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Category Archives: Health

A Deadly Reason to Avoid Deer Ticks

Move over, Lyme disease: Another tick-borne illness is on the rise in various parts of the country, and this one can kill.

Known as babesiosis, the disease is caused by a microscopic parasite that attacks blood cells, causing flu-like symptoms that can make it difficult to accurately diagnose. Like Lyme disease, which is caused by bacteria, babesia microti parasites are carried by deer ticks.

First documented in Massachusetts in 1969, the once-obscure babesiosis has surfaced as a significant public health threat in parts of the Northeast and Upper Midwest over the last several years. A recent study in the journal Emerging Infectious Diseases, published by the U.S. Centers for Disease Control and Prevention, revealed that between 2001 and 2008 cases climbed from six to 119 in New York’s Lower Hudson Valley — a 20-fold regional increase.

And many cases may be escaping detection, experts say.

“I think it’s underreported. One of the reasons we’re seeing more about it is because people are becoming more aware,” said Dr. Peter Krause, a babesiosis researcher and senior research scientist at the Yale University School of Public Health. “The theory is that it’s spreading from east to west, as if you were dropping a pebble in a pond and it spread outward geographically.”

About 1,000 cases are reported annually in affected locales, Krause said, but many people with babesiosis have no symptoms and never know they’re harboring the parasite. For others, symptoms can include high fever, severe headache, fatigue, chills, and muscle aches and pains. It is treated with antimicrobial drugs, such as antibiotics.

People with compromised immune systems — including the elderly and those with cancer, HIV or no spleens — are especially at risk of potentially deadly complications such as organ failure. Between 10 percent and 20 percent of patients in those populations die as a result, Krause said.

The more prolific Lyme disease causes similar symptoms in early stage cases but is easier to diagnose by its telltale bullseye rash, said Dr. Barbara Herwaldt, a medical epidemiologist at the CDC who specializes in parasitic conditions.

Deer are pivotal to the life cycle of ticks carrying the babesia microti parasite by serving as a blood meal, shelter and a place to mate, Krause said. Ticks also feed on birds, who serve as carriers for Lyme disease, which affects the entire continental United States. Fortunately for humans, birds don’t carry babesia microti.

Krause noted that ticks need a moist climate to thrive, so dry states such as Arizona are not likely to see babesiosis cases caused by tick bites. But the disease can potentially spread to all states in an even sneakier way — through the blood supply.

Although a blood screening test is in trials, Krause said, donors are currently only asked if they have had babesiosis, and those who harbored it but never showed symptoms can pass it through their donated blood. And because most blood recipients are already physically compromised, babesiosis has about a 30 percent mortality rate in that group, he said.

“Getting babesiosis through the blood supply is a rare event and people shouldn’t panic,” he said. “I don’t think it will reach a crisis level, but it’s still a concern.”

To help prevent babesiosis, the CDC advises people with compromised immune systems or other vulnerabilities to avoid tick-infested wooded areas, particularly during warm months. The agency also recommends that everyone walk in the middle of trails and avoid bushy areas with lots of leaves or tall grasses and to use the repellent DEET and pre-treat clothes with an insect repellent containing permethrin before going outdoors.

The CDC also recommends doing full-body checks and showering within a few hours of being in the woods, as well as tossing used clothes in the dryer to kill any ticks that might be hiding there.

The authors of the study also advised clinicians to consider babesiosis in patients who have been exposed to ticks or received blood products and who show up for treatment with a fever and anemia resulting from the destruction of red blood cells.

7 Simple Ways to Cut Your Cell Phone Cancer Risk

Does the World Health Organization’s statement that cell phones may cause cancerhave you thinking twice about making that phone call?

Of course it’s alarming to think that something that’s become such a can’t-live-without can be linked to brain cancer, but there’s a lot even the most cell phone-addicted people can do to minimize health risks.

