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June 8, 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, June 8, 2009)
ARCHIVES OF NEUROLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, June 8, 2009)
ARCHIVES OF OPHTHALMOLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, June 8, 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, June 8, 2009
Plant-Based, Low-Carb Diet May Promote Weight Loss and Improve Cholesterol Levels
CHICAGO—Overweight individuals who ate a low-calorie, low-carbohydrate diet high in plant-based proteins for four weeks lost weight and experienced improvements in blood cholesterol levels and other heart disease risk factors, according to a report in the June 8 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. A high-carbohydrate, low-fat vegetarian diet also resulted in weight loss but without the additional cardiovascular benefits. "There is a dilemma relating to the proportion and source of fat, protein and carbohydrate that constitutes the optimal weight loss and cholesterol-lowering diet," the authors write as background information in the article. Newer dietary approaches for the prevention and treatment of chronic disease emphasize increased fruit and vegetable intake and reduced meat consumption. However, low-carbohydrate diets with increased meat consumption have also been promoted for body weight reduction and the prevention and treatment of diabetes and coronary heart disease. These diets have been shown to be effective in inducing weight loss, reducing insulin resistance, lowering blood fats known as triglycerides and raising high-density lipoprotein cholesterol (HDL-C, or "good" cholesterol) levels, but have tended to increase low-density lipoprotein cholesterol (LDL-C, or "bad" cholesterol) levels. "This lack of a benefit for LDL-C control is a major disadvantage in using this dietary strategy in those already at increased risk of coronary heart disease," the authors write. David J.A. Jenkins, M.D., of St. Michael's Hospital and the University of Toronto, Ontario, Canada, and colleagues tested the effects of a low-carbohydrate diet high in vegetable proteins from gluten, soy, nuts, fruits, vegetables, cereals and vegetable oils among overweight men and women with high LDL cholesterol levels. A total of 25 participants were randomly assigned to consume this diet—the "Eco-Atkins" diet—for four weeks, while an additional 25 participants ate a control diet that was high-carbohydrate, lacto-ovo vegetarian and based on low-fat dairy and whole grain products. Study food was provided to participants at 60 percent of their estimated calorie requirements. Of the 47 participants who began the study, 44 (22 in each group) completed the four-week period. Weight loss was similar—about 4 kilograms or 8.8 pounds—in both groups. However, reductions in LDL-C levels and improvements in the ratios between total cholesterol and HDL-C were greater for the low-carbohydrate diet compared with the high-carbohydrate diet. The low-carbohydrate diet also appeared to produce beneficial changes in levels and ratios of apolipoproteins, proteins that bind to fats. In addition, small but significantly greater reductions were seen in both systolic (top number) and diastolic (bottom number) blood pressure for the low-carbohydrate vs. the high-carbohydrate group.
Pending answers to important questions, including whether further reducing carbohydrate intake would produce additional benefits, "a plant-based low-carbohydrate diet high in vegetable proteins and oils may be an effective option in treating those with dyslipidemia for whom both weight loss and lower LDL-C concentrations are treatment goals," the authors conclude.
Editor's Note: This study was supported by Solae, LLC, Loblaw Companies Limited and the Canadian Research Chair Program of the Federal Government of Canada. Co-author Ms. Wong is a recipient of a Canadian Institutes of Health Research Doctoral Research Award. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Additional Research Needed Before Recommending "Eco-Atkins" Diet
"High-protein, low-carbohydrate diets are advocated by many, predominantly commercial, weight loss programs," write Katherine R. Tuttle, M.D., and Joan E. Milton, M.S., R.D., C.D., of the Providence Medical Research Center at Sacred Heart Medical Center and the University of Washington School of Medicine, Spokane, Wash., in an accompanying editorial. "Most of these diets have been promoted within popular culture and until recently have been subjected to little scientific scrutiny. Substantial concern has been raised about the potential for adverse effects. Meat is commonly consumed as a major source of dietary protein. However, meat derived from animal muscle also typically contains large amounts of saturated fat and cholesterol."
