JAMA news releases are made available to the public after 3 pm US Central time on the first 4 Tuesdays of each month. The Archives Journals news releases are made available to the public after 3 pm Central time on Mondays. We also provide a list of previous news releases.
THIS WEEK'S CONTENT
JAMA NEWS RELEASES
(Embargoed for Release: 3:00 p.m. CT, Tuesday, May 16, 2006)
JAMA NEWS RELEASES
STUDY SIMULATING REDUCED CABIN PRESSURE AND REDUCED OXYGEN ENCOUNTERED DURING LONG AIR TRAVEL FINDS NO ACTIVATION OF BLOOD CLOTTING SYSTEM
STUDY INDICATES WIDELY-USED NUTRITIONAL SUPPLEMENT DOES NOT IMPROVE CHOLESTEROL LEVELS
RECENT CLINICAL TRIALS FUNDED BY FOR-PROFIT ORGANIZATIONS MORE LIKELY TO REPORT POSITIVE FINDINGS THAN TRIALS FUNDED BY NOT-FOR-PROFITS
JAMA REPORT (VIDEO NEWS RELEASE SCRIPT)
VIDEO: Windows Media | Quicktime
TYPICAL AIR PRESSURE AND OXYGEN LEVELS DURING AIR TRAVEL DO NOT LEAD TO BLOOD CLOTS IN LEGS
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TV Note: This week's JAMA video news release is on the risk of developing blood clots from long airplane flights. The release will be fed Tuesday, May 16, from 9:00 - 9:30 a.m. ET on Intelsat America 6 (formerly Telstar 6), Transponder 11 (C-Band) and from 2:00 - 2:30 p.m. ET on Intelsat America 6, Transponder 11 (C-Band). For more information, call 312/464-JAMA (5262).
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Embargoed for Release: 3:00 p.m. CT, Tuesday, May 16, 2006
Media Advisory: To contact William D. Toff, M.D., email: w.toff{at}le.ac.uk. To contact editorial author Peter Bärtsch, M.D., email: peter_bartsch{at}med.uni-heidelberg.de.
STUDY SIMULATING REDUCED CABIN PRESSURE AND REDUCED OXYGEN ENCOUNTERED DURING LONG AIR TRAVEL FINDS NO ACTIVATION OF BLOOD CLOTTING SYSTEM
CHICAGO—Researchers simulating conditions of reduced cabin pressure and reduced oxygen levels, such as may be encountered during an 8 hour airplane flight, found no increase in the activation of the blood clotting system among healthy individuals, according to a study in the May 17 issue of JAMA.
Venous thromboembolism (blood clots in vein) has been associated with long-haul air travel, but it has been unclear whether this is due to the effects of sitting for a long time, or whether there is a relationship with some other specific factor in the airplane environment, according to background information in the article. One hypothesis has been that hypoxia (reduced oxygen in the blood), associated with decreased cabin pressure that occurs at altitude, produces changes in blood that increases the risk for blood clots.
William D. Toff, M.D., of the University of Leicester, England, and colleagues conducted a study, from September 2003 to November 2005, to assess the effects of hypoxia in conditions similar to that which might be encountered during commercial air travel, on a variety of markers of activation of the hemostatic (blood clotting) system. The study included 73 healthy volunteers who spent 8 hours seated in a hypobaric (below normal pressure) chamber and were exposed to hypobaric hypoxia, similar to the conditions that would occur with reduced airplane cabin pressure at an altitude of about 8,000 feet. Blood was drawn before and after exposure to assess activation of factors associated with hemostasis (blood clotting). Similar measurements were taken of the volunteers who also spent 8 hours seated in a controlled environment equivalent to atmospheric conditions at ground level (normobaric exposure).
The researchers found that when comparing the results between the normobaric and the hypobaric exposures, there was no significant difference in the overall change for markers of coagulation activation, including reduced fibrinolysis (normal breakdown of small, naturally occurring blood clots), increased platelet activation (mobilization of platelets, cells that promote clot formation), and increased endothelial cell activation (changes in the cells that line the interior surface of blood vessels).
“In conclusion, our findings do not support the hypothesis that hypobaric hypoxia of the degree that might be encountered during long-haul air travel is associated with prothrombotic alterations in the hemostatic system in healthy individuals at low risk of venous thromboembolism,” the authors write.
