Scientists have provided new evidence that using more fish oil than vegetable oil in the diet decreases the formation of chemicals called prostanoids, which, when produced in excess, increase inflammation in various tissues and organs. The results, by William L. Smith, Professor and Chair of Biological Chemistry at the University of Michigan, Ann Arbor, and colleagues, may help in designing new anti-inflammatory drugs with fewer side effects than the ones currently available.
“Prostanoids help control blood pressure, fight allergies, and modulate inflammation, but too much of them – especially those made from vegetable oils – can also lead to increased pain, swelling, and redness in various tissues,” Smith says. “Our study shows that prostanoids made from fish oil are less effective at causing pain and swelling than those made from vegetable oil and that adding fish oil to the diet decreases the amount of prostanoids made from vegetable oil.”
The new study, to be published in the August 3 issue of the Journal of Biological Chemistry (http://www.jbc.org/), was selected as a “Paper of the Week” by the journal’s editors, meaning that it belongs to the top one percent of papers reviewed in significance and overall importance.
Smith and colleagues looked at the mutual effects of both oils by changing their respective amounts in cultured cells. As expected, a relative increase in fish oil lowered the amount of prostanoids from vegetable oil, although not always in the expected proportions.
Both fish and vegetable oils are converted into prostanoids through chemical reactions that are aided by enzymes called cyclo-oxygenases (COX), two types of which – COX-1 and COX-2 – are involved in the reactions. The scientists showed that, in reactions involving COX-1, when more fish oil is present, it preferentially binds to COX-1, thus limiting vegetable oil’s access to this enzyme. But in reactions involving COX-2, increasing the amount of fish oil did not change the way it binds to COX-2, so a significant portion of vegetable oil was still converted to prostanoids.
“This was completely unexpected,” Smith says. “This new result shows that COX-2 does not ‘prefer’ fish oil to vegetable oil. Regardless of the amount of extra fish oil that we added, COX-2 still helped convert all the vegetable oil available.”
This finding reveals for the first time a limit to how the body naturally regulates levels of prostanoids produced by fish and vegetable oil. If both oil types are present in the body, levels of prostanoids from fish oil will, in general, be higher than those coming from vegetable oil, but mechanisms such as the one involving COX-2 can counter this trend.
The researchers are now investigating why COX-1 and COX-2 act differently. One possibility is that since COX-2 has two binding sites, it can bind to both fish and vegetable oils. When fish oil binds to one of the two sites, it may prepare the other site to bind more easily to vegetable oil, a process called allostery.
Smith and his colleagues hope that by further investigating how prostanoids are regulated in the body, they can design potential drugs that bind to COX-2 and decrease levels of the vegetable oil prostanoids.
“The drugs that are currently used to inhibit COX-1 and COX-2 provide relief from the symptoms of inflammation and pain, but they still have many side effects,” Smith says. “By better understanding how prostanoids work at the cellular level, we hope to find new ways to regulate inflammation and create better anti-inflammatory drugs.”
Thursday, July 26, 2007
Tuesday, July 24, 2007
Eat fish -- especially if you drink lots of alcohol
Essential fatty acids (EFAs) are a necessary part of an individual's healthy diet.
New findings indicate that binge-drinking men have lower intakes of n-3 fats, one type of EFA.
This low intake exacerbates the already very low EFA levels.
Essential fatty acids (EFAs) are just that; an "essential" part of the total fat intake necessary for a healthy human diet. Most EFAs come from plants, but some are animal-sourced. A new study has found that men who binge drink have substandard intake of n-3 fats, one of two types of EFAs, indicating poor dietary choices with negative long-term health consequences.
Results are published in the August issue of Alcoholism: Clinical & Experimental Research.
"Essential fatty acids are important building blocks of living cells, making up a substantial part of cell walls," explained Norman Salem, Jr., chief of the Laboratory of Membrane Biochemistry & Biophysics at the National Institute on Alcohol Abuse and Alcoholism "EFAs also have many biological functions, and a lack of them leads to loss of growth and development, infertility, and a host of physiological and biochemical abnormalities." Salem is also the study's corresponding author.
The most important EFAs are polyunsaturated fatty acids (PUFA), said J. Thomas Brenna, professor of human nutrition and of chemistry & chemical biology at Cornell University. Particularly two types, Brenna noted: the omega-6 PUFA linoleic acid (LA), also called n-6 fats, and the omega-3 PUFA linolenic acid (ALA), also called n-3 fats. "Most Americans consume adequate amounts of LA in their diets through the use of vegetable oils, but tend to have low intakes of ALA," said Brenna.
This imbalance, added Salem, has become pronounced only in the last century and many believe it is a source of the increase of many common diseases in Western society. Salem and his co-authors wanted to investigate what influence alcohol consumption might have on EFA imbalance in the Western diet.