"The article by Jenkins et al provides insight into debatably more effective and possibly safer tactics for designing higher-protein diets for weight loss and cardiovascular risk reduction. However, it is premature to recommend the ‘Eco-Atkins' diet as a weight loss diet of choice without confirmation of its efficacy in larger studies of more diverse and higher-risk individuals. Long-term studies are also essential to ascertain both sustainability and safety."
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, June 8, 2009
Less Sleep Associated With High, Worsening Blood Pressure in Middle Age
CHICAGO—Middle-aged adults who sleep fewer hours appear more likely to have high blood pressure and to experience adverse changes in blood pressure over time, according to a report in the June 8 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. Almost one-third of Americans have hypertension or high blood pressure, a condition that contributes to 7 million deaths worldwide each year, according to background information in the article. "Identifying a novel lifestyle risk factor for high blood pressure could lead to new interventions to prevent or reduce high blood pressure," the authors write. "Laboratory studies of short-term sleep deprivation have suggested potential mechanisms for a causal link between sleep loss and hypertension." Sleep deprivation is associated with increased activity in the sympathetic nervous system, which controls the body's stress response. Over time, this activation could contribute to high blood pressure. Kristen L. Knutson, Ph.D., of the University of Chicago, and colleagues studied 578 adults who first had their blood pressure and other clinical, demographic and health variables measured between 2000 and 2001. In 2003 and 2005, sleep duration was measured using surveys and wrist actigraphy, in which a sensor is worn on the wrist to record periods of rest and activity. Blood pressure, demographic and self-reported sleep information were measured again in 2005 and 2006. Participants (average age 40.1) slept an average of six hours per night; only seven (1 percent) averaged eight or more hours of sleep. After excluding patients taking medication for high blood pressure and controlling for age, race and sex, the researchers found that individuals who slept fewer hours were significantly more likely to have higher systolic (top number) and diastolic (bottom number) blood pressure. Sleeping less also predicted increases in blood pressure over five years, along with the onset of hypertension. Each hour of reduction in sleep duration was associated with a 37 percent increase in the odds of developing high blood pressure. "Consistent with other studies, we observed higher blood pressure levels in men, particularly African American men," the authors write. "Also, as described in a previous report from this study, African American men slept much less than white women. These two observations suggested the intriguing possibility that the well-documented higher blood pressure in African Americans and men might be partly related to sleep duration."
"In summary, the present study provides evidence for a link between the duration and quality of sleep and high blood pressure levels using objectively measured sleep characteristics," they conclude. "Intervention studies are needed to determine whether optimizing sleep duration and quality can reduce the risk of increased blood pressure."
Editor's Note: Research for this study was supported by a grant from the National Institute on Aging. The Coronary Artery Risk Development in Young Adults (CARDIA) study is supported by U.S. Public Health Service contracts from the National Heart, Lung and Blood Institute. 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, June 8, 2009
Study Redefines Roles of Alcohol, Smoking in Risk for Pancreatitis
CHICAGO—Although alcohol consumption is known to be associated with chronic pancreatitis, new evidence indicates that a threshold of five or more drinks per day is required to significantly raise risk; however, most patients with chronic pancreatitis do not drink this amount, according to a report in the June 8 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. In addition, smoking is an independent, dose-dependent risk factor. "Chronic pancreatitis is an inflammatory syndrome of the pancreas characterized by progressive parenchymal fibrosis [scarring of the organ], maldigestion, diabetes mellitus and pain," the authors write as background information in the article. "Recurrent acute pancreatitis [acute pancreatitis that occurs on two or more occasions and may become chronic] and chronic pancreatitis are associated with alcohol consumption and cigarette smoking. The etiology of recurrent acute pancreatitis and chronic pancreatitis is complex, and effects of alcohol and smoking may be limited to specific patient subsets." Dhiraj Yadav, M.D., M.P.H., of the University of Pittsburgh, and colleagues in the North American Pancreatic Study Group examined the current prevalence of alcohol use and smoking and their association with pancreatitis in patients evaluated at U.S. referral centers. Between 2000 and 2006, 1,000 patients (540 with chronic pancreatitis and 460 with recurrent acute pancreatitis) were enrolled in the North American Pancreatitis Study 2 (NAPS2), as were 695 healthy controls. All participants (average age 49.7) reported their alcohol consumption and smoking habits. About one-fourth of both controls and patients were lifetime abstainers. Among those with chronic pancreatitis, 38.4 percent of men and 11 percent of women were very heavy drinkers (five or more drinks per day), compared with 16.9 percent of men and 5.5 percent of women with recurrent acute pancreatitis and 10 percent of men and 3.6 percent of women in the control group. "We found the threshold drinking amount for association between alcohol use and chronic pancreatitis to be five or more drinks per day," the authors write. Compared with abstaining and light drinking (half a drink per day or less), very heavy drinking was associated with approximately triple the odds of developing chronic pancreatitis. However, fewer patients with chronic pancreatitis than expected (about one-fourth) drank at this level. Other factors, including genetic mutations, also contribute to pancreatitis risk. Although many heavy drinkers also smoked, cigarette use was an independent risk factor for both chronic pancreatitis and recurrent acute pancreatitis. Among smokers, those with chronic pancreatitis tended to smoke more (26.6 pack-years, vs. 19.5 pack-years for those with recurrent acute pancreatitis and 16.2 pack-years for controls; one pack-year is about 7,300 cigarettes smoked) and had smoked for a longer period of time (a median or midpoint of 30.5 years, vs. 21.9 years for controls and 22.7 years for those with recurrent acute pancreatitis), suggesting a dose-dependent effect.
"In conclusion, only very heavy alcohol consumption and cigarette smoking are independent risk factors for chronic pancreatitis," the authors write. "Risk for chronic pancreatitis from alcohol consumption occurs above a threshold level, while risk due to smoking is dose dependent. Drinking levels in subjects with recurrent acute pancreatitis are similar to controls. Only a minority of patients with recurrent acute pancreatitis and chronic pancreatitis currently seen at secondary or tertiary U.S. centers could be categorized as very heavy drinkers."
Editor's Note: This research was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases, Rockville, Md.; the National Pancreas Foundation, Boston; Robert and Vicki Hall; and Andrew and Michelle Aloe. 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, June 8, 2009
Breastfeeding Associated With a Reduced Risk of Relapse in Women With Multiple Sclerosis
CHICAGO—Women with multiple sclerosis who breastfeed exclusively for at least two months appear less likely to experience a relapse within a year after their baby's birth, according to a report posted online today that will appear in the August print issue of Archives of Neurology, one of the JAMA/Archives journals. "Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that predominantly affects women in their childbearing years," the authors write as background information in the article. "It is well known that women with MS have fewer relapses during pregnancy and a high risk of relapse in the postpartum period." Medications used to treat MS by modifying the immune system—including interferon beta and natalizumab—are not recommended for use during pregnancy or breastfeeding. Therefore, women with MS who give birth must choose between nursing and resuming MS treatment. Annette Langer-Gould, M.D., Ph.D., then of Stanford University School of Medicine, Stanford, Calif., and now of Kaiser Permanente Southern California, Pasadena, and colleagues studied 32 pregnant women with MS and 29 pregnant women without MS who were the same age. The participants were interviewed about clinical, menstrual and breastfeeding history during each trimester and again two, four, six, nine and 12 months after they gave birth. In addition, neurological examination findings were collected from the physicians of women with MS. More healthy women than women with MS breastfed (96 percent vs. 69 percent), and among those who did breastfeed, women with MS were more likely to begin daily formula feedings within two months after birth (30 percent compared with 18 percent). "Of the 52 percent of women with MS who did not breastfeed or began regular supplemental feedings within two months postpartum [15 women], 87 percent [13 women] had a postpartum relapse, compared with 36 percent [five women] of the women with MS who breastfed exclusively for at least two months postpartum [14 women]," the authors write. "Women with MS and healthy women who breastfed exclusively had significantly prolonged lactational amenorrhea [absence of menstruation], which was associated with a decreased risk of relapse in women with MS." Most women with MS who did not breastfeed or supplemented with formula feedings (11 women, or 73 percent) reported that their primary reason for doing so was to take medications for MS. Eight of them (53 percent) resumed MS medications within two months after birth. "Why breastfeeding might be beneficial in humans with an autoimmune disease like MS has not been studied," the authors write. "Studies of immunity and breastfeeding, while plentiful, are predominantly focused on breast milk content and health benefits to the infant. Little is known about maternal immunity during breastfeeding."
