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1.
Context  Basic research provides plausible mechanisms and observational studies suggest that apparently healthy persons, who self-select for high intakes of vitamin E through diet or supplements, have decreased risks of cardiovascular disease and cancer. Randomized trials do not generally support benefits of vitamin E, but there are few trials of long duration among initially healthy persons. Objective  To test whether vitamin E supplementation decreases risks of cardiovascular disease and cancer among healthy women. Design, Setting, and Participants  In the Women’s Health Study conducted between 1992 and 2004, 39 876 apparently healthy US women aged at least 45 years were randomly assigned to receive vitamin E or placebo and aspirin or placebo, using a 2 x 2 factorial design, and were followed up for an average of 10.1 years. Intervention  Administration of 600 IU of natural-source vitamin E on alternate days. Main Outcome Measures  Primary outcomes were a composite end point of first major cardiovascular event (nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death) and total invasive cancer. Results  During follow-up, there were 482 major cardiovascular events in the vitamin E group and 517 in the placebo group, a nonsignificant 7% risk reduction (relative risk [RR], 0.93; 95% confidence interval [CI], 0.82-1.05; P = .26). There were no significant effects on the incidences of myocardial infarction (RR,  1.01; 95% CI, 0.82-1.23; = .96) or stroke (RR, 0.98; 95% CI, 0.82-1.17; = .82), as well as ischemic or hemorrhagic stroke. For cardiovascular death, there was a significant 24% reduction (RR, 0.76; 95% CI, 0.59-0.98; = .03). There was no significant effect on the incidences of total cancer (1437 cases in the vitamin E group and 1428 in the placebo group; RR, 1.01; 95% CI, 0.94-1.08; P = .87) or breast (RR, 1.00; 95% CI, 0.90-1.12; P = .95), lung (RR, 1.09; 95% CI, 0.83-1.44; P = .52), or colon cancers (RR, 1.00; 95% CI, 0.77-1.31; P = .99). Cancer deaths also did not differ significantly between groups. There was no significant effect of vitamin E on total mortality (636 in the vitamin E group and 615 in the placebo group; RR, 1.04; 95% CI, 0.93-1.16; P = .53). Conclusions  The data from this large trial indicated that 600 IU of natural-source vitamin E taken every other day provided no overall benefit for major cardiovascular events or cancer, did not affect total mortality, and decreased cardiovascular mortality in healthy women. These data do not support recommending vitamin E supplementation for cardiovascular disease or cancer prevention among healthy women.   相似文献   

2.
Context  In patients with acute cardiogenic pulmonary edema noninvasive ventilation may reduce intubation rate, but the impact on mortality and the superiority of one technique over another have not been clearly established. Objective  To systematically review and quantitatively synthesize the short-term effect of noninvasive ventilation on major clinical outcomes. Data Sources  MEDLINE and EMBASE (from inception to October 2005) and Cochrane databases (library issue 4, 2005) were searched to identify relevant randomized controlled trials and systematic reviews published from January 1, 1988, to October 31, 2005. Study Selection and Data Extraction  Included trials were all parallel studies comparing noninvasive ventilation to conventional oxygen therapy in patients with acute pulmonary edema. Comparisons of different techniques, either continuous positive airway pressure (CPAP) or bilevel noninvasive pressure support ventilation (NIPSV), were also included. Data Synthesis  Fifteen trials were selected. Overall, noninvasive ventilation significantly reduced the mortality rate by nearly 45% compared with conventional therapy (risk ratio [RR], 0.55; 95% confidence interval [CI], 0.40-0.78; P = .72 for heterogeneity). The results were significant for CPAP (RR, 0.53; 95% CI, 0.35-0.81; P = .44 for heterogeneity) but not for NIPSV (RR, 0.60; 95% CI, 0.34-1.05; P = .76 for heterogeneity), although there were fewer studies in the latter. Both modalities showed a significant decrease in the "need to intubate" rate compared with conventional therapy: CPAP (RR, 0.40; 95% CI, 0.27-0.58; P = .21 for heterogeneity), NIPSV (RR, 0.48; 95% CI, 0.30-0.76; P = .24 for heterogeneity), and together (RR, 0.43; 95% CI, 0.32-0.57; P = .20 for heterogeneity). There were no differences in intubation or mortality rates in the analysis of studies comparing the 2 techniques. Conclusions  Noninvasive ventilation reduces the need for intubation and mortality in patients with acute cardiogenic pulmonary edema. Although the level of evidence is higher for CPAP, there are no significant differences in clinical outcomes when comparing CPAP vs NIPSV.   相似文献   

3.
