Prospective study of diet and venous thromboembolism in US women and men

Association between genetic risk and adherence to the Dietary Approaches to Stop Hypertension diet for developing venous thromboembolism

Background

The relationship between diet and venous thromboembolism (VTE) remains unclear, and the joint effects of diet patterns and genetic susceptibility on VTE risk are unknown.

Objectives

Investigate the independent and joint effects of Dietary Approaches to Stop Hypertension (DASH) diet adherence and polygenic risk scores (PRS) on VTE risk.

Methods

A total of 411,539 UK Biobank participants were included. DASH scores were calculated using Food Frequency Questionnaires, and PRS quantified genetic risk. Cox proportional hazard models estimated hazard ratios (HRs) for VTE, assessing interactions between the DASH diet and genetic susceptibility.

Results

During a median follow-up of 13.4 years, 10,543 participants were diagnosed with VTE. Higher DASH scores were associated with a lower VTE risk (HR, 0.87; 95% CI, 0.82-0.92). A low-adherent DASH diet combined with high-genetic risk had the highest VTE risk (HR, 2.78; 95% CI, 2.47-3.14). High DASH scores reduced VTE risk in high-genetic-risk individuals (HR, 0.84; 95% CI, 0.76-0.92). Sex-specific associations were detected in the joint effect and interaction of DASH scores and PRS. Notably, high DASH scores can offset moderate genetic risk among men (HR, 0.79; 95% CI, 0.67-0.94). There were additive interactions between DASH scores and high genetic risk in total subjects and men, while not observed in women.

Conclusion

The DASH diet is associated with reduced VTE risk and can partially offset genetic predisposition. Low adherence to the DASH diet increases VTE risk, particularly in high-genetic-risk individuals. The protective effect of high DASH scores against genetic risks for VTE is more pronounced in males. Precision medicine should consider both diet and genetics for VTE prevention.

Healthy Plant-Based Diet, Genetic Predisposition, and the Risk of Incident Venous Thromboembolism

Background

Plant-based dietary patterns are becoming increasingly popular due to environmental and health impacts, yet there are few studies exploring the relationship between plant-based dietary patterns and venous thromboembolism (VTE) in different genetic backgrounds.

Objectives

The aim of this study was to investigate how plant-based dietary pattern and genetic susceptibility independently or jointly affect VTE and its subtypes of pulmonary embolism and deep vein thrombosis.

Methods

A total of 183,510 participants who were White British ethnicity background and free of VTE at baseline in the UK Biobank were recruited, in consideration that the selection of genetic variants for VTE was based on results of White European individuals. The healthy plant-based diet index (hPDI) was calculated based on the 17 foods in the Oxford webQ. Genetic risk was quantified by a polygenic risk score (PRS) consisting of 297 single-nucleotide polymorphisms. Incident VTE was identified through hospital inpatient and death databases records from the UK Biobank. Cox regression analyses were conducted to estimate the associations between hPDI and PRS with the incident risk of VTE.

Results

During a mean follow-up of 13 years, a total of 4,587 cases of VTE were recorded. Compared to individuals in the lowest tertile of hPDI, multivariable-adjusted HRs of VTE in the highest tertile were 0.86 (95% CI: 0.80, 0.92; P trend = 0.02). And high PRS was associated with a 47% increase in VTE risk (adjusted HR: 1.47, 95% CI: 1.37, 1.58). No significant interaction between hPDI and PRS (P interaction = 0.540) was observed, even though participants with low hPDI an high PRS had the highest risk of VTE compared to those with high hPDI and low PRS (HR: 1.72, 95% CI: 1.52, 1.95).

Conclusions

Adherence to a healthy plant-based dietary pattern could reduce the risk of developing VTE independent of genetic background, lifestyles, sociodemographic features, and multiple morbidities. Our findings underline the importance of diet in VTE prevention interventions.

Epidemiology and prevention of venous thromboembolism

Venous thromboembolism, that consists of the interrelated conditions deep-vein thrombosis and pulmonary embolism, is an under-appreciated vascular disease. In Western regions, approximately 1 in 12 individuals will be diagnosed with venous thromboembolism in their lifetime. Rates of venous thromboembolism are lower in Asia, but data from other regions are sparse. Numerous risk factors for venous thromboembolism have been identified, which can be classified as acute or subacute triggers (provoking factors that increase the risk of venous thromboembolism) and basal or acquired risk factors (which can be modifiable or static). Approximately 20% of individuals who have a venous thromboembolism event die within 1 year (although often from the provoking condition), and complications are common among survivors. Fortunately, opportunities exist for primordial prevention (prevention of the development of underlying risk factors), primary prevention (management of risk factors among individuals at high risk of the condition) and secondary prevention (prevention of recurrent events) of venous thromboembolism. In this Review, we describe the epidemiology of venous thromboembolism, including the incidence, risk factors, outcomes and opportunities for prevention. Meaningful health disparities exist in both the incidence and outcomes of venous thromboembolism. We also discuss these disparities as well as opportunities to reduce them.

Contrasting Associations of Prudent and Western Dietary Patterns with Risk of Developing Venous Thromboembolism

BACKGROUND

Published studies are inconsistent about whether differences in diet are associated with risk of venous thromboembolism. We studied the association between dietary patterns and incident venous thromboembolism in a large US cohort.

METHODS

The Atherosclerosis Risk in Communities study followed 14,818 middle-aged males and females for incident venous thromboembolism over an average of 22 years between 1987 and 2015. Trained interviewers assessed dietary intake at visits 1 and 3, using a food frequency questionnaire. We derived 2 dietary pattern scores using principal component analysis and ascertained and verified hospitalized venous thromboembolism. In separate proportional hazards regression analyses, we examined associations of quintiles of the prudent and the Western dietary pattern scores with risk of developing non-cancer-related and total venous thromboembolism, adjusting for demographic characteristics, lifestyle factors, body mass index, and diabetes.

RESULTS

With 860 total incident venous thromboembolism events, the hazard ratios (95% confidence intervals) of incident non-cancer-related venous thromboembolism (n = 631) across quintiles of the prudent dietary pattern score were 1 (reference), 1.04 (0.81-1.32), 0.84 (0.65-1.08), 0.70 (0.53-0.91), and 0.88 (0.67-1.15), Ptrend = .04. Across quintiles of the Western dietary pattern score, hazard ratios of non-cancer-related venous thromboembolism were 1 (reference), 1.13 (0.87-1.45), 1.20 (0.92-1.56), 1.03 (0.77-1.39), and 1.58 (1.13-2.21), Ptrend = .04. Associations were similar for total venous thromboembolism.

