins, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, fenofibrate, antibiotics and some hypoglycemic agents are beginning to be appreciated for a potential modest protection from AAAs, but further studies are needed.

Effect of lipid-modifying therapy on long-term mortality after abdominal aortic aneurysm repair: a systemic review and meta-analysis

BACKGROUND

Several observational studies have demonstrated that lipid-modifying therapy may improve long-term survival in abdominal aortic aneurysm (AAA) patients after repair. We carried out a systematic review and meta-analysis of studies evaluating the effect of lipid-modifying therapy on long-term mortality.

PATIENTS AND METHODS

We conducted a systematic search of multiple databases up to April 2014. Studies that evaluated exposure to lipid-modifying therapy, reported mortality data and hazard ratio (HR) or provided survival curve for their estimation were included in the meta-analysis. Pooled HR estimates with 95% confidence intervals (CIs) were calculated using the random-effects model.

RESULTS

Eight studies (seven cohorts, one post hoc study of a randomization controlled trial) reporting 2,605 patients on lipid-modifying therapy were included. Meta-analysis showed a significant 39% reduction in long-term mortality with lipid-modifying therapy (HR 0.61; 95% CI 0.51-0.73). After exclusion of one study which was contributing to considerable heterogeneity, a significant 33% reduction in mortality risk was a more conservative, consistent estimate (HR 0.67; 95% CI 0.59-0.77).

CONCLUSION

Meta-analysis of studies supports a protective role of lipid-modifying therapy on mortality risk after AAA repair. Aggressive lipid intervention should be recommended to those who receiving AAA repair.

Presence of Renal Simple Cysts Is Associated With Increased Risk of Abdominal Aortic Aneurysms

We compared the incidence of renal simple cysts in 271 patients with abdominal aortic aneurysm (AAA) and 1387 patients without AAA (controls) using computed tomography (CT) angiography and abdominal CT, as a health screening program. The AAA group had significantly higher prevalence of renal simple cysts (55% vs 19%, P = .001) and chronic obstructive pulmonary disease (COPD; 12% vs 1%, P = .011) than the controls. After propensity score matching (n = 164), the prevalence of renal simple cysts was still significantly higher in the AAA group. In multivariate analysis, independent predictors of AAA were age, male gender, smoking history, hypertension, high-sensitivity C-reactive protein, creatinine, COPD, and renal simple cysts. The structural weakness predisposing for renal simple cysts may be associated with the initiation of AAA formation. More studies are needed to determine whether the presence of renal simple cysts can be considered as a risk factor for AAA.

Diabetes and abdominal aortic aneurysms

Epidemiologic evidence suggests that patients with diabetes may have a lower incidence of abdominal aortic aneurysm (AAA); however, the link between diabetes and AAA development and expansion is unclear. The aim of this review is to analyze updated evidence to better understand the impact of diabetes on prevalence, incidence, clinical outcome, and expansion rate of AAA. A systematic review of literature published in the last 20 years using the PubMed and Cochrane databases was undertaken. Studies reporting appropriate data were identified and a meta-analysis performed using the generic inverse variance method. Sixty-four studies were identified. Methodological quality was "fair" in 16 and "good" in 44 studies according to a formal assessment checklist (Newcastle-Ottawa). In 17 large population prevalence studies there was a significant inverse association between diabetes and AAA: pooled odds ratio (OR) 0.80; 95% confidence intervals (CI) 0.70-0.90 (p = .0009). An inverse association was also confirmed by pooled analysis of data from smaller prevalence studies on selected populations (OR 0.59; 95% CI 0.35-0.99; p = .05), while no significant results were provided by case-control studies. A significant lower pooled incidence of new AAA in diabetics was found over six prospective studies: OR 0.54; 95% CI 0.31-0.91; p = .03. Diabetic patients showed increased operative (30-day/in-hospital) mortality after AAA repair: pooled OR 1.26; 95% CI 1.10-1.44; p = .0008. The increased operative risk was more evident in studies with 30-day assessment. In the long-term, diabetics showed lower survival rates at 2-5 years, while there was general evidence of lower growth rates of small AAA in patients with diabetes compared to non-diabetics. There is currently evidence to support an inverse relationship between diabetes and AAA development and enlargement, even though fair methodological quality or unclear risk of bias in many available studies decreases the strength of the finding. At the same time, operative and long-term survival is lower in diabetic patients, suggesting increased cardiovascular burden. The higher mortality in diabetics raises the question as to whether AAA repair should be individualized in selected diabetic populations at higher AAA rupture risk.