Context  Basic research and observational evidence as well as results from trials of colon polyp recurrence suggest a role for aspirin in the chemoprevention of cancer. Objective  To examine the effect of aspirin on the risk of cancer among healthy women. Design, Setting, and Participants  In the Women’s Health Study, a randomized 2 x 2 factorial trial of aspirin and vitamin E conducted between September 1992 and March 2004, 39 876 US women aged at least 45 years and initially without previous history of cancer, cardiovascular disease, or other major chronic illness were randomly assigned to receive either aspirin or aspirin placebo and followed up for an average of 10.1 years. Intervention  A dose of 100 mg of aspirin (n=19 934) or aspirin placebo (n=19 942) administered every other day. Main Outcome Measures  Confirmed newly diagnosed invasive cancer at any site, except for nonmelanoma skin cancer. Incidence of breast, colorectal, and lung cancer were secondary end points. Results  No effect of aspirin was observed on total cancer (n = 2865; relative risk [RR], 1.01; 95% confidence interval [CI], 0.94-1.08; P = .87), breast cancer (n = 1230; RR, 0.98; 95% CI, 0.87-1.09; P = .68), colorectal cancer (n = 269; RR, 0.97; 95% CI, 0.77-1.24; P = .83), or cancer of any other site, with the exception of lung cancer for which there was a trend toward reduction in risk (n = 205; RR, 0.78; 95% CI, 0.59-1.03; P = .08). There was also no reduction in cancer mortality either overall (n = 583; RR, 0.95; 95% CI, 0.81-1.11; P = .51) or by site, except for lung cancer mortality (n = 140; RR, 0.70; 95% CI, 0.50-0.99; P = .04). No evidence of differential effects of aspirin by follow-up time or interaction with vitamin E was found. Conclusions  Results from this large-scale, long-term trial suggest that alternate day use of low-dose aspirin (100 mg) for an average 10 years of treatment does not lower risk of total, breast, colorectal, or other site-specific cancers. A protective effect on lung cancer or a benefit of higher doses of aspirin cannot be ruled out.   相似文献   

4.
Context  Sexually transmitted infections (STIs) are common in female sex workers (FSWs) and may enhance susceptibility to infection with human immunodeficiency virus type 1 (HIV-1). Objective  To examine regular antibiotic prophylaxis in FSWs as a strategy for reducing the incidence of bacterial STIs and HIV-1. Design, Setting, and Participants  Randomized, double-blind, placebo-controlled trial conducted between 1998-2002 among FSWs in an urban slum area of Nairobi, Kenya. Of 890 FSWs screened, 466 who were seronegative for HIV-1 infection were enrolled and randomly assigned to receive azithromycin (n = 230) or placebo (n = 236). Groups were well matched at baseline for sexual risk taking and STI rates. Intervention  Monthly oral administration of 1 g of azithromycin or identical placebo, as directly observed therapy. All participants were provided with free condoms, risk-reduction counseling, and STI case management. Main Outcome Measures  The primary study end point was incidence of HIV-1 infection. Secondary end points were the incidence of STIs due to Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Treponema pallidum, and Haemophilus ducreyi, as well as bacterial vaginosis. Analysis of herpes simplex virus type 2 (HSV-2) infection was performed post hoc. Results  Seventy-three percent of participants (n = 341) were followed up for 2 or more years or until they reached an administrative trial end point. Incidence of HIV-1 did not differ between treatment and placebo groups (4% [19 cases per 473 person-years of follow-up] vs 3.2% [16 cases per 495 person-years of follow-up] rate ratio [RR], 1.2; 95% CI, 0.6-2.5). Incident HIV-1 infection was associated with preceding infection with N gonorrhoeae (rate ratio [RR], 4.9; 95% CI, 1.7-14.3) or C trachomatis (RR, 3.0; 95% CI, 1.1-8.9). There was a reduced incidence in the treatment group of infection with N gonorrhoeae (RR, 0.46; 95% CI, 0.31-0.68), C trachomatis (RR, 0.38; 95% CI, 0.26-0.57), and T vaginalis (RR, 0.56; 95% CI, 0.40-0.78). The seroprevalence of HSV-2 infection at enrollment was 72.7%, and HSV-2 infection at baseline was independently associated with HIV-1 acquisition (RR, 6.3; 95% CI, 1.5-27.1). Conclusions  Despite an association between bacterial STIs and acquisition of HIV-1 infection, the addition of monthly azithromycin prophylaxis to established HIV-1 risk reduction strategies substantially reduced the incidence of STIs but did not reduce the incidence of HIV-1. Prevalent HSV-2 infection may have been an important cofactor in acquisition of HIV-1.   相似文献   

5.
