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, November 27, 2006)
OVERWEIGHT YOUNG WOMEN HAVE REDUCED RISK OF DEVELOPING BREAST CANCER BEFORE MENOPAUSE
STATINS REDUCE RISK OF HEART ATTACK AND STROKE IN THOSE WITHOUT HEART DISEASE
WEIGHT CYCLING ASSOCIATED WITH INCREASED RISK FOR GALLSTONES AMONG MEN
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EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, November 27, 2006
Media Advisory: To contact Karin B. Michels, Sc.D., Ph.D., call Leah Gourley at 617-432-3991.
OVERWEIGHT YOUNG WOMEN HAVE REDUCED RISK OF DEVELOPING BREAST CANCER BEFORE MENOPAUSE
CHICAGO—A higher body mass index (BMI), especially in early adulthood, may be associated with a reduced risk of breast cancer before menopause, according to an article in the November 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. This association does not appear to be related to ovulation problems that overweight women may develop.
Previous studies have observed an association between higher body mass index and a lower risk of breast cancer, according to background information in the article. High BMI can be associated with irregular or long menstrual cycles and the development of polycystic ovary syndrome, a condition that occurs when the ovaries malfunction, decreasing fertility and contributing to other illnesses. All of these are related to disruptions in ovulation, which decrease levels of the hormones estradiol and progesterone; the long-held belief was that these lower levels, in turn, might explain the decrease in breast cancer risk. "However, few studies have explored whether these or other factors provide mechanistic insights into the unexpected protection that a high body mass confers on the premenopausal breast," the authors write.
Karin B. Michels, Sc.D., Ph.D., Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues studied 113,130 premenopausal women who were part of the Nurses' Health Study II, a large group of female registered nurses who have been followed since 1989. At the beginning of the study, the women provided information about their adult height and their weight at age 18, as well as their current weight, any fertility problems, their family history of breast cancer and the characteristics of their menstrual cycle. Follow-up questionnaires that included questions about breast cancer and benign breast disease, childbirth, alcohol consumption, oral contraceptive use and physical activity were filled out every two years. The women were followed until 2003 or until they developed breast or any other cancer, died or reached menopause, whichever happened first.
Between 1989 and 2003, 1,398 cases of invasive breast cancer occurred among the women. Those with a current BMI of 30 or higher had a 19 percent lower risk of breast cancer compared with those who had a BMI between 20 and 22.4, after adjusting for family history, personal characteristics, lifestyle habits and menstrual variables. Women whose BMI was 27.5 or higher at age 18 had a 43 percent lower risk of developing breast cancer than those whose 18-year-old BMI was between 20 and 22.4. This association did not change when the researchers considered current BMI.
"A high BMI during adulthood is highly correlated with a high body mass during adolescence, which may be more important for the development of breast cancer before menopause," the authors write. "Although a high birth weight has been fairly consistently linked to an increase in the risk of premenopausal breast cancer, the BMI-breast cancer association seems to reverse at some point during the first years of life, only to revert back after menopause," when breast cancer is most often diagnosed.
Because the failure to ovulate (anovulation) cannot be measured directly, these findings do not rule out the hypothesis that factors related to ovulation contribute to the protective effect of a high BMI. "However, because adjustment for menstrual cycle patterns, infertility due to ovulatory disorder, probable polycystic ovary syndrome and use of oral contraceptives did not even slightly attenuate the association with BMI, anovulation does not seem to be a primary explanation for the reduced risk in heavier women," the authors conclude. "Among women with no history of infertility due to an ovulatory disorder, the inverse association between BMI and premenopausal breast cancer incidence persisted, lending further support to the role of mechanisms other than anovulation." The link may be hormonal, or due to the fact that obese women are less likely to be screened for breast cancer.
(Arch Intern Med. 2006;166:2395-2402. Available to the media pre-embargo at www.jamamedia.org)
Editor's Note: This project was supported by a grant from the Massachusetts Breast Cancer Research Grants Program of the Massachusetts Department of Public Health. The Nurses' Health Study II is supported by a Public Health Service grant from the National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services. 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 27, 2006
Media Advisory: To contact corresponding author Niteesh K. Choudhry, M.D., Ph.D., call Lori J. Shanks at 617-534-1604.
STATINS REDUCE RISK OF HEART ATTACK AND STROKE IN THOSE WITHOUT HEART DISEASE
CHICAGO—Among individuals without cardiovascular disease, taking statins regularly may reduce the risk of major heart and cerebrovascular events such as heart attack and stroke but not coronary heart disease or overall death, according to a meta-analysis of previously published studies, reported in the November 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Statins have been shown to reduce death and other negative outcomes associated with heart and cerebrovascular disease among those who already have these conditions, according to background information in the article. It is less clear whether these medications benefit those without cardiovascular disease. Current national treatment guidelines recommend the use of statins in these patients based on their cardiovascular risk profile and LDL-C or "bad cholesterol" level. For patients without cardiovascular disease and with normal LDL-C levels, statins are recommended only for individuals with diabetes or with two or more other cardiac risk factors that raise their 10-year risk of a heart attack or other heart event to at least 10 percent.
