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, May 28, 2007)
INTAKE OF VITAMIN D AND CALCIUM ASSOCIATED WITH LOWER RISK OF BREAST CANCER BEFORE MENOPAUSE
EXERCISE MAY SLIGHTLY BOOST “GOOD” CHOLESTEROL LEVELS
SOY NUTS MAY IMPROVE BLOOD PRESSURE IN POSTMENOPAUSAL WOMEN
COMMUNITY-ASSOCIATED STAPH INFECTIONS INVOLVING ANTIBIOTIC-RESISTANT BACTERIA INCREASE
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, May 28, 2007
Media Advisory: To contact Jennifer Lin, Ph.D., call Kevin Myron at 617-678-6449.
INTAKE OF VITAMIN D AND CALCIUM ASSOCIATED WITH LOWER RISK OF BREAST CANCER BEFORE MENOPAUSE
CHICAGO—Women who consume higher amounts of calcium and vitamin D may have a lower risk of developing premenopausal breast cancer, according to a report in the May 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Data from animal studies have linked calcium and vitamin D to breast cancer prevention, according to background information in the article. However, epidemiologic studies on humans have been less conclusive.
Jennifer Lin, Ph.D., of Brigham and Women’s Hospital and Harvard Medical School, Boston, and colleagues assessed 10,578 premenopausal and 20,909 postmenopausal women age 45 and older who were part of the Women’s Health Study. At the beginning of the study (in 1993 or 1995), the women completed a questionnaire about their medical history and lifestyle, plus a food frequency questionnaire that detailed how often they consumed certain foods, beverages and supplements during the previous year. Every six months during the first year and then every year after that, participants returned follow-up questionnaires indicating whether they had been diagnosed with breast cancer.
Over an average of 10 years of follow-up, 276 premenopausal women and 743 postmenopausal women developed breast cancer. Calcium and vitamin D intake were moderately associated with a lower risk of breast cancer before but not after menopause. The inverse associated in premenopausal women appeared more pronounced for more aggressive breast tumors.
“A possible explanation for the evident difference by menopause status may be related to the joint relationship among calcium, vitamin D and insulinlike growth factors (IGFs),” they continue. “In vitro studies have suggested that calcium and vitamin D exert anticarcinogenic effects on breast cancer cells expressing high levels of IGF-1 and IGF binding protein 3. Calcium, vitamin D and IGF binding protein 3 have been shown in vitro to interact with each other in promoting growth inhibition in breast cancer cells.” Since blood levels of these compounds decline with age, they would be more prevalent in younger, premenopausal women.
“Further investigation is warranted to study the potential utility of calcium and vitamin D intake in reducing the risk of breast cancer,” the authors conclude.
(Arch Intern Med. 2007;167:1050-1059. Available to the media pre-embargo at www.jamamedia.org)
Editor's Note: This study was supported by a grant from the National Cancer Institute, a grant from the National Heart, Lung, and Blood Institute and a career development award from the National Cancer 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.
Go back to the top.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, May 28, 2007
Media Advisory: To contact corresponding author Hirohito Sone, M.D., Ph.D., e-mail: sone.hirohito{at}ocha.ac.jp.
EXERCISE MAY SLIGHTLY BOOST “GOOD” CHOLESTEROL LEVELS
CHICAGO—Regular exercise appears to modestly increase levels of high-density lipoprotein, or “good,” cholesterol, according to a meta-analysis study in the May 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
A low level of high-density lipoprotein cholesterol (HDL-C) is an independent risk factor for cardiovascular disease, the leading cause of death worldwide, according to background information in the article. There is strong evidence that individuals who are more physically active have higher HDL-C levels. “Thus, the value of regular aerobic exercise in increasing serum [blood] HDL-C level and in reducing the risk of cardiovascular disease has received widespread acceptance,” the authors write. “In contrast, results of aerobic exercise studies vary considerably, depending on the exercise program (e.g., duration, intensity or frequency) and characteristics of subjects at baseline.”
Satoru Kodama, M.D., of Ochanomizu University, Tokyo, and colleagues performed a meta-analysis of 25 articles reporting the results of randomized controlled trials that were published between 1966 and 2005 and assessed the effects of exercise on HDL-C. To be included in the analysis, the studies had to evaluate aerobic exercise in adults with an average age of 20 or older, specify HDL-C measurements at the beginning and end of the study, have a length of at least eight weeks, and randomly assign some participants to a group of exercisers and others to a control group of non-exercisers.