Researchers used data from 4,168 adults who self-reported their alcohol consumption as part of the 2001-2002 National Health and Nutrition Examination Survey. Participants were also interviewed about their EFA intake during a single previous 24-hour period.
Results indicate that EFA intake drops as alcohol consumption increases, particularly among men.
"Our most important finding is the decrease in n-3 EFA intake in binge-drinking men," said Salem. "We really couldn’t evaluate women who binge drink two or more times per week due to the low numbers in this population, although it is quite possible that we would obtain similar findings. The changes we found indicate that those who drink alcohol make food selections in such a way as to decrease foods with this important nutrient. The binge-drinking men have decreases in the longer chain n-3 fatty acids, the ones that we typically get from eating fish, and so this suggests that they eat less fish."
"Previous studies by Dr. Salem and colleagues have shown that requirements for these nutrients actually increase with greater alcohol consumption," noted Brenna. "Considering that the ALA levels are already low compared to the LA levels, these results are further reason for concern over the ALA intake of alcoholics."
"This helps to explain why alcohol abuse leads to losses in polyunsaturated fats in the circulation and organs," said Salem. "However, dietary influence does not explain all of the changes observed in past studies of fatty-acid changes in organs of alcohol abusers. Alcohol also has an effect on fatty acid metabolism, mainly through increasing fat break down."
Furthermore, said Brenna, alcohol has strong, lasting, and deleterious effects on the brain. "The brain depends on a supply of omega-3 PUFA," he said. The brains of men consuming high levels of alcohol, particularly those who regularly binge drink, are further compromised by a low intake of EFA."
"In summary," said Salem, "for those who drink, especially binge drinkers or those who drink more than one drink per day on average: make sure that you obtain your sources of n-3 fatty acids in the diet, that is, eat more fish."
New findings indicate that binge-drinking men have lower intakes of n-3 fats, one type of EFA.
This low intake exacerbates the already very low EFA levels.
Essential fatty acids (EFAs) are just that; an "essential" part of the total fat intake necessary for a healthy human diet. Most EFAs come from plants, but some are animal-sourced. A new study has found that men who binge drink have substandard intake of n-3 fats, one of two types of EFAs, indicating poor dietary choices with negative long-term health consequences.
Results are published in the August issue of Alcoholism: Clinical & Experimental Research.
"Essential fatty acids are important building blocks of living cells, making up a substantial part of cell walls," explained Norman Salem, Jr., chief of the Laboratory of Membrane Biochemistry & Biophysics at the National Institute on Alcohol Abuse and Alcoholism "EFAs also have many biological functions, and a lack of them leads to loss of growth and development, infertility, and a host of physiological and biochemical abnormalities." Salem is also the study's corresponding author.
The most important EFAs are polyunsaturated fatty acids (PUFA), said J. Thomas Brenna, professor of human nutrition and of chemistry & chemical biology at Cornell University. Particularly two types, Brenna noted: the omega-6 PUFA linoleic acid (LA), also called n-6 fats, and the omega-3 PUFA linolenic acid (ALA), also called n-3 fats. "Most Americans consume adequate amounts of LA in their diets through the use of vegetable oils, but tend to have low intakes of ALA," said Brenna.
This imbalance, added Salem, has become pronounced only in the last century and many believe it is a source of the increase of many common diseases in Western society. Salem and his co-authors wanted to investigate what influence alcohol consumption might have on EFA imbalance in the Western diet.
Researchers used data from 4,168 adults who self-reported their alcohol consumption as part of the 2001-2002 National Health and Nutrition Examination Survey. Participants were also interviewed about their EFA intake during a single previous 24-hour period.
Results indicate that EFA intake drops as alcohol consumption increases, particularly among men.
"Our most important finding is the decrease in n-3 EFA intake in binge-drinking men," said Salem. "We really couldn’t evaluate women who binge drink two or more times per week due to the low numbers in this population, although it is quite possible that we would obtain similar findings. The changes we found indicate that those who drink alcohol make food selections in such a way as to decrease foods with this important nutrient. The binge-drinking men have decreases in the longer chain n-3 fatty acids, the ones that we typically get from eating fish, and so this suggests that they eat less fish."
"Previous studies by Dr. Salem and colleagues have shown that requirements for these nutrients actually increase with greater alcohol consumption," noted Brenna. "Considering that the ALA levels are already low compared to the LA levels, these results are further reason for concern over the ALA intake of alcoholics."
"This helps to explain why alcohol abuse leads to losses in polyunsaturated fats in the circulation and organs," said Salem. "However, dietary influence does not explain all of the changes observed in past studies of fatty-acid changes in organs of alcohol abusers. Alcohol also has an effect on fatty acid metabolism, mainly through increasing fat break down."
