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Contains fulltext : 232751.pdf (Publisher’s version ) (Closed access) Clinical research in venous thromboembolism (VTE) is hindered by variability in the collection and reporting of data and outcomes. A consistent data language facilitates efficiencies, leads to higher quality data, and permits between-study comparisons and evidence synthesis. The International Society on Thrombosis and Haemostasis (ISTH) launched an international task force of more than 50 researchers to develop common data elements for clinical research in venous thromboembolism. The project was organized in seven working groups, each focusing on a topic area: General Core Data Elements; Anticoagulation and Other Therapies; Chronic VTE and Functional Outcomes; Diagnosis of VTE; Malignancy; Perioperative; and Predictors of VTE. The groups met via teleconference to collaboratively identify key data elements and develop definitions and data standards that were structured in a project-specific taxonomy. A Steering Committee met by teleconference and in-person to determine the overall scope of the project and resolve questions arising from the working groups. ISTH held an open public comment period to enable broader stakeholder involvement and feedback. The common data elements were then refined by the working groups to create a set of 512 unique data elements that are publicly available at http://isth.breakthrough.healthcare. The ISTH VTE Common Data Elements are intended to be a living project with ongoing curation, future expansion, and adaptation to meet the needs of the thrombosis and hemostasis research community.

IntroductionAfter deep vein thrombosis, up to 50% of patients develop post-thrombotic syndrome (PTS). PTS is a chronic condition that reduces quality of life (QOL). Cornerstones of PTS treatment include the use of elastic compression stockings but this treatment is usually incompletely effective and is burdensome. Venoactive drugs have been reported to be effective to treat chronic venous insufficiency (CVI). However, the level of evidence supporting their use in CVI in general and in PTS in particular is low.Methods and analysisThe MUFFIN-PTS trial is an academic, publically funded, multicentre randomised placebo-controlled trial assessing the efficacy of micronised purified flavonoid fraction (MPFF, Venixxa), a venoactive drug, to treat PTS. Eighty-six patients with PTS (Villalta score (VS) ≥5) and experiencing at least two of the following PTS manifestations among daily leg heaviness, cramps, pain or oedema will be randomised to receive 1000 mg of oral MPFF or a similar appearing placebo for 6 months, in addition to their usual PTS treatment. Total study follow-up will be 9 months, with visits at inclusion/baseline, 3, 6 and 9 months. Primary outcome is the proportion of patients with improvement in VS in each group, where improvement is defined as a decrease of at least 30% in VS or a VS Ethics and disseminationPrimary ethics approval was received from Centre intégré universitaire de santé et de services sociaux (CIUSSS) West-Central Montreal Research Ethics Board. Results of the study will be disseminated via peer-reviewed publications and presentations at scientific conferences.Trial registration numberClinicalTrials.gov Registry (NCT03833024); Pre-results.

Isolated distal deep-vein thrombosis (DVT, infra-popliteal DVT without pulmonary embolism) is a common presentation of venous thromboembolism (VTE), but was an exclusion criterion from the pivotal trials that validated the use of direct oral anticoagulants (DOACs) for VTE management. Using data from the international RIETE registry, we analyzed and compared trends in DOACs prescription between January 2011 and June 2019 in patients with distal vs. proximal DVT. We also assessed DOACs' prescriptions and compared the outcomes (VTE recurrence, bleeding and death) of distal DVT patients treated with DOACs vs. those on vitamin K antagonists (VKAs). 2308 patients with distal DVT and 11,364 patients with proximal DVT were included in the current analysis. DOACs were more frequently prescribed in patients with distal than proximal DVT (25% vs. 16%, p < 0.001). DOACs use increased sharply during the observation period (P < 0.001 for trend). In 2018, 56% of patients with distal DVT received DOACs. Distal DVT patients treated with rivaroxaban or edoxaban received the dose recommended for VTE management in most (> 85%) cases. Patients treated with apixaban were older, more likely to have underlying conditions than patients treated with rivaroxaban and, in most cases (> 75%), did not receive the recommended 1-week loading dose for acute VTE management. Outcomes between distal DVT patients treated with VKAs or DOACs appeared to be similar. In patients with distal DVT, DOACs have become the most common anticoagulant regimen. Specific trials are needed to determine the optimal DOACs dose regimen for treatment of distal DVT.