Any potential links to cancer stem from the low levels of radiation cell phones emit. Lower your exposure to the radiation, and you’ll reduce the potential links to cancer or other health problems:

  1. Use a headset. Sounds obvious, but headsets emit much less radiation than cell phones do, according to the Environmental Working Group (EWG), and they keep your cell phone away from your head. The farther away you are from a source of radiation, the less damage it can do.
  2. Text when you can. Your constantly texting teens are onto something: Cell phones use less energy (and emit less radiation) when you text than when you talk, says the EWG. Texting also keeps the radiation source farther away from your brain.
  3. Use cell phones for FYI-only calls. Don’t use your cell phone for that long overdue, hour-long catch-up with your sister. Keep calls as short as possible —Do you need me to get the dry cleaning, honey? — and switch to a landline if they’re veering off into chitchat territory.
  4. Watch the bars. Can you hear me now? If you’re struggling to maintain a connection, ditch the call and wait until you have better service. When your phone has fewer signal bars, it has to work harder (and, therefore, emit more radiation) to connect.
  5. Keep the phone away from your ear when you can. EMF-Health.comrecommends waiting for the call to connect before you bring the phone to your ear, which minimizes radiation exposure. And when you talk, tilt the phone away from your ear and bring it in close when you’re listening. That’s because the radiation levels are “significantly less when a cell phone is receiving signals than when it is transmitting,” Lin Zhong, assistant professor of electrical and computer engineering at Rice University in Houston, told The New York Times.
  6. Don’t make calls in elevators or cars. You already it’s dangerous to talk and drive; EMF-Health.com says that cell phones use more power to establish a connection in enclosed metal spaces like cars and elevators.
  7. Make sure your kids use the landline. It seems like even toddlers are using cell phones today, but experts say kids are the most vulnerable to potential radiation dangers. The EWG says children’s brains absorb twice as much cell phone radiation as adults. According to The New York Times, health authorities in Britain, France, Germany, and Russia all have warnings against letting children use cell phones.

7 Foolish Health Rumors You Should Ignore

Urban legends and health myths are certainly nothing new — we’re pretty sure even our Neanderthal ancestors passed some version of them around their cave fires. But the Internet has certainly helped outdated advice die hard, so it’s no wonder these fake facts keep popping up in our inboxes. We picked our favorites from such myth-busting sites as Snopes, the authors of Don’t Swallow Your Gum!: Myths, Half-Truths, and Outright Lies About Your Body and Health, and more. Here’s why you should stop falling for these, once and for all:

Chewing gum takes seven years to pass through your digestive tract.

The truth: Gum addicts can relax. Although your body can’t digest chewing gum, it doesn’t just sit in your stomach, according to Snopes.com. You eliminate it when you go to the bathroom just like other food you haven’t digested.

Plucking a gray hair causes two to grow back.

The truth: It’s fine to tweeze that errant hair. Genetics plays a key role in when you go gray, regardless of how often you pluck. It can take six months from the time a hair falls out until it grows back long enough for you to notice it; during that time, you’ll automatically see more gray hair as part of the aging process, explains Snopes.com.

Antiperspirant deodorants cause breast cancer.

The truth: Going au naturel won’t protect your breasts from cancer. This mythprobably came about because some antiperspirants contain aluminum, which can show up as a false-positive finding on a mammogram. All this means is you should skip the white stuff before a breast cancer screening. Though concerns have been raised about parabens in deodorant raising estrogen levels — and thus possibly increasing cancer risk — there’s never been any conclusive evidence to prove a link, according to the National Cancer Institute and FDA.

Cats can steal the air from a baby’s mouth.

The truth: There’s no need to send Fluffy away when baby moves in. This myth dates back hundreds of years to an era when cats were associated with evil spirits and witchcraft, but KidsHealth.org notes that it’s anatomically impossible for a cat or other animal to suffocate a baby by sealing the infant’s mouth with its own. Still, it’s a good idea to supervise pets around babies and small children — for the kitty’s safety just as much as the child’s.

Mountain Dew can shrink a man’s testicles.

