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July 21, 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
JAMA NEWS RELEASES
(Embargoed for Release: 3 p.m. CT Tuesday, July 21, 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. TV Note: PLEASE NOTE, FEED TIMES ARE NOW 15 MINUTES. This week's JAMA Report video is on how adopting certain dietary and lifestyle factors can help lower the risk of high blood pressure. The report will be fed Tuesday, July 21, from 9:00 - 9:15 a.m. ET and 2:00 - 2:15 p.m. ET, on Galaxy 28 (C-Band), Transponder 19, downlink frequency: 4080 vertical, audio 6.2/6.8. For more information, call 312/464-JAMA. The JAMA Report video is also now available on Pathfire every Tuesday. Please look for the JAMA Report "channel". Please Note: Because JAMA does not publish on the 5th Wednesday of a month, there will be no JAMA or news releases for July 29. Save the Date: The Sixth International Congress on Peer Review and Biomedical Publication will be held September 10-12 in Vancouver, Canada. New research will be presented on peer review and the other processes used to evaluate and disseminate medical information. The program and other information on the conference can be found at www.jama-peer.org. 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), Tuesday, July 21, 2009
Biomarkers May Help Predict Risk of Alzheimer Disease in Patients With Mild Cognitive Impairment
CHICAGO—Several cerebrospinal fluid (CSF) biomarkers showed good accuracy in identifying patients with mild cognitive impairment who progressed to Alzheimer disease, according to a study in the July 22/29 issue of JAMA. Alzheimer disease (AD) is the most common cause of dementia, affecting more than 15 million individuals worldwide. Because of the type of progression of the disease, there is a need for methods enabling early diagnosis. "Treatments would need to be initiated very early in the disease process, before the neurodegenerative process is too severe. Much focus has thus been directed on patients with mild cognitive impairment (MCI), which is a syndrome characterized by cognitive impairment beyond the age-adjusted norm, but not severe enough to fulfill the criteria for dementia," the authors write. Biochemical changes in the brain are reflected in the CSF, and intense research efforts have been made to develop biomarkers for the central pathogenic processes in AD that can be used as diagnostic tools. Some studies have shown that CSF biomarkers may be useful to identify incipient (beginning) AD in patients with MCI, but most of these studies have been small and conducted at single centers, according to background information in the article. Niklas Mattsson, M.D., of the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden, and colleagues conducted a multicenter study to assess the diagnostic accuracy of the CSF biomarkers β-amyloid1-42 (Aβ42), total tau protein (T-tau), and tau phosphorylated at position threonine 181 (P-tau) in identifying incipient AD in a large group of patients with MCI. The study had two parts: a cross-sectional study involving patients with AD and controls to identify biomarker cutoff levels, followed by a prospective cohort study involving patients with MCI, conducted 1990-2007. A total of 750 individuals with MCI, 529 with AD, and 304 controls were recruited by 12 centers in Europe and the United States. Individuals with MCI were followed for at least 2 years or until symptoms had progressed to clinical dementia. During follow-up, 271 participants with MCI were diagnosed with AD and 59 with other dementias. The researchers found that the Aβ42 assay in particular had considerable intersite variability. Patients who developed AD had lower median (midpoint) Aβ42 and higher P-tau and T-tau levels than MCI patients who did not develop AD during follow-up. Cut-offs with sensitivity (the proportion of affected individuals who have a positive test result for the disease that the test is intended to reveal) set at 85 percent were defined in the AD and control groups and tested in the MCI group, where the combination of Aβ42/P-tau ratio and T-tau identified incipient AD with a sensitivity of 83 percent and specificity (the proportion of individuals with correct negative test results for the disease the test is intended to reveal) of 72 percent. "We determined in a large multicenter study that the CSF biomarkers Aβ42, T-tau, and P-tau can be used to predict with good accuracy which MCI patients will develop AD, as previously found in smaller studies. This multicenter collaboration avoids several of the risks of biases associated with single-center studies by having included substantially more patients than previous studies. Cerebrospinal fluid biomarker changes were found to be significantly associated with incipient AD. However, the considerable intercenter variations in assays and patient assessments described point to a need for standardization of sample handling as well as of clinical assessments. Although each memory clinic center followed up its cohorts prospectively and used established clinical criteria, a limitation of the present study is the lack of fully harmonized study protocols for all centers, which might account for some of the intercenter variations that we observed," the researchers write.
