By ANN LUKITS
A year of modest aerobic exercise reversed normal brain shrinkage by one to two years in older adults and improved their memory function, according to a study published in the Proceedings of the National Academy of Sciences. As people age, the hippocampus, the brain's memory center, loses 1% to 2% of its volume annually, affecting memory and possibly increasing the risk for dementia. A growing body of evidence has pointed to aerobic exercise as a low-cost hedge against neurocognitive decline. In this study, magnetic resonance imaging was used to measure the effects of aerobic exercise on the hippocampus in 120 Americans in their late 50s to early 80s. Half the group walked three times a week for 40 minutes, aiming for their target heart rate, while the other half did yoga and toning exercises. The hippocampus in walkers increased by 2% after a year and shrank by 1.4% in controls. Both groups showed significant improvements on spatial memory tests conducted before and after the study. This could be due to taking the test repeated times, the researchers said. In the walking group, however, changes in hippocampus volume were directly related to improved memory performance, they said.
Caveat: The study found that exercise had a selective effect on the brain, influencing the volume of the anterior hippocampus but not the posterior. Researchers suspect aerobic exercise might have the most effect on regions of the brain that show the largest decline in late adulthood, such as the anterior hippocampus.
Migraine surgery: Surgery can reduce the frequency and pain of chronic migraines and eliminate the headaches completely in some people, according to a study in the journal Plastic and Reconstructive Surgery. Five years after 69 U.S. patients underwent surgery to deactivate one to four migraine trigger sites, 61, or 88%, reported a positive outcome from the procedure. Migraines disappeared in 20 patients, significantly decreased in 41 and were unchanged in eight. Patients had an average of four headaches per month after the surgery compared with 11 per month before surgery. Surgery also reduced the duration of headaches to about a third of a day from an average of 1.4 days, and cut their intensity in half. Migraines affect more than 30 million Americans, causing an estimated 112 million missed workdays a year. Recent studies reported that Botox injections temporarily helped to reduce the pain of migraine. In this study, Botox was used to identify migraine trigger sites that were subsequently treated surgically. Researchers note there is a high placebo response in migraine sufferers but an 88% placebo effect lasting five years has never been documented.
Caveat: Researchers tried to identify patients who suffered rebound or recurring headaches due to over-medication and had become addicted to narcotics. Regardless of how successful the surgery may seem, these patients may still experience rebound headaches and pain due to addiction, they said. The study sample was small.
Stopping MRSA: U.S. scientists believe they have found a way to disable the superbug MRSA, according to a study in PLoS Pathogens. Researchers expect the finding could help lead to the development of a new generation of drugs to fight antibiotic-resistant pathogens. Methicillin-resistant Staphylococcus aureus kills more than 19,000 people in the U.S. a year and hospitalizes another 500,000. Hospital-acquired MRSA is a global health issue, and the organism has recently started to infect otherwise healthy people. Researchers screened 29,066 compounds before finding a molecule called RNPA1000 that was capable of inhibiting MRSA's ability to reproduce, a process known as RNA degradation, which is essential for bacteria to thrive. The study found RNPA1000 acted against the main strains of MRSA and also against bacteria called biofilms, which colonize on implanted medical devices. The compound was tested on infected mice and half survived, while all untreated mice died. Researchers said RNPA1000 is toxic when used in humans but its discovery may help scientists design new and more potent antibiotics.
Caveat: The compound RNPA1000 has only been tested on mice and in the lab.
Transit riders and flu: Commuters who occasionally travel on public-transit vehicles are at greater risk for catching the flu from other passengers than are people using public transit on a regular basis, according to a study in BMC Infectious Diseases. A study of transit use during the 2008-2009 influenza season in Britain found that passengers who used the system infrequently had almost six times as great a risk of developing a respiratory infection as did regular riders. Occasional riders were defined as those who had used buses or trams within five days of the onset of symptoms, the maximum incubation period identified by researchers. Researchers suggested regular users of public transit may have benefited from repeated exposure to common respiratory viruses that led them to develop protective antibodies. The study included 72 subjects with acute respiratory illness and 66 controls with acute non-respiratory conditions. Questionnaires measured transit use, smoking, number of children, vaccination status and other variables.
Caveat: The study may have underestimated the risk to the control group because of undiagnosed respiratory viruses. Also, information was unavailable on the subjects' normal working environment, time of transit use and passenger density.