CONCLUSIONS

In this community-based cohort, a prudent dietary pattern was associated with a lower risk of future venous thromboembolism, whereas a Western dietary pattern was associated with a higher risk.

Meta-analysis of alcohol consumption and venous thromboembolism

BACKGROUND

The associations of alcohol consumption and venous thromboembolism (VTE) have been investigated widely, but the conclusions were inconsistent.

OBJECTIVE

To summarize the relationship of alcohol consumption and VTE.

METHODS

This study has been registered in PROSPERO (ID: CRD42020164567). We searched the PubMed, Embase, Web of Science and the Cochrane Library databases from inception to September 2019 and reviewed the reference list of relevant articles to identify studies assessing the association between alcohol consumption and risk of VTE.

RESULTS

Fourteen cohorts and four case-control studies were included in the meta-analysis. Compared with non-drinkers, the risk of VTE was decreased (RR: 0.93; 95% confidence interval [CI] 0.88-0.99) for alcohol drinkers. The pooled RRs of VTE were 0.91 (95% CI 0.84-0.99) for low to moderate alcohol intake (0.1-14.0 drinks/week) and 0.91 (95% CI 0.78-1.06) for high alcohol intake (>14.0 drinks/week) compared with non-drinker. Subgroup analysis showed liquor intake might slightly increase the risk of VTE (1.01; 95% CI 0.85-1.21) although the difference was not significant.

CONCLUSIONS

Alcohol consumption in low to moderate was associated with a lower risk of VTE. However, precautions are needed when providing personal drinking advice considering the potential harm of alcohol. Further studies are warranted to determine whether moderate alcohol consumption has a causal role in VTE.

Lifestyle factors and venous thromboembolism in two cohort studies

INTRODUCTION

Evidence on the associations of lifestyle factors with venous thromboembolism (VTE) is inconsistent. We aimed to investigate the associations of modifiable lifestyle factors with VTE in women and men.

METHODS

We used data from two cohorts comprising 30,137 women and 36,193 men aged over 45 years and free of cancer and VTE. Information on lifestyle factors was collected in 1997 via a self-administrated questionnaire. VTE cases were ascertained by linkage with the National Patient Register until the end of 2019.

RESULTS

During a mean of 16.9-years follow-up, 1784 women and 2043 men were diagnosed with VTE. Compared with individuals with <10 min/day of physical activity, the multivariable hazard ratios (HRs) of VTE were 0.67 (95% confidence interval (CI), 0.58, 0.79) and 0.78 (95% CI, 0.67, 0.92) in women and men with >60 min/day, respectively. Compared with individuals with the lowest adherence to a modified Dietary Approaches to Stop Hypertension diet, the multivariable HRs of VTE were 0.87 (95% CI, 0.75, 0.99) and 0.88 (95% CI, 0.80, 1.00) for women and men with the highest adherence. In women, the multivariable HRs of VTE were 1.16 (95% CI, 1.03, 1.29) for past smoker and 1.28 (95% CI, 1.14, 1.45) for current smoker compared with never smoker. Alcohol and coffee consumption were not associated with VTE.

CONCLUSIONS

This study suggests that being physically active and adhering to a healthy diet may lower the risk of VTE in women and men. Cigarette smoking was positively associated with VTE in women.

Associations of Fish and Omega-3 Fatty Acids Consumption With the Risk of Venous Thromboembolism. A Meta-Analysis of Prospective Cohort Studies

Objective: This study aims to investigate the effect of fish and omega-3 fatty acids consumption on the risk of VTE. Methods: A comprehensive literature search in the databases of PubMed, Web of Science, and Embase (up to September 2020), was conducted to identify the prospective cohort studies concerning the associations of fish and omega-3 fatty acids consumption with the risk of VTE. The pooled relative risk (RR) of VTE for the highest vs. lowest category of fish and omega-3 fatty acids consumption, as well as their corresponding 95% confidence interval (CI) were calculated. Results: A total of seven articles with eight prospective cohort studies were included. Specifically, six studies were related to fish consumption, and the overall multi-variable adjusted RR showed no significant relationship between fish consumption and the risk of VTE (RR = 1.02, 95% CI: 0.93-1.11; P = 0.709). In the four studies related to omega-3 fatty acids consumption, the overall multi-variable adjusted RR suggested that omega-3 fatty acids consumption was associated with a lower risk of VTE (RR = 0.89, 95% CI: 0.80-0.98; P = 0.024). Moreover, two studies were related to recurrent VTE, and the overall multi-variable adjusted RR demonstrated a significant inverse association between omega-3 fatty acids consumption and the risk of recurrent VTE (RR = 0.45, 95% CI: 0.25-0.81; P = 0.008). Conclusion: Although current evidence is still insufficient to demonstrate any relationship between fish consumption and the risk of VTE, omega-3 fatty acids consumption seems to be associated with a lower risk of both VTE and recurrent VTE. Further large well-designed prospective cohort studies are warranted to elaborate the issues examined in this study.

Exploring Opportunities for Primary Prevention of Unprovoked Venous Thromboembolism: Ready for Prime Time?

Venous thromboembolism (VTE) is an important vascular disease and public health problem. Prevention of VTE has focused mainly on using thromboprophylaxis to avoid provoked VTE or recurrent VTE, with little attention paid to the possibility of preventing the one third to one half of VTEs that are unprovoked. We review growing research suggesting that unhealthy lifestyle risk factors may cause a considerable proportion of unprovoked VTE. Using epidemiologic data to calculate population attributable risks, we estimate that in the United States obesity may contribute to 30% of VTEs, physical inactivity to 4%, current smoking to 3%, and Western dietary pattern to 11%. We also review possibilities for VTE primary prevention either through a high-risk individual approach or a population-wide approach. Interventions for outpatients at high VTE risk but without VTE provoking factors have not been fully tested; yet, improving patient awareness of risk and symptoms, lifestyle counseling, and possibly statins or direct oral anticoagulants may prove useful in primary prevention of unprovoked VTE. A population approach to prevention would bolster awareness of VTE and aim to shift lifestyle risk factors downward in the whole population using education, environmental changes, and policy. Assuming the epidemiological associations are accurate, causal, and independent of each other, a reduction of obesity, physical inactivity, current smoking, and Western diet by 25% in the general population might reduce the incidence of unprovoked VTE by 12%. We urge further research and consideration that primary prevention of unprovoked VTE may be a worthwhile public health aim.