The truth: Mountain Dew-drinking guys everywhere can breathe a sigh of relief. The gist of this ridiculous rumor, according to Snopes.com, is that drinking Mountain Dew can lower a man’s sperm count or cause his penis to shrink. The alleged culprit is food coloring Yellow No. 5, and the myth that it has a harmful effect on the male reproductive system is unfounded, the site says.

You can catch a cold from being outside too long.

The truth: It’s actually a good idea to let your kids spend plenty of time outdoors. “Going outside — with or without a wet head — is one of the best things you can do toprevent catching a cold,” D.J. Verret, MD, a Dallas otolaryngologist, toldWomansDay.com. “Colds are caused by viruses or bacteria, which are more often spread in the winter because of close contact from everyone being indoors.” So spending time al fresco can actually make you less likely to catch a cold.

Cracking your knuckles causes arthritis.

Truth: The sound can be extremely grating, but this uncouth habit won’t harm your joints. Researchers found no difference in instances of arthritis when they compared a group of longtime knuckle crackers with those who left their hands alone, according to Prevention.com. However, the study did find that people who cracked their knuckles had weaker grips and more hand swelling — good reasons to kick the habit.

The Truth About Everyday Radiation Exposure

Japan’s ongoing nuclear crisis understandably has people around the world worried about radiation exposure and the potential health risks it may pose. According to the latest reports, radiation from Japan was detected in Southern California late this week, but experts are quick to point out that the levels are far from dangerous. The readings were “about a billion times beneath levels that would be health threatening,” a diplomat with access to United Nations’ radiation tracking told the Associated Press.

Nor is it unexpected. “Whenever radioactive particles get in the atmosphere, they have the potential to spread around the world,” says James Thrall, MD, president of the American College of Radiology. “But they get diluted as they travel, so they’re unlikely to pose any real health problem.”

In fact, we’re probably exposed to significantly more radiation every day than the miniscule fallout arriving from Japan. Here’s a quick tutorial on radiation to put our collective anxiety in perspective:

What Is Radiation?

Radiation is a form of energy in waves. It exists on a spectrum, with low-frequency radiation (from radio waves and microwaves) on the low end and high-frequency radiation (from gamma rays and x-rays) on the high end. All radiation affects the cells in our bodies to some extent, but the lower the frequency of the waves and the lower the exposure, the less dangerous it is.

To understand the risks of high-frequency radiation — the kind we’re talking about in this article — think back to high school physics: These waves have enough energy to knock electrons off molecules, which can cause damage to cell DNA that can ultimately lead to cancer.

How Are We Exposed to Radiation?

We encounter radiation each day from a variety of sources. The average American is exposed to about 6 millisieverts (mSv) of radiation annually, according to the United States Nuclear Regulatory Commission (USNRC). Half of this typically comes from background radiation that occurs naturally in the environment, and half comes from medical tests, such as X-rays, mammograms, and CT scans.

According to Kelly Classic, MS, spokesperson for the Health Physics Society, sources of environmental radiation include:

  • Radioactive compounds in soil and building materials like concrete, brick, and stone
  • Radiation from outer space that your encounter when you fly on airplanes or visit high-altitude places
  • The mineral potassium in your own body (a small fraction of potassium, which our bodies need to function, is radioactive)
  • Radon gas in the home, which accounts for about 2 mSv of exposure each year, and is the largest contributor of background radiation

Finally, there’s the kind of radiation released during nuclear reactions, such as what’s disseminating from Japan’s Fukushima Daiichi plant.

Here’s a look at various sources of radiation exposure (dose of radiation in millisieverts (mSv)), according to data from the Health Physics Society and the U.S. Environmental Protection Agency (EPA). By way of comparison, a single dose of radiation below 0.01 mSv is considered negligible by the National Council on Radiation Protection and Measurements.