Teen self-injury: Online videos depicting teens and young adults injuring themselves, most often by cutting on the wrists and arms, represent an alarming new trend that may encourage and normalize self-destructive behavior, according to a study in Pediatrics. So-called nonsuicidal self-injury affects 14% to 24% of teens and young adults. Researchers examined the 100 most-viewed self-injury videos on YouTube and found they had been viewed over two million times. About 95% of the videos were uploaded by young women. Although 80% of the videos were approved for a general audience, cautionary warnings about content were included on just 42% of videos. The videos' tones were largely factual or educational (53%) and/or melancholic (51%). Explicit imagery of self-injury was common. About a quarter of the videos were against self-destructive behavior. Youth who self-injure are likely to continue harming themselves, and are at risk for interpersonal difficulties, elevated psychiatric symptoms, and, in some cases, attempted suicide and death by suicide, the researchers said.
Caveat: The study identified 5,000 videos posted to YouTube containing images of self-harm, so the 100 videos analyzed, although they were the most viewed, might not be representative of the total. Also, the study didn't examine how viewers are influenced and react to the videos.
Type I diabetes: A virus that causes a host of ailments ranging from mild respiratory illnesses to meningitis and polio was found to be associated with the development of type I diabetes, especially in children under 5, according to a meta-analysis in the British Medical Journal. The global incidence of type I diabetes has been steadily increasing, particularly the juvenile form of the disease. Previous studies have associated enterovirus infections with type I diabetes and pre-diabetes autoimmunity but the findings weren't conclusive. In this study, Australian researchers analyzed 24 studies and two abstracts published from 1965 to 2010 that involved a combined total of 4,448 subjects who had undergone molecular testing for enteroviruses. They found type I diabetics were almost 10 times as likely to have had a recent enterovirus infection as non-diabetics and to experience persistent enterovirus infections. Children with recent enterovirus infections had three times higher risk for pre-diabetes. Researchers recommended further studies of the environmental, geographical and genetic factors believed to play a role in the development of type 1 diabetes.
Caveat: Other factors that weren't measured may have influenced the risk of developing diabetes, such as cow's milk, vitamin D and weight gain in infancy, researchers said. Also, there was uneven reporting among the various studies of the methodology used to detect enteroviruses.
Pancreatic cancer: American Jews may be genetically predisposed to developing pancreatic cancer, according to a study in Cancer Epidemiology, Biomarkers and Prevention. Jewish ethnicity and pancreatic cancer have been examined in four previous studies dating to the 1950s, three of which reported higher mortality among Jews than non-Jews. This study is the first to consider the known risk factors for pancreatic cancer—smoking, obesity and diabetes—and the birthplace of Jews and their parents. Data were analyzed from an American Cancer Society study that followed 1,014,625 men and women from 1982 to 2006. Of the 6,727 deaths from pancreatic cancer during this period, 480 were among Jewish participants. Deaths were 43% higher among Jews than non-Jews and didn't vary significantly by age, family history or immigration background. Genetic factors and non-O blood type may contribute to the higher mortality, the study suggests. About 65% of U.S. Jews have non-O blood compared with 55% of white non-Jews. Understanding the reasons why Jews are at greater risk for pancreatic cancer may provide clues to its cause and lead to screening techniques, researchers said.
Caveat: The study lacked information on Ashkenazi or Sephardic Jewish origin. As the U.S. Jewish population is predominantly Ashkenazi, the results may not generalize to Sephardic Jews, researchers said. Information on the number of Jewish converts involved in the study wasn't available.
Red meat and stroke: A diet rich in red and processed meats may boost the risk of stroke in women, according to a study in the journal Stroke. Red meat has previously been linked to coronary artery disease and some cancers. To date, only one of three studies that looked at red meat and stroke found a higher risk in meat eaters. A recent analysis of the dietary habits of 34,670 healthy Swedish women and their risk of stroke found those who ate the most red meat, 3.6 ounces or more a day, were 42% more likely to suffer a stroke due to blocked blood flow to the brain than women who consumed less than one ounce a day. The women, who ranged in age from 49 to 83, were followed from 1998 to 2008 and reported their meat consumption on questionnaires. During the 10 years of follow-up, there were 1,680 cases of stroke. Poultry consumption wasn't associated with risk of any type of stroke. The study notes the saturated fat and cholesterol in red meat and the high sodium content in processed meat are linked to hypertension, a key risk factor for stroke.
Caveat: Women who consumed large amounts of red meat may have been at increased risk for stroke because of other unhealthy habits and behaviors not measured in the study. The use of questionnaires to assess diet can result in polling errors.