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March 1, 2011 — Embargoed ContentJAMA 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. JAMA NEWS RELEASES
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JAMA REPORT (VIDEO SCRIPT)
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: This week's JAMA Report video is on gene variations associated with an increased risk of type 2 diabetes. The report will be fed Tuesday, March 1, from 9:00 - 9:15 a.m. ET and 2:00 - 2:15 p.m. ET, on Galaxy 28 (C-Band, analog), Transponder 10, downlink frequency: 3900 horizontal, audio 6.2/6.8. For more information, call 312/464-JAMA. The JAMA Report video is also now available on Pathfire every Tuesday, in VNF Provider A. Please look for the JAMA Report tab. 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, March 1, 2011
Gene Variations Associated With Risk of Type 2 Diabetes
CHICAGO—For individuals of white European descent, certain variations of the gene HMGA1 are associated with type 2 diabetes mellitus, according to a study in the March 2 issue of JAMA. Type 2 diabetes mellitus (DM) is a common metabolic disorder that affects nearly 250 million people worldwide, and is associated with major diabetes-related complications, including retinopathy, kidney disease and cardiovascular disease. Insulin resistance in muscle, liver, and fat tissue is a major feature of most patients with type 2 DM. There is considerable evidence that heredity is a major contributor to the insulin resistance of type 2 DM, according to background information in the article. "However, despite extensive investigations, including studies of candidate genes and the recent genome-wide association studies, the common genetic causes of insulin resistance remain elusive," the authors write. The researchers previously found that the protein HMGA1 is a key regulator of insulin receptor (INSR) gene expression. Eusebio Chiefari, M.D., of the University of Catanzaro, Catanzaro, Italy and colleagues conducted a study to examine the association of HMGA1 gene variants with type 2 DM, and included patients with type 2 DM and controls from 3 populations of white European ancestry. Italian patients with type 2 DM (n = 3,278) and 2 groups of controls (n = 3,328) were attending outpatient clinics and other health care sites in Calabria, Italy, during 2003-2009; U.S. patients with type 2 DM (n = 970) were recruited in Northern California clinics between 1994 and 2005 and controls (n = 958) were senior athletes without DM evaluated in 2004 and 2009; and French patients with type 2 DM (n = 354) and healthy controls (n = 50) were enrolled at the University of Reims in 1992. Genomic DNA was either directly sequenced or analyzed for specific HMGA1 mutations. The researchers found that the most frequent functional HMGA1 variant, IVS5-13insC, was present in 7 percent to 8 percent of patients with type 2 DM in all 3 populations. The prevalence of this variant was higher among patients with type 2 DM (nearly 16 times higher odds of having this variant) than among controls in the Italian population (7.23 percent vs. 0.43 percent in one control group; and 7.23 percent vs. 3.32 percent in the other control group). In the U.S. population, the prevalence of IVS5-13insC variant was 7.7 percent among patients with type 2 DM vs. 4.7 percent among controls; in the French population, the prevalence of this variant was 7.6 percent among patients with type 2 DM and 0 percent among controls. In the Italian population, 3 other functional variants were observed. When all 4 variants were analyzed, HMGA1 defects were present in 9.8 percent of Italian patients with type 2 DM and 0.6 percent of controls. "We believe our observation that nearly 10 percent of individuals with type 2 DM have deleterious variations in the gene encoding HMGAl has important clinical implications, First, the presence of these variants could serve as an early predictive marker of both insulin resistance and type 2 DM, especially in those individuals who have a family history of type 2 DM and related conditions. Second, the presence of these variants may predict the response to therapy. ... Third, individuals who have functional HMGA1 variants and type 2 DM may have a different clinical course than other patients with type 2 DM, including differences in the development of macrovascular and microvascular complications. Fourth, the search for new therapies for type 2 DM could include agents that upregulate the expression of HMGA1," the authors write.
"In conclusion, our results indicate that variants in the HMGA1 gene are associated with type 2 DM in individuals of white, European descent. Further studies of the HMGAl gene and it variants, including studies in other racial types, are needed to understand the role of HMGA1 in insulin resistance and type 2 DM."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Please Note: For this study, there will be multimedia content available, including the JAMA Report video, embedded and downloadable video, audio files, text, documents, and related links. This content will be available at 3 p.m. CT Tuesday, March 1 at this link. Editorial: HMCA1, A Novel Locus for Type 2 Diabetes Mellitus
In an accompanying editorial, Abhimanyu Garg, M.D., of the University of Texas Southwestern Medical Center, Dallas, comments on the findings of this study.
"With the discovery of novel loci for type 2 DM and development of better understanding of the molecular mechanisms by which these variants affect the susceptibility of diabetes combined with the sophisticated metabolic phenotyping related to beta cell dysfunction, insulin resistance, incretin hormones, hepatic glucose, and lipid metabolism, distinct subtypes of type 2 DM will be recognized more clearly. This information may lead to targeted therapies for various subtypes of type 2 DM. ... It is anticipated that the discoveries of novel loci such as HMGA1 will soon be translated into therapeutic decision making, and thereby improve the health of patients with type 2 DM."
