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New Risk Model Developed for Brain AVMs
Hemorrhagic stroke with bleeding into the brain is a serious possible complication for patients with brain arteriovenous malformations, (AVMs), but determining the best treatment strategy is a complicated process dependent on a number of factors. Christian Stapf, M.D., adjunct assistant professor of neurology in the Division of Stroke & Critical Care Center, and his collaborators at the Neurological Institute have developed the “Columbia AVM Risk Model” in an effort to predict the risk of spontaneous hemorrhage based on a patient’s medical history and certain anatomic features of the AVM.
In studying the demographic, clinical and morphological characteristics of AVMs and risk of
Arteriovenous malformations
Arteriovenous malformations (AVMs) are masses of abnormal blood vessels that grow in the brain. An angiogram of an AVM is shown above.
stroke, Dr. Stapf and co-workers found that patients without specific risk factors (such as unruptured AVMs at the surface of the brain and superficial veins) had a very low bleeding risk, and those with AVMs deep in the brain and with deep venous drainage showed an increased risk of hemorrhage.
   Since brain AVMs are diagnosed most often in patients in their 30s and 40s, it is not always clear whether treatments such as interventional neuroradiology, neurosurgery, or radiotherapy will positively affect the patient’s prognosis. By using the new risk model, Dr. Stapf hopes to balance the natural history risk with the presumed treatment risk.
    “Considering that any form of AVM treatment is invasive and carries an average complication risk between 5 percent to 10 percent, the question is whether patients with a low spontaneous bleeding risk will benefit from invasive therapy,” says Dr. Stapf. “This is the first time that such a prospective risk model has been proposed, and we hope it may be useful for colleagues working in treatment centers both in the United States and worldwide.” Elements of the Columbia AVM Risk Model will soon be tested world-wide in a randomized clinical trial (www.
Neurology 66: 1350-1355. This study was supported by the NIH/NINDS (PI: J.P. Mohr, M.D.).

Obesity Hurts Women’s Health More than Men’s
Overweight and obese women experience more severe health problems and live shorter lives than overweight and obese men, according to a new study from health disparities researchers in the Mailman School of Public Health and the School of Nursing. The researchers suggest that the difference may be due to extra stigma faced by overweight and obese women.
   “The results are surprising and they present a new puzzle in the obesity debate,” says the study’s lead author, Peter Muennig, M.D., M.P.H., assistant professor in the Department of Health Policy and Management at Mailman. “If obesity keeps rising in the United States, it’s conceivable that such trends will eventually erase the gender gap in life expectancy.”
   Dr. Muennig found that each year, overweight women (BMI between 25 and 30) in the United States lose a total of 1 million years of life compared to normal weight women. That’s 20 times more than the figure for males: Overweight men only lose a total of 47,000 years compared to normal weight men.
   Quality of life, including physical and psychological health, also differs. Each overweight man loses only half a year of perfect health during his life (measured in quality-adjusted life years, or QALYs), while each overweight woman loses 2.9 QALYs.
   Obesity (BMI 30 or more) had a large impact on both sexes, though greater for women. Obese women lose a total of 1.89 million years of life compared to men’s 1.21 million. Each obese woman loses 7 QALYs compared to a man’s 4 QALYs.
   Dr. Muennig says a pattern of high morbidity in young women and high mortality in older women that was also revealed by the study suggests that the gender difference is due to greater stigma faced by overweight and obese women.
   “There’s a large amount of literature showing stigma is associated with health risks,” Dr. Muennig says. “The messages women get about body image may be contributing to the burden of disease, but more research is needed to iron out the reasons for the gender disparity.”
American Journal of Public Health 96(9): 1662. The research was supported by a grant from the Agency for Healthcare Research and Quality.

Number of Pregnant Women Carrying Staph Increases
Recent bacteria cultures from pregnant New York City women reveal that more women than ever carry colonies of Staphylococcus aureus and some harbor a dangerous new strain of the bug, community-associated MRSA, that is resistant to antibiotics and produces a toxin.
   Infections with community-associated MRSA (methicillin-resistant S. aureus) are increasingly detected among children and newborns and are sometimes fatal. No one is sure where children acquire MRSA, but one possibility is from their mothers during delivery. The increase in community-associated MRSA infections prompted Katherine Chen, M.D, M.P.H., assistant professor in obstetrics & gynecology and epidemiology, to reassess the prevalence of S. aureus in pregnant women and, for the first time, measure the rate of community-associated MRSA colonization.
   Dr. Chen and colleague Richard Huard, M.D., assistant professor of clinical pathology, found that the rate of S. aureus colonization in the genital tract in expectant mothers has doubled in the last 15 years: 17 percent of expectant mothers in their study carried the bacteria, up from 8 percent in the early 1990s. Dr. Chen and Dr. Huard also found that about 3 percent of those carrying S. aureus were colonized with MRSA, the majority community-associated.
   It is still unknown if S. aureus or MRSA can be transmitted from mother to child during delivery, or what dangers MRSA would pose to infants who acquire it during delivery. Dr. Chen is conducting studies to determine the risk factors associated with carrying MRSA and if the bacteria can be transmitted to infants during delivery.
   “It’s an area that we need to monitor in the future. Are we on the edge of a cliff or just a ditch? We have no idea right now,” Dr. Chen says. “But for mothers right now, there’s nothing to worry about.”
Obstetrics & Gynecology 108(3) Part 1: 482. The study was supported by the National Institute of Child Health and Human Development and by the Center for Interdisciplinary Research on Antimicrobial Resistance of Columbia University.

Subway Racket May Impair Hearing
Just 30 minutes of exposure a day to noise in New York City subways over a lifetime of commuting may cause enough hearing loss to impair normal conversation, according to a new study conducted by researchers in the Mailman School’s Department of Sociomedical Sciences.
   “The general rule of thumb is that if you have to shout to communicate with somebody who is an arm length away, you’re probably over the noise limit set by the U.S. Occupational Safety and Health Administration,” says the study’s senior author, Robyn Gershon, Dr.P.H. “I ride the subway a lot and I knew that it was almost certainly over the limit, but I wasn’t sure of the actual extent.”
   To more precisely measure noise levels in subway cars and platforms, Dr. Gershon and her colleagues recorded sound on platforms including every major hub, and inside of moving train cars. The maximum level of noise ranged from 83 to 106 decibels on platforms and from 84 to 112 decibels inside subways cars. EPA and WHO guidelines recommend that everyone should limit their daily exposure to 100 decibel noise to only a minute and a half.
   People who frequently ride the subway should consider wearing earplugs, Dr. Gershon suggests. “Many people think that iPods and other personal listening devices are protective, but they can actually increase noise exposure if played at high volumes,” she says. “And fingers only reduce noise by four or five decibels.”
   To be effective, ear plugs must totally block the ear canal with an airtight seal. When inserted properly, your own voice will sound louder and deeper than normal. For more information on preventing noise-induced hearing loss, go to http://www.
Journal of Urban Health doi:101007/s 11524-006-9083-. The study was published in the Sept/Oct 2006 issue.