Furthermore, said Brenna, alcohol has strong, lasting, and deleterious effects on the brain. "The brain depends on a supply of omega-3 PUFA," he said. The brains of men consuming high levels of alcohol, particularly those who regularly binge drink, are further compromised by a low intake of EFA."
"In summary," said Salem, "for those who drink, especially binge drinkers or those who drink more than one drink per day on average: make sure that you obtain your sources of n-3 fatty acids in the diet, that is, eat more fish."
Monday, July 23, 2007
Childhood sun exposure may lower risk of MS
People who spent more time in the sun as children may have a lower risk of developing multiple sclerosis (MS) than people who had less sun exposure during childhood, according to a study published in the July 24, 2007, issue of Neurology®, the medical journal of the American Academy of Neurology.
For the study, researchers surveyed 79 pairs of identical twins with the same genetic risk for MS in which only one twin had MS. The twins were asked to specify whether they or their twin spent more time outdoors during hot days, cold days, and summer, and which one spent more time sun tanning, going to the beach and playing team sports as a child.
The study found the twin with MS spent less time in the sun as a child than the twin who did not have MS. Depending on the activity, the twin who spent more hours outdoors had a 25 to 57 percent reduced risk of developing MS. For example, the risk of developing MS was 49 percent lower for twins who spent more time sun tanning than their siblings.
“Sun exposure appears to have a protective effect against MS,” said study authors Talat Islam, MBBS, PhD, and Thomas Mack, MD, MPH, with the Keck School of Medicine of the University of Southern California in Los Angeles. “Exposure to ultra violet rays may induce protection against MS by alternative mechanisms, either directly by altering the cellular immune response or indirectly by producing immunoactive vitamin D.”
The study also found the protective effect of sun exposure was seen only among female twin pairs, but Mack says this novel finding must be viewed with caution since only a few male twins were involved in the study.
“Our findings note the importance of sun exposure among people with identical genetic risk for MS,” said Mack. “High priority should be given to research into how sun exposure reduces MS risk if we are to unravel the mystery of what causes MS.”
For the study, researchers surveyed 79 pairs of identical twins with the same genetic risk for MS in which only one twin had MS. The twins were asked to specify whether they or their twin spent more time outdoors during hot days, cold days, and summer, and which one spent more time sun tanning, going to the beach and playing team sports as a child.
The study found the twin with MS spent less time in the sun as a child than the twin who did not have MS. Depending on the activity, the twin who spent more hours outdoors had a 25 to 57 percent reduced risk of developing MS. For example, the risk of developing MS was 49 percent lower for twins who spent more time sun tanning than their siblings.
“Sun exposure appears to have a protective effect against MS,” said study authors Talat Islam, MBBS, PhD, and Thomas Mack, MD, MPH, with the Keck School of Medicine of the University of Southern California in Los Angeles. “Exposure to ultra violet rays may induce protection against MS by alternative mechanisms, either directly by altering the cellular immune response or indirectly by producing immunoactive vitamin D.”
The study also found the protective effect of sun exposure was seen only among female twin pairs, but Mack says this novel finding must be viewed with caution since only a few male twins were involved in the study.
“Our findings note the importance of sun exposure among people with identical genetic risk for MS,” said Mack. “High priority should be given to research into how sun exposure reduces MS risk if we are to unravel the mystery of what causes MS.”
Association between low cholesterol levels and cancer
Study finds association between low cholesterol levels and cancer
Benefits of statin therapy outweigh potential small risk
Millions of Americans take statins to lower their cholesterol, but how low should you go" Many scientific studies support the benefits of lowering low-density lipoprotein (LDL) cholesterol, and achieving low LDL cholesterol levels is one of the most important steps in preventing heart disease. New research, however, provides evidence for an association between low LDL levels and cancer risk.
The authors of the study, published in the July 31, 2007, issue of the Journal of the American College of Cardiology (JACC), set out to understand how and why statins cause side effects, particularly damage to the liver and muscle cells. The study findings support taking multiple medications rather than high-dose statins to minimize those side effects. The researchers did not expect to find the increased cancer risk (one additional incident per 1,000 patients) from low LDL levels, and additional studies have already begun to investigate this potential risk further. A key component in future studies will be to confirm the risk and to identify whether the risk may be a side effect of statins or just low LDL.
“This analysis doesn’t implicate the statin in increasing the risk of cancer,” said lead author Richard H. Karas, M.D., F.A.C.C., professor of medicine at Tufts University School of Medicine. “The demonstrated benefits of statins in lowering the risk of heart disease remain clear; however, certain aspects of lowering LDL with statins remain controversial and merit further research.”