Outcomes of symptomatic venous thromboembolism after haploidentical donor hematopoietic stem cell transplantation and comparison with human leukocyte antigen-identical sibling transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is regarded as a curative therapy for majority of hematologic malignancies and some non-malignant hematologic diseases. Venous thromboembolism (VTE) has become increasingly recognized as a severe complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVES

To show the characteristics of VTE after haploidentical donor hematopoietic stem cell transplantation (HID-HSCT) and make comparisons with matched related donor HSCT (MRD-HSCT).

PATIENTS/METHODS

A retrospective nested case-control study design was used, cases with VTE and matched controls were selected, with 3534 patients underwent HID-HSCT and 1289 underwent MRD-HSCT.

RESULTS

During follow-up, 114 patients with VTE were identified. The incidence of VTE in HID-HSCT group was similar to that of MRD-HSCT group (2.4% versus 2.3%, P = 0.92). In HID-HSCT group, VTE occurred at a median time of 92.5 days, which was earlier than MRD-HSCT group (243.5 days). For HID-HSCT, advanced disease status, cardiovascular risk factors, acute graft-versus-host disease (aGVHD), and relapse were the independent risk factors for VTE. For MRD-HSCT, cardiovascular risk factors, aGVHD, and relapse were associated with VTE. Overall survival (OS) of patients following HID-HSCT and MRD-HSCT were similar, but the OS in patients with VTE was significantly lower than patients without VTE.

CONCLUSIONS

There was no statistical difference in the incidence of VTE after HID-HSCT compared with MRD-HSCT. The development of VTE adversely impacted the OS after allo-HSCT.

The Type and Amount of Dietary Fat Affect Plasma Factor VIIc, Fibrinogen, and PAI-1 in Healthy Individuals and Individuals at High Cardiovascular Disease Risk: 2 Randomized Controlled Trials

BACKGROUND

Factor VIIc, fibrinogen, and plasminogen activator inhibitor 1 (PAI-1) are cardiovascular disease (CVD) risk factors and are modulated, in part, by fat type and amount.

OBJECTIVE

We evaluated fat type and amount on the primary outcomes: factor VIIc, fibrinogen, and PAI-1.

METHODS

In the Dietary Effects on Lipoproteins and Thrombogenic Activity (DELTA) Trial, 2 controlled crossover feeding studies evaluated substituting carbohydrate or MUFAs for SFAs. Study 1: healthy participants (n = 103) were provided with (8 wk) an average American diet [AAD; designed to provide 37% of energy (%E) as fat, 16% SFA], a Step 1 diet (30%E fat, 9% SFA), and a diet low in SFA (Low-Sat; 26%E fat, 5% SFA). Study 2: participants (n = 85) at risk for CVD and metabolic syndrome (MetSyn) were provided with (7 wk) an AAD, a step 1 diet, and a high-MUFA diet (designed to provide 37%E fat, 8% SFA, 22% MUFA).

RESULTS

Study 1: compared with AAD, the Step 1 and Low-Sat diets decreased mean factor VIIc by 1.8% and 2.6% (overall P = 0.0001), increased mean fibrinogen by 1.2% and 2.8% (P = 0.0141), and increased mean square root PAI-1 by 0.0% and 6.0% (P = 0.0037), respectively. Study 2: compared with AAD, the Step 1 and high-MUFA diets decreased mean factor VIIc by 4.1% and 3.2% (overall P < 0.0001), increased mean fibrinogen by 3.9% and 1.5% (P = 0.0083), and increased mean square-root PAI-1 by 2.0% and 5.8% (P = 0.1319), respectively.

CONCLUSIONS

Replacing SFA with carbohydrate decreased factor VIIc and increased fibrinogen in healthy and metabolically unhealthy individuals and also increased PAI-1 in healthy subjects. Replacing SFA with MUFA decreased factor VIIc and increased fibrinogen but less than carbohydrate. Our results indicate an uncertain effect of replacing SFA with carbohydrate or MUFA on cardiometabolic risk because of small changes in hemostatic factors and directionally different responses to decreasing SFA. This trial was registered at https://clinicaltrials.gov/ct2/show/NCT00000538?term=NCT00000538&rank=1 as NCT00000538.

Nutrition, Thrombosis, and Cardiovascular Disease

Previous studies reported an inverse association between healthy dietary patterns (such as Mediterranean diet) and the incidence of cardiovascular events. As the mechanism accounting for cardiovascular disease is prevalently due to the atherothrombosis, where a pivotal role is played by platelet activation, it would be arguable that diets with protective effects against cardiovascular disease exert an anti-atherothrombotic effect via inhibition of platelet activation. There are several and sparse typologies of studies, which investigated if single nutrients by diets recognized as having cardiovascular protection may exert an antithrombotic effect. The most investigated nutrients are key components of the Mediterranean diets such as fruits and vegetables, fish, olive oil, and wine; other diets with protective effects include nuts and cocoa. Here we summarize experimental and human interventional studies which investigated the antithrombotic effects of such nutrients in experimental models of thrombosis or analyzed biomarkers of clotting, platelet, and fibrinolysis activation in human; furthermore in vitro studies explored the underlying mechanism at level of several cell lines such as platelets or endothelial cells. In this context, we analyzed if nutrients affect simultaneously or separately clotting, platelet, and fibrinolysis pathways giving special attention to the relationship between oxidative stress and thrombosis as most nutrients are believed to possess antioxidant properties.

Alcohol Consumption and Risk for Venous Thromboembolism: A Meta-Analysis of Prospective Studies

The association between alcohol consumption and venous thromboembolism (VTE) risk has been investigated by various observational studies with inconsistent results. We examined this association by performing a meta-analysis of prospective studies. A comprehensive literature search was carried out in the PubMed, EMBASE, and Web of Science from its inception to February 2020. Pooled effect estimates were calculated using a random effect model. Ten prospective studies (14 cohorts) were included in this meta-analysis with a total of 441,128 individuals and 10,221 VTE cases. Overall, the highest consumption of alcohol was not associated with the VTE risk compared with the lowest group [relative risk (RR), 0.96 (95% CI, 0.89–1.04), P = 0.293]. No obvious heterogeneity of RRs was observed across these studies (P = 0.249 for heterogeneity, I² = 18.8%). Egger's and Begg's tests showed no evidence of publication bias (Egger, P = 0.443; Begg, P = 0.730). In the subgroup analysis by sex, a borderline significant association between alcohol consumption and VTE risk was observed in women [RR, 0.91 (95% CI, 0.82–1.00)]. In the dose–response analysis, we observed a linear decrease in VTE risk with increasing alcohol intake (P = 0.634 for nonlinearity). However, the reduced risk was not statistically significant. In conclusion, the results from this meta-analysis suggest that alcohol intake is not related with the risk of VTE. Further large well-designed cohort studies are warranted to investigate a potential protective role of alcohol against VTE in women.