The 25 articles analyzed included a total of 1,404 participants with an average age range of 23 to 75 years and an average study period of 27.4 weeks. The exercise groups were told to exercise for an average of 3.7 sessions per week at an average of 40.5 minutes each, burning an average of 1,019 calories per week.
In all the studies combined, HDL-C increased by an average of 2.53 milligrams per deciliter in the exercise groups. The minimum amount of weekly exercise that appeared necessary to change HDL-C levels was 120 minutes or 900 calories burned. The effect of exercise was greater in those who had a higher total cholesterol level (220 milligrams per deciliter or greater) and in those with a body mass index of less than 28.
“In a previous observational study, every 1–milligram per deciliter increment in HDL-C level was reported to be associated with a 2 percent and 3 percent decreased risk of cardiovascular disease in men and women, respectively,” the authors write. “If this observation were applied to our results, the increase in HDL-C level by exercise determined by this analysis would, by a rough estimate, result in a cardiovascular disease risk reduced by approximately 5.1 percent in men and 7.6 percent in women. This is potentially of substantial importance in public health, although the effect of reducing cardiovascular risk by increasing HDL-C level might be smaller than that by use of medications such as fibrates or niacin.”
Only exercise duration, and not frequency or intensity, was associated with a change in HDL-C levels in the analysis. When the participants exercised for 23 to 74 minutes per session, each 10-minute increase in exercise duration corresponded to a 1.4–milligram per deciliter increase in HDL-C level. “This suggests that in improving blood HDL-C values, increasing time per session is better than performing multiple brief exercise sessions when total time for exercise is limited, as is the case for many people,” the authors write.
(Arch Intern Med. 2007;167:999-1008. Available to the media pre-embargo at www.jamamedia.org).
Editor's Note: This work was supported by Health Sciences Research Grants from the Japanese Ministry of Health, Labor, and Welfare. Dr. H. Sone is a recipient of a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science. 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.
Go back to the top.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, May 28, 2007
Media Advisory: To contact Francine K. Welty, M.D., Ph.D., call Zineb Marchoudi at 617-678-6449.
SOY NUTS MAY IMPROVE BLOOD PRESSURE IN POSTMENOPAUSAL WOMEN
CHICAGO—Substituting soy nuts for other protein sources in a healthy diet appears to lower blood pressure in postmenopausal women, and also may reduce cholesterol levels in women with high blood pressure, according to a report in the May 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
The American Heart Association estimates that high blood pressure (hypertension) affects approximately 50 million Americans and 1 billion individuals worldwide. The most common—and deadly—result is coronary heart disease, according to background information in the article. Women with high blood pressure have four times the risk of heart disease as women with normal blood pressure.
Francine K. Welty, M.D., Ph.D., and colleagues at Beth Israel Deaconess Medical Center, Boston, assigned 60 healthy post-menopausal women to eat two diets for eight weeks each in random order. The first diet, the Therapeutic Lifestyle Changes (TLC) diet, consisted of 30 percent of calories from fat (with 7 percent or less from saturated fat), 15 percent from protein and 55 percent from carbohydrates; 1,200 milligrams of calcium per day; two meals of fatty fish (such as salmon or tuna) per week; and less than 200 milligrams of cholesterol per day. The other diet had the same calorie, fat and protein content, but the women were instructed to replace 25 grams of protein with one-half cup of unsalted soy nuts. Blood pressure and blood samples for cholesterol testing were taken at the beginning and end of each eight-week period.
At the beginning of the study, 12 women had high blood pressure (140/90 milligrams of mercury or higher) and 48 had normal blood pressure. “Soy nut supplementation significantly reduced systolic [top number] and diastolic [bottom number] blood pressure in all 12 hypertensive women and in 40 of the 48 normotensive women,” the authors write. “Compared with the TLC diet alone, the TLC diet plus soy nuts lowered systolic and diastolic blood pressure 9.9 percent and 6.8 percent, respectively, in hypertensive women and 5.2 percent and 2.9 percent, respectively, in normotensive women.”