  • Banana: 0.0001
  • Dental X-ray: 0.005
  • Living within 50 miles of a nuclear power plant: 0.01 (per year)
  • A flight from New York to Los Angeles: 0.04
  • Smoking 1 ½ packs of cigarettes: 0.08
  • Chest X-ray: 0.1
  • Living at sea level: 0.25 (per year)
  • Mammogram: 0.3
  • Living in Denver: 0.5 (per year)
  • Abdominal CT scan: 14
  • Measures between reactors No. 3 and No. 4 during the March 15 explosion at the Fukushima plant: As high as 400 per hour

What Level of Radiation Exposure Is Safe?

It’s well-established that exposure to large amounts of radiation at once can cause acute sickness and even cancer. (A 1,000 mSv-dose can trigger acute radiation sickness, causing symptoms such as nausea and vomiting; 3,000 mSV can be lethal, according to Thrall.)

But there’s no good data on the long-term risks of the low levels of radiation to which we’re continually exposed.

According to the World Nuclear Association, annual exposure to 100 mSv or greater carries a measurable, though small, increase in cancer risk. Below that level, it’s believed that your body’s cells are able to heal themselves from radiation. “There are enzyme systems in the body that repair damage from these low levels of background radiation,” says Thrall.

But even small levels of radiation exposure may impact cancer risks later in life.

This has been of particular concern in the medical community, where some experts worry that increasing use of diagnostic CT scans (which has skyrocketed from 3 million annual scans nationwide in 1980 to 70 million in 2007, according to MedPage Today) will impact future cancer rates. For example, in one 2009 study, National Cancer Institute researchers estimated that one in 270 women and one in 595 men who had a heart CT at age 40 would eventually develop cancer related to the test.

While the health benefits of necessary diagnostic imaging usually outweigh the small risks of secondary cancers, it’s always a good idea to talk to your doctor before any procedure involving radiation to understand exactly what you’re getting, why you need it, and what the potential health risks may be.

Bottom line: Americans are exposed to far more radiation in their daily lives — and especially from certain medical tests — than from dispersed particles traveling across the Pacific. “With what we know now about the situation in Japan, there are no personal or public health risks apparent for people in the United States,” Thrall says.

Global Warming May Pose Health Risks

Medical and public health groups are banding together to explain how global warming has taken a toll on human health and will continue to cause food-borne illnesses, respiratory problems, and deaths unless policy changes are enacted.

In a conference call with reporters, the heads of the American Medical Association (AMA) and the American Public Health Association (APHA) joined with a pediatrician and a scientist to lay out what they say is a major public health issue: climate change caused by global warming.

The “evidence has only grown stronger” that climate change is responsible for an increasing number of health ills, including asthma, diarrheal disease, and even deaths from extreme weather such as heat waves, said Dr. Georges Benjamin, executive director of the APHA.

For one, rising temperatures can mean more smog, which makes children with asthma sicker, explained pediatrician Dr. Perry Sheffield, assistant professor in the Department of Pediatrics and the Department of Preventive Medicine at the Mount Sinai School of Medicine, in New York.

There is also evidence that pollen season is also getting longer, she said, which could lead to an increase in the number of people with asthma.

Climate change also is thought to lead to increased concentrations of ozone, a pollutant formed on clear, cloudless days. Ozone is a lung irritant which can affect asthmatics, those with chronic obstructive pulmonary disease, and those with heart disease, said Dr. Kristie Ebi, who is a member of the Intergovernmental Panel on Climate Change.

More ozone can mean more health problems and more hospital visits, she said.

Aside from air-related ailments and illnesses, extreme weather can have a devastating effect on health, Sheffield said.

“As a result of global warming, extreme storms including hurricanes, heavy rainfall, and even snowstorms are expected to increase,” Sheffield said. “And these events pose risk of injury and disruption of special medical services, which are particularly important to children with special medical needs.”

Extreme heat waves and droughts are responsible for more deaths than any other weather-related event, Sheffield said.

The 2006 heat wave that spread through most of the U.S. and Canada saw temperatures that topped 100 degrees. In all, 450 people died, 16,000 visited the emergency room, and 1,000 were hospitalized, said Dr. Cecil Wilson, president of the AMA.