(JAMA. 2006;295:2251-2261. Available pre-embargo to the media at www.jamamedia.org)
Editor's Note: This study was funded by the UK Department for Transport, the UK Department of Health, and the European Commission.
EDITORIAL: HOW THROMBOGENIC IS HYPOXIA?
In an accompanying editorial, Peter Bärtsch, M.D., of the Universitätsklinikum Heidelberg, Germany, comments on the study that examines hypobaric hypoxia.
“The surprising finding in the studies by Toff et al and [another study] that prolonged sitting did not enhance markers of thrombin [an enzyme that causes blood to clot] formation may be due to several factors that are different from the usual setting of traveling. In the first study, participants were allowed to stand and walk for 5 minutes each hour; in both studies, narcotics and alcohol were not allowed ...In addition, it has been suggested that the minor decrease of prothrombin fragment 1 + 2 [a protein in the blood that assists in clotting] observed with prolonged sitting in both studies confirming a previous report could indicate less activation of protein C, a major inhibitor of coagulation, and thus indicate a shift toward a procoagulant state.”
(JAMA. 2006;295:2297-2299. Available pre-embargo to the media at www.jamamedia.org)
For More Information: Contact the JAMA/Archives Media Relations Department at 312/464-JAMA (5262) or email: mediarelations{at}jama-archives.org.
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Embargoed for Release: 3:00 p.m. CT, Tuesday, May 16, 2006
Media Advisory: To contact Heiner K. Berthold, M.D., Ph.D., email: berthold{at}uni-bonn.de.
STUDY INDICATES WIDELY-USED NUTRITIONAL SUPPLEMENT DOES NOT IMPROVE CHOLESTEROL LEVELS
CHICAGO—A new study suggests that use of the nutritional supplement policosanol does not lower cholesterol levels any more than placebo, apparently contradicting the results of previous studies, according to a study in the May 17 issue of JAMA.
Policosanol is a natural substance produced from the waxy coating of sugar cane. Cuban sugar cane policosanol is sold in more than 40 countries mainly because of its supposed lipid-lowering effects, according to background information in the article. Numerous policosanol products from a variety of sources (sugar cane, wheat germ, rice bran, beeswax) are available over-the-counter and on the Internet in several countries. Advertising emphasizes predominantly its reputed lipid-lowering effects, comparable with statins (prescription medications taken to lower cholesterol). Most of the published scientific literature, more than 80 trials, supporting the beneficial effects of policosanol on lipids has been authored by a single research group from Cuba. One clinical trial from the Netherlands showed wheat germ–derived policosanol ineffective in lowering total cholesterol and low-density lipoprotein cholesterol (LDL-C), sometimes called “bad” cholesterol.
Heiner K. Berthold, M.D., Ph.D., of the University of Cologne, Germany, and colleagues conducted a study to determine the lipid-lowering effects of policosanol. The multicenter, randomized, double-blind, placebo-controlled, trial included 143 patients with hypercholesterolemia (high cholesterol) or combined hyperlipidemia (excess of fats or lipids in the blood) having baseline LDL-C levels of at least 150 mg/dL and either no or 1 cardiovascular risk factor other than known coronary heart disease, or baseline LDL-C levels of between 150 and 189 mg/dL and 2 or more risk factors. The patients were randomized into 5 groups: 10, 20, 40, or 80 mg/d of policosanol or placebo. The study was conducted from September 2000 to May 2001.
In none of the 5 treatment groups did LDL-C levels decrease more than 10 percent from baseline. No statistically significant difference between policosanol and placebo was observed. In none of the secondary outcome measures, namely total cholesterol, high-density lipoprotein cholesterol (HDL-C; known as “good” cholesterol), very low-density lipoprotein cholesterol, triglycerides, lipoprotein(a) (a family of lipoprotein particles varying in density and size), and ratio of total or LDL-C to HDL-C, were there any significant effects of policosanol. Policosanol was tolerated well and no severe adverse events occurred.
“Our results suggest that [policosanol] is devoid of clinically relevant lipoprotein-lowering properties in white patients. Still, more independent studies are required to counterbalance the vast body of available positive trials. Although policosanol has been used for more than a decade in clinical trials, there are still no data on patient-related outcomes, such as cardiovascular morbidity and mortality. Moreover, independent information should be given to consumers who might take policosanol to improve their cardiovascular risk profile,” the authors conclude.