The researchers found one additional incident of cancer per 1,000 patients with low LDL levels when compared to patients with higher LDL levels. In their evaluation of randomized controlled statin trials published before November 2005, the researchers looked at 13 treatment arms consisting of 41,173 patients.
Researchers assessed absolute change and percentage of change in LDL reduction and the resulting achieved LDL levels in relation to rates of newly diagnosed cancer in each treatment arm. They also looked at the relationship between low, intermediate and high doses of statins and rates of newly diagnosed cancer. Although they did not find a relationship between percent of change and absolute change in LDL levels, they observed higher rates of newly diagnosed cancer among patients with lower achieved LDL levels. In addition, the new cancers were not of any specific type or location.
Recent data from large-scale statin trials have shown that more intensive LDL lowering can provide significant cardiovascular benefits to higher-risk patients. In response to these findings, recent national guidelines have advocated for lower LDL goals and higher doses of statins to reach them. However, informal observations linking intensive LDL lowering and higher incidence of reported health problems, including liver and muscle toxicity and cancer, has introduced some concern over the safety of such treatments.
These concerns in part prompted the current study. However, the current findings are not definitive, as limitations of the study show. Researchers performed their analysis from summary data taken directly from published manuscripts of each trial. An analysis based on data for each individual patient would have yielded more specific and potentially more compelling results, said Dr. Karas.
“These current findings provide insufficient evidence that there is any problem with LDL lowering that outweighs its significant benefits on vascular disease,” said John C. La Rosa, M.D., who wrote an accompanying editorial in the July 31 issue of JACC. However, “we must continue to be vigilant in ensuring that its benefit clearly outweighs its risk.”
Although the cancer risk was surprising, the researchers primarily sought to determine how and why statins cause side effects, particularly damage to the liver and muscle cells. For this portion of the study, researchers analyzed 23 statin treatment arms that included 75,317 patients with a combined 309,506 years of follow up. A link between LDL lowering and liver or muscle irritation was not found. However, liver toxicity levels increased with higher statin dosage. Based on their findings, the researchers concluded that moderate-dose therapy with multiple medications including statins may prove to be preferable to high-dose therapy with statins alone. Dr. Karas emphasized that patients are advised to continue their statin treatments and, as always, consult their doctor before discontinuing use of any medication.
“While these results raise important new questions about statin use, they do not demonstrate a causal relationship between statins and cancer,” said James Dove, M.D., F.A.C.C., president of the American College of Cardiology. “This study is hypothesis-generating, not hypothesis-proving.”
Benefits of statin therapy outweigh potential small risk
Millions of Americans take statins to lower their cholesterol, but how low should you go" Many scientific studies support the benefits of lowering low-density lipoprotein (LDL) cholesterol, and achieving low LDL cholesterol levels is one of the most important steps in preventing heart disease. New research, however, provides evidence for an association between low LDL levels and cancer risk.
The authors of the study, published in the July 31, 2007, issue of the Journal of the American College of Cardiology (JACC), set out to understand how and why statins cause side effects, particularly damage to the liver and muscle cells. The study findings support taking multiple medications rather than high-dose statins to minimize those side effects. The researchers did not expect to find the increased cancer risk (one additional incident per 1,000 patients) from low LDL levels, and additional studies have already begun to investigate this potential risk further. A key component in future studies will be to confirm the risk and to identify whether the risk may be a side effect of statins or just low LDL.
“This analysis doesn’t implicate the statin in increasing the risk of cancer,” said lead author Richard H. Karas, M.D., F.A.C.C., professor of medicine at Tufts University School of Medicine. “The demonstrated benefits of statins in lowering the risk of heart disease remain clear; however, certain aspects of lowering LDL with statins remain controversial and merit further research.”
The researchers found one additional incident of cancer per 1,000 patients with low LDL levels when compared to patients with higher LDL levels. In their evaluation of randomized controlled statin trials published before November 2005, the researchers looked at 13 treatment arms consisting of 41,173 patients.
Researchers assessed absolute change and percentage of change in LDL reduction and the resulting achieved LDL levels in relation to rates of newly diagnosed cancer in each treatment arm. They also looked at the relationship between low, intermediate and high doses of statins and rates of newly diagnosed cancer. Although they did not find a relationship between percent of change and absolute change in LDL levels, they observed higher rates of newly diagnosed cancer among patients with lower achieved LDL levels. In addition, the new cancers were not of any specific type or location.
Recent data from large-scale statin trials have shown that more intensive LDL lowering can provide significant cardiovascular benefits to higher-risk patients. In response to these findings, recent national guidelines have advocated for lower LDL goals and higher doses of statins to reach them. However, informal observations linking intensive LDL lowering and higher incidence of reported health problems, including liver and muscle toxicity and cancer, has introduced some concern over the safety of such treatments.
