JAMA 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, January 12, 2009)
Getting Less Sleep Associated With Lower Resistance to Colds
Elderly May Have Higher Blood Pressure in Cold Weather
Job Strain Associated With Stroke in Japanese Men
ARCHIVES OF NEUROLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), January 12, 2009)
Diabetes Associated With Different Types of Brain Injury in Patients With Dementia
Relapses More Frequent in Patients Diagnosed With Pediatric-Onset Multiple Sclerosis
ARCHIVES OF OPHTHALMOLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), January 12, 2009)
Glaucoma May Be Linked to Higher Rates of Reading Impairment in Older Adults
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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, January 12, 2009
Media Advisory: To contact Sheldon Cohen, Ph.D., call Teresa Thomas at 412-268-3580 or e-mail ts2h{at}andrew.cmu.edu.
Getting Less Sleep Associated With Lower Resistance to Colds
CHICAGO—Individuals who get less than seven hours of sleep per night appear about three times as likely to develop respiratory illness following exposure to a cold virus as those who sleep eight hours or more, according to a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Studies have demonstrated that sleep deprivation impairs some immune function, according to background information in the article. Research indicates that those who sleep approximately seven to eight hours per night have the lowest rates of heart disease illness and death. However, there has previously been little direct evidence that poor sleep increases susceptibility to the common cold.
Sheldon Cohen, Ph.D., of Carnegie Mellon University, Pittsburgh, and colleagues studied 153 healthy men and women (average age 37) between 2000 and 2004. Participants were interviewed daily over a two-week period, reporting how many hours they slept per night, what percentage of their time in bed was spent asleep (sleep efficiency) and whether they felt rested. They were then quarantined and administered nasal drops containing the common-cold–causing rhinovirus. For five days afterward, the study participants reported any signs and symptoms of illness and had mucus samples collected from their nasal passages for virus cultures; about 28 days later, they submitted a blood sample that was tested for antibody responses to the virus.
The less an individual slept, the more likely he or she was to develop a cold. Lower sleep efficiency was also associated with developing a cold—participants who spent less than 92 percent of their time in bed asleep were five and a half times more likely to become ill than those whose efficiency was 98 percent or more. Feeling rested was not associated with colds.
"What mechanisms might link sleep to cold susceptibility? When the components of clinical illness (infection and signs or symptoms) were examined separately, sleep efficiency but not sleep duration was associated with signs and symptoms of illness. However, neither was associated with infection," the authors write. "A possible explanation for this finding is that sleep disturbance influences the regulation of pro-inflammatory cytokines, histamines and other symptom mediators that are released in response to infection."
The results suggest that seven to eight hours of sleep per night is a reasonable target, they conclude.
(Arch Intern Med. 2009;169[1]:62-67. Available to the media pre-embargo at www.jamamedia.org).
Editor's Note: This study was funded by grants to the Pittsburgh Mind-Body Center from the National Heart, Lung and Blood Institute, by the National Institute of Allergy and Infectious Diseases and by supplementary funds provided by the John D. and Catherine T. MacArthur Foundation Network on Socioeconomic Status and Health. 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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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, January 12, 2009
Media Advisory: To contact Christophe Tzourio, M.D., e-mail christophe.tzourio{at}inserm.fr.
Elderly May Have Higher Blood Pressure in Cold Weather
CHICAGO—Outdoor temperature and blood pressure appear to be correlated in the elderly, with higher rates of hypertension in cooler months, according to a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Seasonal variations in blood pressure have been recognized among the general population for 40 years, according to background information in the article. However, few previous studies have looked specifically at older adults. "Elderly persons may be particularly susceptible to temperature-related variations in blood pressure," the authors write. "The baroreflex, which is one of the mechanisms of blood pressure regulation, is modified in elderly subjects, and it has been hypothesized that disorders of baroreflex control and enhanced vasoreactivity [sensitivity of blood vessels] could contribute to the aging-associated increase in cardiovascular morbidity [illness]."
