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April 13, 2009JAMA news releases are made available to the public after 3 pm US Central time on the first 4 Tuesdays of each month. The Archives of 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 CONTENTS
ARCHIVES OF INTERNAL MEDICINE NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, April 13, 2009)
ARCHIVES OF NEUROLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, April 13, 2009)
ARCHIVES OF OPHTHALMOLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, April 13, 2009)
INFORMATION CONTAINED IN THESE NEWS RELEASES IS PROTECTED BY COPYRIGHT. JOURNAL ATTRIBUTION IS REQUIRED. JOURNALISTS CAN NOW ACCESS EMBARGOED JAMA/ARCHIVES STUDIES ON-LINE. Go to www.jamamedia.org for more information and to apply for access. Please Note: The FOR THE MEDIA website now has a search feature to enable media to find previous JAMA/Archives news releases on specific medical topics. This search feature link is located on the home page at www.jamamedia.org
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
Review Identifies Dietary Factors Associated With Heart Disease Risk
CHICAGO—A review of previously published studies suggests that vegetable and nut intake and a Mediterranean dietary pattern appear to be associated with a lower risk for heart disease, according to a report published in the April 13 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. However, intake of trans-fatty acids and foods with a high glycemic index may be harmful to heart health. "The relationship between dietary factors and coronary heart disease has been a major focus of health research for almost half a century," the authors write as background information in the article. Although "a wealth of literature" has been published on the topic, "the strength of the evidence supporting valid associations has not been evaluated systematically in a single investigation." Andrew Mente, Ph.D., of the Population Health Research Institute, and colleagues conducted a systematic search for articles investigating dietary factors in relation to heart disease published between 1950 and June 2007. A total of 146 prospective cohort studies (looking back on the habits of a particular group of individuals) and 43 randomized controlled trials (where participants are randomly assigned to a dietary intervention or a control group) were identified and included in the systematic review. When the researchers pooled the study results and applied a predefined algorithm, "we identified strong evidence of a causal relationship for protective factors, including intake of vegetables, nuts and monounsaturated fatty acids and Mediterranean, prudent and high-quality dietary patterns, and harmful factors, including intake of trans–fatty acids and foods with a high glycemic index or load and a western dietary pattern," they write. "Among these dietary exposures, however, only a Mediterranean dietary pattern has been studied in randomized controlled trials and significantly associated with coronary heart disease." In addition, modest relationships were found supporting a causal relationship between intake of several other foods and vitamins and heart disease risk, including fish, omega-3 fatty acids from marine sources, folate, whole grains, alcohol, fruits, fiber and dietary vitamins E and C and beta carotene. Weak evidence also supported causal relationships between vitamin E and ascorbic acid supplements, saturated and polyunsaturated fatty acids and total fats, alpha-linoleic acid, meat, eggs and milk. "The modest or weak evidence of these dietary exposures is mostly consistent with the findings of randomized controlled trials, although randomized controlled trials have yet to be conducted for several factors," the authors write. "Taken together, these findings support a causal relationship between only a few dietary exposures and coronary heart disease, whereas the evidence for most individual nutrients or foods is too modest to be conclusive."
"Although investigations of dietary components may help to shed light on mechanisms behind the benefits of dietary patterns, it is unlikely that modifying the intake of a few nutrients or foods would substantially influence coronary outcomes," they conclude. "Our findings support the strategy of investigating dietary patterns in cohort studies and randomized controlled trials for common and complex chronic diseases such as coronary heart disease."