These concerns in part prompted the current study. However, the current findings are not definitive, as limitations of the study show. Researchers performed their analysis from summary data taken directly from published manuscripts of each trial. An analysis based on data for each individual patient would have yielded more specific and potentially more compelling results, said Dr. Karas.
“These current findings provide insufficient evidence that there is any problem with LDL lowering that outweighs its significant benefits on vascular disease,” said John C. La Rosa, M.D., who wrote an accompanying editorial in the July 31 issue of JACC. However, “we must continue to be vigilant in ensuring that its benefit clearly outweighs its risk.”
Although the cancer risk was surprising, the researchers primarily sought to determine how and why statins cause side effects, particularly damage to the liver and muscle cells. For this portion of the study, researchers analyzed 23 statin treatment arms that included 75,317 patients with a combined 309,506 years of follow up. A link between LDL lowering and liver or muscle irritation was not found. However, liver toxicity levels increased with higher statin dosage. Based on their findings, the researchers concluded that moderate-dose therapy with multiple medications including statins may prove to be preferable to high-dose therapy with statins alone. Dr. Karas emphasized that patients are advised to continue their statin treatments and, as always, consult their doctor before discontinuing use of any medication.
“While these results raise important new questions about statin use, they do not demonstrate a causal relationship between statins and cancer,” said James Dove, M.D., F.A.C.C., president of the American College of Cardiology. “This study is hypothesis-generating, not hypothesis-proving.”
NSAIDs treatment can reduce colorectal cancer risk
Study confirms that NSAIDs treatment can reduce colorectal cancer risk
Safer drugs needed before regular preventive therapy can be recommended
A study of Medicare patients with osteoarthritis provides additional evidence that non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin reduce the risk of colorectal cancer. Earlier investigations of the drugs’ impact on tumor development could not rule out the possibility that an observed protective effect was caused by other preventive health care measures. The current study, led by a Massachusetts General Hospital (MGH) physician, appears in the August 2007 Journal of General Internal Medicine.
“This is good news for people who take NSAIDs regularly for osteoarthritis,” says Elizabeth Lamont, MD, MS, of the MGH Cancer Center, the study’s lead author. “Although patients face risks such as bleeding or kidney damage from this therapy, they probably are at a lower risk of developing colorectal cancer.” Because of the risks posed by the dosage used to treat osteoarthritis, she and her co-authors stress that currently available NSAIDs should not be used solely to prevent cancer.
Earlier randomized trials clearly showed that NSAID treatment can prevent the development of precancerous colorectal polyps, but whether or not such therapy also reduces the risk of invasive colorectal cancer has not yet been confirmed. Those trials used relatively low doses of aspirin and showed no significant differences in colorectal cancer rates between the aspirin and placebo groups. While many observational studies have shown a protective effect of NSAIDs against colorectal cancer, interpretation of some of those results may have been clouded by other healthy behaviors of the participants.
“It would be ideal to conduct a randomized clinical trial – in which half the patients receive NSAIDs at doses higher than those used in prior trials and half receive placebos – and follow both groups for many years for evidence of cancer. But such trials are expensive, time consuming, and could present real health risks to participants. Therefore, we took advantage of a natural ‘experiment’ by comparing data from patients known to regularly take higher amounts of NSAIDs with that from those taking lower doses in order to evaluate any effect on colorectal cancer risk.”
First the researchers reviewed data from the 1993-94 National Ambulatory Medical Care Survey, in which physicians report on the diagnoses of and treatments prescribed to patients seen during a randomly selected week. Those results verified that older patients with osteoarthritis were more than four times as likely to take NSAIDs as were those without osteoarthritis. They then analyzed information from the Survival Epidemiology and End-Results (SEER)-Medicare program, studying groups of elderly Medicare patients with and without colorectal cancer, to search for associations with NSAID use.
Comparing information on 4,600 individuals with colorectal cancer to data from 100,000 controls, they found that a history of osteoarthritis was associated with a 15 percent reduction in the likelihood of a colorectal cancer diagnosis. A similar association was seen when total knee replacement was used as a marker for NSAID treatment.
“The magnitude of colorectal cancer risk reduction between patients with and without osteoarthritis is completely consistent with the risk reduction for pre-cancerous polyps reported in clinical trials of NSAIDs,” Lamont says. “Confirming this association supports the need for further research to identify NSAID agents safe enough to be used for regular, preventive therapy by the general population.”
Safer drugs needed before regular preventive therapy can be recommended
A study of Medicare patients with osteoarthritis provides additional evidence that non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin reduce the risk of colorectal cancer. Earlier investigations of the drugs’ impact on tumor development could not rule out the possibility that an observed protective effect was caused by other preventive health care measures. The current study, led by a Massachusetts General Hospital (MGH) physician, appears in the August 2007 Journal of General Internal Medicine.