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, March 1, 2011
Use of High Blood Pressure Medications by Patients With Cardiovascular Disease Associated With Decreased Risk of Stroke, Congestive Heart Failure
CHICAGO—An analysis of previous studies indicates that among patients with a history of cardiovascular disease, but not hypertension, use of high blood pressure medication is associated with a reduced risk of stroke, congestive heart failure and death from all causes, according to an article in the March 2 issue of JAMA. Cardiovascular disease (CVD) is the leading cause of death in the United States and globally, representing 30 percent of all deaths worldwide. "Cardiovascular disease risk increases beginning at systolic blood pressure levels of 115 mm Hg. Use of antihypertensive medications among patients with a history of CVD or diabetes and without hypertension has been debated," according to background information in the article. In adults 55 years and older, lifetime risk of developing hypertension is greater than 90 percent. Angela M. Thompson, M.S.P.H., of the Tulane University School of Public Health and Tropical Medicine, New Orleans, and colleagues conducted a meta-analysis to evaluate the association between antihypertensive treatment and secondary prevention of CVD events and all-cause death among persons without clinically defined hypertension (140 mm Hg systolic or greater or 90 mm Hg diastolic or greater and/or use of antihypertensive medications or history of hypertension). From 874 potentially relevant publications, the researchers identified 25 trials that fulfilled the predetermined inclusion and exclusion criteria for the meta-analysis. These 25 studies incorporated data from 64,162 participants without hypertension, of whom 76 percent were men. For the various outcomes, the researchers found that there was a 23 percent reduction in risk of stroke; 29 percent reduction in risk of congestive heart failure (CHF) events; 15 percent reduction in risk of composite (a combination of disease outcomes) CVD events; and a 13 percent reduction in risk for all-cause mortality. "Our results show that persons with a history of CVD but with blood pressures in the normal and prehypertensive ranges can obtain significant benefit from antihypertensive treatments," the authors write.
"Prehypertension affects nearly 30 percent of the adult population and carries an elevated risk for CVD incidence and mortality. To our knowledge, this meta-analysis is the first to examine the association between antihypertensive medications and CVD morbidity and mortality as well as all-cause mortality in individuals without hypertension. Among patients with clinical history of CVD but without hypertension, antihypertensive treatment was associated with decreased risk of stroke, CHF, composite CVD events, and all-cause mortality. Additional randomized trial data are necessary to assess these outcomes in patients without CVD clinical recommendations."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Antihypertensive Therapy for Prehypertension
Hector O. Ventura, M.D., and Carl J. Lavie, M.D., of the John Ochsner Heart and Vascular Institute, New Orleans, and University of Queensland School of Medicine, Brisbane, Australia, write in an accompanying editorial that because many patients with prehypertension could potentially begin taking medications at young ages and for many years to prevent cardiovascular events, even modest costs and adverse effects need to be considered.
"Lifestyle modifications that have been shown to reduce blood pressure and decrease cardiovascular morbidity and mortality should be recommended for all patients with blood pressure levels less than 140/90 mm Hg. However, to reach firmer conclusions will require more data from randomized trials involving patients with levels less than 140/90 mm Hg to evaluate the effects of various pharmacological therapies on preventing CVD outcomes."
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, March 1, 2011
Nitric Oxide Does Not Appear to Improve Treatment of Sickle Cell Pain-Attacks
CHICAGO—Among patients with sickle cell disease, treatment of a vaso-occlusive crisis (characterized by episodes of severe pain) in the hospital with inhalation of nitric oxide gas for up to 3 days did not result in a shorter time to resolution of the pain, compared to patients who received placebo, according to a study in the March 2 issue of JAMA. Vaso-occlusive crisis (VOC) is common among patients with sickle cell disease (SCD), with an average length of hospitalization during VOC of 4.5 days for children ages 10 to 14 years. As many as 20 percent of patients hospitalized for VOC develop acute chest syndrome (ACS), a life-threatening acute lung injury that lengthens hospital stay to an average of 14 days, according to background information in the article. "Given the severe pain, high rate of morbidity, cost of care for VOC in SCD, and the absence of a current treatment option, there is an imperative to identify and evaluate new treatments," the authors write. Inhaled nitric oxide, a relatively safe agent already approved by the Food and Drug Administration for hypoxic respiratory failure in newborn infants, showed evidence of efficacy in 2 small placebo-controlled trials for treatment of VOC. To further evaluate the efficacy of inhaled nitric oxide, Mark T. Gladwin, M.D., of the University of Pittsburgh, and colleagues conducted a phase 2, randomized, placebo-controlled, multicenter study. The trial, which took place at 11 centers between October 2004 and December 2008, included 150 SCD patients with VOC who were randomized to receive up to 72 hours of inhaled nitric oxide gas vs. inhaled nitrogen placebo. The primary outcome measured was the time to resolution of a painful crisis, defined by freedom from parenteral (by injection) opioid use for 5 hours; pain relief as assessed by certain scores on a visual analog pain scale (VAS); ability to walk; and the patient's and family's decision, with physician consensus, that the remaining pain could be managed at home. The researchers found that time to VOC resolution did not differ significantly according to treatment. The estimated median (midpoint) time to resolution of crisis was 73 hours for the inhaled nitric oxide group and 65.5 hours in the placebo group. Additionally, other analyses did not differ significantly according to treatment, including median length of hospitalization (4.1 days vs. 3.1 days for inhaled nitric oxide vs. placebo, respectively); average VAS scores at 24 hours; and median total opioid use. There were also no differences between the groups in the percentage of participants who developed ACS requiring a transfusion over the entire study period or in those with ACS as a reported serious adverse event during study gas inhalation. Inhaled nitric oxide was well tolerated, with no increase in serious adverse events.
"In summary, the results of this study indicate that inhaled nitric oxide in the doses and methods of administration used in this study does not reduce VOC severity in SCD. These results underscore the need for new agents and a sustained clinical trials apparatus for studying VOC, with sufficient numbers of patients to provide adequate power to rapidly test promising therapeutics in patients with SCD," the authors 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.
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GENE MUTATION ASSOCIATED WITH TYPE 2 DIABETES IN U-S AND EUROPEAN PATIENTS
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