Diabetics are less likely to develop thoracic aortic dissection: a 10-year single-center analysis

BACKGROUND

Diabetes mellitus (DM) is an acknowledged risk factor for atherosclerosis, and diabetics are more likely to have hypertension. Atherosclerosis and hypertension are risk factors for aortic dissection. However, recent studies have shown that DM is associated with changes in aortic wall collagen. In this retrospective study we assess the relationship between DM and thoracic aortic dissection (TAD).

METHODS

Patients with a diagnosis of thoracic aortic dissection during the last 10 years were identified from our hospital records. The prevalence of DM in Stanford type A and B TAD was compared with that of two age- and gender-matched control groups. For every diabetic dissection case, 10 controls were selected from the hospital data.

RESULTS

Two hundred nineteen patients (median age 61 years, male:female ratio 145:74) were identified with TAD, comprising 131 type A dissections and 88 type B dissections. Only 3 of 131 (2.3%) type A aortic dissections were diabetics, whereas, in control group 1, 241 of 1310 (18.4%) were diabetics and, in control group 2, 116 of 1310 (8.9%) were diabetics [odds ratios: 0.1 (0.03-0.32) and 0.24 (0.07-0.76), respectively] (P = 0.0001 and 0.007, respectively). Similarly, only 2 of 88 (2.3%) type B aortic dissections were diabetics, whereas 228 of 880 (26.0%) and 102 of 880 (11.6%) were diabetics in groups 1 and 2 [odds ratios: 0.07 (0.02-0.27) and 0.18 (0.04-0.73), respectively] (P = 0.0001 and 0.0035, respectively). All these odds ratios were statistically significant (P < 0.01).

CONCLUSIONS

Patients with thoracic aortic dissection are less likely to be diabetic. Although we identified association only, not causality, it is possible that DM, or its treatment, has a protective effect against aortic dissection.

Current status of medical treatment for abdominal aortic aneurysm

Although cardiovascular disease is widely recognized as the leading cause of death, a lesser known fact is that aortic aneurysm is the 15th leading cause of death over the age of 65 years in the USA. The golden standard of the treatments are invasive interventions either with open surgical repair (OS) or endovascular aneurysm repair (EVAR). The concept of medical treatment is to prevent abdominal aortic aneurysm (AAA) from rupture and avoid surgical treatment by preventing aneurysm enlargement or even reducing aneurysm size. Matrix metalloproteinases (MMP) are structurally related metalloendopeptidases that can degrade the extracellular matrix and is thought to play important roles in AAA. There are many proposed pharmacological treatments including: β-blockers, angiotensin-converting enzyme inhibitor (ACE inhibitors), angiotensin-receptor blocker (ARB), statins, macrolides and, doxycycline, an inhibitor of the MMP. The latter is a potential promising drug as medical treatment for AAA and the Non-invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA(3)CT) is currently ongoing in the USA. Here, the pathophysiology and potential medical therapy for AAA will be reviewed.

Diabetes mellitus and aortic aneurysm rupture: a favorable association?

INTRODUCTION

Recent reports suggest that diabetic patients are relatively unlikely to have abdominal aortic aneurysms (AAAs). This retrospective study assesses the relationship between diabetes mellitus (DM) and aortic aneurysm rupture.

METHODS

Patients with a diagnosis of any aortic aneurysm during a 10-year period were identified from our records. Patients with diagnoses of aortic aneurysm (thoracic, thoracoabdominal, and abdominal, treated and untreated) were included. Patients with nonatheromatous aneurysms (transection, dissection, mycotic, or isolated iliac) were excluded.