Context  Drug intervention in placebo-controlled trials has been beneficial in isolated systolic hypertension. Objective  To test the hypothesis that losartan improves outcome better than atenolol in patients with isolated systolic hypertension and electrocardiographically documented left ventricular hypertrophy (ECG-LVH). Design  Double-blind, randomized, parallel-group study conducted in 1995-2001. Setting and Participants  A total of 1326 men and women aged 55 through 80 years (mean, 70 years) with systolic blood pressure of 160 to 200 mm Hg and diastolic blood pressure of less than 90 mm Hg (mean, 174/83 mm Hg) and ECG-LVH, recruited from 945 outpatient settings in the Nordic countries, the United Kingdom, and the United States. Interventions  Patients were randomly assigned to receive once-daily losartan (n = 660) or atenolol (n = 666) with hydrochlorothiazide as the second agent in both arms, for a mean of 4.7 years. Main Outcome Measure  Composite end point of cardiovascular death, stroke, or myocardial infarction. Results  Blood pressure was reduced by 28/9 and 28/9 mm Hg in the losartan and atenolol arms. The main outcome was reduced by 25% with losartan compared with atenolol, 25.1 vs 35.4 events per 1000 patient-years (relative risk [RR], 0.75; 95% confidence interval [CI], 0.56-1.01; P = .06, adjusted for risk and degree of ECG-LVH; unadjusted RR, 0.71; 95% CI, 0.53-0.95; P = .02). Patients receiving losartan had reductions in the following without a difference in the incidence of myocardial infarction: cardiovascular mortality (8.7 vs 16.9 events per 1000 patient-years; RR, 0.54; 95% CI, 0.34-0.87; P = .01), nonfatal and fatal stroke (10.6 vs 18.9 events per 1000 patient-years; RR, 0.60; 95% CI, 0.38-0.92; P = .02), new-onset diabetes (12.6 vs 20.1 events per 1000 patient-years; RR, 0.62; 95% CI, 0.40-0.97; P = .04), and total mortality (21.2 vs 30.2 events per 1000 patient-years; RR, 0.72; 95% CI, 0.53-1.00; P = .046). Losartan decreased ECG-LVH more than atenolol (P<.001) and was better tolerated. Conclusion  These data suggest that losartan is superior to atenolol for treatment of patients with isolated systolic hypertension and ECG-LVH.   相似文献   

6.