Climate change has already caused temperatures to rise and precipitation to increase, which, in turn, can cause diseases carried by tics, mosquitoes, and other animals to spread past their normal geographical range, explained Ebi.

For instance, Lyme disease is increasing in some areas, she said, including in Canada, where scientists are tracking the spread of Lyme disease north.

Ebi also recounted the 2004 outbreak of the leading seafood-related cause of gastroenteritis, Vibrio parahaemolyticus, from Alaskan seafood, which was attributed to increased ocean temperatures causing infected sea creatures to travel 600 miles north.

Salmonella outbreaks also increase when temperatures are very warm, Sheffield said.

A 2008 study also projected that global warming will lead to a possible increase in the prevalence of kidney stones due to increased dehydration, although the link hasn’t been proven.

Wilson said the AMA wants to make doctors aware of the projected rise in climate-related illnesses. To combat climate change, Wilson says physicians and public health groups can advocate for policies that improve public health, and should also serve as role models by adopting environmentally-friendly policies such as eliminating paper waste and using energy-efficient lighting in their practices.

“Climate instability threatens our health and life-supporting system, and the risk to our health and well-being will continue to mount unless we all do our part to stabilize the climate and protect the nation’s health,” said Wilson.

Benjamin added that doctors should pay attention to the Air Quality Index. For instance, if there’s a “Code Red” day, which indicates the air is unhealthy, physicians should advise patients (particularly those with cardiac or respiratory conditions) that it’s not the day to try and mow the grass.

“ER docs are quite aware of Code Red days because we know that when those occur, we’re going to see lots of patients in the emergency room,” Benjamin said.

The conference call came as Congress is considering what role the Environmental Protection Agency (EPA) should have in updating its safeguards against carbon dioxide and other pollutants.

While the EPA has the authority to regulate levels of CO2, a budget bill passed by the House of Representatives last the weekend prohibited the EPA from exercising that authority. Meanwhile, other bills are pending in Congress that would significantly delay the agency’s ability to regulate air pollutants.

AMA has a number of policies on the books regarding climate change, including a resolution supporting the EPA’s authority to regulate the control of greenhouse gases, and a statement endorsing findings from the most recent Intergovernmental Panel on Climate Change report that concludes the Earth is undergoing adverse climate changes, and that humans are a significant contributor to the changing weather.

In that statement, the AMA said it supports educating the medical community about climate change and its health implications through medical education on topics such as “population displacement, heat waves and drought, flooding, infectious and vector-borne diseases, and potable water supplies.”

The statement also said the AMA supports physician involvement in policymaking to “search for novel, comprehensive, and economically sensitive approaches to mitigating climate change to protect the health of the public.”

Medical Leech Linked to Infection

A resistant Aeromonas infection transmitted by a medicinal leech developed in a man undergoing reconstructive surgery of the jaw, leading to total failure of the graft, investigators reported.

“Leech therapy is the most effective nonsurgical management of soft-tissue venous congestion,” explained Dr. Brian Nussenbaum, of Washington University School of Medicine in St. Louis, and colleagues.

However, because a bug — Aeromonas hydrophila — lives in the gut of leeches where this bacteria aids in the digestion of blood, infections can occur in as many as 20 percent of patients treated with medical leeches, according to a report in the February Archives of Otolaryngology-Head and Neck Surgery.

So to prevent infection, researchers are recommending that when medical leeches are used, patients should be given antibiotics, preferably Cipro (ciprofloxacin) or Septra (trimethoprim-sulfamethoxazole).

The patient was a 56-year-old man undergoing a reconstructive procedure for a large benign tumor in his jaw. He was given ampicillin-sulbactam as prophylaxis.

Approximately 24 hours after the surgery, he developed a condition called acute venous congestion, meaning a lack of blood supply that turns skin and tissue blue, in the area of the surgery.

In preparation for revision of the surgery, which revealed widespread clot formation, the patient was given 400 mg of intravenous ciprofloxacin and three leeches were applied to the area.