RESULTS

In all, 1830 patients with nonruptured aneurysms and 232 ruptured aneurysms were included giving a total of 2062 patients with aortic aneurysms (abdominal, thoracic, and thoracoabdominal). Of these 1830, 225 (12.3%) patients with nonruptured aneurysm were diabetic; however, only 13 (5.6%) of the 232 patients with ruptured aortic aneurysm were diabetic (odds ratio [OR] = 0.42; confidence interval [CI]: 0.23-0.75, P = .004). Considering only those with AAAs, 184 (12.4%) of the 1482 nonruptured AAA were diabetic; however, only 12 (6.4%) of the 188 patients with ruptured AAA were diabetic (OR = 0.48 [CI: 0.26-0.88], P = .02). In this study group, the odds of dying due to aneurysm rupture in the diabetic group are significantly lower compared to the nondiabetic groups (OR = 0.31 [CI: 0.13-0.69], P = .004), despite the finding that diabetic patients had almost the same life expectancy as nondiabetic patients (DM, 73 years [67-80] vs non-DM, 75 years [68-82] P = .23).

CONCLUSIONS

Diabetic patients with aortic aneurysms are significantly less likely to present with rupture or to die from aneurysm rupture when compared to nondiabetic patients with aortic aneurysms. We have identified association only, not causality. However, it is plausible that DM, or the treatment of DM, may have a protective effect on aortic aneurysm rupture.

Moderate alcohol use and health: a consensus document

AIMS

The aim of this consensus paper is to review the available evidence on the association between moderate alcohol use, health and disease and to provide a working document to the scientific and health professional communities.

DATA SYNTHESIS

In healthy adults and in the elderly, spontaneous consumption of alcoholic beverages within 30 g ethanol/d for men and 15 g/d for women is to be considered acceptable and do not deserve intervention by the primary care physician or the health professional in charge. Patients with increased risk for specific diseases, for example, women with familiar history of breast cancer, or subjects with familiar history of early cardiovascular disease, or cardiovascular patients should discuss with their physician their drinking habits. No abstainer should be advised to drink for health reasons. Alcohol use must be discouraged in specific physiological or personal situations or in selected age classes (children and adolescents, pregnant and lactating women and recovering alcoholics). Moreover, the possible interactions between alcohol and acute or chronic drug use must be discussed with the primary care physician.

CONCLUSIONS

The choice to consume alcohol should be based on individual considerations, taking into account the influence on health and diet, the risk of alcoholism and abuse, the effect on behaviour and other factors that may vary with age and lifestyle. Moderation in drinking and development of an associated lifestyle culture should be fostered.

The strange relationship between diabetes and abdominal aortic aneurysm

In a 1997 report of a large abdominal aortic aneurysm (AAA) screening study, we observed a negative association between diabetes and AAA. Although this was not previously described and negative associations between diseases are rare, the credibility of the finding was supported by consistent results in several previous studies and by the absence of an obvious artifactual explanation. Since that time, a variety of studies of AAA diagnosis, both by screening and prospective clinical follow-up, have confirmed the finding. Other studies have reported slower aneurysm enlargement and fewer repairs for rupture in diabetics. The seeming protective effect of diabetes for AAA contrasts with its causal role in occlusive vascular disease and so provides a strong challenge to the traditional view of AAA as a manifestation of atherosclerosis. Research focused on a protective effect of diabetes has already increased our understanding of the etiology of AAA, and might eventually pave the way for new therapies to slow AAA progression.

Pathophysiology and epidemiology of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are found in up to 8% of men aged >65 years, yet usually remain asymptomatic until they rupture. Rupture of an AAA and its associated catastrophic physiological insult carries overall mortality in excess of 80%, and 2% of all deaths are AAA-related. Pathologically, AAAs are associated with inflammation, smooth muscle cell apoptosis, and matrix degradation. Once thought to be a consequence of advanced atherosclerosis, accruing evidence indicates that AAAs are a focal representation of a systemic disease of the vasculature. Risk factors for AAAs include increasing age, male sex, smoking, and low HDL-cholesterol levels. Familial associations exist and although susceptibility genes have been described on the basis of candidate-gene studies, robust genetic studies have failed to discover causative gene mutations. The surgical management of AAAs has been revolutionized by minimally invasive endovascular repair. Ongoing randomized trials will establish whether endovascular repair confers a survival advantage over open surgery for patients with a ruptured AAA. In many countries, centralization of vascular surgical services has largely been driven by the improved outcomes of elective aneurysm surgery in specialized centers, the widespread adoption of endovascular techniques, and the introduction of screening programs.

