Monday, November 24, 2008
The season of a baby's birth may help predict that child's risk of asthma, new research suggests.
Babies born in autumn -- about four months before the peak of winter virus season -- have almost a 30 percent increased risk of asthma compared to babies born at other times of the year, reports a study in the first December issue of the American Journal of Respiratory and Critical Care Medicine.
"Children in the Northern hemisphere born in the fall months have the highest rates of asthma, which suggests that winter viruses, like RSV, cause asthma," said study senior author Dr. Tina Hartert, director of the Center for Asthma Research and Environmental Health at Vanderbilt University School of Medicine, in Nashville, Tenn.
"What we need to prove now is that preventing these viruses could prevent asthma," she added.
Respiratory syncytial virus (RSV) is a very common infection. In fact, Hartert said that about 70 percent of U.S. infants will have an RSV infection before their first birthday. Not all children who have an RSV infection will develop asthma, but those with more severe infections appear to have a higher risk. More than 40 percent of infants hospitalized for a respiratory virus develop asthma by their teen years, according to background information in the study.
The author of an accompanying editorial in the same issue of the journal said genetic factors play a role as well. "Asthma, like many other complex diseases, has a genetic background that is importantly affected by the surrounding environment. Different factors, like allergies or maternal/paternal history of asthma, when in combination with early life infections by respiratory viruses, seem to increase substantially the risk for asthma, or at least, persistent wheeze," said Dr. Renato Stein, head of the pediatric pulmonary service at Pontificia Catholic University in Porto Alegre, Brazil.
What hasn't been clear in the past is whether RSV and other viruses actually cause asthma, or whether children who are predisposed to asthma are the ones most likely to get such viruses, according to Dr. Jennifer Appleyard, chief of allergy and immunology at St. John Hospital in Detroit.
The current study, which included a group of more than 95,000 infants born between 1995 and 2000, hoped to answer that question.
All of the infants were part of the Tennessee Medicaid program and were followed from birth through early childhood to see if the timing of birth in relation to winter virus season had any effect on the development of asthma.
And, the researchers found that it clearly did. Babies born in the fall, which is generally about four months before the peak of the winter virus season, had a 29 percent higher risk of asthma, according to the study.
For fall-born babies, said Hartert, the winter virus season tends to coincide with a vulnerable period of development, where babies are transitioning from maternal antibodies to their own. But, she said, babies' immune systems aren't really developed until about 6 months of age.
Hartert said she "hopes this study's findings will generate heightened interest in development of an RSV vaccine." She said that RSV is unique among viruses because the human body doesn't ever develop antibodies against it. She said there are vaccines in development currently, but that they're "probably a ways off."
Appleyard said that parents shouldn't worry if they've had, or are going to have a fall baby, "because no one specific trigger is going to be the cause of all asthma."
Likewise, she said, don't feel like you're to blame if your child has ever had RSV, because most children have had this ubiquitous virus.
However, Hartert, Appleyard and Stein all suggested that parents might want to take steps to try to reduce the risk of infection. If it's at all possible, said Stein, try to avoid day care before the age of 3. Hartert said that parents should also employ good hygiene and infection-control measures, such as staying away from sick children and washing their hands frequently.
Babies born in autumn -- about four months before the peak of winter virus season -- have almost a 30 percent increased risk of asthma compared to babies born at other times of the year, reports a study in the first December issue of the American Journal of Respiratory and Critical Care Medicine.
"Children in the Northern hemisphere born in the fall months have the highest rates of asthma, which suggests that winter viruses, like RSV, cause asthma," said study senior author Dr. Tina Hartert, director of the Center for Asthma Research and Environmental Health at Vanderbilt University School of Medicine, in Nashville, Tenn.
"What we need to prove now is that preventing these viruses could prevent asthma," she added.
Respiratory syncytial virus (RSV) is a very common infection. In fact, Hartert said that about 70 percent of U.S. infants will have an RSV infection before their first birthday. Not all children who have an RSV infection will develop asthma, but those with more severe infections appear to have a higher risk. More than 40 percent of infants hospitalized for a respiratory virus develop asthma by their teen years, according to background information in the study.
The author of an accompanying editorial in the same issue of the journal said genetic factors play a role as well. "Asthma, like many other complex diseases, has a genetic background that is importantly affected by the surrounding environment. Different factors, like allergies or maternal/paternal history of asthma, when in combination with early life infections by respiratory viruses, seem to increase substantially the risk for asthma, or at least, persistent wheeze," said Dr. Renato Stein, head of the pediatric pulmonary service at Pontificia Catholic University in Porto Alegre, Brazil.
What hasn't been clear in the past is whether RSV and other viruses actually cause asthma, or whether children who are predisposed to asthma are the ones most likely to get such viruses, according to Dr. Jennifer Appleyard, chief of allergy and immunology at St. John Hospital in Detroit.