Annick Alpérovitch, M.D., of the Institut National de la Santé et de la Récherche Médicale, Paris, and colleagues assessed the relationship between blood pressure and temperature in 8,801 individuals 65 or older. All were part of the Three-City study, conducted in three French metropolitan areas. Participants’ blood pressure was measured at the beginning of the study (starting in 1999) and again about two years later. Outdoor temperatures on the day of measurement were obtained from local meteorological offices.
Both systolic (top-number) and diastolic (bottom-number) blood pressures differed across the four seasons and across the distributions of outdoor temperatures. Average systolic blood pressure was 5 millimeters of mercury higher in winter than in summer. High blood pressure—defined as a systolic blood pressure of 160 millimeters of mercury or higher, or a diastolic blood pressure of 95 millimeters of mercury or higher—was detected in 33.4 percent of participants during winter and 23.8 percent during summer.
On average, each individual’s blood pressure decreased between the initial and follow-up measurements. This decrease was also strongly correlated with outdoor temperature. "The higher the temperature at follow-up compared with baseline, the greater the decrease in blood pressure," the authors write. These differences over time were larger in participants age 80 and older.
"Mechanisms that could explain the association between blood pressure and temperature remain undetermined," the authors continue. The sympathetic nervous system (which helps control involuntary actions, such as stress response) is activated and the hormone catecholamine is released in response to cold temperatures, which may increase blood pressure by speeding the heart rate and decreasing the responsiveness of blood vessels, they suggest.
"Although our study does not demonstrate a causal link between blood pressure and external temperature, the observed relationship nevertheless has potentially important consequences for blood pressure management in the elderly," the authors write. It may explain well-established seasonal variations in illness and death from stroke, aneurysm ruptures and other vascular diseases. "Because the risk of stroke or aneurysmal rupture is highest in the elderly, improved protection against these diseases by close monitoring of blood pressure and antihypertensive medication when outdoor temperature is very low could be considered."
(Arch Intern Med. 2009;169[1]:75-80. Available to the media pre-embargo at www.jamamedia.org)
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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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, January 12, 2009
Media Advisory: To contact Akizumi Tsutsumi, M.D., e-mail tsutsumi{at}med.uoeh-u.ac.jp.
Job Strain Associated With Stroke in Japanese Men
CHICAGO—Japanese men in high-stress jobs appear to have an increased risk of stroke compared with those in less demanding positions, according to a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Stress is considered a risk factor for stroke, according to background information in the article. Several models of job stress have been developed and provide clues as to how occupational factors may be modified to reduce risk. "The job demand–control model is the most often used occupational stress model," the authors write. "It posits that workers who face high psychological demands in their occupation and have little control over their work (i.e., those who have job strain) are at a greater risk of becoming ill than are workers with low psychological demands and a high degree of control in their occupation (i.e., those with low-strain occupations)."
Akizumi Tsutsumi, M.D., of the University of Occupational and Environmental Health, Fukuoka, Japan, and colleagues studied 6,553 Japanese workers (3,190 men and 3,363 women, age 65 and younger) who completed an initial questionnaire and physical examination between 1992 and 1995. The workers were followed up annually through phone calls, letters and interviews for an average of 11 years.
Over this time, 147 strokes occurred, including 91 in men and 56 in women. These stroke events occurred in seven men and 11 women with "low-strain" jobs (low job demand and high job control), in 23 men and 15 women with "active" jobs (high job demand and high job control), 33 men and 15 women with "passive" jobs (low job demand and low job control) and 28 men and 15 women with "high-strain" jobs (high job demand and low job control).
"Multivariable analysis revealed a more than two-fold increase in the risk of total stroke among men with job strain (combination of high job demand and low job control) compared with counterpart men with low strain (combination of low job demand and high job control) after adjustment for age, educational attainment, occupation, smoking status, alcohol consumption, physical activity and study area," the authors write.
"Although women with high-strain jobs tended to have a higher risk of stroke than women with low-strain jobs, no statistically significant differences were found for any stroke incidence among the job characteristic categories for women," they continue.
Among men, adjusting the results for other stroke risk factors slightly lessened the association between job strain and stroke. This suggests that the relationship may be mediated by chronic diseases such as obesity, high blood pressure, glucose intolerance and abnormal cholesterol levels. Other factors that may contribute include poor adaptation to stress, activation of the sympathetic nervous system (which controls involuntary reactions to stress) and inflammatory conditions.