The results suggest that women with MS should be encouraged to breastfeed exclusively for at least the first two months after birth instead of resuming medications, the authors note. "Our findings call into question the benefit of foregoing breastfeeding to start MS therapies and should be confirmed in a larger study," they conclude.
Editor's Note: This work was supported by a National Institutes of Health National Institute of Neurological Disorders and Stroke Patient-Oriented Research Career Development Award and a Wadsworth Foundation Young Investigator 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, June 8, 2009
Cognitive Impairment Associated With Reduced Survival Among Both African-American and White Older Adults
CHICAGO—Alzheimer's disease and its precursor, mild cognitive impairment, appear to be associated with an increased risk of death among both white and African American older adults, according to a report in the June issue of Archives of Neurology, one of the JAMA/Archives journals. Alzheimer's disease reduces life expectancy and has emerged as a leading cause of death in the United States, according to background information in the article. "Data from two national surveys suggest that life expectancy among patients with Alzheimer's disease may be greater for African Americans than for whites," the authors write. "However, not all surveys have reported this difference. Furthermore, in these surveys, the diagnosis of Alzheimer's disease is not based on a uniform clinical evaluation but derived from medical records, increasing the likelihood of substantial variation in the quality of diagnostic classifications." Robert S. Wilson, Ph.D., and colleagues at Rush University Medical Center, Chicago, studied 1,715 older adults (average age 80.1, 52.5 percent African American) from four adjacent neighborhoods in Chicago. Each participant had a clinical evaluation that included medical history, a neurological examination and cognitive (thinking, learning and memory) function testing. Based on these evaluations, an experienced physician diagnosed 296 (17.3 percent) of the participants with Alzheimer's disease, 597 (34.8 percent) with mild cognitive impairment and 20 (1.2 percent) with other forms of dementia, while 802 (46.8 percent) had no cognitive impairment. During up to 10 years of follow-up (average observation period, 4.7 years) 634 individuals died (37 percent), including 25.8 percent of those without cognitive impairment, 40.4 percent of those with mild cognitive impairment, 59.1 percent of those with Alzheimer's disease and 60 percent of those with other forms of dementia. "Compared with people without cognitive impairment, risk of death was increased by about 50 percent among those with mild cognitive impairment and was nearly three-fold greater among those with Alzheimer's disease," the authors write. "These effects were seen among African Americans and whites and did not differ by race." Among individuals with mild cognitive impairment, risk of death increased as cognitive impairment became more severe, another association that did not differ by race. A similar association between disease severity and survival was seen among patients with Alzheimer's disease, although that effect was slightly stronger for African Americans than for whites.
"Overall, these results do not suggest strong racial differences in survival for persons with mild cognitive impairment and Alzheimer's disease," the authors conclude.