The current study, which included a group of more than 95,000 infants born between 1995 and 2000, hoped to answer that question.
All of the infants were part of the Tennessee Medicaid program and were followed from birth through early childhood to see if the timing of birth in relation to winter virus season had any effect on the development of asthma.
And, the researchers found that it clearly did. Babies born in the fall, which is generally about four months before the peak of the winter virus season, had a 29 percent higher risk of asthma, according to the study.
For fall-born babies, said Hartert, the winter virus season tends to coincide with a vulnerable period of development, where babies are transitioning from maternal antibodies to their own. But, she said, babies' immune systems aren't really developed until about 6 months of age.
Hartert said she "hopes this study's findings will generate heightened interest in development of an RSV vaccine." She said that RSV is unique among viruses because the human body doesn't ever develop antibodies against it. She said there are vaccines in development currently, but that they're "probably a ways off."
Appleyard said that parents shouldn't worry if they've had, or are going to have a fall baby, "because no one specific trigger is going to be the cause of all asthma."
Likewise, she said, don't feel like you're to blame if your child has ever had RSV, because most children have had this ubiquitous virus.
However, Hartert, Appleyard and Stein all suggested that parents might want to take steps to try to reduce the risk of infection. If it's at all possible, said Stein, try to avoid day care before the age of 3. Hartert said that parents should also employ good hygiene and infection-control measures, such as staying away from sick children and washing their hands frequently.
Monday, November 17, 2008
Review of Prostate Cancer Prevention Study Shows No Benefit for Use of Selenium and Vitamin E Supplements
Initial, independent review of study data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT), funded by the National Cancer Institute (NCI) and other institutes that comprise the National Institutes of Health shows that selenium and vitamin E supplements, taken either alone or together, did not prevent prostate cancer. The data also showed two concerning trends: a small but not statistically significant increase in the number of prostate cancer cases among the over 35,000 men age 50 and older in the trial taking only vitamin E and a small, but not statistically significant increase in the number of cases of adult onset diabetes in men taking only selenium. Because this is an early analysis of the data from the study, neither of these findings proves an increased risk from the supplements and both may be due to chance.
The Southwest Oncology Group (SWOG), an international network of research institutions, coordinates SELECT at more than 400 clinical sites in the United States, Puerto Rico, and Canada.
SELECT participants are receiving letters explaining the study review and telling them to stop taking their study supplements. Participants will continue to have their health monitored by study staff, which may include regular digital rectal exams and PSA (prostate-specific antigen) tests to detect prostate cancer. Investigators intend to follow the participants for about three years to determine the long-term effects of having taken either supplement or placebo and to complete a biorepository of blood samples that will be used in extensive molecular analyses to give researchers a better understanding of prostate cancer, other cancers, and other diseases of male aging. This additional data collection is a vital part of the study.
Neither the men nor their physicians know which supplements or placebos the men have been taking, a procedure known as blinding or masking. As followup of the SELECT participants continues, the participants will continue to be blinded. A blinded followup may avoid unintentional bias and potentially false conclusions. However, at the request of a participant, they will be informed which supplement, if any, they received.
" was always designed as a study that would answer more than a single question about prostate cancer," said Eric Klein, M.D., a study co-chair for SELECT, and a physician at the Cleveland Clinic. "As we continue to monitor the health of these 35,000 men, this information may help us understand why two nutrients that showed strong initial evidence to be able to prevent prostate cancer did not do so."
SELECT was undertaken to substantiate earlier, separate findings from studies in which prostate cancer was not the primary outcome: a 1998 study of 29,133 male smokers in Finland who took vitamin E to prevent lung cancer surprisingly showed 32 percent fewer prostate cancers in men who took the supplement, and a 1996 study of 1,312 men and women with skin cancer who took selenium for prevention of the disease showed that men who took the supplement had 52 percent fewer prostate cancers than men who did not take the supplement.
Based on these and other earlier findings, in 2001, men were recruited to participate in SELECT. They were randomly assigned to take one of four sets of supplements or placebos, with more than 8,000 men in each group. One group took both selenium and vitamin E; one took selenium and a vitamin E placebo; one took vitamin E and a selenium placebo; and the final group received placebos of both supplements.
It should be noted that in 2003, while SELECT was recruiting men, a different SWOG-sponsored study reported that the drug finasteride reduced the incidence of prostate cancer by 25 percent. When this was discovered, men on SELECT were informed and allowed to take finasteride. Finasteride has not yet been approved by the U.S. Food and Drug Administration for prostate cancer prevention.