Dietary intake of marine n-3 polyunsaturated fatty acids and future risk of venous thromboembolism

BACKGROUND

Studies on the association between long-chained n-3 polyunsaturated fatty acids (n-3 PUFAs) and risk of venous thromboembolism (VTE) are conflicting, potentially due to challenges related to assessment of n-3 PUFA intake and changes in diet during follow-up.

OBJECTIVES

To investigate whether dietary intake of marine n-3 PUFAs was associated with risk of incident VTE in a population-based cohort with repeated assessments of n-3 PUFA intake.

METHODS

We recruited 21 970 participants (after excluding 7570 with incomplete data) from the fourth (1994-1995) and sixth (2007-2008) surveys of the Tromsø Study, and recorded incident VTEs up to 2016. Intake of n-3 PUFAs was computed from self-reported consumption of fat and lean fish, fish spread, and supplements. Cox proportional hazards regression models with n-3 PUFA intake as a time-varying variable were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for VTE across quartiles (Q) of n-3 PUFA intake.

RESULTS

There were 541 incident VTEs during follow-up. Compared to Q1, subjects in Q2-4 had 22%-26% lower risk of VTE (HR Q2 0.74, 95% CI 0.57-0.96; HR Q3 0.77, 95% CI 0.59-0.99; HR Q4 0.78, 95% CI 0.61-1.00). The association was most pronounced for provoked VTE, particularly provoked pulmonary embolism (PE), with risk estimates of 0.42 (95% CI 0.25-0.72), 0.40 (95% CI 0.23-0.68), and 0.61 (95% CI 0.38-0.96) for Q2-4, respectively.

CONCLUSIONS

Dietary intake of marine n-3 PUFAs was associated with a lower risk of VTE, particularly provoked PE. The association displayed a threshold pattern and suggested a protective effect of an n-3 PUFA intake ≥4.7 g/week.

Metabolites Associated With the Risk of Incident Venous Thromboembolism: A Metabolomic Analysis

Background Venous thromboembolism ( VTE ) is a complex thrombotic disorder that constitutes a major source of mortality and morbidity. To improve understanding of the cause of VTE , we conducted a metabolomic analysis in a case-control study including 240 incident VTE cases and 6963 controls nested within 3 large prospective population-based cohorts, the Nurses' Health Study, the Nurses' Health Study II , and the Health Professionals Follow-Up Study. Methods and Results For each individual, we measured 211 metabolites and collected detailed information on lifestyle factors. We performed logistic regression and enrichment analysis to identify metabolites and biological categories associated with incident VTE risk, accounting for key confounders, such as age, sex, smoking, alcohol consumption, body mass index, and comorbid diseases (eg, cancers). We performed analyses of all VTEs and separate analyses of pulmonary embolism. Using the basic model controlling for age, sex, and primary disease, we identified 60 nominally significant VTE - or pulmonary embolism-associated metabolites ( P<0.05). These metabolites were enriched for diacylglycerols ( P_permutation<0.05). However, after controlling for multiple testing, only 1 metabolite (C5 carnitine; odds ratio, 1.25; 95% confidence interval, 1.10-1.41; P_corrected=0.03) remained significantly associated with VTE . After further adjustment for body mass index, no metabolites were significantly associated with disease after accounting for multiple testing, and no metabolite classes were enriched for nominally significant associations. Conclusions Although our findings suggest that circulating metabolites may influence the risk of incident VTE , the associations we observed were confounded by body mass index. Larger studies involving additional individuals and with broader metabolomics coverage are needed to confirm our findings.

Adiposity throughout the life course and risk of venous thromboembolism

OBJECTIVE

Adult body mass index (BMI) is strongly associated with venous thromboembolism (VTE), however whether earlier-life adiposity or other measures of adult adiposity are associated with VTE risk remains largely unknown.

MATERIALS AND METHODS

We evaluated associations of childhood somatotype, BMI in early adulthood, adult adiposity, and change in weight since early adulthood with incident VTE risk over ≥20 years of follow-up among 205,935 participants from Nurses' Health Studies (NHS/NHS II) and Health Professionals Follow-Up Study (HPFS), ages 29-76 at baseline. We estimated multivariable-adjusted hazard ratios for VTE using Cox proportional hazards models.

RESULTS AND CONCLUSIONS

Somatotype in childhood and young adulthood BMI were not significantly associated with VTE risk, after accounting for adult BMI. Adult BMI was strongly associated with VTE in all three cohorts (e.g., multivariable-adjusted HRs comparing ≥35 kg/m² vs. <22.5 kg/m²: NHS:3.03[95% CI: 2.58, 3.56], NHS II:3.82[95% CI: 3.24, 4.51], HPFS:2.81 [95% CI: 2.08, 3.80]; all p-trends < 0.01). Adult waist circumference was associated with greater VTE risk, even after adjusting for adult BMI (all p-trends < 0.01). Increasing weight gain from young adulthood was significantly associated with VTE after adjusting for current BMI among women (HR comparing gain ≥20 kg vs. no change: NHS:1.36[95% CI: 1.13, 1.65], NHS II:1.48[95% CI: 1.17, 1.87]) and not men (HPFS:1.20[95% CI: 0.97, 1.50]). These results indicate that BMI and adiposity are likely more important acutely than cumulatively over time in the etiology and prevention of VTE. Clinically, encouraging weight loss in individuals who are overweight or obese could help reduce VTE risk.

Alcohol consumption and the risk of incident pulmonary embolism in US women and men

Essentials The association of moderate alcohol consumption with pulmonary embolism (PE) risk remains unclear. In three large US cohorts, we evaluated the association of alcohol consumption with PE risk. We found no evidence of an association of alcohol consumption amount or frequency with PE risk. Secondary analyses of type and heavy episodic drinking also yielded null findings.