Editor's Note: This research was supported by grants from the National Institute on Aging and by a grant from the National Institute of Environmental Health Sciences. 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, June 8, 2009
Boys With Intermittent Eye Deviation Appear More Likely to Develop Mental Illness
CHICAGO—Children and especially boys diagnosed with intermittent exotropia, a condition in which the eye turns outward (away from the nose) only some of the time, appear more likely to develop mental illness by young adulthood than children without strabismus (when the eyes deviate or are misaligned when looking at an object), according to a report in the June issue of Archives of Ophthalmology, one of the JAMA/Archives journals. "Intermittent exotropia occurs in approximately 1 percent of developmentally healthy children in the United States and, given its predominance over esodeviations [when the eye turns in] among Asian populations, it may be the most prevalent form of strabismus worldwide," the authors write as background information in the article. Jeff A. McKenzie, B.A., and colleagues at Mayo Clinic, Rochester, Minn., analyzed the medical records of 183 children younger than 19 in Olmsted County, Minn., who were diagnosed with intermittent exotropia between 1975 and 1994. For each patient, the researchers identified one control child who was the same age but did not have a diagnosis of any type of strabismus. Both groups were followed to an average age of 22. During the 20-year study period, 97 of the children with intermittent exotropia (53 percent) were diagnosed with a mental health disorder, compared with 55 controls (30.1 percent)—meaning that patients with the condition had an increased risk of developing a psychiatric illness. Mental health disorders were diagnosed in 63 percent of boys (41 of 65) and 47 percent of girls (56 of 118) with intermittent exotropia, compared with 33 percent of boys (22 of 66) and 28 percent of girls (33 of 117) in the control group. "Additionally, males with intermittent exotropia had a greater use of psychotropic medication, psychiatric emergency department visits, psychiatric hospital admissions, suicide attempts and suicidal ideation than controls, and females with intermittent exotropia had more suicidal ideation than controls," the authors write. The reasons underlying these associations remain unclear, the authors note. "Studies regarding the psychosocial impact of strabismus have reported that individuals with intermittent exotropia are not judged more poorly than individuals with orthotropia [the absence of strabismus] by adult observers. However, a negative bias toward people with strabismus has been demonstrated in children," the authors write. "Although this study focused on mental illness that was diagnosed by early adulthood, there is also evidence to suggest that the social problems associated with strabismus persist and even intensify into adult life."
"Further study is needed to determine whether interventions for intermittent exotropia can decrease or otherwise alter the future development of mental illness," they conclude.
Editor's Note: This study was supported in part by an unrestricted grant from Research to Prevent Blindness Inc., New York, New York. 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, June 8, 2009
An Estimated 4 Percent of Older U.S. Men Have Dry Eye Disease
CHICAGO—Dry eye disease is common among American men older than 50 and increases with age, high blood pressure, benign prostate disease and the use of antidepressants, according to a report in the June issue of Archives of Ophthalmology, one of the JAMA/Archives journals. Dry eye is one of the most common eye diseases and reason that older adults seek eye care, according to background information in the article. "It is an important public health problem, causing increased risk of ocular infections and bothersome symptoms of ocular discomfort, fatigue and visual disturbance that interfere with crucial activities such as reading, working on a computer and driving a car," the authors write. Debra A. Schaumberg, Sc.D., O.D., M.P.H., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues estimated the prevalence of and examined risk factors for dry eye disease among 25,444 U.S. men who participated in the Physicians' Health Study I and II. The men were asked if they had ever been diagnosed with dry eye disease and also whether they had symptoms, including dry or irritated eyes. Overall, 765 men (3 percent) reported being diagnosed with dry eye, 6.8 percent experienced at least one symptom (dryness or irritation) constantly or often and 2.2 percent reported both symptoms constantly or often. The total age-standardized prevalence of dry eye disease among men 50 and older was estimated to be 4.34 percent. Men 75 years and older were more likely to have the condition—prevalence increased from 3.9 percent among men age 50 to 54 to 7.7 percent among men age 80 and older. High blood pressure, benign prostatic hyperplasia (a non-cancerous enlargement of the prostate) and the use of medications to treat depression, hypertension or hyperplasia were also associated with an increased risk of dry eye disease. "The present study estimates that approximately 1.68 million men 50 years and older are affected with dry eye disease in the United States," the authors write. "These data, derived from studying more than 25,000 men, show a significantly lower prevalence of dry eye disease than was found in a similar study using the same methods in U.S. women, among whom the prevalence was estimated at 3.23 million women. Nonetheless, there is a significant increase in the prevalence of dry eye disease with age among men, as is the case among women, and there is a predicted growth to 2.79 million U.S. men affected by dry eye disease in 2030."
"Given the increasing recognition of the adverse visual impact of dry eye disease, and the high level of bother patients report because of its irritative symptoms, we hope that these data from a large and well-characterized group of U.S. men will provide further motivation for clinicians and researchers to understand this disease and develop more effective and targeted interventions for patients," they conclude.
Editor's Note: This work was supported by National Institutes of Health grants and the Joint Clinical Research Center, Massachusetts Eye and Ear Infirmary and Schepens Eye Research Institute, Boston. 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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