Except for skin cancer, prostate cancer is the most common type of cancer in men in the United States. In 2008, there will be an estimated 186,320 new cases of prostate cancer and 28,660 deaths from this disease in the United States. "Finding methods to prevent and treat prostate cancer remains a priority for the NCI, and with the aid of new molecular diagnostic tools and applications, we hope to continue to make headway in reducing deaths and new cases of this disease," said NCI director John E. Niederhuber, M.D. "The science of cancer prevention is also leading toward individualized, molecular prevention, in which we will calculate risk and design preventive steps based on an individual's genome."
SELECT has been funded by NCI for $114 million, with additional monies from the National Center for Complementary and Alternative Medicine, and with substudies funded and conducted by the National Heart, Lung and Blood Institute, the National Institute of Aging and the National Eye Institute at NIH. The substudies were evaluating the effects of selenium and vitamin E on chronic obstructive pulmonary disease, the development of Alzheimer's disease, and the development of macular degeneration and cataracts, and will continue without participants taking study supplements. An NCI-funded substudy is looking at the effects of the supplements on men who developed colon polyps.
"The SELECT trial owes a tremendous debt to our volunteers, the thousands of men who offered their time and enthusiastic participation, all in the interest of a future when prostate cancer can be prevented," said Laurence H. Baker, D.O., chairman of the Southwest Oncology Group. SELECT investigators are analyzing the data and will submit the analysis for publication in a peer-reviewed medical journal.
The Southwest Oncology Group (SWOG), an international network of research institutions, coordinates SELECT at more than 400 clinical sites in the United States, Puerto Rico, and Canada.
SELECT participants are receiving letters explaining the study review and telling them to stop taking their study supplements. Participants will continue to have their health monitored by study staff, which may include regular digital rectal exams and PSA (prostate-specific antigen) tests to detect prostate cancer. Investigators intend to follow the participants for about three years to determine the long-term effects of having taken either supplement or placebo and to complete a biorepository of blood samples that will be used in extensive molecular analyses to give researchers a better understanding of prostate cancer, other cancers, and other diseases of male aging. This additional data collection is a vital part of the study.
Neither the men nor their physicians know which supplements or placebos the men have been taking, a procedure known as blinding or masking. As followup of the SELECT participants continues, the participants will continue to be blinded. A blinded followup may avoid unintentional bias and potentially false conclusions. However, at the request of a participant, they will be informed which supplement, if any, they received.
" was always designed as a study that would answer more than a single question about prostate cancer," said Eric Klein, M.D., a study co-chair for SELECT, and a physician at the Cleveland Clinic. "As we continue to monitor the health of these 35,000 men, this information may help us understand why two nutrients that showed strong initial evidence to be able to prevent prostate cancer did not do so."
SELECT was undertaken to substantiate earlier, separate findings from studies in which prostate cancer was not the primary outcome: a 1998 study of 29,133 male smokers in Finland who took vitamin E to prevent lung cancer surprisingly showed 32 percent fewer prostate cancers in men who took the supplement, and a 1996 study of 1,312 men and women with skin cancer who took selenium for prevention of the disease showed that men who took the supplement had 52 percent fewer prostate cancers than men who did not take the supplement.
Based on these and other earlier findings, in 2001, men were recruited to participate in SELECT. They were randomly assigned to take one of four sets of supplements or placebos, with more than 8,000 men in each group. One group took both selenium and vitamin E; one took selenium and a vitamin E placebo; one took vitamin E and a selenium placebo; and the final group received placebos of both supplements.
It should be noted that in 2003, while SELECT was recruiting men, a different SWOG-sponsored study reported that the drug finasteride reduced the incidence of prostate cancer by 25 percent. When this was discovered, men on SELECT were informed and allowed to take finasteride. Finasteride has not yet been approved by the U.S. Food and Drug Administration for prostate cancer prevention.
Except for skin cancer, prostate cancer is the most common type of cancer in men in the United States. In 2008, there will be an estimated 186,320 new cases of prostate cancer and 28,660 deaths from this disease in the United States. "Finding methods to prevent and treat prostate cancer remains a priority for the NCI, and with the aid of new molecular diagnostic tools and applications, we hope to continue to make headway in reducing deaths and new cases of this disease," said NCI director John E. Niederhuber, M.D. "The science of cancer prevention is also leading toward individualized, molecular prevention, in which we will calculate risk and design preventive steps based on an individual's genome."
SELECT has been funded by NCI for $114 million, with additional monies from the National Center for Complementary and Alternative Medicine, and with substudies funded and conducted by the National Heart, Lung and Blood Institute, the National Institute of Aging and the National Eye Institute at NIH. The substudies were evaluating the effects of selenium and vitamin E on chronic obstructive pulmonary disease, the development of Alzheimer's disease, and the development of macular degeneration and cataracts, and will continue without participants taking study supplements. An NCI-funded substudy is looking at the effects of the supplements on men who developed colon polyps.