(JAMA. 2006;295:2262-2269. Available pre-embargo to the media at www.jamamedia.org)
Editor's Note: This study was sponsored by Madaus AG, Cologne, Germany, which also provided funding of the contract research organization involved. Neither Madaus AG nor any of their subsidiary companies manufacturers or distributes any lipid-lowering drugs, including statins.
For More Information: Contact the JAMA/Archives Media Relations Department at 312/464-JAMA (5262) or email: mediarelations{at}jama-archives.org.
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Embargoed for Release: 3:00 p.m. CT, Tuesday, May 16, 2006
Media Advisory: To contact Paul M. Ridker, M.D., call Kevin Myron at 617-534-1605.
RECENT CLINICAL TRIALS FUNDED BY FOR-PROFIT ORGANIZATIONS MORE LIKELY TO REPORT POSITIVE FINDINGS THAN TRIALS FUNDED BY NOT-FOR-PROFITS
CHICAGO—Cardiovascular clinical trials published between 2000 and 2005 were significantly more likely to report positive findings if they were funded by for-profit organizations than those funded by not-for-profit organizations, according to a study in the May 17 issue of JAMA.
Surveys of randomized trials published between 1990 and 2000 raised awareness in the medical community that trials funded by for-profit (FP) organizations were more likely to report positive findings than those funded by not-for-profit (NFP) organizations. These surveys raised questions regarding the design and conduct of industry funded clinical trials as well as certain ethical concerns, according to background information in the article. Whether recognition of these concerns has affected contemporary clinical trials was unknown.
Paul M. Ridker, M.D., of Brigham and Women’s Hospital, and Jose Torres, B.A., of Harvard Medical School, Boston, analyzed outcomes of 324 cardiovascular clinical trials published between 2000 and 2005 in JAMA, The Lancet, and the New England Journal of Medicine, stratifying the results on whether the trial was funded by for-profit or not-for-profit organizations and if the trial outcome favored newer treatments over the standard of care. Of the 324 trials, 21 cited no funding source.
Overall, 58.6 percent of the 324 trials reported evidence significantly favoring newer treatments, while 34.6 percent reported no significant difference between therapies, and 6.8 percent reported evidence significantly favoring standard of care. Among not-for-profit trials, 49 percent of 104 reported evidence significantly favoring newer treatments, whereas 51 percent either significantly favored standard of care or showed no difference.
Among for-profit trials, 67.2 percent of 137 reported evidence significantly favoring newer treatments with 32.8 percent reporting data favoring standard of care or no difference. The proportion of trials significantly favoring new treatments for studies jointly funded by for-profit and not-for-profit organizations was approximately midway between these 2 values (56.5 percent).
For 202 randomized trials evaluating drugs, the proportions favoring newer agents were 39.5 percent for not-for-profit, 54.4 percent for jointly sponsored, and 65.5 percent for for-profit trials. For the 38 randomized trials evaluating cardiovascular devices, the proportions favoring newer treatments were 50.0 percent, not-for-profit; 69.2 percent, jointly funded; and 82.4 percent, for-profit trials.
Regardless of funding source, clinical trials using surrogate end points, such as intravascular ultrasound, quantitative angiography, plasma biomarkers, and functional measures were more likely to report positive findings (67.0 percent) than were clinical trials using clinical end points (54.1 percent).
“As suggested in surveys of randomized trials published prior to 2000, these contemporary data appear to show that incentives surrounding for-profit organizations have the potential to influence clinical trial outcomes. Previous attempts to explain this phenomenon have focused largely on design bias, interpretation bias, data suppression, and differential data quality,” the authors write.
“...we believe there are additional issues that help to explain, in part, the observed results. For example, when the first trial report of a truly novel therapy is null or negative, it becomes less likely that any funding source will support subsequent studies. On the other hand, when the first trial of a truly novel therapy is positive, the likelihood of further trials is increased. These subsequent trials understandably and perhaps appropriately are more likely to be funded by for-profit organizations,” the researchers write.
(JAMA. 2006;295:2270-2274. Available pre-embargo to the media at www.jamamedia.org)
For More Information: Contact the JAMA/Archives Media Relations Department at 312/464-JAMA (5262) or email: mediarelations{at}jama-archives.org.