Summary Objectives To assess: (1) lower limb primary lymphedema or post-thrombotic syndrome patient's pathway in terms of health care professional use and (2) if aetiology of edema has an impact on this pathway. Methods Ancillary survey of the transversal prospective CHROEDEM pilot study. Forty patients with either lower limb primary lymphedema or post-thrombotic syndrome were invited to participate. Results Seventy-five percent of primary lymphedema patients and 50% of post-thrombotic patients benefited from a multidisciplinary management (P = 0.10) including the general practitioner, the vascular medicine physician and either a physiotherapist (particularly in case of primary lymphedema), a registered nurse (particularly in case of post-thrombotic syndrome). Main ambulatory health care professionals’ correspondent of hospital-based vascular medicine physicians were general practitioners (80%) in post-thrombotic patients, and general practitioners (60%) and physiotherapists (45%) in primary lymphedema patients. Pharmacists were also involved in patient education. Conclusion Management of primary lymphedema and post-thrombotic related chronic edema is usually multidisciplinary. General practitioners and vascular medicine physicians are the cornerstones of this management, that also involves the physiotherapist in case of primary lymphedema and in a lesser extent the registered nurse and the pharmacist. This suggests that these five healthcare professional should play a key role in case of development of standardized patient pathways for primary lymphedema and post-thrombotic syndrome.

International audience; The post-thrombotic syndrome (PTS) is a form of chronic venous insufficiency secondary to prior deep vein thrombosis (DVT). It affects up to 50% of patients after proximal DVT. There is no effective treatment of established PTS and its management lies in its prevention after DVT. Optimal anticoagulation is key for PTS prevention. Among anticoagulants, low-molecular-weight heparins have anti-inflammatory properties, and have a particularly attractive profile. Elastic compression stockings (ECS) may be helpful for treating acute DVT symptoms but their benefits for PTS prevention are debated. Catheter-directed techniques reduce acute DVT symptoms and might reduce the risk of moderate–severe PTS in the long term in patients with ilio-femoral DVT at low risk of bleeding. Statins may decrease the risk of PTS, but current evidence is lacking. Treatment of PTS is based on the use of ECS and lifestyle measures such as leg elevation, weight loss and exercise. Venoactive medications may be helpful and research is ongoing. Interventional techniques to treat PTS should be reserved for highly selected patients with chronic iliac obstruction or greater saphenous vein reflux, but have not yet been assessed by robust clinical trials.

International audience; After a proximal lower limb deep vein thrombosis (DVT; involving popliteal veins or above), up to 40% of patients develop postthrombotic syndrome (PTS) as assessed by the Villalta scale (VS). Poor initial anticoagulant treatment is a known risk factor for PTS. The risk of developing PTS after isolated distal DVT (infra-popliteal DVT without pulmonary embolism), and the impact of anticoagulant treatment on this risk, are uncertain.Methods: Long-term follow-up of CACTUS double-blind trial comparing 6 weeks of s.c. nadroparin (171 IU/kg/d) versus s.c. placebo for a first symptomatic isolated distal DVT. At least 1 year after randomization, patients had a PTS assessment in clinic or by phone using the VS.Results: After a median follow-up of 6 years, PTS was present in 30% (n = 54) of the 178 patients who had a PTS assessment. PTS was moderate or severe in 24% (n = 13) of cases. There was no statistically significant difference in prevalence of PTS in the nadroparin versus placebo groups (29% versus 32%, P = .6), except in patients without evidence of primary chronic venous insufficiency (9% versus 24%, P = .04). Rates of venous thromboembolism recurrence during follow-up in the nadroparin and placebo groups were, respectively, 8% (n = 7) and 14% (n = 13; P = .2).Conclusion: After a first isolated distal DVT, the risk of PTS is substantial but much lower than that reported after proximal DVT. Anticoagulation with nadroparin doesn't provide any clear benefit to prevent PTS, except in patients without preexisting chronic venous insufficiency. Anticoagulation might be associated with a lower risk of venous thromboembolism recurrence.