"The SELECT trial owes a tremendous debt to our volunteers, the thousands of men who offered their time and enthusiastic participation, all in the interest of a future when prostate cancer can be prevented," said Laurence H. Baker, D.O., chairman of the Southwest Oncology Group. SELECT investigators are analyzing the data and will submit the analysis for publication in a peer-reviewed medical journal.
Thursday, November 6, 2008
Researchers report that huge doses of an ordinary vitamin appeared to eliminate memory problems in mice with the rodent equivalent of Alzheimer's disease.
At the moment, there's no way to know if the treatment will have the same effect in humans. Researchers are beginning to enroll Alzheimer's patients in a new study, and scientists aren't ready to recommend that people try the vitamin on their own outside of normal doses.
Still, "it's definitely promising, and if we combine this with other things already out there, we'd probably see a large effect," said study author Kim Green, a researcher at the University of California at Irvine.
Alzheimer's disease affects an estimated 5.2 million Americans, causing senility and often leading to death. The Alzheimer's Association estimates that the disease will strike one in eight Baby Boomers.
There's no cure for the neurodegenerative condition, and medications have only limited effects.
In the new study, Green and colleagues looked at nicotinamide, a form of Vitamin B3 that is found in foods such as pork, peanuts, turkey, chicken, veal, fish, salmon, swordfish, tuna and sunflower seeds.
Previous research has suggested that vitamins such as Vitamin E, Vitamin C and Vitamin B12 may help people lower their risk of developing Alzheimer's disease, said Dr. Ralph Nixon, vice chair of the Alzheimer's Association Medical & Scientific Advisory Council.
In the new study, researchers genetically engineered mice to develop the equivalent of human Alzheimer's disease. They tested their memory by putting them in a shallow pool of water and seeing if they could remember the location of a platform that would allow them to emerge from the water.
The researchers then gave Vitamin B3 to some of the mice; the amount was equal to about 2 grams to 3 grams of the vitamin for humans, Green said. The mice were again tested in the pool.
The findings were published online Nov. 5 in The Journal of Neuroscience.
The forgetful mice who took the vitamin did well. "Cognitively, they were cured," Green said. "They performed as if they'd never developed the disease."
The vitamin appears to work by clearing "tangles" of a protein known as tau in brain cells. In Alzheimer's disease, the protein becomes poisonous and contributes to dangerous clogging inside brain cells.
The vitamin holds promise for people, because it's cheap -- Green bought a year's supply for $30 -- and appears to be safe. Even so, "until we've done the proper clinical trials, I wouldn't advocate people rush out and eat grams of this stuff each day," he said.
Nixon said the new study is "intriguing," but people should be cautious and not assume that "more is better" when it comes to possible treatments, even ones that appear to be safe.
At the moment, there's no way to know if the treatment will have the same effect in humans. Researchers are beginning to enroll Alzheimer's patients in a new study, and scientists aren't ready to recommend that people try the vitamin on their own outside of normal doses.
Still, "it's definitely promising, and if we combine this with other things already out there, we'd probably see a large effect," said study author Kim Green, a researcher at the University of California at Irvine.
Alzheimer's disease affects an estimated 5.2 million Americans, causing senility and often leading to death. The Alzheimer's Association estimates that the disease will strike one in eight Baby Boomers.
There's no cure for the neurodegenerative condition, and medications have only limited effects.
In the new study, Green and colleagues looked at nicotinamide, a form of Vitamin B3 that is found in foods such as pork, peanuts, turkey, chicken, veal, fish, salmon, swordfish, tuna and sunflower seeds.
Previous research has suggested that vitamins such as Vitamin E, Vitamin C and Vitamin B12 may help people lower their risk of developing Alzheimer's disease, said Dr. Ralph Nixon, vice chair of the Alzheimer's Association Medical & Scientific Advisory Council.
In the new study, researchers genetically engineered mice to develop the equivalent of human Alzheimer's disease. They tested their memory by putting them in a shallow pool of water and seeing if they could remember the location of a platform that would allow them to emerge from the water.
The researchers then gave Vitamin B3 to some of the mice; the amount was equal to about 2 grams to 3 grams of the vitamin for humans, Green said. The mice were again tested in the pool.
The findings were published online Nov. 5 in The Journal of Neuroscience.
The forgetful mice who took the vitamin did well. "Cognitively, they were cured," Green said. "They performed as if they'd never developed the disease."
The vitamin appears to work by clearing "tangles" of a protein known as tau in brain cells. In Alzheimer's disease, the protein becomes poisonous and contributes to dangerous clogging inside brain cells.
The vitamin holds promise for people, because it's cheap -- Green bought a year's supply for $30 -- and appears to be safe. Even so, "until we've done the proper clinical trials, I wouldn't advocate people rush out and eat grams of this stuff each day," he said.
Nixon said the new study is "intriguing," but people should be cautious and not assume that "more is better" when it comes to possible treatments, even ones that appear to be safe.