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JAMA REPORTS
VIDEO: Windows Media | Quicktime
TYPICAL AIR PRESSURE AND OXYGEN LEVELS DURING AIR TRAVEL DO NOT LEAD TO BLOOD CLOTS IN LEGS
VIDEO:
B-ROLL
Simon looking at photo album
Pictures of Sydney opera house
Airplane flying
AUDIO:
AS SIMON SNEDDEN THINKS ABOUT A RECENT TRIP TO AUSTRALIA, HE REMEMBERS HOW HE USED TO APPROACH LONG FLIGHTS.
VIDEO:
SOT/FULL
@ :07
Super: Simon Snedden
Takes long flights
Runs :07
AUDIO:
“The plan was always get in, get sat down, get a book, have a snooze, watch the film.”
VIDEO:
B-ROLL
Simon looking at photo album
Man in airport with legs stretched out over luggage
Airplane in flight
AUDIO:
BUT THEN HE VOLUNTEERED TO BE PART OF A NEW STUDY ABOUT DVT – DEEP VEIN THROMBOSIS – BLOOD CLOTS IN THE LEGS THAT SOME PEOPLE HAVE EXPERIENCED AFTER LONG FLIGHTS.
VIDEO:
SOT/FULL
@ :13
Super: William Toff, M.D.
University of Leicester
Runs :12
AUDIO:
“Particularly in clots that form in the larger leg veins, higher up, they may break away and travel through the heart to the lungs, where they block the blood flow and may in some cases prove fatal.”
VIDEO:
B-ROLL
Dr. Toff and colleague at table looking over study
Photo of exterior of chamber (all photos provided by Dr. Toff – camera moves put on them during editing)
Motion on all photos
Photo of interior – close on table
Pull wide to full photo of people in chamber
Photo of monitors outside chamber
Video of airplane in flight
Photo of volunteer lying on exam table
Photo of arm/blood being drawn
Photo of researcher testing blood
AUDIO:
DR. WILLIAM TOFF AND COLLEAGUES AT UNIVERSITY OF LEICESTER (lester) CONDUCTED THE STUDY. SEVENTY-THREE HEALTHY VOLUNTEERS TOOK EIGHT-HOUR SHIFTS SITTING IN THIS HYPOBARIC CHAMBER. RESEARCHERS PUT A TABLE IN THE MIDDLE TO SIMULATE THE CLOSE QUARTERS OF AN AIRPLANE. THEY LOWERED THE AIR PRESSURE AND OXYGEN LEVELS IN THE CHAMBER TO MATCH LEVELS DURING FLIGHTS. THEY ALSO HAD THE VOLUNTEERS SPEND EIGHT HOURS IN THE CHAMBER WITH NORMAL OXYGEN AND PRESSURE LEVELS. THEY TESTED VOLUNTEERS’ BLOOD BEFORE AND AFTER EACH TIME IN THE CHAMBER.
VIDEO:
SOT/FULL
William Toff, M.D.
University of Leicester
Runs :10
First 6 seconds covered with blood dripping into test tube
AUDIO:
“We looked at a very wide range of blood markers, looking at all aspects of the body’s clotting mechanism.”
“We found no evidence that the low pressure and low oxygen were activating the body’s blood-clotting mechanism.”
VIDEO:
B-ROLL
Plane in flight
GFX/JAMA Cover
Lab tech working with blood
People in airport pulling luggage
AUDIO:
SO OXYGEN AND AIR PRESSURE ARE NOT THE PROBLEM. BUT THE STUDY, WHICH APPEARS IN THE JAMA, THE JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION, DID FIND SOME CLOTTING CHANGES IN THE BLOOD. THE AUTHORS SAY THOSE WERE MOST LIKELY DUE TO SITTING STILL FOR EIGHT HOURS. DR. TOFF HAS THIS ADVICE FOR PEOPLE WHO TRAVEL BY AIR, ROAD OR RAIL.
VIDEO:
SOT/FULL
William Toff, M.D.
University of Leicester
Runs :12
AUDIO:
“Take care to exercise their legs, to stretch their legs whenever they can, particularly to extend and flex at the ankle and knee, and to stand up and walk around when they can.”
VIDEO:
B-ROLL
Airplane taking off
AUDIO:
THIS IS MAVIS PRALL WITH THE JAMA REPORT.
