Colds and flu cut by one-third in study of Canada's top cold fighter in vaccinated seniors
17 sept 2008--A winter free from colds and flu? Not yet. But a new study offers new evidence that Canada's top cold and flu-fighting product provides significant help. The three-year study showed that trial participants who took COLD-FX were about one-third less likely to get a "Jackson" cold or flu. The very sensitive Jackson scoring method is a well-accepted scientific approach for judging clinical symptoms, which include coughing, sneezing, runny noses and others. COLD-FX is a unique extract of North American ginseng discovered by 25 Canadian scientists. The multi-center study also revealed that COLD-FX gave trial participants added protection on top of the flu shot's benefit.
The multi-centre study confirmed the results of previous clinical trials reviewed by Health Canada, the federal government's regulatory body. One study published in the Canadian Medical Association Journal showed that for trial participants who regularly suffer two colds a year, COLD-FX reduced their chance of getting a second one by 56%. Health Canada approved strong claims for the product last year.
The multi-centre trial involved 780 healthy seniors in four major Canadian cities who took the flu shot just prior to their six-month treatment phase as part of the study. Participants were given either the standard dose of two capsules a day or double the standard dose or a placebo. The study was led by Dr. Gerald Predy, Medical Officer of Health for Alberta Health Services, in collaboration with various leading Canadian researchers. Neither the participants nor the investigators were aware of who was receiving what in this double-blind, placebo controlled trial.
The viral analysis was conducted in the lab of internationally recognized influenza expert, Dr. Albert Osterhaus. Based in the Netherlands, Dr. Osterhaus is one of the world's leading virologists and utilizes the most sensitive test methods available. Among his achievements and those of his group of 100 scientists were the identification of the first human infection with avian flu H5N1 in 1997 and the identity of the SARS virus during the first outbreak in Hong Kong in 2003.
Investigators employed two principal methods to check on upper respiratory infections: lab tests and the Jackson method. (A third method – non-Jackson assessment of symptoms in combination with lab tests – was also used.) While both methods were utilized, the Jackson method is actually more sensitive than lab testing in confirming symptomatic upper respiratory infections and gauging their severity.)
Compared to the placebo, both COLD-FX regimes produced similar and statistically significant reductions in the number of upper respiratory infections per individual – 36% for the lower dose and 33% for the higher dose.
Also, the number of Jackson infections in the standard dose COLD-FX group was 31% less than for the placebo group, while infections for the double dose group were 33% below the placebo group – statistically significant results.
However, investigators did not find statistically significant differences in confirmed infections, compared to placebo, when they looked at the data in a couple of other ways: based on lab testing alone; and considering lab plus symptom-based (but not Jackson) testing. It's possible the differences weren't statistically significant in these scenarios because the overall influenza numbers were so low during the two flu seasons studied. Also, the trial wasn't designed to measure viral load (the amount of virus in the body). So COLD-FX may actually have reduced the degree of infection in some people but the trial didn't check this.
It did confirm that both COLD-FX dosage levels were safe and well tolerated. Adverse events in the COLD-FX groups showed up at about the same rates as for the placebo group – with one intriguing exception. Both COLD-FX groups showed fewer negative cardiovascular events. The reason might be found in COLD-FX's effectiveness in reducing upper respiratory infections, which often go hand in hand with cardiovascular problems in seniors. This result was obtained through assessing safety aspects of the trial. It represents a potential new application for COLD-FX which, if pursued, would require more in-depth review.
Other than COLD-FX, there is no known clinically proven therapy for both prevention and treatment that naturally enhances the immune system to fight viral respiratory infections.
Showing posts with label cold. Show all posts
Showing posts with label cold. Show all posts
Wednesday, September 17, 2008
Tuesday, July 24, 2007
Echinacea Helps Colds, Major Review Shows
By NICHOLAS BAKALAR
Echinacea helps banish colds. Echinacea has no effect on colds. The verdict seems to shift with each new scientific study of the herbal remedy.
In the latest twist, a review of more than 700 studies has concluded that echinacea has a substantial effect in preventing colds and in limiting their duration.
The paper, published in the July issue of The Lancet Infectious Diseases, used statistical techniques to combine the results of existing studies and reach conclusions based on the larger sample that resulted. The researchers selected only those trials that used randomized and placebo-controlled techniques: 14 studies involving 1,356 participants for the number of colds and 1,630 for the prevention of colds. The studies varied in the dosages of the herb, the duration it was taken and the species of echinacea used, and the number of participants ranged from 40 to more than 300.
The analysis concluded that echinacea reduced the risk of catching a cold by 58 percent. It also found that the herb significantly shortened the duration of a cold, but there was no general agreement about the magnitude of this effect.
“Our analysis doesn’t say that the stuff works without question,” said Dr. Craig I. Coleman, an assistant professor of pharmacy practice at the University of Connecticut, and the senior author of the paper. “But the preponderance of evidence suggests that it does.”
The authors acknowledged certain weaknesses in their study. For example, they did not examine the safety of the herbal remedy, only its effectiveness.