International audience; Background: Distal deep vein thrombosis (infrapopliteal DVT without proximal DVT or pulmonary embolism [PE]) generally shares the same triggering risks factors as proximal DVT. In women of childbearing age, a frequent triggering risk factor is the use of combined oral contraceptive (COC) pills. However, data on the epidemiology and long-term outcomes of COC-associated distal DVT are lacking.Objectives: To assess the epidemiology and long-term outcomes of COC-associated distal DVT.Methods: Using data from the OPTIMEV (Optimisation de l'Interrogatoire dans l'évaluation du risque thrombo-Embolique Veineux [Optimization of Interrogation in the Assessment of Thromboembolic Venous Risk]) multicenter cohort study of patients with objectively confirmed venous thromboembolism (VTE) enrolled between 2004 and 2006, we assessed in nonpregnant or postpartum women aged ≤ 50 years without cancer or history of VTE (i) proportion of COC-associated distal DVTs among women with distal DVTs and among women with COC-associated VTEs (distal DVT, proximal DVT, or PE) and (ii) 3-year incidence of death, bleeding, and VTE recurrence.Results: COC-associated distal DVTs (n = 54) represented 43.9% of all distal DVTs and 51.9% of COC-associated VTEs. All but one woman with a COC-associated distal DVT received therapeutic anticoagulation for a median of 3 months. At 3-year follow-up, all women with COC-associated distal DVTs were alive, and none had bled during anticoagulant treatment or had experienced a DVT or PE recurrence after stopping anticoagulants. Similar results were found in patients with COC-associated proximal DVT and PE: The VTE recurrence rate was 1.7% per patient-year (PY) and 0% PY, respectively, and there were no deaths or major bleeds in either group.Conclusions: Distal DVT was the most frequent clinical presentation of COC-associated VTE and had similarly favorable long-term outcomes as other COC-associated VTE.

International audience; In its promotion and scientific program, the French Society for Vascular Medicine (SFMV) has addressed a consensus statement regarding the “Unresolved questions on venous thromboembolic disease”.Indeed, several international guidelines were already proposed regarding management of venous thromboembolic disease, but many questions remain without clear established recommendations.In this context, a task force, mandated by the French society, has addressed issues regarding: Diagnosis of lower-limb deep vein thrombosis recurrence; Therapeutic management of superficial vein thrombosis; Therapeutic management of distal vein thrombosis; Therapeutic management of post thrombotic syndrome.The purpose of the consensus process was to provide expert guidance to answer to these specific cases that are not currently entirely resolved.For each of the identified questions, a systematic review of the available literature through Medline (1980–2017) and the Cochrane Central Register of Controlled Trials analysis was performed. References in included studies and previous systematic reviews were also reviewed for additional potential studies.A multidisciplinary expert consensus group from 19 participants with expertise in the areas of vascular medicine, haematology, internal medicine, methodology, identified important clinical challenges for each issue. A steering committee of 5 to 6 participants was designed for each issue and developed the initial statements, associated with summaries of the evidence graded according to level of evidence

Essentials Management of patients with calf deep vein thrombosis remains controversial. We conducted a post-hoc analysis of a placebo controlled LMWH randomized clinical trial. Pain was assessed using visual analogue scale at inclusion, one and six weeks. There was no difference in pain control between the two arms. SUMMARY: Background The optimal management of distal deep vein thrombosis (DVT) is highly debated. The only available placebo-controlled trial suggested the absence of clear benefit of anticoagulation. Many physicians feel that, beyond preventing thromboembolic complications, anticoagulation with low-molecular-weight heparin (LMWH) has the potential to improve pain control. Objectives To analyze whether LMWHs decrease pain in patients with distal deep vein thrombosis. Patients and methods Two-hundred and fifty-two patients included in a multicenter, placebo-controlled, randomized clinical trial of LMWH in patients with acute distal DVT and who were asked to rate their pain at inclusion and at each medical visit, using a visual analogue pain scale (VAS). Results One hundred and thirty patients were randomized in the therapeutic nadroparin arm and 122 patients were randomized in the placebo arm. Mean VAS values were 4.6 (standard deviation [SD] 2.5) at inclusion, 2.1 (SD 2.0) at 1 week and 0.4 (SD 1.2) at 6 weeks. We calculated the individual variation in VAS between inclusion and 1 week in patients in whom VAS was available at the two study time-points. There was no difference in the mean VAS reduction between patients treated with therapeutic nadroparin (n = 106) and with placebo (n = 109): -2.6 (SD 2.4) vs. -2.3 (SD 2.0) after 1 week and -4.4 (SD 2.8) vs. -4.0 (SD 2.4) after 6 weeks, respectively. The use of compression stockings was associated with a reduction in pain. Conclusion These data suggests that LMWH use does not improve pain control as compared with placebo in patients with acute distal DVT.