Editor's Note: This study was supported by a Heart and Stroke Foundation of Canada Postdoctoral Research Fellowship, the Canadian Institutes of Health Research Clinician-Scientist Phase 2 Award and a Heart and Stroke Foundation of Ontario Michael E. DeGroote Research Chair in Population Health Research. Co-author Mr. de Koning is a recipient of a Canadian Institutes of Health Research Canada Graduate Scholarship Doctoral Award. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
Former Inmates Have Increased Risk of High Blood Pressure
CHICAGO—Young adults who have been incarcerated appear more likely to have high blood pressure and left ventricular hypertrophy, an enlarging of the heart muscle that is a common consequence of hypertension, according to a report in the April 13 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. They also appear less likely to have access to regular medical care than those who have not been incarcerated. "Incarceration has become increasingly frequent in the lives of young adults," the authors write as background information in the article. Between 1987 and 2007, the U.S. prison population tripled. More than one in 30 men and one in nine black men between the ages of 20 and 34 are incarcerated. "This rise in incarceration as a normative experience for young men and young black men in particular makes it especially important to understand the implications of incarceration on future health status." Emily A. Wang, M.D, of San Francisco General Hospital and the University of California, San Francisco, and colleagues studied the association of prior incarceration with future onset of high blood pressure (hypertension), diabetes and abnormal cholesterol in 4,350 individuals involved in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were enrolled in 1985 to 1986, at ages 18 to 30, and were followed up after two, five, seven, 10, 15 and 20 years. Of these, 288 or 7 percent of participants reported being incarcerated one year prior to or two years following their enrollment. Former inmates were more likely to have hypertension in young adulthood than those who had not been incarcerated (12 percent vs. 7 percent three to five years later), even after considering other related factors such as smoking, alcohol and drug use and family income. In addition, left ventricular hypertrophy was more common among those with a history of incarceration (2 percent vs. 0.6 percent). "Former inmates were also more likely to lack treatment for their hypertension at the year seven examination (17 percent [former inmates] vs. 41 percent [no prior incarceration] treated) and in each of the follow-up visits during the entire 20-year duration of the CARDIA study," the authors write. The mechanisms by which incarceration may lead to high blood pressure are not well understood, the authors note. Commonly cited factors such as drug and alcohol use, obesity and lower socioeconomic status may not entirely explain the association, since the current findings indicated an association between incarceration and hypertension after considering these factors. Other explanations include increased hostility and stress among former inmates, which may raise hormone levels that contribute to higher blood pressure.
"For the more than 7 million people that pass through U.S. jails and prisons each year, incarceration may be an independent risk factor for the development of hypertension and left ventricular hypertrophy, both of which put such persons at higher risk for clinical cardiovascular disease," the authors conclude. "Incarceration may be a cause for hypertension and cardiovascular disease, but may also present an underused opportunity for intervention and improving health and access to health care."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
Many Clinicians Unaware of Federally Funded Research on Alternative Therapies
CHICAGO—Approximately one in four practicing clinicians appear to be aware of two major federally funded clinical trials of alternative therapies, and many do not express confidence in their ability to interpret research results, according to a report in the April 13 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. Complementary and alternative (CAM) therapies are widely used, but until recently few rigorous studies of their safety and effectiveness have been conducted, according to background information in the article. The National Institutes of Health (NIH) has invested more than $2 billion into this type of scientific research in the past decade. "For this investment to achieve its anticipated social value, clinical research must be translated into improvements in clinical and public health practice—a process fraught with obstacles," the authors write. "For evidence from clinical research to have an impact on medical practice, health care professionals must first be aware of the research. Once aware, health care professionals must be able to interpret these findings, judging both their validity and their implications. Finally, they must apply the scientific evidence to their own practices," they continue. To assess this translation process surrounding CAM research, Jon C. Tilburt, M.D., M.P.H., of the NIH, Bethesda, Md., and Mayo Clinic, Rochester, Minn., and colleagues surveyed 2,400 practicing acupuncturists, naturopaths, internists and rheumatologists about their awareness of and attitudes toward CAM research. A total of 1,561 clinicians (65 percent) completed the survey. Of those, 59 percent were aware of at least one of two major clinical trials recently published on CAM therapies for osteoarthritis of the knee (on assessing acupuncture and the other about the supplement glucosamine); only 23 percent were aware of both trials. Acupuncturists (46 percent) and rheumatologists (49 percent) were more likely to be aware of the acupuncture study than naturopaths (30 percent) and general internists (22 percent), whereas for the glucosamine trial, internists (59 percent) and rheumatologists (88 percent) were more aware than acupuncturists (20 percent) and naturopaths (39 percent). A minority of clinicians in all groups said they were "very confident" in their ability to critically interpret research literature (20 percent of acupuncturists, 25 percent of naturopaths, 17 percent of internists and 33 percent of rheumatologists); more described themselves as "moderately confident" (59 percent of acupuncturists, 64 percent of naturopaths, 67 percent of internists and 59 percent of rheumatologists) "Compared with those who were not aware of CAM trials, clinicians who were aware of CAM trials were much more likely to be rheumatologists, to be practicing in an institutional or academic setting, to have some research experience, to express greater ability to interpret evidence and to report greater acceptance of evidence," the authors write.