"Using CSF Aβ42, T-tau, and P-tau in memory clinics will result in some false-positive cases, as well as false-negative cases, and the biomarkers may therefore be useful primarily as screening tools, selecting individuals for a detailed further clinical follow-up. Furthermore, they may be useful in enriching study populations for clinical trials of future disease-modifying AD treatments. Until such treatments become available, however, these tests are not generally appropriate for routine clinical use because it is not currently possible to alter the development of AD."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Use of Alzheimer Disease Biomarkers
In an accompanying editorial, Ronald C. Petersen, Ph.D., M.D., of the Mayo Clinic Study of Aging, Rochester, Minn., and John Q. Trojanowski, M.D., Ph.D., of the University of Pennsylvania School of Medicine, Philadelphia, comment on the findings of Mattsson and colleagues.
"Of critical importance... is what the clinician and patient will do with such results. The sensitivity and specificity of Aβ42, T-tau, and P-tau in the study by Mattsson et al were sufficient to be used for screening but not as a diagnostic test. Alzheimer disease has no treatment to prevent or alter the course of the disease, so making the diagnosis with good accuracy may aid in planning but also could be devastating news for some patients and families. Furthermore, false positives and false negatives occur as with any screening test. However, as biomarkers become more sophisticated, they are likely to take on an increasingly important role in the diagnosis and management of AD."
Editor's Note: Please see the article for additional information, including 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), Tuesday, July 21, 2009
Adopting Low-Risk Dietary and Lifestyle Factors Related to Lower Incidence of High Blood Pressure
CHICAGO—Adherence to modifiable lifestyle and dietary factors including maintaining normal weight, daily vigorous exercise, eating a diet high in fruits, vegetables, low-fat dairy products and low in sodium and taking a folic acid supplement was associated with a significantly lower incidence of self-reported hypertension among women, according to a study in the July 22/29 issue of JAMA. Hypertension (high blood pressure) contributes to more excess deaths in women than any other preventable factor. "Pharmacological treatment of established hypertension has proven benefits, yet these efforts are costly, require medical intervention, and have adverse effects," the authors write. "Primary prevention of hypertension, therefore, would have major positive public health ramifications." While several modifiable risk factors have been identified, the proportion of patients with new-onset hypertension that could conceivably be prevented by modification of a combination of lifestyle factors has not previously been evaluated. John P. Forman, M.D., M.Sc., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues examined the association between combinations of low-risk lifestyle factors and the risk of developing hypertension. The study included 83,882 adult women (age 27 to 44 years) in the second Nurses' Health Study who did not have hypertension, cardiovascular disease, diabetes, or cancer in 1991, and who had normal reported blood pressure (defined as systolic blood pressure of ≤120 mm Hg and diastolic blood pressure of ≤80 mm Hg). There was follow-up for new hypertension for 14 years through 2005. Six modifiable lifestyle and dietary factors for hypertension were identified and included a body mass index (BMI) of less than 25; a daily average of 30 minutes of vigorous exercise; a high score on the Dietary Approaches to Stop Hypertension (DASH) diet based on responses to a food frequency questionnaire; modest alcohol intake; use of nonnarcotic analgesics less than once per week; and intake of 400 μg/d or more of supplemental folic acid. A DASH score was determined based on high intake of fruits, vegetables, nuts and legumes, low-fat dairy products, and whole grains, and low intake of sodium, sweetened beverages, and red and processed meats. The association between combinations of 3 (normal BMI, daily vigorous exercise, and DASH-style diet), 4 (3 low-risk factors plus modest alcohol intake), 5 (4 low-risk factors plus avoidance of nonnarcotic analgesics), and 6 (folic acid supplementation ≥400 μg/d) low-risk factors and the risk of developing hypertension was analyzed. During the follow-up, a total of 12,319 new cases of hypertension were reported. All 6 modifiable risk factors were independently associated with the risk of developing hypertension during follow-up after also adjusting for age, race, family history of hypertension, smoking status, and use of oral contraceptives. For women who had all 6 low-risk factors (0.3 percent of the population), they had about an 80 percent lower risk of developing high blood pressure. The hypothetical population attributable risks (PARs; an estimate of the percentage of new hypertension cases occurring in this population that hypothetically could have been prevented if all women had been in the low-risk group) was 78 percent for women who lacked these low-risk factors. The PARs were 72 percent for 5 low-risk factors (0.8 percent of the population); 58 percent for 4 low-risk factors (1.6 percent of the population); and 53 percent for 3 low-risk factors (3.1 percent of the population). Body mass index alone was the most powerful predictor of hypertension, with a BMI of 25 or greater having an adjusted PAR of 40 percent compared with a BMI of less than 25. The authors add that their "data indicate that adherence to a combination of low-risk lifestyle factors could have the potential to prevent the majority of new-onset hypertension in young women irrespective of family history of hypertension and irrespective of oral contraceptive use. The former conclusion is particularly poignant given that some women may mistakenly believe that their parental history signifies that their own development of hypertension may be unavoidable; rather, these women may conceivably at least delay onset of hypertension by reducing their risk factors."