Association between serum lipoproteins and abdominal aortic aneurysm

The importance of dyslipidemia in the etiology of abdominal aortic aneurysm (AAA) is poorly defined, in part because previous association analyses have often not considered the use of current lipid-modifying medications. Medications targeted at altering the concentrations of circulating lipids have an established role in occlusive atherosclerosis but are of unknown value in the primary prevention of AAA. We examined the association between fasting serum levels of triglycerides low- and high-density lipoprotein and the presence of an AAA in a cohort of 3,327 men aged 65 to 83 years. The analyses were adjusted for established risk factors of AAA and the prescription of lipid-modifying agents using multiple logistic regression analysis. Of the 3,327 men, 1,043 (31%) were receiving lipid-modifying therapy at the fasting lipid measurement. The lipid-modifying therapy was statins in most cases (n = 1,023). The serum high-density lipoprotein concentrations were lower in patients with AAAs. The serum high-density lipoprotein concentration was independently associated with a reduced risk of having an AAA in men not receiving current lipid-modifying therapy (odds ratio 0.72, 95% confidence interval 0.56 to 0.93 per 0.4-mM increase) and in the total cohort (odds ratio 0.76, 95% confidence interval 0.63 to 0.91 per 0.4-mM increase, adjusted for lipid-modifying therapy). The concentrations of low-density lipoprotein and triglycerides were not associated with the presence of AAAs. In conclusion, high-density lipoprotein appeared to be the most important lipid in predicting the risk of AAA development, with potential value as a therapeutic target. Current cardiovascular strategies aimed at lowering low-density lipoprotein might not have any effect on the prevention of AAAs.

Risk factors for abdominal aortic aneurysms: a 7-year prospective study: the Tromsø Study, 1994-2001

BACKGROUND

Abdominal aortic aneurysm is an asymptomatic condition with a high mortality rate related to rupture.

METHODS AND RESULTS

In a cohort of 2035 men and 2310 women in Tromsø, Norway, who were 25 to 82 years old in 1994, the authors identified risk factors for incident abdominal aortic aneurysm over the next 7 years. The impact of smoking was studied in particular. Ultrasound examination was performed initially in 1994/1995 and repeated in 2001. There were 119 incident cases of abdominal aortic aneurysms (an incidence of 0.4% per year). Male sex and increasing age were strong risk factors. In addition, the following variables were significantly associated with increased abdominal aortic aneurysm incidence: Smoking (OR=13.72, 95% CI 6.12 to 30.78, comparing current smokers of > or =20 cigarettes/d with never-smokers), hypertension (OR=1.54, 95% CI 1.03 to 2.30), hypercholesterolemia (OR=2.11, 95% CI 1.23 to 3.64, comparing subjects with serum total cholesterol > or =7.55 mmol/L with those with total cholesterol <5.85 mmol/L), and low high-density lipoprotein cholesterol (OR=3.25, 95% CI 1.68 to 6.27, comparing subjects with high-density lipoprotein cholesterol <1.25 mmol/L with those with high-density lipoprotein > or =1.83 mmol/L). In addition, use of statins was associated with increased risk of abdominal aortic aneurysm (OR=3.77, 95% CI 1.45 to 9.81), but this was probably a marker of high risk of cardiovascular diseases.

CONCLUSIONS

The results demonstrate strong associations between traditional atherosclerosis risk factors and the risk of incident abdominal aortic aneurysms.