The results suggest that the translation of CAM trial results into clinical practice may vary widely based on the training, attitudes and experiences of the clinicians who might apply them, they continue. "For clinical research in CAM (and conventional medicine) to achieve its potential social value, concerted efforts must be undertaken that more deliberately train clinicians in critical appraisal, biostatistics and use of evidence-based resources, as well as expanded research opportunities, dedicated training experiences and improved dissemination of research results," the authors conclude.
Editor's Note: Funding for this research was provided by the National Center for Complementary and Alternative Medicine and the Department of Bioethics, National Institutes of Health. Co-author Dr. Curlin as supported by a grant from the National Center for Complementary and Alternative Medicine. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Evidence-Based Medicine Goes Beyond Research Results
"If we are to teach more evidence-based medicine to physicians, we need to broaden and deepen our understanding of what counts as ‘evidence' and which types of evidence are best used to inform differing aspects of clinical decision making," writes Wayne B. Jonas, M.D., of the Samueli Institute, Alexandria, Va., in an accompanying editorial. "Rather than imposing an academic, hierarchical structure on medical decision making, evidence-based medicine should seek to inform the processes practitioners actually use in making clinical decisions to more effectively incorporate science into practice," Dr. Jonas writes. "That is, physicians need to know how to use a complete ‘evidence house' and not just the ‘evidence hierarchy' currently dominating evidence-based medicine in both conventional and complementary medicine."
"As with any skill, sufficient time and supervised application is needed before evidence-based medicine can become a habit in daily practice. Thus, both CAM and conventional practitioners should each seek to fill their respective gaps in knowledge and skills to make practices both more patient relevant and scientifically rigorous."
Editor's Note: Please see the article for additional information, including author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
Aspirin and Similar Drugs May Be Associated With Brain Microbleeds in Older Adults
CHICAGO—Individuals who take aspirin or other medications that prevent blood clotting by inhibiting the accumulation of platelets appear more likely to have tiny, asymptomatic areas of bleeding in the brain, according to a report posted online today that will appear in the June print issue of Archives of Neurology, one of the JAMA/Archives journals. Cerebral microbleeds—small deposits of the iron-storing protein hemosiderin in the brain—may be a sign of cerebral small-vessel disease, according to background information in the article. This condition, common among older adults, occurs when the walls of blood vessels in the brain become weakened. When microbleeds occur in certain brain areas, they may indicate a type of small vessel disease known as cerebral amyloid angiopathy, in which the accumulation of amyloid (a protein often related to Alzheimer's disease) causes degeneration of smooth muscle cells and increases the susceptibility of blood vessels to ruptures and hemorrhages. Meike W. Vernooij, M.D., and colleagues at Erasmus MC University Medical Center, Rotterdam, the Netherlands, investigated the relationship between cerebral microbleeds and the use of anti-clotting medications in 1,062 individuals without dementia involved in the Rotterdam Scan Study. Participants (average age 69.6) underwent magnetic resonance imaging examinations in 2005 and 2006. Pharmacy records were used to assess whether any of the individuals took anti-clotting drugs. These included aspirin and carbasalate calcium—called platelet aggregation inhibitors because they prevent the accumulation of platelets that form blood clots. In the years before MRI, 363 (34.2 percent) of the participants had used any anti-clotting drugs, including 245 (23.1 percent) who took platelet aggregation inhibitors (67 taking aspirin and 141 taking carbasalate calcium). Compared with patients who did not use anti-clotting drugs, those who took aspirin or carbasalate calcium were more likely to have cerebral microbleeds visible on MRI. This association was particularly strong among individuals taking these drugs at higher doses, typically used to treat or prevent heart disease. Microbleeds in the frontal lobe were more common among aspirin users than carbasalate calcium users. There was no association between other types of anti-clotting drugs and cerebral microbleeds. "There is currently major interest in bleeding risks with the use of antithrombotic or thrombolytic treatment in persons who have microbleeds that are apparent on MRI because this may affect treatment in patients with cardiovascular or cerebrovascular disease," the authors write. "The cross-sectional design of our analyses prohibited an investigation of whether persons with cerebral microbleeds are at increased risk for symptomatic hemorrhage [excessive bleeding] when using platelet aggregation inhibitors."