In patients with deep-vein thrombosis (DVT) in the lower limbs, venous ulcer is the most debilitating and end-stage clinical expression of the post-thrombotic syndrome (PTS). To date, risk factors for PTS-related ulcer in DVT patients have not been identified.We used the international observational RIETE registry to assess the evolution of PTS signs and symptoms during a 3-year follow-up period and to identify independent predictors of PTS ulcer at 1 year in patients with acute DVT.Among 1,866 eligible patients, cumulative rates of PTS ulcer at 1, 2 and 3 years were 2.7% (n = 50), 4.3% (n = 54) and 7.1% (n = 60), respectively. The proportion of patients with PTS symptoms at 1, 2 or 3 years remained stable (≈40%), while the proportion of patients with PTS signs increased slightly over time (from 49 to 53%). Prior history of venous thromboembolism (VTE) (odds ratio [OR] = 5.5 [2.8–10.9]), diabetes (OR = 2.3 [1.1–4.7]), pre-existing leg varicosities (OR = 3.2 [1.7–6.1]) and male sex (OR = 2.5 [1.3–5.1]) independently increased the risk of PTS ulcer at 1 year. Obesity also increased the risk but failed to reach statistical significance (OR = 1.8 [0.9–3.3]). DVT treatment characteristics (duration or drug) did not influence the risk.Our results evidence that after acute DVT, pre-existing leg varicosities, prior venous thromboembolism, diabetes and male gender independently increased the risk for PTS ulcer. This suggests that clinicians should consider strategies aimed to prevent ulcers in high-risk DVT patients, such as preventing VTE recurrence, use of stockings in those with pre-existing venous insufficiency, careful monitoring of diabetic patients and encouraging weight loss in obese patients.

International audience; BACKGROUND: Cancer patients who develop a deep-vein thrombosis (DVT) or a pulmonary embolism (PE) are at higher risk of death than similar cancer patients who do not develop DVT or PE. The impact of isolated superficial venous thrombosis (SVT) (i.e. without DVT or PE) on the prognosis of cancer patients is unknown. METHODS: Data from the OPTIMEV, multicentre, observational study, to compare at 3 years the incidences of death, DVT-PE recurrence and bleeding of cancer patients with objectively confirmed SVT vs. cancer patients with DVT (matched 1:2 on age, sex, cancer stage) and vs. patients with SVT without cancer (matched 1:3 on age and sex). RESULTS: Cancer patients with SVT (n = 34) had a high risk of death (23.2%patient-year(PY)), that was similar to that of cancer patients with DVT (aHR = 1.0[0.6-1.9]) and higher to that of SVT patients without cancer (aHR = 9.0[3.5-23.1]). Cancer patients with SVT received anticoagulants for a median duration of 45 days and had a high risk of DVT-PE recurrence (6.0%PY), similar to that of cancer patients with DVT (adjusted cause-specific HR (aCHR) = 1.5[0.4-5.8]) and higher to that of SVT patients without cancer (aCHR = 2.9[0.7-11.9]). In our population, venous thrombosis on varicose veins was associated with a lower risk of death (aHR = 0.6[0.3-1.0]) and DVT-PE recurrence (aCHR = 0.6[0.2-1.7]). CONCLUSION: Our results suggest that cancer patients with SVT have a poor prognosis, similar to that of patients with cancer-related DVT. The high rate of DVT-PE recurrence suggests that such patients may need longer duration of anticoagulant treatment.