SUMMARY

Background Moderate alcohol consumption has been variably associated with hemostatic and fibrinolytic factor levels, but the association between alcohol consumption and the risk of incident pulmonary embolism (PE) remains uncertain. Objective To evaluate alcohol consumption amount and frequency in relation to PE risk. Methods Nurses' Health Study (NHS), NHS II and Health Professionals Follow-Up Study participants free of venous thromboembolism (VTE) at baseline (n = 217 442) reported alcohol consumption by type, quantity and frequency, every 2-4 years. Incident PE cases were identified by self-report and confirmed for participants without cancer. In this cohort study, we used Cox proportional hazards models to estimate multivariable-adjusted hazard ratios (HRs) for PE associated with alcohol consumption amount and, separately, frequency. Secondary analyses evaluated alcohol type and heavy episodic drinking in relation to PE risk, and amount and frequency in relation to medical record-confirmed idiopathic PE and any self-reported VTE risk. Cohort-specific analyses were pooled using random-effects meta-analysis. Results During ≥ 20 years of follow-up, we identified 1939 PE events. We found no strong evidence of an association between PE risk and alcohol consumption amount (pooled HRadj for 5.0-14.9 g day-1 vs. abstention = 0.97 [95% CI, 0.79, 1.20]) or frequency (pooled HRadj for 5-7 drinking days per week vs. abstention = 1.04 [95% CI, 0.88, 1.23]). Secondary analyses of type, heavy episodic drinking, idiopathic PE and VTE also yielded null findings. Conclusions Among three large prospective cohorts of US men and women, we found no evidence of an association between the amount or frequency of alcohol consumption and PE risk.

Fish Intake and Death From Pulmonary Embolisms Among Japanese Men and Women - The Japan Collaborative Cohort (JACC) Study

BACKGROUND

Numerous studies have reported the association of cardiovascular risk factors with pulmonary embolism (PE), but the association of dietary factors, especially fish intake, with the risk of PE has not been fully established.

METHODS AND RESULTS

Using a prospective design, we studied the risk of PE mortality in relation to fish intake in 90,791 community-dwelling men and women in Japan aged 40-79 years. The hazard ratios (HRs) and 95% confidence intervals (CIs) for PE death were estimated using the Cox proportional hazards model. Compared with participants in the lowest fresh fish intake group (<1 time/month), the HRs (95% CIs) for PE death for those in the other intake groups were 0.35 (0.08-1.59) for 1-2 times/month, 0.19 (0.05-0.69) for 1-2 times/week, 0.20 (0.06-0.74) for 3-4 times/week, and 0.18 (0.05-0.66) for fish intake every day. In addition to these findings, compared with the participants in the lowest 10% of ω3 polyunsaturated fatty acid intake, those in the other groups had a 60-76% lower risk of PE death.

CONCLUSIONS

Fresh fish intake, even 1-2 times/week, is associated with a lower risk of death from PE among Japanese men and women.

Reduction in physical function in women after venous thromboembolism

Essentials The association of venous thromboembolism (VTE) with subsequent physical function remains unclear. We prospectively evaluated this relationship among women from the Nurses' Health Studies. We found a decline in physical function over four years in women with incident VTE. This decline was somewhat greater among women specifically reporting a pulmonary embolism.

SUMMARY

Background Physical function is integral to healthy aging; however, limited research has examined the association of venous thromboembolism(VTE) with subsequent physical function. Objectives To prospectively evaluate the relationship between VTE and decline in physical function among 80 836 women from the Nurses' Health Study(NHS), ages 46-72 in 1992, and 84 304 women from the Nurses' Health Study II(NHS II), ages 29-48 in 1993. Methods Physical function was measured by the Medical Outcomes Short Form-36 physical function scale, administered every 4 years. We compared change in physical function for women with vs. without an incident VTE in each 4-year follow-up period using multivariable linear regression. Results We observed a decline in physical function over 4 years when comparing women with vs. those without incident VTE in both older (NHS) and younger (NHS II) women (multivariable-adjusted mean difference NHS, -6.5 points [95% CI -7.4, -5.6] per 4 years; NHS II, -3.8 [95% CI -5.6, -2.0]). This difference appeared greater among women specifically reporting a pulmonary embolism (NHS, -7.4 [95% CI -8.7, -6.1]; NHS II, -4.8 [95% CI -6.8, -2.8]), and was equivalent to 6.2 years of aging. Whereas longer-term slopes of physical function decline following a VTE were not different from the slopes of decline in women without a VTE, the absolute level of physical function of women with VTE was worse at the end of follow-up compared to women without VTE. Conclusions In this prospective cohort, incident VTE was strongly associated with an acute decline in physical function. These results suggest it may be clinically important to consider approaches to ameliorating functional deficits shortly after VTE diagnosis.

Interaction of a genetic risk score with physical activity, physical inactivity, and body mass index in relation to venous thromboembolism risk

INTRODUCTION

Venous thromboembolism (VTE) is highly heritable. Physical activity, physical inactivity and body mass index (BMI) are also risk factors, but evidence of interaction between genetic and environmental risk factors is limited.

METHODS

Data on 2,134 VTE cases and 3,890 matched controls were obtained from the Nurses' Health Study (NHS), Nurses' Health Study II (NHS II), and Health Professionals Follow-up Study (HPFS). We calculated a weighted genetic risk score (wGRS) using 16 single nucleotide polymorphisms associated with VTE risk in published genome-wide association studies (GWAS). Data on three risk factors, physical activity (metabolic equivalent [MET] hours per week), physical inactivity (sitting hours per week) and BMI, were obtained from biennial questionnaires. VTE cases were incident since cohort inception; controls were matched to cases on age, cohort, and genotype array. Using conditional logistic regression, we assessed joint effects and interaction effects on both additive and multiplicative scales. We also ran models using continuous wGRS stratified by risk-factor categories.

RESULTS

We observed a supra-additive interaction between wGRS and BMI. Having both high wGRS and high BMI was associated with a 3.4-fold greater risk of VTE (relative excess risk due to interaction = 0.69, p = 0.046). However, we did not find evidence for a multiplicative interaction with BMI. No interactions were observed for physical activity or inactivity.

CONCLUSION

We found a synergetic effect between a genetic risk score and high BMI on the risk of VTE. Intervention efforts lowering BMI to decrease VTE risk may have particularly large beneficial effects among individuals with high genetic risk.

Alcohol intake and risk of venous thromboembolism

Knowledge about the influence of alcohol intake on the risk of venous thromboembolism (VTE) is limited. We investigated the risk of VTE according to alcohol intake and drinking pattern among 27,178 men and 29,876 women participating in the Danish follow-up study Diet, Cancer and Health. Information on alcohol exposure and potential confounders were obtained from baseline questionnaires. We used Cox proportional hazard models to assess the association between VTE and alcohol intake. We performed separate analyses for the two sexes. During follow-up 619 incidents VTE events were verified. The lowest incidence rates of VTE were found for an average weekly intake of 3.9–13.9 standard drinks per weeks both for men and women. The adjusted hazard ratio (HR) was 0.91 [95%CI: 0.69–1.19] for women and 0.75 [95%CI: 0.56–1.02] for men according to an average alcohol intake of 3.9–13.9 standard drinks per week compared with low alcohol intake. In men, alcohol intake 2–6 times per week was associated with a lower risk of VTE compared to once per week (HR 0.77 [95%CI: 0.59–0.99]), but the difference disappeared after adjustment for total alcohol intake. We found no difference in the risk of VTE according to wine and beer intake. In conclusion, we found no consistent or statistically significant association between VTE and alcohol intake. Our data showed a u-formed association between alcohol intake and VTE, indicating that moderate alcohol intake may lower the risk of VTE with 10–30% in men.