Dr. Bruce P. Barrett, an associate professor of family medicine at the University of Wisconsin who was not involved with the review, said he was not convinced of the value of combining the studies in a single analysis.
“If you’re testing the same intervention on the same population using the same outcome measures, then meta-analysis is a very good technique,” Dr. Barrett said. “But here every one of those things fails.” One of Dr. Barrett’s papers on echinacea was included in the analysis.
Other experts also expressed skepticism. J. David Gangemi, director of the Institute for Neutraceutical Research at Clemson University, said he found the study interesting, but added, “I think that many of the people who have dedicated their careers to clinical trials in studying these effects are not at all convinced from this analysis that there is this large reduction in incidence and duration of disease.”
Dr. Gangemi is the senior author of a 2005 study, published in The New England Journal of Medicine and included in the review, that found no benefit in the herb.
There are several possible reasons that even a carefully devised single study might fail to show an effect that actually exists. There are more than 200 species of virus that cause colds, Dr. Coleman said, and a study could test one species against which echinacea proves ineffective, while leaving open the question of whether it works for others.
In addition, some studies might not use large enough doses of the herb; others might use a species of echinacea that is less effective. Some might not have a large enough sample to find a small but statistically significant effect.
Dr. Barrett said there was probably little harm in using echinacea, and he was cautiously optimistic that the herb does have a very small positive effect.
“There’s some danger of kids getting a rash, and it would be inadvisable to give it to women in the early stages of pregnancy,” he said. “But if adults believe in echinacea, they’re going to get benefits — maybe from placebo — but they’ll get benefits.”
Dr. Coleman, who described himself as “not much of a pill taker,” hedged a bit when asked if he planned to use echinacea himself. “I’ll probably consider taking it if I feel a cold coming on,” he said. “These results have pushed me toward the idea. Whether I’m actually going to take it, well, we’ll see.”
By NICHOLAS BAKALAR
Echinacea helps banish colds. Echinacea has no effect on colds. The verdict seems to shift with each new scientific study of the herbal remedy.
In the latest twist, a review of more than 700 studies has concluded that echinacea has a substantial effect in preventing colds and in limiting their duration.
The paper, published in the July issue of The Lancet Infectious Diseases, used statistical techniques to combine the results of existing studies and reach conclusions based on the larger sample that resulted. The researchers selected only those trials that used randomized and placebo-controlled techniques: 14 studies involving 1,356 participants for the number of colds and 1,630 for the prevention of colds. The studies varied in the dosages of the herb, the duration it was taken and the species of echinacea used, and the number of participants ranged from 40 to more than 300.
The analysis concluded that echinacea reduced the risk of catching a cold by 58 percent. It also found that the herb significantly shortened the duration of a cold, but there was no general agreement about the magnitude of this effect.
“Our analysis doesn’t say that the stuff works without question,” said Dr. Craig I. Coleman, an assistant professor of pharmacy practice at the University of Connecticut, and the senior author of the paper. “But the preponderance of evidence suggests that it does.”
The authors acknowledged certain weaknesses in their study. For example, they did not examine the safety of the herbal remedy, only its effectiveness.
Dr. Bruce P. Barrett, an associate professor of family medicine at the University of Wisconsin who was not involved with the review, said he was not convinced of the value of combining the studies in a single analysis.
“If you’re testing the same intervention on the same population using the same outcome measures, then meta-analysis is a very good technique,” Dr. Barrett said. “But here every one of those things fails.” One of Dr. Barrett’s papers on echinacea was included in the analysis.
Other experts also expressed skepticism. J. David Gangemi, director of the Institute for Neutraceutical Research at Clemson University, said he found the study interesting, but added, “I think that many of the people who have dedicated their careers to clinical trials in studying these effects are not at all convinced from this analysis that there is this large reduction in incidence and duration of disease.”
Dr. Gangemi is the senior author of a 2005 study, published in The New England Journal of Medicine and included in the review, that found no benefit in the herb.
There are several possible reasons that even a carefully devised single study might fail to show an effect that actually exists. There are more than 200 species of virus that cause colds, Dr. Coleman said, and a study could test one species against which echinacea proves ineffective, while leaving open the question of whether it works for others.
In addition, some studies might not use large enough doses of the herb; others might use a species of echinacea that is less effective. Some might not have a large enough sample to find a small but statistically significant effect.
Dr. Barrett said there was probably little harm in using echinacea, and he was cautiously optimistic that the herb does have a very small positive effect.
“There’s some danger of kids getting a rash, and it would be inadvisable to give it to women in the early stages of pregnancy,” he said. “But if adults believe in echinacea, they’re going to get benefits — maybe from placebo — but they’ll get benefits.”
Dr. Coleman, who described himself as “not much of a pill taker,” hedged a bit when asked if he planned to use echinacea himself. “I’ll probably consider taking it if I feel a cold coming on,” he said. “These results have pushed me toward the idea. Whether I’m actually going to take it, well, we’ll see.”
Thursday, July 19, 2007
Vitamin C Won't Prevent Colds in Most Adults
HELSINKI, Finland, July 18 -- Although most people won't find vitamin C effective protection against colds, marathon runners can cut their risk by about 50% if they take at least 200 mg every day.