Prevalence of risk factors, coronary and systemic atherosclerosis in abdominal aortic aneurysm: comparison with high cardiovascular risk population

Background:

Abdominal aortic aneurysm (AAA) is considered a manifestation of atherosclerosis, however there are epidemiologic, biochemical, and structural differences between occlusive atherosclerosis and AAA. The pathogenesis of AAA involves several factors, first of all destruction of collagen and elastin in the aortic wall. Classical risk factors may influence the evolution and development of AAA, though no consistent association has been found. Aims of the study were to evaluate associations between risk factors and to establish the prevalence of carotid, peripheral vascular and coronary atherosclerosis in patients with AAA.

Methods:

We studied 98 patients with AAA (Group 1) awaiting surgery compared with high cardiovascular risk population having two or more risk factors (n = 82 Group 2). We evaluated traditional risk factors and we studied by eco-doppler and echocardiography the presence of carotid peripheral and coronaric atherosclerosis in two groups.

Results:

We found a higher incidence of AAA in males (p < 0.01). The prevalence of infrarenal AAA was significantly higher than suprarenal AAA (81 vs 17 p < 0.001). No differences in total cholesterol (199 ± 20 vs. 197 ± 25 mg/dl), low-density lipoprotein (142 ± 16 vs. 140 ± 18 mg/dl), triglycerides (138 ± 45 vs. 144 ± 56 mg/dl), glycemia (119 ± 15 vs. 122 ± 20 mg/dl), and fibrinogen (388 ± 154 vs. 362 ± 92 mg/dl) were found between groups. We demonstrated significant differences for cigarette smoking (p < 0.002), systolic and diastolic blood pressure (150 ± 15 vs. 143 ± 14 mmHg and 88 ± 6 vs. 85 ± 7 mmHg, p < 0.0001 and p < 0.05, respectively) and high sensititivity C reactive protein (2.8 ± 1.3 vs. 1.3 ± 0.7 mg/dl, p < 0.001). High-density lipoprotein (HDL) cholesterol levels were significant greater in Group 1 than Group 2 (p < 0.003). Subgroups of patients with AAA and luminal thrombus showed higher fibrinogen levels (564 ± 235 vs. 341 ± 83 mg/dl, p < 0.001) and lower HDL than in controls (46.6 ± 6.5 vs. 52.1 ± 7.8 mg/dl, p < 0.01). We did not find any difference in body mass index, or prevalence of coronary and peripheral atherosclerosis between groups. Conversely, we found higher prevalence of carotid atherosclerosis in Group 2 (9% vs. 25%, p < 0.004).

Conclusion:

Our AAA patients had fewer and different risk factors respect to patients with atherosclerosis. Only elevated blood pressure, C reactive protein, and smoking showed a significant association with AAA. Atherosclerosis in other arterial districts did not differ respect to subjects with high cardiovascular risk. Our results confirm the hypothesis that AAA and atherosclerosis are two different pathological entities with different risk profiles.

Review of Current Theories for Abdominal Aortic Aneurysm Pathogenesis

Atherosclerotic plaques are a feature of abdominal aortic aneurysms (AAAs). Atherosclerosis and AAA appear to share similar risk factors. These observations have led to the conclusion that AAAs are a consequence of advanced atherosclerosis.

This review explores current theories regarding the pathogenesis of AAA and their implications for treatment.

A systematic literature search was conducted using the search terms abdominal aortic aneurysm, atherosclerosis, pathogenesis, and systemic disease. Articles were categorized according to the association of AAAs with atherosclerosis, arteriomegaly, peripheral aneurysm, systemic expression, genetics, autoimmunity, oxidative stress, and systemic disease. Twenty-nine articles reporting changes in the systemic vasculature associated with AAA and 12 articles examining the shared risk factor hypothesis were identified.

There is insufficient evidence to confirm that AAAs are the result of advanced atherosclerosis. The bulk of evidence points to AAA disease being a systemic disease of the vasculature, with a predetermined genetic susceptibility leading to a phenotype governed by environmental factors.

Are periods of low atmospheric pressure associated with an increased risk of abdominal aortic aneurysm rupture?