Epidemiology and pathophysiology of venous thromboembolism: similarities with atherothrombosis and the role of inflammation

Venous thromboembolism (VTE) is a multifactorial disease. Major provoking factors (e. g. surgery, cancer, major trauma, and immobilisation) are identified in 50–60 % of patients, while the remaining cases are classified as unprovoked. However, minor predisposing conditions may be detectable in these patients, possibly concurring to the pathophysiology of the disease, especially when co-existing. In recent years, the role of chronic inflammatory disorders, infectious diseases and traditional cardiovascular risk factors has been extensively investigated. Inflammation, with its underlying prothrombotic state, could be the potential link between these risk factors, as well as the explanation for the reported association between arterial and venous thromboembolic events.

Omega-3 fatty acids predict recurrent venous thromboembolism or total mortality in elderly patients with acute venous thromboembolism

Essentials The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) is unknown. Association of n-3 FAs with recurrent VTE or total mortality was investigated in 826 patients. Whole blood n-3 FAs were inversely correlated with recurrent VTE or total mortality. Major and non-major bleeding was not increased in patients with higher levels of n-3 FAs.

SUMMARY

Background The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) remains unknown. Objectives To investigate the association of n-3 FAs with recurrent VTE or total mortality at 6 months and 3 years. Methods N-3 FAs were assessed in 826 patients aged ≥ 65 years, categorized into low, medium and high based on the 25th and 75th percentile. Mean follow-up was 29 months. Results At 6 months, subjects with medium (adjusted hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.22-0.62) and high n-3 FA levels (adjusted HR, 0.36; 95% CI, 0.20-0.67) were less likely to develop recurrent VTE or total mortality, compared with those with low n-3 FAs. At 3 years, medium levels (adjusted HR, 0.67; 95% CI, 0.47-0.96) were associated with lower risk of recurrent VTE or total mortality. As compared with low n-3 FAs, the adjusted sub-hazard ratio [SHR] of recurrent VTE was 0.39 (95% CI, 0.15-0.99) in patients with medium and 0.17 (95% CI, 0.03-0.82) in patients with high n-3 FAs. The cumulative incidence of recurrent VTE was lower in the medium and high n-3 FA groups as compared with the low n-3 FA groups, but seems to have worn off after 3 years. The incidence of major and non-major bleeding was not greater in the high n-3 FA group. Conclusion Higher levels of n-3 FAs were associated with a lower risk of recurrent VTE or total mortality in elderly patients with VTE, but not with greater bleeding risk.

Environmental and Genetic Risk Factors Associated with Venous Thromboembolism

Venous thromboembolism (VTE) includes deep vein thrombosis and pulmonary embolism, and a combination of environmental and genetic risk factors contributes to VTE risk. Within environmental risk factors, some are provoking (e.g., cancer, surgery, trauma or fracture, immobilization, pregnancy and the postpartum period, long-distance travel, hospitalization, catheterization, and acute infection) and others are nonprovoking (e.g., age, sex, race/ethnicity, body mass index and obesity, oral contraceptive or hormone therapy use, corticosteroid use, statin use, diet, physical activity, sedentary time, and air pollution). Additionally, VTE has a strong genetic basis, with approximately 50 to 60% of the variance in VTE incidence attributed to genetic effects. Some genetic susceptibility variants that contribute to risk have been identified in candidate genes, mostly related to the clotting system and responsible for inherited hypercoagulable states (e.g., factor V Leiden, prothrombin, fibrinogen gamma, or blood group non-O). Other susceptibility single-nucleotide polymorphisms have been identified from genome-wide association studies, such as the two new loci in TSPAN15 (rs78707713) and SCL44A2 (rs2288904) genes. Risk factors are not always associated with VTE in isolation; however, and an understanding of how environmental and genetic factors interact may provide insight into the pathophysiology of VTE, possibly identifying opportunities for targeted prevention and treatment.

Associations of Trauma Exposure and Posttraumatic Stress Symptoms With Venous Thromboembolism Over 22 Years in Women

Background

Trauma exposure and posttraumatic stress disorder (PTSD) have been linked to myocardial infarction and stroke in women, with biological and behavioral mechanisms implicated in underlying risk. The third most common cardiovascular illness, venous thromboembolism (VTE), is a specific health risk for women. Given previous associations with other cardiovascular diseases, we hypothesized that high levels of trauma and PTSD symptoms would be associated with higher risk of incident VTE in younger and middle‐aged women.

Methods and Results

We used proportional hazards models to estimate hazard ratios (HRs) and 95% CIs for new‐onset VTE (960 events) over 22 years in 49 296 women in the Nurses’ Health Study II. Compared to no trauma exposure, both trauma exposure and PTSD symptoms were significantly associated with increased risk of developing VTE, adjusting for demographics, family history, and childhood adiposity. Women with the most PTSD symptoms exhibited the greatest risk elevation: trauma/6 to 7 symptoms: HR=2.42 (95% CI, 1.83–3.20); trauma/4 to 5 symptoms: HR=2.00 (95% CI, 1.55–2.59); trauma/1 to 3 symptoms: HR=1.44 (95% CI, 1.12–1.84); trauma/no symptoms: HR=1.72 (95% CI, 1.43–2.08). Results were similar, although attenuated, when adjusting for VTE‐relevant medications, medical conditions, and health behaviors.

Conclusions

Women with the highest PTSD symptom levels had nearly a 2‐fold increased risk of VTE compared to women without trauma exposure in fully adjusted models. Trauma exposure alone was also associated with elevated VTE risk. Trauma and PTSD symptoms may be associated with a hypercoagulable state. Treatment providers should be aware that women with trauma exposure and PTSD symptoms may be vulnerable to VTE.

Alcohol consumption and venous thromboembolism: friend or foe?