This latest -- although probably not final -- word on vitamin C comes from a review published online in issue 3 of The Cochrane Library.
Pooled data from more than 11,350 participants in 30 trials found that the relative risk of catching a cold was 0.96 (0.92 to 1.00) for people who took prophylactic vitamin C, said Harri Hemilä, Ph.D., M.D., of the University of Helsinki, a co-author of the review.
The finding suggests that it "doesn't make sense to take vitamin C 365 days a year to lessen the chance of catching a cold," he said.
But a subgroup of six trials that enrolled 642 long distance runners, skiers, and soldiers deployed in sub-arctic regions revealed that vitamin C supplementation reduced by half the risk of catching cold in those populations (RR 0.50, 95% CI 0.38-0.66).
Pooled data from 9,676 people who caught colds while taking the vitamin prophylactically did find that vitamin C reduced the duration of sneezing, congestion, and other cold symptoms by about 8% in adults (95% CI 3% to 13%) and by 13.6% in children (95% CI 5% to 22%).
Trials of high dose vitamin C initiated at the first signs of a cold demonstrated no consistent effect on either duration or severity of symptoms, but, Dr. Hemilä said, there were few such trials in the literature and "their quality was variable."
Vitamin C has steadily gained status as a cold remedy since its discovery in the 1930s, but the mega-vitamin C movement took off in the 1970s when Nobel Prize-winning chemist Linus Pauling published his book, Vitamin C and the Common Cold. Pauling encouraged people to take 1,000 mg of vitamin C daily.
The first Cochrane Review of prophylactic vitamin C was published in 1998. That review was updated in 2004 and this latest update includes a single new study but no change in the Cochrane take on vitamin C.
Dr. Hemilä said he sees little use in further study of the vitamin in colds for adults. However, he would like to see more studies on vitamin C and colds in children and vitamin C and pneumonia.
Vitamin C, he said in a statement, is not a panacea, but it is not useless either. "Pauling was overly optimistic, but he wasn't completely wrong."
Dr. Hemilä disclosed no conflicts. The Commonwealth Department of Health and Aging and the Australian National University funded the study.Primary source: Cochrane Collaboration Cochrane LibrarySource reference: Douglas R.M. "Vitamin C for Preventing and Treating the Common Cold (Review)" Cochrane Database of Systematic Reviews 2007; Issue 3 Published online July 18, 2007 DOI: 10.1002/14651858.CD00980.pub3
HELSINKI, Finland, July 18 -- Although most people won't find vitamin C effective protection against colds, marathon runners can cut their risk by about 50% if they take at least 200 mg every day.
This latest -- although probably not final -- word on vitamin C comes from a review published online in issue 3 of The Cochrane Library.
Pooled data from more than 11,350 participants in 30 trials found that the relative risk of catching a cold was 0.96 (0.92 to 1.00) for people who took prophylactic vitamin C, said Harri Hemilä, Ph.D., M.D., of the University of Helsinki, a co-author of the review.
The finding suggests that it "doesn't make sense to take vitamin C 365 days a year to lessen the chance of catching a cold," he said.
But a subgroup of six trials that enrolled 642 long distance runners, skiers, and soldiers deployed in sub-arctic regions revealed that vitamin C supplementation reduced by half the risk of catching cold in those populations (RR 0.50, 95% CI 0.38-0.66).
Pooled data from 9,676 people who caught colds while taking the vitamin prophylactically did find that vitamin C reduced the duration of sneezing, congestion, and other cold symptoms by about 8% in adults (95% CI 3% to 13%) and by 13.6% in children (95% CI 5% to 22%).
Trials of high dose vitamin C initiated at the first signs of a cold demonstrated no consistent effect on either duration or severity of symptoms, but, Dr. Hemilä said, there were few such trials in the literature and "their quality was variable."
Vitamin C has steadily gained status as a cold remedy since its discovery in the 1930s, but the mega-vitamin C movement took off in the 1970s when Nobel Prize-winning chemist Linus Pauling published his book, Vitamin C and the Common Cold. Pauling encouraged people to take 1,000 mg of vitamin C daily.
The first Cochrane Review of prophylactic vitamin C was published in 1998. That review was updated in 2004 and this latest update includes a single new study but no change in the Cochrane take on vitamin C.
Dr. Hemilä said he sees little use in further study of the vitamin in colds for adults. However, he would like to see more studies on vitamin C and colds in children and vitamin C and pneumonia.
Vitamin C, he said in a statement, is not a panacea, but it is not useless either. "Pauling was overly optimistic, but he wasn't completely wrong."
Dr. Hemilä disclosed no conflicts. The Commonwealth Department of Health and Aging and the Australian National University funded the study.Primary source: Cochrane Collaboration Cochrane LibrarySource reference: Douglas R.M. "Vitamin C for Preventing and Treating the Common Cold (Review)" Cochrane Database of Systematic Reviews 2007; Issue 3 Published online July 18, 2007 DOI: 10.1002/14651858.CD00980.pub3
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