"In conclusion, adherence to low-risk dietary and lifestyle factors was associated with significant reductions in the incidence of self-reported hypertension and could have the potential to prevent a large proportion of new-onset hypertension occurring among young women. Prevention of hypertension would, in turn, have major public health benefits."
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), Tuesday, July 21, 2009
Adhering to Healthy Lifestyle Habits Associated With Reduced Lifetime Risk of Heart Failure
CHICAGO—Men who exercised regularly, drank moderately, did not smoke, who were not overweight and had a diet that included cereal and fruits and vegetables had a lower lifetime risk of heart failure, according to a study in the July 22/29 issue of JAMA. With an annual incidence of 550,000, heart failure remains a major public health issue and is the leading cause of hospitalization among older adults in the United States. Despite improved medical and surgical management, death after onset of heart failure remains high, ranging from 20 percent to 50 percent. The lifetime risk of heart failure at age 40 years is approximately 1 in 5 in the general population; however, it has been unclear whether adherence to healthy lifestyle factors, such as regular exercise and not smoking, could lead to a reduction in lifetime risk of heart failure, according to background information in the article. "A demonstration of beneficial influence of healthy lifestyle habits on the lifetime risk has potential clinical and public health implications." Luc Djoussé, M.D., Sc.D., M.P.H., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues assessed the association between modifiable lifestyle factors and the remaining lifetime risk of heart failure in a large group of men. The study included data from 20,900 men (average age at the start of the study, 53.6 years) from the Physicians' Health Study I (1982-2008) who were apparently healthy at baseline. Six modifiable lifestyle factors were assessed: body weight, smoking, exercise, alcohol intake, consumption of breakfast cereals and consumption of fruits and vegetables. During an average follow-up of 22.4 years, 1,200 new cases of heart failure (5.7 percent) and 4,999 confirmed deaths (23.9 percent) occurred in the study. Compared with participants adhering to no healthy lifestyle factors, those adhering to 4 or more factors tended to be older and had a lower prevalence of hypertension and diabetes mellitus. Analysis indicated that overall, the lifetime risk of heart failure was 13.8 percent at age 40 years and remained constant through age 70; at age 80 years, the lifetime risk for heart failure was 10.6 percent. The remaining lifetime risk of heart failure was approximately 2 percent to 4 percent higher in men with hypertension than in those without hypertension. The researchers found that normal body weight, never smoking, regular exercise, moderate alcohol intake, and consumption of breakfast cereal and fruits and vegetables were individually associated with a lower lifetime risk of heart failure compared to a corresponding undesirable behavior. There was an inverse and graded association between the number of healthy lifestyle factors and lifetime risk of heart failure. "For example, the lifetime risk for heart failure was approximately 1 in 5 (21.2 percent) in men adhering to none of the desirable lifestyle factors, compared to 1 in 10 (10.1 percent) in those adhering to 4 or more healthy lifestyle factors," the authors write. When restricted to body weight, smoking, and exercise, the association between lifestyle factors and lifetime risk of heart failure persisted in the overall population as well as in men with and without hypertension.
"Our estimate of lifetime risk of heart failure could help public health officials allocate resources for the prevention and management of this condition. Our findings of a low lifetime risk in men who adhere to modifiable lifestyle factors emphasize the need for incorporation of these behaviors in prevention strategies against heart failure at both the individual and the population level," the authors write.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Lifestyle and Cardiovascular Health — Individual and Societal Choices
Véronique L. Roger, M.D., M.P.H., of the Mayo Clinic, Rochester, Minn., comments in an accompanying editorial on the two studies in this issue of JAMA that examine the effect of lifestyle factors on heart failure and hypertension. "At this point, the national cost of treating cardiovascular diseases cannot be sustained, and prevention is urgent. Because prevention can benefit from policies aimed at creating a healthier environment, this approach must be expanded, with obvious targets being school-based meals provided to children, which still do not meet national dietary recommendations for good health, and the conceptualization and restructuring of the environment to promote physical activity. These and other public health measures should be envisioned as complementary and synergistic with clinical care, because unhealthy societal choices that lead to illness result in unsustainable strain on health care systems."
"The studies by Forman et al and Djoussé et al underscore that healthy lifestyle will help prevent cardiovascular disease and greatly enhance health, which is a compelling reminder that health is the shared responsibility of individuals and communities. This in turn implies that public health policies and clinical care must join forces to achieve effective disease prevention."
Editor's Note: Please see the article for additional information, including 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.
JAMA REPORTS
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STUDY FINDS ADOPTION OF MULTIPLE LIFESTYLE BEHAVIORS SIGNIFICANTLY LOWERS HYPERTENSION RISK
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