Obesity, weight gain, and the risk of kidney stones   总被引:8,自引:0,他引:8  
Taylor EN  Stampfer MJ  Curhan GC 《JAMA》2005,293(4):455-462
Context  Larger body size may result in increased urinary excretion of calcium, oxalate, and uric acid, thereby increasing the risk for calcium-containing kidney stones. It is unclear if obesity increases the risk of stone formation, and it is not known if weight gain influences risk. Objective  To determine if weight, weight gain, body mass index (BMI), and waist circumference are associated with kidney stone formation. Design, Setting, and Participants  A prospective study of 3 large cohorts: the Health Professionals Follow-up Study (N = 45 988 men; age range at baseline, 40-75 years), the Nurses’ Health Study I (N = 93 758 older women; age range at baseline, 34-59 years), and the Nurses’ Health Study II (N = 101 877 younger women; age range at baseline, 27-44 years). Main Outcome Measures  Incidence of symptomatic kidney stones. Results  We documented 4827 incident kidney stones over a combined 46 years of follow-up. After adjusting for age, dietary factors, fluid intake, and thiazide use, the relative risk (RR) for stone formation in men weighing more than 220 lb (100.0 kg) vs men less than 150 lb (68.2 kg) was 1.44 (95% confidence interval [CI], 1.11-1.86; P = .002 for trend). In older and younger women, RRs for these weight categories were 1.89 (95% CI, 1.52-2.36; P<.001 for trend) and 1.92 (95% CI, 1.59-2.31; P<.001 for trend), respectively. The RR in men who gained more than 35 lb (15.9 kg) since age 21 years vs men whose weight did not change was 1.39 (95% CI, 1.14-1.70; P = .001 for trend). Corresponding RRs for the same categories of weight gain since age 18 years in older and younger women were 1.70 (95% CI, 1.40-2.05; P<.001 for trend) and 1.82 (95% CI, 1.50-2.21; P<.001 for trend). Body mass index was associated with the risk of kidney stone formation: the RR for men with a BMI of 30 or greater vs those with a BMI of 21 to 22.9 was 1.33 (95% CI, 1.08-1.63; P<.001 for trend). Corresponding RRs for the same categories of BMI in older and younger women were 1.90 (95% CI, 1.61-2.25; P<.001 for trend) and 2.09 (95% CI, 1.77-2.48; P<.001 for trend). Waist circumference was also positively associated with risk in men (P = .002 for trend) and in older and younger women (P<.001 for trend for both). Conclusions  Obesity and weight gain increase the risk of kidney stone formation. The magnitude of the increased risk may be greater in women than in men.   相似文献   

7.
Context  Hypoxemia complicates the recovery of 30% to 50% of patients after abdominal surgery; endotracheal intubation and mechanical ventilation may be required in 8% to 10% of cases, increasing morbidity and mortality and prolonging intensive care unit and hospital stay. Objective  To determine the effectiveness of continuous positive airway pressure compared with standard treatment in preventing the need for intubation and mechanical ventilation in patients who develop acute hypoxemia after elective major abdominal surgery. Design and Setting  Randomized, controlled, unblinded study with concealed allocation conducted between June 2002 and November 2003 at 15 intensive care units of the Piedmont Intensive Care Units Network in Italy. Patients  Consecutive patients who developed severe hypoxemia after major elective abdominal surgery. The trial was stopped for efficacy after 209 patients had been enrolled. Interventions  Patients were randomly assigned to receive oxygen (n = 104) or oxygen plus continuous positive airway pressure (n = 105). Main Outcome Measures  The primary end point was incidence of endotracheal intubation; secondary end points were intensive care unit and hospital lengths of stay, incidence of pneumonia, infection and sepsis, and hospital mortality. Results  Patients who received oxygen plus continuous positive airway pressure had a lower intubation rate (1% vs 10%; P = .005; relative risk [RR], 0.099; 95% confidence interval [CI], 0.01-0.76) and had a lower occurrence rate of pneumonia (2% vs 10%, RR, 0.19; 95% CI, 0.04-0.88; P = .02), infection (3% vs 10%, RR, 0.27; 95% CI, 0.07-0.94; P = .03), and sepsis (2% vs 9%; RR, 0.22; 95% CI, 0.04-0.99; P = .03) than did patients treated with oxygen alone. Patients who received oxygen plus continuous positive airway pressure also spent fewer mean (SD) days in the intensive care unit (1.4 [1.6] vs 2.6 [4.2], P = .09) than patients treated with oxygen alone. The treatments did not affect the mean (SD) days that patients spent in the hospital (15 [13] vs 17 [15], respectively; P = .10). None of those treated with oxygen plus continuous positive airway pressure died in the hospital while 3 deaths occurred among those treated with oxygen alone (P = .12). Conclusion  Continuous positive airway pressure may decrease the incidence of endotracheal intubation and other severe complications in patients who develop hypoxemia after elective major abdominal surgery.   相似文献   

8.