“This is good news for people who take NSAIDs regularly for osteoarthritis,” says Elizabeth Lamont, MD, MS, of the MGH Cancer Center, the study’s lead author. “Although patients face risks such as bleeding or kidney damage from this therapy, they probably are at a lower risk of developing colorectal cancer.” Because of the risks posed by the dosage used to treat osteoarthritis, she and her co-authors stress that currently available NSAIDs should not be used solely to prevent cancer.
Earlier randomized trials clearly showed that NSAID treatment can prevent the development of precancerous colorectal polyps, but whether or not such therapy also reduces the risk of invasive colorectal cancer has not yet been confirmed. Those trials used relatively low doses of aspirin and showed no significant differences in colorectal cancer rates between the aspirin and placebo groups. While many observational studies have shown a protective effect of NSAIDs against colorectal cancer, interpretation of some of those results may have been clouded by other healthy behaviors of the participants.
“It would be ideal to conduct a randomized clinical trial – in which half the patients receive NSAIDs at doses higher than those used in prior trials and half receive placebos – and follow both groups for many years for evidence of cancer. But such trials are expensive, time consuming, and could present real health risks to participants. Therefore, we took advantage of a natural ‘experiment’ by comparing data from patients known to regularly take higher amounts of NSAIDs with that from those taking lower doses in order to evaluate any effect on colorectal cancer risk.”
First the researchers reviewed data from the 1993-94 National Ambulatory Medical Care Survey, in which physicians report on the diagnoses of and treatments prescribed to patients seen during a randomly selected week. Those results verified that older patients with osteoarthritis were more than four times as likely to take NSAIDs as were those without osteoarthritis. They then analyzed information from the Survival Epidemiology and End-Results (SEER)-Medicare program, studying groups of elderly Medicare patients with and without colorectal cancer, to search for associations with NSAID use.
Comparing information on 4,600 individuals with colorectal cancer to data from 100,000 controls, they found that a history of osteoarthritis was associated with a 15 percent reduction in the likelihood of a colorectal cancer diagnosis. A similar association was seen when total knee replacement was used as a marker for NSAID treatment.
“The magnitude of colorectal cancer risk reduction between patients with and without osteoarthritis is completely consistent with the risk reduction for pre-cancerous polyps reported in clinical trials of NSAIDs,” Lamont says. “Confirming this association supports the need for further research to identify NSAID agents safe enough to be used for regular, preventive therapy by the general population.”
Saturday, July 21, 2007
Prostate drug doesn't limit sex in most men
Finasteride, found earlier to reduce prostate cancer incidence by nearly 25 percent, has slight impact that lessens over time
Men and their physicians need not hesitate to use a drug proven effective in preventing prostate cancer out of concern that it is likely to cause sexual dysfunction, say authors of a study conducted by the Southwest Oncology Group.
The authors, who surveyed more than 17,000 men 55 and older for seven years, reported their results in the July 4 Journal of the National Cancer Institute. The study found that men given finasteride reported on average more dysfunction than did men given a placebo. That small effect diminished over the seven years.
The results allay concerns about a negative side effect associated with finasteride up till now. Physicians usually warn that sexual dysfunction is a possibility when they discuss the drug with patients. Finasteride is an FDA-approved drug for the treatment of benign prostatic hyperplasia, but it is not yet FDA-approved for the prevention or reduction in risk for prostate cancer.
The study’s large sample and long follow-up period allowed researchers to examine whether or not finasteride negatively affected sexual function and, if so, whether this effect was lasting, said Carol Moinpour, Ph.D., of the Fred Hutchison Cancer Research Center in Seattle, the study’s lead author. She coordinates quality-of-life studies for the Southwest Oncology Group, the nation’s largest National Cancer Institute-funded clinical trials network.
The study grew out of the Prostate Cancer Prevention Trial, a large double-blind National Cancer Institute-funded study which found that finasteride, a drug which curbs the proliferation of prostate gland cells, is effective at preventing prostate cancer in men age 55 and older. The 2003 results of that trial, conducted by the Southwest Oncology Group in more than 18,000 men, showed that finasteride could reduce a man’s chances of getting prostate cancer by almost 25 percent.
The authors of the newly published sexual function results wanted to assess how many men in the Prostate Cancer Prevention Trial reported experiencing sexual dysfunction, and whether the problems decreased or increased over time. In earlier studies, some men taking finasteride reported decreased libido, impotence and other signs of diminished sexual function. But these studies were short-term and didn’t try to assess the effects of age and other health factors, as well as individual variation.
The study authors used two surveys, a widely used Sexual Problems Scale and another questionnaire which they created, the Sexual Activity Scale. They also gathered other data to take into account other health factors that affect sexual function, such as age, medical conditions and smoking status. They surveyed the subjects three times in the first year and then annually for seven years.