A light to moderate consumption of certain types of alcoholic beverages may exert a favorable effect on cardiovascular risk, but no conclusive information is available on the putative relationship between alcohol intake and the risk of venous thromboembolism (VTE). We performed an electronic search on Medline and Scopus, using the keywords "venous thromboembolism", "venous thrombosis" and "alcohol", to identify clinical studies linking alcohol intake and VTE risk. The literature search generated 16 studies, 4 of which are case-control, 1 cross-sectional and 11 prospective. Significant reduction of VTE associated with alcohol intake is observed in only 4/16 studies, and in all these the association is only meaningful for a moderate amount of alcohol (i.e., 2-4 glasses). Unlike these trials, two other studies observe that alcohol intake is associated with an increased risk of VTE, whereas the association is insignificant in the remainder. Binge drinking increases the VTE risk in one study but not in another. The consumption of beer is associated with a decreased VTE risk in one study but not in two others. We hence conclude that the relationship between intake of alcoholic beverages and increased or decreased risk of VTE is largely elusive.

Fish Intake and Venous Thromboembolism: A Systematic Literature Review

Diet plays an important role in modulating the risk of arterial and venous thrombosis. Several lines of evidence attest that consumption of fish and its compounds, especially omega-3 fatty acids, may be effective to decrease the cardiovascular risk. Since the pathogenesis of arterial and venous thrombosis share some common aspects, we performed a systematic review of published clinical studies that investigated the association between fish intake and venous thrombosis. An electronic search was carried out in Medline, Scopus, and ISI Web of Science using the key words "fish" OR "seafood" AND "venous thromboembolism" OR "deep vein thrombosis" OR "pulmonary embolism", with no language or date restriction. Overall, 6 studies (5 prospective and 1 case-control) were finally identified. In only 1 small case-control study, a larger intake of total fish was found to be negatively associated with the risk of venous thromboembolism. No association was found in 4 large prospective studies, whereas a positive association was observed in the remaining. No substantial difference was also noticed between intake of fatty or lean fish. Taken together, the current epidemiological evidence does not support the existence of a significant effect of total fish consumption on the risk of venous thromboembolism.

Red meat, processed meat and the risk of venous thromboembolism: friend or foe?

Venous thromboembolism (VTE) is a highly prevalent condition worldwide, which can be triggered by a combination of inherited and acquired risk factors, including diet. Several lines of evidence suggest that consumption of red and processed meat is associated with a significant risk of colorectal cancer, cardiovascular disease and diabetes. Therefore, an electronic search was conducted to identify clinical studies investigating the potential association between the risk of venous thrombosis and consumption of red or processed meat. Seven articles were finally included in this review, 6 prospective studies and 1 case-control investigation. Taken together, the evidence of the current scientific literature suggests that whether or not a pathophysiological link may exist between red or processed meat consumption and venous thrombosis, the association is definitely weak, since it was found to be non-statistically significant in four prospective cohort studies, marginally significant in one prospective cohort study and highly significant in the remaining prospective cohort study. In the single case-control study, the risk was also found to be non-statistically significant. Although further studies will be needed to definitely establish the existence of a thrombotic risk associated with different subtypes of red or processed meat, it seems premature to conclude that a reduced consumption of red and processed meat lowers the risk of VTE.

Rice consumption and risk of cardiovascular disease: results from a pooled analysis of 3 U.S. cohorts

BACKGROUND

Health concerns have been raised about rice consumption, which may significantly contribute to arsenic exposure. However, little is known regarding whether habitual rice consumption is associated with cardiovascular disease (CVD) risk.

OBJECTIVE

We examined prospectively the association of white rice and brown rice consumption with CVD risk.

DESIGN

We followed a total of 207,556 women and men [73,228 women from the Nurses' Health Study (1984-2010), 92,158 women from the Nurses' Health Study II (1991-2011), and 42,170 men from the Health Professionals Follow-Up Study (1986-2010)] who were free of CVD and cancer at baseline. Validated semiquantitative food-frequency questionnaires were used to assess consumption of white rice, brown rice, and other food items. Fatal and nonfatal CVD (coronary artery disease and stroke) was confirmed by medical records or self-reports.

RESULTS

During 4,393,130 person-years of follow-up, 12,391 cases of CVD were identified. After adjustment for major CVD risk factors, including demographics, lifestyle, and other dietary intakes, rice consumption was not associated with CVD risk. The multivariable-adjuted HR of developing CVD comparing ≥5 servings/wk with <1 serving/wk was 0.98 (95% CI: 0.84, 1.14) for white rice, 1.01 (0.79, 1.28) for brown rice, and 0.99 (0.90, 1.08) for total rice. To minimize the potential impact of racial difference in rice consumption, we restricted the analyses to whites only and obtained similar results: the HRs of CVD for ≥5 servings/wk compared with <1 serving/wk were 1.04 (95% CI: 0.88, 1.22) for white rice and 1.01 (0.78, 1.31) for brown rice.

CONCLUSIONS

Greater habitual consumption of white rice or brown rice is not associated with CVD risk. These findings suggest that rice consumption may not pose a significant CVD risk among the U.S. population when consumed at current amounts. More prospective studies are needed to explore these associations in other populations.

Familial Transmission of Venous Thromboembolism

Background—

Venous thromboembolism (VTE) clusters in families, but the familial risk of VTE has not been determined among adoptees. The aim was to disentangle the contributions of genetic and environmental factors to the familial transmission of VTE.

Methods and Results—

The Swedish Multi-Generation Register was used to follow all Swedish-born adoptees born from 1932 to 2004 (n=80,214) between January 1, 1964, and December 31, 2010, for VTE. The risk of VTE was estimated in adoptees with ≥1 biological parent with VTE compared with adoptees without a biological parent with VTE. The risk of VTE was also estimated in adoptees with ≥1 adoptive parent with VTE compared with adoptees without an adoptive parent with VTE. Adoptees with ≥1 biological parent with VTE (n=137) were more likely to have VTE than adoptees without a biological parent with VTE (standardized incidence ratio) 1.51 (95% confidence interval, 1.27–1.79). The standardized incidence ratio for VTE was highest for adoptees with a biological parent diagnosed with VTE before the age of 50 years (standardized incidence ratio=2.03, 1.24–3.14). In contrast, adoptees with ≥1 adoptive parent with VTE (n=156) were not at increased risk of VTE (standardized incidence ratio=1.07, 0.91–1.25).

Conclusions—

These novel findings suggest that genetic factors make a stronger contribution to the familial transmission of VTE from parents to offspring than family environmental factors.