"In conclusion, job strain was associated with incident stroke among Japanese men," the authors write. "Because modification of work structures based on the job demand–control model can be useful for stress reduction, our study has implications regarding the prevention of incident strokes among male workers."
(Arch Intern Med. 2009;169[1]:56-61. Available to the media pre-embargo at www.jamamedia.org).
Editor's Note: This study was partly supported by a grant-in-aid from the Foundation for the Development of the Community, Tochigi, Japan, and by a Grant-in-Aid for Scientific Research. 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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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, November 10, 2008
Media Advisory: To contact corresponding author Suzanne Craft, Ph.D., call Clare Hagerty at 206-685-1323 or e-mail clareh{at}u.washington.edu.
Diabetes Associated With Different Types of Brain Injury in Patients With Dementia
CHICAGO—Patients with dementia and diabetes appear to display a different pattern of injuries in their brains than patients with dementia but without diabetes, according to an article posted online today that will appear in the March print issue of Archives of Neurology, one of the JAMA/Archives journals.
"The association between diabetes mellitus and increased risk for dementia in the elderly is well documented," the authors write as background information in the article. Several possible mechanisms have been proposed for this association, including the direct effects of high blood glucose and insulin, the build-up of beta-amyloid plaques in the brain and the effects of diabetes-related vascular disease on blood vessels in the brain.
Joshua A. Sonnen, M.D., of the University of Washington, Seattle, and colleagues studied 196 individuals who were part of the Adult Changes in Thought Study, a community-based investigation of dementia. After the participants died, their brains were autopsied and their cases were divided into four groups based on clinical information: those with diabetes and dementia, those with diabetes but not dementia, those with dementia but not diabetes and those without either disease.
In the 125 patients without dementia, neuropathological and biochemical factors did not differ based on diabetes status. However, among the 71 with dementia, two patterns of injury emerged based on whether the patients had diabetes and received diabetes treatment. Those without diabetes had larger amounts of beta-amyloid buildup and greater free radical damage, whereas those with diabetes had more microvascular infarcts (microscopic injury to small blood vessels in the brain known as aterioles) and more inflammation in neural tissue. This pattern was related to diabetes treatment, in that patients with dementia receiving treatment for diabetes had more microvascular infarcts, and untreated diabetic patients with dementia had beta-amyloid build-up similar to non-diabetic patients with dementia.
"These novel characterizations of two apparently different patterns of injury in dementia depending on diabetes mellitus status may have important etiologic and therapeutic implications," the authors conclude.
(Arch Neurol. 2009;66[3]:(doi:10.1001/archneurol.2008.579). Available to the media pre-embargo at www.jamamedia.org)
Editor's Note: This work was supported by grants from the National Institutes of Health; by the Nancy and Buster Alvord Endowment; and by the U.S. Department of Veterans Affairs. 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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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, January 12, 2009
Media Advisory: To contact corresponding author Tanuja Chitnis, M.D., call Kevin Myron at 617-534-1605 or e-mail kmyron{at}partners.org.
Relapses More Frequent in Patients Diagnosed With Pediatric-Onset Multiple Sclerosis
CHICAGO—Patients who develop multiple sclerosis before age 18 appear to experience more relapses of symptoms than those diagnosed with the disease as adults, according to a report in the January issue of Archives of Neurology, one of the JAMA/Archives journals.
"Although the clinical onset of multiple sclerosis (MS) typically occurs between ages 20 and 40 years, 2.7 percent to 10.5 percent of patients have been reported to develop their first symptoms before their 18th birthday," the authors write as background information in the article. Previous reports suggest the progression of MS—an inflammatory disease in which myelin, the protective coating covering nerve cells, degenerates—is slower in patients who are diagnosed in childhood.
Mark P. Gorman, M.D., of Brigham and Women’s Hospital and Massachusetts General Hospital, Boston, and colleagues studied 110 patients diagnosed with relapsing-remitting MS in adulthood (average age at diagnosis, 34.4) and 21 with pediatric-onset MS (average age at diagnosis, 15.4). Relapsing-remitting is the most common type of MS, in which patients experience periods of symptoms followed by periods of symptom-free remission. Study participants developed their first symptoms in July 2001 or later, were monitored with semi-annual neurological examinations and were followed for 12 months or longer (an average of 3.67 years for pediatric-onset patients and 3.98 years for adult-onset).