International audience

International audience; BACKGROUND:The efficacy and safety of anticoagulant treatment is not established for patients with acute symptomatic deep vein thrombosis (DVT) of the calf. We aimed to assess whether therapeutic anticoagulation is superior to placebo in patients with symptomatic calf DVT.METHODS:In this randomised, double-blind, placebo-controlled trial, we enrolled low-risk outpatients (without active cancer or previous venous thromboembolic disease) with a first acute symptomatic DVT in the calf from 23 university medical centres or community medical clinics in Canada, France, and Switzerland. We randomly assigned (1:1) patients to receive either the low-molecular-weight heparin nadroparin (171 UI/kg, subcutaneously, once a day) or placebo (saline 0·9%, subcutaneously, once a day) for 6 weeks (42 days). Central randomisation was done using a computer-generated randomisation list, stratified by study centre. Random allocation sequences of variable block size were centrally determined by an independent research clinical centre. Study staff, patients, and outcome assessors (central adjudication committee) were masked to group assignment. Numbered boxes of active drug or placebo were provided to pharmacies in identical packaging. All patients were prescribed compression stockings and followed up for 90 days. The primary efficacy outcome was a composite measure of extension of calf DVT to proximal veins, contralateral proximal DVT, and symptomatic pulmonary embolism at day 42 in the modified intention-to-treat population. The primary safety outcome was major or clinically relevant non-major bleeding at day 42. The trial was registered with ClinicalTrials.gov, number NCT00421538.FINDINGS:Between Feb 1, 2008, and Nov 30, 2014, we screened 746 patients, enrolling 259 patients (50% of the prespecified sample size), before the trial steering committee terminated the trial because of expiry of study drug and slow recruitment. The intention-to-treat analysis population comprised 122 patients in the nadroparin group and 130 in the placebo group. There was no significant difference between the groups in the composite primary outcome, which occurred in four patients (3%) in the nadroparin group and in seven (5%) in the placebo group (risk difference -2·1%, 95% CI -7·8 to 3·5; p=0·54). Bleeding occurred in five patients (4%) in the nadroparin group and no patients in the placebo group (risk difference 4·1, 95% CI 0·4 to 9·2; p=0·0255). In the nadroparin group one patient died from metastatic pancreatic cancer and one patient was diagnosed with heparin-induced thrombocytopenia type 2.INTERPRETATION:Nadroparin was not superior to placebo in reducing the risk of proximal extension or venous thromboembolic events in low-risk outpatients with symptomatic calf DVT, but did increase the risk of bleeding. Avoidance of systematic anticoagulation for calf DVT could have a substantial impact on individual patients and from a public health perspective.FUNDING:Swiss National Science Foundation, the Programme Hospitalier de Recherche Clinique in France, and the Canadian Institutes of Health Research.

International audience; The post-thrombotic syndrome (PTS), which refers to chronic clinical manifestations of venous insufficiency after a deep vein thrombosis (DVT), is a frequent occurrence. Because treatment options for PTS are limited, its management mainly relies on the prevention of its occurrence after DVT. Among identified predictors of PTS, extensive proximal location of DVT directly modifies the treatment of DVT because of the possibility of performance of complementary endovascular techniques. The association between poor international normalized ratio control and subsequent PTS should encourage physicians to perform frequent and regular international normalized ratio monitoring of patients receiving vitamin K antagonists. Other identified PTS risk factors are ipsilateral DVT recurrence, older age, pre-existing primary venous insufficiency, obesity, and residual venous obstruction, but these are less amenable to therapy. Because of their potential therapeutic implications, identification of biomarkers that are predictive of PTS such as markers of inflammation is crucial and such research is ongoing.

International audience; The post-thrombotic syndrome (PTS) is a frequent, potentially disabling complication of deep vein thrombosis (DVT) that reduces quality of life and is costly. Clinical manifestations include symptoms and signs such as leg pain and heaviness, edema, redness, telangiectasia, new varicose veins, hyperpigmentation, skin thickening and in severe cases, leg ulcers. The best way to prevent PTS is to prevent DVT with pharmacologic or mechanical thromboprophylaxis used in high risk patients and settings. In patients whose DVT is treated with a vitamin K antagonist, subtherapeutic INRs should be avoided. We do not suggest routine use of elastic compression stockings (ECS) after DVT to prevent PTS, but in patients with acute DVT-related leg swelling that is bothersome, a trial of ECS is reasonable. We suggest that selecting patients for catheter-directed thrombolytic techniques be done on a case-by-case basis, with a focus on patients with extensive thrombosis, recent symptoms onset, and low bleeding risk, who are seen at experienced hospital centers. For patients with established PTS, we suggest prescribing 20-30 mm Hg knee-length ECS to be worn daily. If ineffective, a stronger pressure stocking can be tried. We suggest that intermittent compression devices or pneumatic compression sleeve units be tried in patients with moderate-to-severe PTS whose symptoms are inadequately controlled with ECS alone. We suggest that a supervised exercise training program for 6 months or more is reasonable for PTS patients who can tolerate it. We suggest that management of post-thrombotic ulcers should involve a multidisciplinary approach. We briefly discuss upper extremity PTS and PTS in children.

