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RESEARCH BRIEFSWorkplace Exposure May Be Similar for Smokers, NonsmokersUsing a new method to measure second-hand tobacco smoke exposure, Wael Al-Delaimy, now a research fellow at the Harvard School of Public Health, and colleagues found that bar and restaurant workers can be exposed to levels of tobacco smoke as high as the exposure of active smokers.
Hair nicotine levels of nonsmokers working in bars or restaurants that are 100 percent smoke-free, 50 percent smoke-free, or totally without smoking restrictions (shades of purple) are compared to the level in bar and restaurant workers who actively smoke (pink). Researchers found no significant difference between hair nicotine levels, a measure of long-term exposure to environmental tobacco smoke, of active smokers and those of nonsmokers who work in restaurants or bars with no smoking restrictions. While working in New Zealand, Al-Delaimy and colleagues determined that hair nicotine levels, which serve as a marker of long-term environmental smoke exposure, increased according to the amount of smoking permitted in the restaurant: workers in smoke-free bars or restaurants had minimal hair nicotine levels; workers in 50 percent smoke-free establishments had intermediate hair nicotine levels; and those in establishments with no smoking restrictions had hair nicotine levels similar to active smokers. The study appeared in the March 9 New Zealand Medical Journal. The researchers analyzed hair samples from 114 participants from 62 urban sites using high-performance liquid chromatography. Applied to detecting hair nicotine levels, the method is more sensitive and cost-effective than other avail-able techniques, making it particularly useful for epidemiological studies, said Al-Delaimy. In addition, the ease with which hair can be collected, stored, and analyzed opens new possibilities in tobacco research and control, he said. Nicotine enters the hair shaft through the bloodstream after being inhaled. "This study demonstrates, in a quantitative manner, that nonsmokers are exposed to tobacco smoke levels from their workplace that are equivalent to active smokers' exposure levels," said Al-Delaimy. To protect workers and patrons from these high levels of exposure, the Massachusetts legislature is currently considering a bill banning smoking in workplaces statewide, including restaurants and bars. In addition, the New Zealand parliament is citing the results of this study in an effort to ban smoking in bars and restaurants nationwide.
Breast-feeding May Limit Teenage ObesityMore months on breast milk for infants may mean fewer pounds on teens later on, according to a study of 15,000 boys and girls reported in the May 16 Journal of the American Medical Association. "Breast-feeding may prevent obesity later in life," said lead author Matthew Gillman, associate professor at HMS and Harvard Pilgrim Health Care. "Our study, along with others, supports the recommendation of the American Academy of Pediatrics to breast-feed infants for the first year." Obesity has risen dramatically among children and adults. Overweight teens tend to have higher blood pressure and cholesterol, lower self-esteem, lower grades in school, and lower earnings as young adults. They also are much more likely to grow into obese adults who face serious health consequences such as heart disease, diabetes, and arthritis. "Once present, obesity is hard to treat," Gillman said. "For these reasons, prevention is paramount." Infants who were breast-fed more than formula-fed or who were breast-fed for longer periods had approximately 20 percent lower risk of being overweight in the preteen and teen years. The results were adjusted for age, gender, sexual maturity, total calorie intake, physical activity, time watching television, mother's body mass index, and other social, economic, and lifestyle factors known to influence weight. In this study, breast-feeding includes feeding infants breast milk extracted from breast pumps. Among the mostly breast-fed children, about 4 percent of the girls and 7 percent of the boys were overweight compared to 6 percent of the girls and 11 percent of the boys fed mostly infant formula. Among those who were breast-fed for seven months or more, about 4 percent of the girls and 7 percent of the boys were overweight compared to about 6 percent of girls and 12 percent of boys who drank breast milk for three months or less. Gillman and his colleagues analyzed questionnaires filled out by 8,186 girls and 7,155 boys ages 9 to 14 in the Growing Up Today Study. The study group had slightly lower rates of obesity compared to the general U.S. preteen and teen population. When the researchers checked in with the mothers—all part of the Nurses' Health Study II—they found that 62 percent of the children were only or mostly fed breast milk—about double the national breast-feeding rate. Just less than half were breast-fed for at least seven months. —Carol Cruzan Morton
Some Medical Errors More Common with Children than AdultsEfforts to document and reduce medical errors have concentrated on the adult population, largely ignoring pediatric patients. Now researchers at Brigham and Women's Hospital, Massachusetts General Hospital, and Children's Hospital report in the April 25 Journal of the American Medical Association that medical errors with the potential to harm patients are three-fold higher in the pediatric inpatient setting than the rate reported for adult inpatient care. Rainu Kaushal, HMS instructor in medicine at BWH, Donald Goldmann, HMS professor of pediatrics at Children's, and colleagues collected data from Children's and MGH on the rate of medication errors: errors in drug ordering, transcribing, dispensing, administering, and monitoring. The researchers then reviewed the errors to identify potential adverse drug events, errors that could have significantly harmed patients; and preventable adverse drug events, errors that actually did harm. Of the 10,778 medication orders reviewed, 616 contained errors, 115 of which were potentially harmful. This rate of potential adverse drug events, 1.1 percent, was three times higher than that reported for adults. Five preventable adverse drug events resulted in harm to patients. The rates of medication errors and preventable adverse drug events were similar to those reported in adults. Physician ordering was the most common stage at which errors occurred. The youngest, most vulnerable patients, those in the neonatal intensive care unit, experienced the highest rate of error: 46 potential adverse drug events per 100 admissions. These especially high rates are likely due in part to the difficulty of ordering correct dosages for neonates, whose weight changes rapidly, and the need for pharmacists to dilute stock solutions and divide pills. The researchers judged that a computerized physician-order entry system or a ward-based clinical pharmacist might have prevented more than 90 percent of potential adverse drug events. —Heather Ettinger
Rod Cells Pay for Light Sensitivity With Reaction TimeRetinal rod cells pack a billion light-absorbing rhodopsin molecules into membranous disks to ensure capture of single photons of light. Yet researchers at HMS and the Massachusetts Eye and Ear Infirmary report in the May 3 Nature that this high sensitivity comes at a price: slower reaction and recovery time. Light-activated rhodopsin turns on its downstream partner, the G protein transducin, in the disk membrane. Once activated, transducin diffuses in the membrane to trigger a signaling cascade that eventually reaches the brain. Amplification of the light signal continues until recovery, when molecules are turned off by another series of membrane protein interactions. Until now, it was unclear whether the speeds of photoresponse and recovery were limited by the rate of protein collisions in the disk membrane or by the rate of processes that occur when two proteins have bound to one another. Using mice that have one rhodopsin allele deleted, Peter Calvert, HMS instructor in ophthalmology, and Clint Makino, HMS assistant professor of ophthalmology, both at MEEI, and colleagues found that decreasing rhodopsin levels by 50 percent increased the rod response onset and recovery rates 1.7-fold. Their results demonstrate that "the rate of activation and inactivation of phototransduction is limited by rates of protein interactions at the membrane surface," said Calvert. "This is the first time that people have been able to examine the effect of protein crowding on generating a biological signal in a living, active neuron," he said. —Heather Ettinger |