In women with high blood pressure, the soy diet also decreased levels of low-density lipoprotein (“bad”) cholesterol by an average of 11 percent and levels of apoliprotein B (a particle that carries bad cholesterol) by an average of 8 percent. Cholesterol levels remained the same in women with normal blood pressure.
“A 12-millimeter of mercury decrease in systolic blood pressure for 10 years has been estimated to prevent one death for every 11 patients with stage one hypertension treated; therefore, the average reduction of 15 milligrams of mercury in systolic blood pressure in hypertensive women in the present study could have significant implications for reducing cardiovascular risk and death on a population basis,” the authors write.
“This study was performed in the free-living state; therefore, dietary soy may be a practical, safe and inexpensive modality to reduce blood pressure. If the findings are repeated in a larger group they may have important implications for reducing cardiovascular risk in postmenopausal women on a population basis,” they conclude.
(Arch Intern Med. 2007;167:1060-1067. Available to the media pre-embargo at www.jamamedia.org).
Editor's Note: This study was funded by the Harvard Medical School’s Center of Excellence in Women’s Health (National Institutes of Health); a contract from the Office on Women’s Health, Department of Health and Human Services; and in part by a grant to the Beth Israel Deaconess Medical Center General Clinical Research Center from the National Institutes of 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.
Go back to the top.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, May 28, 2007
Media Advisory: To contact Bala Hota, M.D., M.P.H., call Don Rashid at 312-864-0070.
COMMUNITY-ASSOCIATED STAPH INFECTIONS INVOLVING ANTIBIOTIC-RESISTANT BACTERIA INCREASE
CHICAGO—The incidence of antibiotic-resistant staph infections associated with being acquired in the community and not in health care institutions increased almost seven-fold in Chicago’s Cook County Hospital system between 2000 and 2005, according to a report in the May 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Methicillin-resistant Staphylococcus aureus (MRSA) infections—which do not respond to standard antibiotic treatments—are typically associated with hospitals and other health care environments. Beginning in 1998, a community-associated form of the bacteria (CA-MRSA) emerged globally, according to background information in the article. Risk factors for CA-MRSA include jail or prison time, exposure while playing certain sports, intravenous drug use, overcrowded housing, tattooing and poor hygiene. “An understanding of factors promoting acquisition and emergence of CA-MRSA may aid in the development of prevention strategies,” the authors write.
Bala Hota, M.D., M.P.H., and colleagues at Rush University Medical Center and John H. Stroger Jr. Hospital of Cook County, Chicago, examined tissue, fluid and bone cultures at the 464-bed public hospital and its associated clinics between 2000 and 2005. They restricted their study to patients with infections of community onset, not hospital onset, to understand infection rates in the community; patients studied were those who did not have recent hospitalizations, MRSA infection or other health care exposures. To determine characteristics associated with CA-MRSA, 518 community-onset cases that occurred between 2001 and 2004 were compared with 704 controls who had community-associated methicillin-susceptible Staphylococcus aureus (CA-MSSA), which responds to methicillin-like antibiotics.
“The incidence of CA-MRSA skin and soft tissue infections increased from 24 cases per 100,000 people in 2000 to 164.2 cases per 100,000 people in 2005,” the authors write. The number of infections susceptible to antibiotics remained stable over this time, indicating that MRSA occurred in addition to and not in place of MSSA. For MRSA, “risk factors were incarceration, African-American race/ethnicity and residence at a group of geographically proximate public housing complexes; older age was inversely related.”
“Why CA-MRSA has emerged at such a rapid rate remains unclear,” the authors write. Hospitals and long-term care facilities have long been thought to be “epicenters” for antimicrobial resistance, promoting cross-transmission of resistant bacteria because individuals with and without the bacteria are housed at the same location. These findings suggest that prisons, public housing and other community settings also may promote cross-transmission because large at-risk populations remain together for long periods of time.
“In conclusion, among Cook County Hospital patients, the rate of CA-MRSA skin and soft tissue infections increased rapidly between 2000 and 2005, adding significantly to the overall burden of staphylococcal disease,” the authors write. “Epidemiological analysis suggests that control measures could focus initially on core groups that have contributed disproportionately to risk, although CA-MRSA becomes endemic as it disseminates within communities.”
(Arch Intern Med. 2007;167:1026-1033. 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.
Go back to the top.