Paaladinesh Thavendiranathan, M.D., M.Sc., University of Toronto, Ontario, and colleagues analyzed the results of seven previously published clinical trials that assessed the benefits of statins in a total of 42,848 patients, 90 percent of whom had no history of cardiovascular disease. In each study, patients were randomly assigned to receive either statins or another form of care and were followed for at least one year, at least 100 major cardiovascular events occurred and 80 percent or more of the participants did not have cardiovascular disease.
In total, 21,409 patients in the trials took statins and 21,439 were assigned to placebo. The average follow-up period for the studies ranged from 3.2 to 5.2 years; average age of the participants ranged from 55.1 to 75.4 years; and the proportion of men included ranged from 42 percent to 100 percent. In patients on statin therapy, there were 924 major coronary events such as heart attack compared with 1,219 among those in control groups—a 29.2 percent reduction in risk. Major cerebrovascular events, including stroke, occurred in 440 patients taking statins and 517 controls, a 14.4 percent lower risk. Statin treatment was also associated with a 31.7 percent reduction in risk for non-fatal heart attacks and a 33.8 percent reduction in the number of revascularization procedures, which restore blood flow and include angioplasty and bypass surgery. There were no statistically significant differences between the statin and control groups in the rates of patients who died from cardiovascular disease or from all causes.
Assuming that individuals not taking statins have a 5.7 percent chance of having a major heart event over a 4.3-year period, statins can reduce that risk to 4 percent, the authors write. "Therefore, 60 patients would need to be treated for an average of 4.3 years to prevent one major coronary event." Similarly, 268 patients would need to be treated to prevent one stroke or other major cerebrovascular event; 61 to prevent one non-fatal heart attack; and 93 to prevent one revascularization procedure.
Statins are expensive and other therapies also may work to reduce risk, the authors conclude. "Therefore, even though universal lipid-lowering therapy appears attractive, especially in an intermediate-risk primary prevention population, further studies are needed to clarify the cost-effectiveness of therapy in this group."
(Arch Intern Med. 2006;166:2307-2313. 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, November 27, 2006
Media Advisory: To contact Chung-Jyi Tsai, M.D., call Melanie Jackson at 859-323-6363.
WEIGHT CYCLING ASSOCIATED WITH INCREASED RISK FOR GALLSTONES AMONG MEN
CHICAGO—Intentionally losing weight and then regaining it may increase men's risk for gallstones later in life, according to a report in the November 27 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Gallstone disease—which occurs when a solid mass of cholesterol, bile and calcium salts forms in the gall bladder—is common among adults in Western countries, according to background information in the article. Obesity is a risk factor for gallstone disease, as is rapid weight loss for the treatment of severe obesity. "Although approximately 30 percent of adult U.S. men are trying to lose weight, intentional weight loss is rarely sustained and is often associated with unintentional weight regain, leading to weight cycling," the authors write. "The long-term health consequences of repeated intentional weight loss and the mechanisms of weight recovery are still not well understood. Studies have suggested that large weight fluctuations at some point earlier in life represent an independent risk factor for chronic diseases, including metabolic syndrome."
To assess whether weight cycling influenced the risk of developing gallstones, Chung-Jyi Tsai, M.D., Sc.D., University of Kentucky Medical Center, Lexington, and colleagues analyzed data from 24,729 men who were part of the Health Professionals Follow-up Study. The men provided information about any weight fluctuations between 1988 and 1992. They were then sent a questionnaire every two years from 1992 to 2002 to monitor whether they had developed gallstone disease.
A total of 7,443 men reported that they were weight maintainers—in other words, that they had remained within five pounds of their initial weight between 1988 and 1992. Of those who were weight cyclers, 10,027 were light cyclers (who had a maximum weight loss per attempt of between 5 and 9 pounds); 5,185 were moderate cyclers (weight loss between 10 and 19 pounds); and 2,074 were severe cyclers (weight loss of 20 pounds or more).
Overall, 1,222 cases of symptomatic gallstones developed between 1992 and 2002. Gallstones were more likely in each of the weight cycling groups than in the weight maintaining group. Those who were light cyclers had a 21 percent increased risk, moderate cyclers had a 38 percent increased risk and severe cyclers increased their risk by 76 percent, compared with weight maintainers. Risk for gallstones also increased when the number of weight cycles increased, with severe cyclers who had more than one weight cycle experiencing nearly double the risk of weight maintainers. The associations remained when researchers considered each participant's body mass index (BMI), further suggesting that it is the weight cycling, rather than being overweight or obese alone, that increases risk.
"The potential mechanisms contributing to the association between weight cycling and gallstone formation observed in our study are likely to be multiple," the authors write. When an individual loses and then regains weight, much of that additional weight is made up of body fat. "Studies have shown that large swings of body weight, especially the phase of weight recovery, are particularly sensitive to the accumulation of body fat and to the development of metabolic abnormalities, including insulin resistance, and thereby may facilitate gallstone formation," they write. In addition, levels of the compounds leptin and insulin in the blood have been shown to be higher in weight cyclers than weight maintainers, which could also contribute to gallstone risk.
(Arch Intern Med. 2006;166:2369-2374. Available to the media pre-embargo at www.jamamedia.org).
Editor's Note: This study was supported by research grants from the National Institutes of Health and from the Centers for Disease Control and Prevention. 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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