The beneficial effects of anti-clotting drugs for individuals at risk for heart attack and stroke typically outweigh any risks of bleeding, they note. "Nevertheless, it may be that in selected persons (e.g., those with signs of cerebral amyloid angiopathy), this risk-benefit ratio may differ for certain drugs (e.g., aspirin), thus influencing treatment decision," they conclude.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
Imaging Reveals Abnormalities in Pathways Connecting Brain Areas in Those With Writer's Cramp
CHICAGO—Abnormalities in the fibers connecting different brain areas may contribute to muscle disorders such as writer's cramp, according to a report in the April issue of Archives of Neurology, one of the JAMA/Archives journals. Previous studies of individuals with writer's cramp have identified changes in the gray matter of several brain areas, according to background information in the article. These include the basal ganglia (structures that help control and start movement), sensorimotor cortex (controls sensory and motor functions), thalamus (coordinates multiple impulses including some related to the senses) and cerebellum (controls voluntary movements, posture and balance). In the new study, Christine Delmaire, M.D., of Centre Hospitalier Régional Universitaire Roger Salengro, Lille, France, and Institut National de la Santé et de la Récherche Médicale, Paris, studied 26 right-handed patients with writer's cramp and 26 right-handed control participants who were the same sex and age but did not have writer's cramp. All participants underwent diffusion-tensor magnetic resonance imaging (DTI), which has been shown to assess the status of white matter (coated nerve fibers that allow impulses to travel through the brain). The DTI scans of patients with writer's cramp revealed areas of abnormalities in the white matter of nerve pathways connecting the main sensorimotor cortex to brain areas below the cortex, such as the thalamus. The same abnormalities were not observed in healthy controls.
"In conclusion, this study suggests that writer's cramp is associated with microstructural changes involving fibers that carry afferents [information from senses to the brain] and efferents [motor information from the brain to the muscles] to the primary sensorimotor cortex," the authors write. "However, it is unknown how these changes relate to the physiopathology of the disease."
Editor's Note: This study was supported by grants from the Clinical Investigation Center of the Salpêtrière Hospital, the Action Concerté e Incitative 2001, the IFR49, the INSERM French Dystonia Network 19 and GIS maladies rares and the Action de Recherche Cooperative DMRI 2007. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
Erectile Dysfunction Treatments Do Not Appear to Damage Vision Over Six Months
CHICAGO—Two medications used to treat erectile dysfunction in men (tadalafil and sildenafil) do not appear to have visual side effects when taken daily for six months, despite concerns about eye-related complications, according to a report in the April issue of Archives of Ophthalmology, one of the JAMA/Archives journals. The advent of the medications sildenafil citrate (sold as Viagra), tadalafil (sold as Cialis) and verdenafil hydrochloride (sold as Levitra) has profoundly changed the treatment of erectile dysfunction, according to background information in the article. These medications are known as selective phodiesterase type 5 (PDE5) inhibitors because they treat erectile dysfunction by interfering with the action of the compound PDE5 on the blood vessels in the penis. However, PDE5 inhibitors may also act on similar compounds in the retina, the part of the eye that receives and transmits images. Mild and transient blurred vision, blue-tinged vision and altered light perception have been reported by men taking these drugs, and some visual complications of long-term use have been suggested. William H. Cordell, M.D., of Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, and colleagues conducted a randomized placebo-controlled study to assess changes in the retina among men taking tadalafil or sildenafil. A total of 244 healthy men, some with mild erectile dysfunction, age 30 to 65 were recruited. Of these, 85 were randomly assigned to take 5 milligrams of tadalafil, 77 to take 50 milligrams of sildenafil and 82 to take a placebo daily for six months. The men underwent comprehensive ophthalmologic examinations including electroretinography (a test to measure the electrical response of the light-sensitive rods and cones in the eye, used to detect diseases of the retina) before, during and after treatment. Among the 194 men (79.5 percent) who completed the study, no significant differences were found between treatment and placebo groups on electroretinography, visual function tests, measurements of intraocular pressure (pressure within the eyeball) or assessments of the anatomy of the eye. Nine participants (two in the placebo group, one in the tadalafil group and six in the sildenafil group) discontinued the study because of an adverse event, but only one of those was an ophthalmologic event (in the placebo group). No abnormalities that would be suggestive of drug toxicity were observed in any of the participants. "There are several reasons ophthalmologists need to be acquainted with the pharmacologic profiles of PDE5 inhibitors and their potential side effects," the authors write. "The frequency of erectile dysfunction, which is a form of peripheral vascular disease that impairs men's abilities to achieve and maintain an erection, increases dramatically with age and in the presence of cardiovascular risk factors. Therefore, many men who take PDE5 inhibitors to treat their erectile dysfunction will also be followed up by ophthalmologists for ocular disorders such as diabetic retinopathy, macular degeneration and ocular vascular disease."