Context  Experimental and epidemiological data suggest that vitamin E supplementation may prevent cancer and cardiovascular events. Clinical trials have generally failed to confirm benefits, possibly due to their relatively short duration. Objective  To evaluate whether long-term supplementation with vitamin E decreases the risk of cancer, cancer death, and major cardiovascular events. Design, Setting, and Patients  A randomized, double-blind, placebo-controlled international trial (the initial Heart Outcomes Prevention Evaluation [HOPE] trial conducted between December 21, 1993, and April 15, 1999) of patients at least 55 years old with vascular disease or diabetes mellitus was extended (HOPE–The Ongoing Outcomes [HOPE-TOO]) between April 16, 1999, and May 26, 2003. Of the initial 267 HOPE centers that had enrolled 9541 patients, 174 centers participated in the HOPE-TOO trial. Of 7030 patients enrolled at these centers, 916 were deceased at the beginning of the extension, 1382 refused participation, 3994 continued to take the study intervention, and 738 agreed to passive follow-up. Median duration of follow-up was 7.0 years. Intervention  Daily dose of natural source vitamin E (400 IU) or matching placebo. Main Outcome Measures  Primary outcomes included cancer incidence, cancer deaths, and major cardiovascular events (myocardial infarction, stroke, and cardiovascular death). Secondary outcomes included heart failure, unstable angina, and revascularizations. Results  Among all HOPE patients, there were no significant differences in the primary analysis: for cancer incidence, there were 552 patients (11.6%) in the vitamin E group vs 586 (12.3%) in the placebo group (relative risk [RR], 0.94; 95% confidence interval [CI], 0.84-1.06; P = .30); for cancer deaths, 156 (3.3%) vs 178 (3.7%), respectively (RR, 0.88; 95% CI, 0.71-1.09; P = .24); and for major cardiovascular events, 1022 (21.5%) vs 985 (20.6%), respectively (RR, 1.04; 95% CI, 0.96-1.14; P = .34). Patients in the vitamin E group had a higher risk of heart failure (RR, 1.13; 95% CI, 1.01-1.26; P = .03) and hospitalization for heart failure (RR, 1.21; 95% CI, 1.00-1.47; P = .045). Similarly, among patients enrolled at the centers participating in the HOPE-TOO trial, there were no differences in cancer incidence, cancer deaths, and major cardiovascular events, but higher rates of heart failure and hospitalizations for heart failure. Conclusion  In patients with vascular disease or diabetes mellitus, long-term vitamin E supplementation does not prevent cancer or major cardiovascular events and may increase the risk for heart failure.   相似文献   

9.
Context  Restenosis within bare-metal stents is often treated with repeat percutaneous coronary intervention, although subsequent recurrence rates are high, with vascular brachytherapy (VBT) affording the best results. The effectiveness of drug-eluting stents in this setting has not been established. Objective  To investigate the safety and efficacy of the polymer-based, slow-release paclitaxel-eluting stent in patients with restenotic lesions after prior stent implantation in native coronary arteries. Design, Setting, and Patients  Prospective, multicenter, randomized trial conducted between June 6, 2003, and July 16, 2004, at 37 North American academic and community-based institutions in 396 patients with in-stent restenosis of a previously implanted bare-metal coronary stent (vessel diameter, 2.5-3.75 mm; lesion length, 46 mm). Interventions  Patients were randomly assigned to undergo angioplasty followed by VBT with a source (n = 201) or paclitaxel-eluting stent implantation (n = 195). Clinical and angiographic follow-up at 9 months was scheduled in all patients. Main Outcome Measure  Ischemia-driven target vessel revascularization at 9 months. Results  Diabetes mellitus was present in 139 patients (35.1%). Median reference vessel diameter was 2.65 mm and median lesion length was 15.3 mm. In the VBT group, new stents were implanted in 22 patients (10.9%) and in the paclitaxel-eluting stent group, multiple stents were required in 57 patients (29.2%), with median stent length