Patients who developed the disease in childhood had, on average, a higher yearly rate of relapses than those who were diagnosed as adults (1.13 vs. 0.4 relapses per year). "These findings persisted in multivariate regression models when controlling for sex, race and proportion of disease spent undergoing disease-modifying treatment and when age at onset was treated as a continuous variable," the authors write.
"In general, the disease course of MS has been divided into a relapsing-remitting phase, during which inflammatory mechanisms predominate, and a secondary progressive phase, during which neurodegenerative mechanisms predominate," they continue. "Acute relapses are the clinical hallmark of the inflammatory phase of MS. The higher relapse rate in the pediatric-onset group in our study may therefore suggest that patients with pediatric-onset MS are coming to medical attention closer to the true biological onset of their disorder than patients with adult onset during a more inflammatory phase, as has been previously suggested."
If patients with pediatric-onset diseases do indeed have more relapses despite their disease progressing more slowly, "this discrepancy may suggest greater plasticity, less neurodegeneration and potentially more repair and remyelination in the younger nervous system. Further study of the biological basis for this discrepancy may yield insight into the apparent disconnect between relapses and long-term disability progression."
(Arch Neurol. 2009;66[1]:54-59. Available to the media pre-embargo at www.jamamedia.org)
Editor's Note: This study was supported by the Pediatric Multiple Sclerosis Centers of Excellence Grant from the National Multiple Sclerosis Society. Dr. Gorman is supported by a National Multiple Sclerosis Society Clinical Fellowship. 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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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, January 12, 2009
Media Advisory: To contact Pradeep Y. Ramulu, M.D., Ph.D., call John M. Lazarou at 410-502-8902 or e-mail jlazaro1{at}jhmi.edu.
Glaucoma May Be Linked to Higher Rates of Reading Impairment in Older Adults
CHICAGO—Glaucoma appears to be associated with slower spoken reading and increased reading impairment in older adults, according to a report in the January issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
"Glaucoma [a common eye condition, which can damage the eye and cause loss of vision] affects 2 percent of U.S. adults older than 40 years, and as many as 10 percent have suspected glaucoma," according to background information in the article. "Determining who should be treated requires that we understand when and how glaucoma produces disability."
Pradeep Y. Ramulu, M.D., Ph.D., and colleagues at the Wilmer Eye Institute, Johns Hopkins University, Baltimore, tested 1,154 individuals (average age 79.7) to evaluate the relationship between glaucoma and spoken reading speed. Participants were asked to read non-scrolling text aloud. Those who read slower than 90 words per minute were defined as having impairment. Glaucoma status was determined by testing participants’ visual fields, optic nerve images and medical records. Demographic information was also noted.
A total of 1,017 (95.6 percent) of participants did not have glaucoma. An additional 73 had unilateral glaucoma (glaucoma in one eye) and 64 had bilateral glaucoma (glaucoma in both eyes). "Univariate analysis demonstrated reading impairment in 16 percent of subjects without glaucoma, 21.1 percent of subjects with unilateral glaucoma and 28.4 percent of subjects with bilateral glaucoma," the authors write. "Subjects with unilateral glaucoma showed similar reading speeds and odds of reading impairment when compared with subjects without glaucoma. Subjects with bilateral glaucoma read 29 words per minute slower than those without glaucoma and had roughly twice the odds of reading impairment."
"Lower levels of education were associated with slower reading speeds, and race persisted as a significant predictor of reading speed even after adjusting for education," the authors write.
"As reading out loud was necessary to measure reading speed, racial differences in speaking rates could account for the difference in the measured reading rate...," the authors conclude. "Future work should evaluate reading in subjects with glaucoma under more realistic conditions to further explore if reading impairment is more prevalent than reported herein."
(Arch Ophthalmol. 2009;127[1]:82-87. Available to the media pre-embargo at www.jamamedia.org).
Editor's Note: This study was supported by National Institutes of Health grants. 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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