International audience; Epidemiological studies have been consistent in showing that cigarette smoking is inversely associated with Parkinson's disease (PD), whereas pesticide use is positively associated with PD. However, the relationship between PD and cigarette smoking remains poorly understood. Our objective was to study the relationship between cigarette smoking and PD in a population characterized by a high prevalence of pesticide exposure. This case-control study was carried out among subjects enrolled in the Mutualite Sociale Agricole, the French health insurance organization for workers connected to the agricultural world. We included 247 cases and 676 controls matched on age, sex, and region of residency. Information on smoking was obtained through in-person interviews. Pesticide exposure was assessed using a case-by-case expert evaluation procedure. We found an inverse relationship between ever cigarette smoking and PD (odds ratio [OR] = 0.6; 95% confidence interval [CI] = 0.4-0.9). The strength of this association increased with the number of pack-years. This relationship was present even when smoking was considered as long as 40 years before PD onset. An inverse association was also present among subjects professionally exposed to pesticides (OR = 0.5; 95% CI = 0.3-0.8) and was independent of the duration of exposure among men. We confirm the inverse association between cigarette smoking and PD in a population characterized by a high prevalence of professional pesticide exposure. The relationship between PD and cigarette smoking was not significantly modified or confounded by exposure to pesticides.

Background A current debate concerning suspected superficial vein thrombosis (SVT) focuses on the need of performing a compression ultrasound (CUS) exploration for confirming the diagnosis of SVT. This study was conducted to determine the clinical relevance and optimal CUS exploration in patients with symptomatic SVT. Methods We analyzed the characteristics of SVT and concomitant deep vein thrombosis (DVT) in patients included in the Prospective Observational Superficial Thrombophlebitis (POST) multicenter, observational prospective study. All patients underwent complete bilateral lower limb CUS, exploring both the superficial and deep venous systems. Results A total of 844 patients with clinical symptoms of SVT were recruited, of which 99 isolated SVTs (21.4%) had saphenofemoral/popliteal junction involvement, and 198 (23.5%) had a concomitant DVT, with 41.8% of them proximal DVTs. In 83 patients (41.9%), DVT and SVT were not contiguous. Five of 639 patients (1%) had an isolated contralateral DVT (ie, not bilateral). Age ≥75 years (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.6-3.4), inpatient status (OR, 5.4; 95% CI, 3.4-8.7), a personal history of DVT or pulmonary embolism (OR, 1.8; 95% CI, 1.2-2.8), and SVT on nonvaricose veins (OR, 3.3; 95% CI, 2.1-5.0) were significantly and independently associated with an increased risk of concomitant DVT. Half of the patients exhibited none of these risk factors, and the prevalence of concomitant DVT dropped to 11%. Conclusions In patients with symptomatic SVT, a CUS exploration screening the whole venous system of the affected limb is useful because it provides information that has important consequences for the management of these patients.

International audience; BACKGROUND: The Saitohin gene has recently been identified in intron 9 of the Tau gene. Because an association between Parkinson's disease and Tau has been described, Saitohin represents a candidate gene for Parkinson's disease. OBJECTIVE: To test these two genes for their association with Parkinson's disease in a large community based case-control study. RESULTS: Cases (n = 208) were more often homozygotes for the Tau H1 haplotype than controls (n = 483; odds ratio (OR) = 1.71 (95% confidence interval, 1.20 to 2.43); p = 0.003), and the saitohin Q allele was in complete linkage disequilibrium with the H1 haplotype. This association was stronger among cases with Parkinson's disease onset below 65 years (< or =65 years: OR = 2.52 (1.49 to 4.25); p65 years: OR = 1.20 (0.73 to 1.98); p

International audience; Excess of nitric oxide (NO) has been shown to exert neurotoxic impacts in the brain. Moreover, inhibition of two NO-synthesizing enzymes, neuronal NOS (nNOS) and inducible NOS (iNOS), displays neuroprotective effects in the MPTP model of Parkinson's disease (PD). These data suggest a possible involvement of NOS as factors controlling the resistance of the nigral dopaminergic neurons to environmental insults. Therefore, we investigated whether polymorphisms present in these genes could contribute to the risk of developing PD. We carried out a community-based case-control study among subjects enrolled in the Mutualit?ociale Agricole, the French health insurance organization for workers connected to agriculture. Two-hundred and nine PD patients and 488 controls of European (mostly French) ancestry and matched for age, sex and region of residency were included in this study. Associations were observed with polymorphisms present in exon 22 of iNOS (OR for AA carriers=0.50, 95% CI=0.29-0.86, P=0.01) and in exon 29 of nNOS (OR for carriers of the T allele=1.53, 95% CI=1.08-2.16, P=0.02); no association was observed with a polymorphism in exon 18 of nNOS (OR for carriers of the T allele=1.20, 95% CI=0.85-1.69, P=0.30). Moreover, a significant interaction of the nNOS polymorphisms with current and ever cigarette smoking was found (nNOS 18, P=0.05; nNOS 29, P=0.04). All together, these data favour an involvement of these two genes as new modifier genes in PD.