“Was this average decrease (in sexual function) an important difference" We concluded it was not,” Moinpour said, adding that there were much larger differences due simply to individual variation among men in the trial.
The study suggests that finasteride will cause little or no sexual dysfunction for most men who decide to take it, conclude the authors.
Men and their physicians need not hesitate to use a drug proven effective in preventing prostate cancer out of concern that it is likely to cause sexual dysfunction, say authors of a study conducted by the Southwest Oncology Group.
The authors, who surveyed more than 17,000 men 55 and older for seven years, reported their results in the July 4 Journal of the National Cancer Institute. The study found that men given finasteride reported on average more dysfunction than did men given a placebo. That small effect diminished over the seven years.
The results allay concerns about a negative side effect associated with finasteride up till now. Physicians usually warn that sexual dysfunction is a possibility when they discuss the drug with patients. Finasteride is an FDA-approved drug for the treatment of benign prostatic hyperplasia, but it is not yet FDA-approved for the prevention or reduction in risk for prostate cancer.
The study’s large sample and long follow-up period allowed researchers to examine whether or not finasteride negatively affected sexual function and, if so, whether this effect was lasting, said Carol Moinpour, Ph.D., of the Fred Hutchison Cancer Research Center in Seattle, the study’s lead author. She coordinates quality-of-life studies for the Southwest Oncology Group, the nation’s largest National Cancer Institute-funded clinical trials network.
The study grew out of the Prostate Cancer Prevention Trial, a large double-blind National Cancer Institute-funded study which found that finasteride, a drug which curbs the proliferation of prostate gland cells, is effective at preventing prostate cancer in men age 55 and older. The 2003 results of that trial, conducted by the Southwest Oncology Group in more than 18,000 men, showed that finasteride could reduce a man’s chances of getting prostate cancer by almost 25 percent.
The authors of the newly published sexual function results wanted to assess how many men in the Prostate Cancer Prevention Trial reported experiencing sexual dysfunction, and whether the problems decreased or increased over time. In earlier studies, some men taking finasteride reported decreased libido, impotence and other signs of diminished sexual function. But these studies were short-term and didn’t try to assess the effects of age and other health factors, as well as individual variation.
The study authors used two surveys, a widely used Sexual Problems Scale and another questionnaire which they created, the Sexual Activity Scale. They also gathered other data to take into account other health factors that affect sexual function, such as age, medical conditions and smoking status. They surveyed the subjects three times in the first year and then annually for seven years.
“Was this average decrease (in sexual function) an important difference" We concluded it was not,” Moinpour said, adding that there were much larger differences due simply to individual variation among men in the trial.
The study suggests that finasteride will cause little or no sexual dysfunction for most men who decide to take it, conclude the authors.
Wednesday, July 11, 2007
Poor diets = more respiratory symptoms in teens
Can an apple a day keep asthma away?
Poor diets show increased respiratory symptoms in teens
Teenagers who forego a healthy and balanced diet may have a harder time catching their breath. A new study, published in the July issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians (ACCP), shows that a low dietary intake of certain nutrients increases the likelihood of respiratory symptoms such as asthma, especially in teens who smoke. Furthermore, a lack of these nutrients may also lead to lower lung function.
“Our study, as well as other research, suggests that higher intakes of antioxidant and anti-inflammatory micronutrients are associated with lower reports of cough, respiratory infections, and less severe asthma-related symptoms,” said lead study author Jane Burns, ScD, Harvard School of Public Health. “Teenagers who have low dietary intakes of fruit, vitamin E, and omega-3 fatty acids are at greater risk of having asthma, emphasizing the importance of a balanced diet, composed of whole foods.”
While observing 12th-grade students from 12 communities around the US and Canada, Dr. Burns and her colleagues from the Harvard School of Public Health, Health Canada, Brigham and Women’s Hospital, and the Environmental Protection Agency (EPA), examined the associations of low dietary nutrient intake with low pulmonary function and respiratory symptoms. Over the period of one school year, 2,112 students completed a standardized respiratory questionnaire and a dietary questionnaire. They also answered questions about medication use, smoking habits, and recent exercise, before participating in lung function testing. Dr. Burns explained that the researchers focused on teens because it is the ideal age at which to test lung capacity and eating habits.
“During late adolescence, physical stature has, on average, been attained and lung growth closely parallels this growth. Therefore we were observing a time when lung function was close to its optimal capacity,” she said. “Also, although our diet survey targeted eating habits only during the past year, it did give us some idea of the teens’ general past diet. However, their current respiratory health may be a reflection of diet during childhood, as well as during the past year.”