"Furthermore, PDE5 inhibitors can exert direct effects on the retina, and such effects probably account for many of the visual side effects such as blue-tinged vision and light sensitivity that have been reported," they conclude. However, "our results indicate that there is no cumulative damage or effect of clinical significance for either 5 milligrams of tadalafil or 50 milligrams of sildenafil taken daily for six months."
Editor's Note: This study was supported by Eli Lilly and Company (Bothell, Wash., and Indianapolis). Co-authors Dr. Cordell, Dr. Costigan, Dr. Sides and Ms. Klise report being employees of Eli Lilly and Company. Co-authors Dr. Coupland, Dr. Danis, Dr. Marmor, Dr. Maturi and Dr. Weleber report being paid consultants to Eli Lilly and Company. Dr. Antoszyk and Dr. McGettigan report no financial disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, April 13, 2009
New Therapies Expected to Help Reduce Future Visual Burden of Age-Related Eye Disease
CHICAGO—The prevalence of the eye disease age-related macular degeneration is projected to increase substantially by 2050, but the use of new therapies is expected to help mitigate its effects on vision, according to results of simulation modeling reported in the April issue of Archives of Ophthalmology, one of the JAMA/Archives journals. Age-related macular degeneration (AMD) occurs when the macula, the area of the eye's retina responsible for sharp vision, begins to deteriorate. In 2000, as many as 1.75 million Americans reached the advanced, vision-threatening stages of AMD, according to background information in the article. "The prevalence of AMD and its resultant morbidity [illness and disability] is likely to increase as the U.S. population ages because the annual incidence of AMD increases with age from less than 1 percent for those younger than 60 years to greater than 5 percent for people aged 80 years and older," the authors write. "Newly discovered prophylactic [preventive] and treatment therapies for AMD offer substantial improvements over past therapies and could potentially offset some degree of future AMD morbidity," they continue. Preventive therapies include antioxidant vitamins that could slow the progression of AMD from early to late stages. Treatments for more advanced forms of the disease include laser and photodynamic therapies and anti–vascular endothelial growth factor (anti-VEGF) injections, which can prevent growth of excess blood vessels in the eye and thereby improve vision or prevent further vision loss for up to two years. To estimate the possible effects these new treatments might have on future disease burden, David B. Rein, Ph.D., of Research Triangle Institute International, Research Triangle Park, N.C., and colleagues simulated cases of AMD and related complications for the years 2010 through 2050. Using existing data to estimate the number of individuals in each stage of the disease based on age, sex and race or ethnicity, they modeled the population's progression over time under five different treatment scenarios. These ranged from no treatment at all to combinations of vitamins to prevent progression of early AMD with laser and anti-VEGF therapies for those at later stages. "Cases of early AMD increased from 9.1 million in 2010 to 17.8 million in 2050 across all scenarios," the authors write. However, the forecast indicated that the rate of visual impairment and blindness due to AMD could be reduced from 0.73 percent with no treatment to 0.48 percent when combining the use of antioxidant vitamins for prevention and anti-VEGF and laser therapy for individuals with AMD. "Our model predicts large increases in both cases of early and advanced AMD and the visual impairment and blindness attributable to it over the next 40 years regardless of the treatment steps taken, with virtually all of these increases attributable to the aging of the U.S. population," the authors continue. "However, existing medical therapies have the potential to reduce the visual impairment and blindness attributable to AMD by as much as 35 percent, translating to 565,000 fewer cases of visual impairment and blindness in 2050."
With an annual cost of approximately $100 per patient, vitamin therapy is a cost-effective method of delaying AMD progression, but research indicates it is not widely used among patients with early-stage disease. "Public prevention efforts should focus on expanding the use of antioxidant vitamins in people with early AMD and ensuring that these patients use the correct dosage," the authors write. Efforts should also be undertaken to improve access to anti-VEGF and laser therapies for eligible patients, they conclude.
Editor's Note: This study was supported by the Centers for Disease Control and Prevention's Division of Diabetes Translation through a U.S. Federal Contract. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. |
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