INTRODUCTION

Seasonal variation in rates of abdominal aortic aneurysm (AAA) rupture has previously been described. However, only two studies, to date, have suggested that periods of low atmospheric pressure may account for this observation and both returned apparently contradictory findings. The objective of this study was to demonstrate whether periods of low atmospheric pressure are indeed associated with an increased likelihood of AAA rupture presentation.

PATIENTS AND METHODS

A total of 182 cases of ruptured AAA were identified retrospectively from two centres over a 6-year period from January 2000 to December 2005. Local meteorological data for the corresponding period was obtained from the UK Meteorological Office which was recorded daily at a local weather station. Statistical analysis using Student's t-test, ANOVA (Kruskal-Wallis), linear regression and multiple logistic regression was conducted to identify significant relationships from the data.

RESULTS

Days of rupture presentation were associated with a significantly lower daily mean atmospheric pressure when compared with days when no rupture occurred (P = 0.025). Multiple logistic regression demonstrated a significant association between low daily atmospheric pressure and rupture incidence (P = 0.033) which appeared to be independent of temperature. A significant seasonal trough in atmospheric pressure was observed in October and November (Kruskal-Wallis, P < 0.001); however, there was no corresponding autumnal peak in rupture incidence (P = 0.232).

CONCLUSIONS

The findings of this study appear to confirm the assertion that low atmospheric pressure is associated with an increased risk of AAA rupture on a day-to-day basis; however, no evidence was identified to support a change in policy regarding prioritising elective surgery based on seasonal risk.

Traditional and novel risk factors for clinically diagnosed abdominal aortic aneurysm: the Kaiser multiphasic health checkup cohort study

BACKGROUND

Identification of risk factors for and early diagnosis of clinically significant abdominal aortic aneurysm (AAA) before rupture is vital to optimize outcomes in these patients. Our aim was to examine traditional and three novel potential risk factors (abdominal obesity, white blood cell count, and kidney function) for abdominal aortic aneurysm (AAA, comprising discharge diagnosis or surgical repair) in a large multiethnic population.

METHODS

Cohort study (N =104,813) conducted at an integrated health care delivery system in northern California.

RESULTS

After a median of 13 years, 605 AAA events (490 in men and 115 in women; 91 [15%] fatal) were observed. In multivariable analysis, factors significantly associated with risk of clinically detected AAA included male gender, older age, black race (inversely), low educational attainment, cigarette smoking (with dose-response relation), height, treated and untreated hypertension, high total serum cholesterol, elevated white blood cell count, known coronary artery disease, history of intermittent claudication, and reduced kidney function. A significant Asian race by gender interaction was found such that Asian race had a (borderline significant) protective association with AAA in men but not in women.

CONCLUSIONS

Our findings confirm that major atherosclerotic risk factors, except for diabetes and obesity, are also prospectively related to AAA and suggest that elevated white blood cell count and reduced kidney function may improve risk stratification for clinically relevant AAA.

Alcohol intake and noncoronary cardiovascular diseases

Moderate drinking has complex associations with cardiovascular diseases other than coronary heart disease. Recent cohort studies examining the relationship between alcohol use and ischemic stroke have shown a modest association, with risk ratios approximating 0.8 and the lowest risk among those who drink less than daily. In contrast, alcohol use is generally associated with an approximate dose-dependent risk for hemorrhagic stroke throughout the full range of intake. Several prospective studies of alcohol intake and congestive heart failure have found lower risk with moderate drinking. This risk is also dose dependent through the moderate range, but its underlying mechanism remains uncertain. Accounting for the lower risk of myocardial infarction associated with moderate intake does not eliminate the observed association. Cohort studies have found no association of long-term alcohol intake with risk of atrial fibrillation below levels of at least 3 standard drinks per day. Finally, two prospective studies have found lower risks of claudication or clinically more severe peripheral arterial disease among moderate drinkers, an association also supported by cross-sectional studies of alcohol intake and ankle-brachial index.

Exposure-measurement error is frequently ignored when interpreting epidemiologic study results

INTRODUCTION

One important source of error in study results is error in measuring exposures. When interpreting study results, one should consider the impact that exposure-measurement error (EME) might have had on study results.