The majority of adolescents in the study were white, one third was overweight, and 72% did not consume multivitamins. Also, nearly 25% reported smoking on a daily basis. Researchers also found that at least one third of the students’ diets were below the recommended levels of fruit, vegetable, vitamins A and E, beta-carotene, and omega-3 fatty acid intake.
“Vitamin supplements can help teens meet their daily recommended levels,” said Dr. Burns, “and surprisingly, even relatively low levels of omega-3 fatty acids appeared to protect teens from higher reported respiratory symptoms.”
Results showed that low dietary intakes of fruit, vitamins C and E, and omega-3 fatty acids were associated with decreased lung function and a greater risk of chronic bronchitic symptoms, wheeze, and asthma. These risks were further increased among students with the lowest intakes and who also smoked.
“I wish we could say that an apple a day can keep asthma away, but it’s a complex disease with a genetic component. However, it may be that certain foods can lessen or prevent asthma symptoms,” said Dr. Burns. “The most important thing to remember is that diet can have a significant impact on teens’ respiratory health. I would encourage them to make healthy eating a part of their daily routine, and stress to them that smoking is bad.” Researchers emphasized that fresh fruits make for convenient snacks. They also suggest preparing a simple, daily family meal, as a method to promote both communication and good nutrition.
“A balanced diet is not only good for lung health, but for general health,” said Mark J. Rosen, MD, FCCP, President of the American College of Chest Physicians. “Parents and physicians should work together to monitor and maintain healthy diets and lifestyles for children of all ages.”
Poor diets show increased respiratory symptoms in teens
Teenagers who forego a healthy and balanced diet may have a harder time catching their breath. A new study, published in the July issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians (ACCP), shows that a low dietary intake of certain nutrients increases the likelihood of respiratory symptoms such as asthma, especially in teens who smoke. Furthermore, a lack of these nutrients may also lead to lower lung function.
“Our study, as well as other research, suggests that higher intakes of antioxidant and anti-inflammatory micronutrients are associated with lower reports of cough, respiratory infections, and less severe asthma-related symptoms,” said lead study author Jane Burns, ScD, Harvard School of Public Health. “Teenagers who have low dietary intakes of fruit, vitamin E, and omega-3 fatty acids are at greater risk of having asthma, emphasizing the importance of a balanced diet, composed of whole foods.”
While observing 12th-grade students from 12 communities around the US and Canada, Dr. Burns and her colleagues from the Harvard School of Public Health, Health Canada, Brigham and Women’s Hospital, and the Environmental Protection Agency (EPA), examined the associations of low dietary nutrient intake with low pulmonary function and respiratory symptoms. Over the period of one school year, 2,112 students completed a standardized respiratory questionnaire and a dietary questionnaire. They also answered questions about medication use, smoking habits, and recent exercise, before participating in lung function testing. Dr. Burns explained that the researchers focused on teens because it is the ideal age at which to test lung capacity and eating habits.
“During late adolescence, physical stature has, on average, been attained and lung growth closely parallels this growth. Therefore we were observing a time when lung function was close to its optimal capacity,” she said. “Also, although our diet survey targeted eating habits only during the past year, it did give us some idea of the teens’ general past diet. However, their current respiratory health may be a reflection of diet during childhood, as well as during the past year.”
The majority of adolescents in the study were white, one third was overweight, and 72% did not consume multivitamins. Also, nearly 25% reported smoking on a daily basis. Researchers also found that at least one third of the students’ diets were below the recommended levels of fruit, vegetable, vitamins A and E, beta-carotene, and omega-3 fatty acid intake.
“Vitamin supplements can help teens meet their daily recommended levels,” said Dr. Burns, “and surprisingly, even relatively low levels of omega-3 fatty acids appeared to protect teens from higher reported respiratory symptoms.”
Results showed that low dietary intakes of fruit, vitamins C and E, and omega-3 fatty acids were associated with decreased lung function and a greater risk of chronic bronchitic symptoms, wheeze, and asthma. These risks were further increased among students with the lowest intakes and who also smoked.
“I wish we could say that an apple a day can keep asthma away, but it’s a complex disease with a genetic component. However, it may be that certain foods can lessen or prevent asthma symptoms,” said Dr. Burns. “The most important thing to remember is that diet can have a significant impact on teens’ respiratory health. I would encourage them to make healthy eating a part of their daily routine, and stress to them that smoking is bad.” Researchers emphasized that fresh fruits make for convenient snacks. They also suggest preparing a simple, daily family meal, as a method to promote both communication and good nutrition.
“A balanced diet is not only good for lung health, but for general health,” said Mark J. Rosen, MD, FCCP, President of the American College of Chest Physicians. “Parents and physicians should work together to monitor and maintain healthy diets and lifestyles for children of all ages.”
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