High fish plus fish oil intake is associated with slightly reduced risk of venous thromboembolism: the Tromsø Study

Current knowledge of the effect of fish consumption on risk of venous thromboembolism (VTE) is scarce and diverging. Therefore, the purpose of the present study was to investigate the impact of fish consumption and fish oil supplements on the risk of VTE in a population-based cohort. Weekly intake of fish for dinner and intake of fish oil supplements during the previous year were registered in 23,621 persons aged 25-97 y who participated in the Tromsø Study from 1994 to 1995. Incident VTE events were registered throughout follow-up (31 December 2010). Cox-regression models were used to calculate HRs for VTE, adjusted for age, body mass index, sex, triglycerides, HDL cholesterol, physical activity, and education level. During a median of 15.8 y of follow-up there were 536 incident VTE events. High fish consumption was associated with a slightly reduced risk of VTE. Participants who ate fish ≥3 times/wk had 22% lower risk of VTE than those who consumed fish 1-1.9 times/wk (multivariable HR: 0.78; 95% CI: 0.60, 1.01; P = 0.06). The addition of fish oil supplements strengthened the inverse association with risk of VTE. Participants who consumed fish ≥3 times/wk who additionally used fish oil supplements had 48% lower risk than those who consumed fish 1-1.9 times/wk but did not use fish oil supplements (HR: 0.52; 95% CI: 0.34, 0.79; P = 0.002). In conclusion, a high weekly intake (≥3 times/wk) of fish was associated with a slightly reduced risk of VTE, and the addition of fish oil supplements strengthened the inverse effect.

Fish intake and venous thromboembolism: a Danish follow-up study

INTRODUCTION

Data on the association between fish intake and venous thromboembolism (VTE) is sparse and inconsistent.

OBJECTIVE

To investigate whether intake of total, lean or fatty fish is associated with development of incident VTE.

MATERIAL AND METHODS

This study is based on the Danish follow-up study Diet, Cancer and Health including 27,178 men and 29,876 women aged 50-64 with no history of cancer. Participants were included between 1993 and 1997 and followed through 2006. Information on fish intake and potential confounders was obtained from baseline questionnaires. The outcome was incident VTE (all) and idiopathic VTE. We used Cox proportional hazard models with age as time axis. Separate analyses were performed for men and women. Adjustment was made for BMI, smoking, physical activity, energy intake and women's use of hormone replacement therapy.

RESULTS

During follow-up, 641 incident VTE events were verified. We found no association between total fish intake and VTE, but moderate intake of fatty fish was associated with a statistically non-significant 20-40% lower risk of idiopathic VTE compared with consumption of a low intake (less than 8g) of fatty fish per day.

CONCLUSIONS

Intake of neither total nor fatty fish was statistically significantly associated with the incidence rate of VTE. However, intake of fatty fish may be associated with a reduction of the risk of idiopathic VTE.

Current issues surrounding the definition of trans-fatty acids: implications for health, industry and food labels

The definition of trans-fatty acids (TFA) was established by the Codex Alimentarius to guide nutritional and legislative regulations to reduce TFA consumption. Currently, conjugated linoleic acid (CLA) is excluded from the TFA definition based on evidence (primarily preclinical studies) implying health benefits on weight management and cancer prevention. While the efficacy of CLA supplements remains inconsistent in randomised clinical trials, evidence has emerged to associate supplemental CLA with negative health outcomes, including increased subclinical inflammation and oxidative stress (particularly at high doses). This has resulted in concerns regarding the correctness of excluding CLA from the TFA definition. Here we review recent clinical and preclinical literature on health implications of CLA and ruminant TFA, and highlight several issues surrounding the current Codex definition of TFA and how it may influence interpretation for public health. We find that CLA derived from ruminant foods differ from commercial CLA supplements in their isomer composition/distribution, consumption level and bioactivity. We conclude that health concerns associated with the use of supplemental CLA do not repudiate the exclusion of all forms of CLA from the Codex TFA definition, particularly when using the definition for food-related purposes. Given the emerging differential bioactivity of TFA from industrial v. ruminant sources, we advocate that regional nutrition guidelines/policies should focus on eliminating industrial forms of trans-fat from processed foods as opposed to all TFA per se.

Mediterranean style diet and 12-year incidence of cardiovascular diseases: the EPIC-NL cohort study

Background

A recent meta-analysis showed that a Mediterranean style diet may protect against cardiovascular diseases (CVD). Studies on disease-specific associations are limited. We evaluated the Mediterranean Diet Score (MDS) in relation to incidence of total and specific CVDs.

Methods

The EPIC-NL Study is a cohort of 40,011 men and women aged 20–70 years, examined between 1993 and 1997, with 10–15 years of follow-up. Diet was assessed with a validated food frequency questionnaire and the MDS was based on the daily intakes of vegetables, fruits, legumes and nuts, grains, fish, fatty acids, meat, dairy, and alcohol. Cardiovascular morbidity and mortality were ascertained through linkage with national registries. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) adjusted for age, sex, cohort, smoking, physical activity, total energy intake, and educational level.

Results

In 34,708 participants free of CVD at baseline, 4881 CVD events occurred, and 487 persons died from CVD. A two unit increment in MDS (range 0–9) was inversely associated with fatal CVD (HR: 0.78; 95%CI: 0.69–0.88), total CVD (HR: 0.95 (0.91–0.98)), myocardial infarction (HR: 0.86 (0.79–0.93)), stroke (HR: 0.88 (0.78–1.00)), and pulmonary embolism (HR: 0.74 (0.59–0.92)). The MDS was not related to incident angina pectoris, transient ischemic attack and peripheral arterial disease.

Conclusion

Better adherence to a Mediterranean style diet was more strongly associated with fatal CVD than with total CVD. Disease specific associations were strongest for incident myocardial infarction, stroke and pulmonary embolism.

Invited commentary: Diet and risk of venous thromboembolism--a hard nut to crack

Recently, there has been interest in determining whether diet is associated with the risk of venous thromboembolism. The article by Varraso et al. (Am J Epidemiol. 2012;175(2):114-126) published in this issue of the Journal is an important contribution to this literature. In this commentary, the author discusses the findings of Varraso et al. within the context of the existing literature and posits epidemiologic explanations for why investigators might have failed to identify strong associations between diet and venous thromboembolism.

The effects of obesity on venous thromboembolism: A review

Obesity has emerged as a global health issue that is associated with wide spectrum of disorders, including coronary artery disease, diabetes mellitus, hypertension, stroke, and venous thromboembolism (VTE). VTE is one of the most common vascular disorders in the United States and Europe and is associated with significant mortality. Although the association between obesity and VTE appears to be moderate, obesity can interact with other environmental or genetic factors and pose a significantly greater risk of VTE among individuals who are obese and who are exposed simultaneously to several other risk factors for VTE. Therefore, identification of potential interactions between obesity and certain VTE risk factors might offer some critical points for VTE interventions and thus minimize VTE morbidity and mortality among patients who are obese. However, current obesity measurements have limitations and can introduce contradictory results in the outcome of obesity. To overcome these limitations, this review proposes several future directions and suggests some avenues for prevention of VTE associated with obesity as well.