METHODS

To assess how often this consideration is made and the form it takes, journal articles were randomly sampled from original articles appearing in the American Journal of Epidemiology and Epidemiology in 2001, and the International Journal of Epidemiology between December 2000 and October 2001.

RESULTS

Twenty-two (39%) of the 57 articles surveyed mentioned nothing about EME. Of the 35 articles that mentioned something about EME, 16 articles described qualitatively the effect EME could have had on study results. Only one study quantified the impact of EME on study results; the investigators used a sensitivity analysis. Few authors discussed the measurement error in their study in any detail.

CONCLUSIONS

Overall, the potential impact of EME on error in epidemiologic study results appears to be ignored frequently in practice.

O processo aterosclerótico em artérias de coelhos submetidos a dieta suplementada com gema de ovo: modelo experimental de baixo custo

OBJETIVO: Verificar a aterogenicidade do modelo de hipercolesterolemia por suplementação alimentar com gema de ovo em coelhos e seu uso como modelo de aterosclerose experimental de baixo custo. MATERIAL E MÉTODO: Foram utilizados 14 coelhos divididos em dois grupos de sete animais: grupo controle (G1), que recebeu ração comercial ad libitum, e grupo tratado (G2), que foi alimentado com dieta suplementada com gema de ovo. Ambos os grupos foram alimentados por 90 dias. Foram realizadas dosagens do perfil lipídico dos animais nos momentos 0, 30, 60 e 90 dias. Ao término do período experimental, os animais foram submetidos a eutanásia e retirada da aorta e de seus ramos diretos para realização de estudo anatomopatológico. RESULTADOS Apenas no grupo G2 houve aumento significativo nos níveis de colesterol total e frações. Ao exame macroscópico, foram observadas estrias gordurosas no arco aórtico e aorta abdominal e, à microscopia, acúmulos lipídicos discretos na íntima da aorta abdominal, renal, carótida, transição toracoabdominal e femoral. Portanto, a dieta com gema de ovo provocou aterosclerose leve no animal de experimentação e alterações equivalentes àquelas provocadas pelo colesterol purificado comercial quando fornecido em baixa dosagem. Assim sendo, a gema de ovo pode ser utilizada como fonte de colesterol alimentar de baixo custo em modelos de aterosclerose experimental.

Factors Associated with Development of Large Abdominal Aortic Aneurysm in Middle-aged Men

OBJECTIVES

To investigate whether any variables in a health-screened population study were associated with later development of large abdominal aortic aneurysms (AAA).

SETTING

Malmö, Southern Sweden.

MATERIAL AND METHODS

Within the Malmö Preventive Study 22,444 men and 10,982 women were investigated between 1974 and 1991. The mean age at the health screening was 43.7 years.

RESULTS

After a median follow-up of 21 years, 126 men and six women (p<0.001) had large AAA that were symptomatic or evaluated for operation (5 cm diameter or more) or had autopsy-verified ruptured AAA. The male group (mean age 47 years) was, because of difference in age (p<0.001) also compared with an age-matched control group. The male patients with AAA showed increased diastolic blood pressure (p<0.007) at the health screening. Smoking predicted the development of AAA (p<0.0001). No difference in forced vital capacity or BMI was seen. Those who were physically inactive (e.g. not walking or cycling to work) had an increased risk of developing AAA (p<0.001). Among the laboratory markers measured, the erythrocyte sedimentation rate did not differ (7.1+/-5.9 vs. 6.4+/-5.7), but cholesterol (6.3+/-1.12 vs. 5.8+/-1.0) (p<0.0001) and triglycerides (1.9+/-0.12 vs. 1.5+/-0.07) (p<0.001) were significantly elevated in these individuals who subsequently developing AAA. The inflammatory proteins alfa-1-antitrypsin, ceruloplasmin, orosmucoid, fibrinogen, and haptoglobulin were increased (p<0.001).

CONCLUSION

Male gender, smoking, physical inactivity and cholesterol are significant factors associated with the development of AAA.