of 24 mm. Follow-up at 9 months was complete in 194 patients in the VBT group and 191 patients in the paclitaxel-eluting stent group (96.5% and 97.9%, respectively). For VBT and paclitaxel-eluting stents, respectively, the number of events and 9-month rates for ischemic target lesion revascularization were 27 (13.9%) vs 12 (6.3%) (relative risk [RR], 0.45; 95% confidence interval [CI], 0.24-0.86; P = .01); for ischemic target vessel revascularization, 34 (17.5%) vs 20 (10.5%) (RR, 0.60; 95% CI, 0.36-1.00; P = .046); and for overall major adverse cardiac events, 39 (20.1%) vs 22 (11.5%) (RR, 0.57; 95% CI, 0.35-0.93; P = .02), with similar rates of cardiac death or myocardial infarction (10 [5.2%] vs 7 [3.7%]; RR, 0.71; 95% CI, 0.28-1.83; P = .48) and target vessel thrombosis (5 [2.6%] vs 3 [1.6%]; RR, 0.61; 95% CI, 0.15-2.50; P = .72). Angiographic restenosis at 9 months was 31.2% (53 of 170 patients) with VBT and 14.5% (25 of 172 patients) with paclitaxel-eluting stents (RR, 0.47; 95% CI, 0.30-0.71; P<.001). Conclusion  Treatment of bare-metal in-stent restenotic lesions with paclitaxel-eluting stents rather than angioplasty followed by VBT reduces clinical and angiographic restenosis at 9 months and improves event-free survival. Trial Registration  ClinicalTrials.gov Identifier: NCT00287573   相似文献   

10.
Context  Despite many therapeutic advances, mortality in patients with acute ST-segment elevation myocardial infarction (STEMI) remains high. The role of additional antithrombotic agents is unclear, especially among patients not receiving reperfusion therapy. Objective  To evaluate the effect of fondaparinux, a factor Xa inhibitor, when initiated early and given for up to 8 days vs usual care (placebo in those in whom unfractionated heparin [UFH] is not indicated [stratum 1] or unfractionated heparin for up to 48 hours followed by placebo for up to 8 days [stratum 2]) in patients with STEMI. Design, Setting, and Participants  Randomized double-blind comparison of fondaparinux 2.5 mg once daily or control for up to 8 days in 12 092 patients with STEMI from 447 hospitals in 41 countries (September 2003-January 2006). From day 3 through day 9, all patients received either fondaparinux or placebo according to the original randomized assignment. Main Outcome Measures  Composite of death or reinfarction at 30 days (primary) with secondary assessments at 9 days and at final follow-up (3 or 6 months). Results  Death or reinfarction at 30 days was significantly reduced from 677 (11.2%) of 6056 patients in the control group to 585 (9.7%) of 6036 patients in the fondaparinux group (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.77-0.96; P = .008); absolute risk reduction, 1.5%; 95% CI, 0.4%-2.6%). These benefits were observed at 9 days (537 [8.9%] placebo vs 444 [7.4%] fondaparinux; HR, 0.83; 95% CI, 0.73-0.94; P = .003, and at study end (857 [14.8%] placebo vs 756 [13.4%] fondaparinux; HR, 0.88; 95% CI, 0.79-0.97; P = .008). Mortality was significantly reduced throughout the study. There was no heterogeneity of the effects of fondaparinux in the 2 strata by planned heparin use. However, there was no benefit in those undergoing primary percutaneous coronary intervention. In other patients in stratum 2, fondaparinux was superior to unfractionated heparin in preventing death or reinfarction at 30 days (HR, 0.82; 95% CI, 0.66-1.02; P = .08) and at study end (HR, 0.77; 95% CI, 0.64-0.93; P = .008). Significant benefits were observed in those receiving thrombolytic therapy (HR, 0.79; P = .003) and those not receiving any reperfusion therapy (HR, 0.80; P = .03). There was a tendency to fewer severe bleeds (79 for placebo vs 61 for fondaparinux; P = .13), with significantly fewer cardiac tamponade (48 vs 28; P = .02) with fondaparinux at 9 days. Conclusion  In patients with STEMI, particularly those not undergoing primary percutaneous coronary intervention, fondaparinux significantly reduces mortality and reinfarction without increasing bleeding and strokes. Trial Registration  ClinicalTrials.gov Identifier NCT00064428   相似文献   

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