The surgery appeared to have been successful, but despite maintenance therapy with ciprofloxacin, 48 hours later purulent secretions appeared, and cultures with sensitivity testing identified a strain of A. hydrophila that was resistant to both trimethoprim-sulfamethoxazole and ciprofloxacin.

Ciprofloxacin was withdrawn and the fourth-generation cephalosporin, cefepime, was prescribed.

The wound did not heal completely and eight months later the patient required a second reconstruction eight months later.

To determine the source of this resistant infection, Nussenbaum’s group conducted a two-part investigation.

First, to see if the infection was acquired within their hospital, they performed cultures on samples of water from their leech tank — and found that all samples were susceptible to multiple antimicrobials, including ciprofloxacin and trimethoprim-sulfamethoxazole.

They also noted that no other resistant Aeromonas infections had been seen at their institution.

“This practice-based investigation suggests that this strain was not acquired within our hospital,” they stated.

They then conducted a broader investigation, contacting various organizations including the Centers for Disease Control and Prevention and the Emerging Infections Network, finding that no other cases of similar resistant infections associated with medical leeches had been reported.

The leech supplier also reported careful maintenance of holding tanks, although antibiotic resistance tests were not routinely done.

The investigators found, however, that ciprofloxacin-resistant strains of Aeromonashad been identified from environmental sources such as drinking water in Turkey, a lake in Switzerland, and the Seine River.

These isolates contained a plasmid encoding fluoroquinolone resistance, which had previously only been found in Enterobacteriaceae.

“These findings suggest the possibility of emerging ciprofloxacin resistance in environmental water supplies, which is concerning,” observed Nussenbaum and colleagues.

Limitations of the study included the investigators’ inability to culture the gut contents of other leeches from the same batch, and the lack of specimens that could be tested for the presence of the resistance-conferring plasmid.

The study suggests that, although resistance to trimethoprim-sulfamethoxazole and ciprofloxacin is rare in A. hydrophila, it can occur and should be considered when antibiotic prophylaxis is undertaken, according to the investigators.

“Surgeons using leech therapy should be aware of this possibility and collaborate with infectious disease specialists in their hospital to determine appropriate antibiotic prophylaxis on local resistance patterns,” they cautioned.

Chemical Found in Blood Holds Clues to Survival

Even within the normal range, higher bilirubin levels appear to be associated with reduced risks of lung cancer, chronic obstructive pulmonary disease (COPD), and death, a longitudinal, prospective analysis of a large database showed.

For every 0.1-mg/dL increase in bilirubin level, the rate of lung cancer dropped by 8 percent in men and 11 percent in women, according to Laura Horsfall, MSc, of University College London, and colleagues.

In addition, the same incremental increase in bilirubin was associated with a 6 percent decline in the rate of COPD and a 3 percent decline in mortality for both sexes, the researchers reported in the Feb. 16 issue of the Journal of the American Medical Association.

“Based on our findings, bilirubin levels within the normal range appear to capture information about patients that may reflect a combination of environmental and genetically determined susceptibility to respiratory diseases,” they wrote.

Most people are familiar with bilirubin because of its role in jaundice — the yellowing of the skin that is sometimes seen in newborns but is also associated with liver disease.

Bilirubin is actually a byproduct of the turn over of red blood cells — the cells that carry oxygen throughout the body. Healthy individuals constantly replace old red blood cells with new ones. As the old cells are broken down they produce bilirubin, a chemical characterized by a distinctive yellow color.

The spleen and the liver taking in bilirubin and use it to break down or metabolize other substances into bile, which is used to aid digestion.

Although the study cannot establish causality for any of the relationships, there is some experimental evidence that bilirubin has benefits for respiratory health because of its cytoprotective properties, including antioxidant, anti-inflammatory, and antiproliferative effects, according to the researchers.

They noted that a better understanding of the possible mechanisms linking bilirubin levels to lung cancer, COPD, and death may lead to potential therapies that target the activity of UGT1A1, a liver enzyme responsible for converting insoluble bilirubin to an excretable form.

Horsfall and her colleagues examined data from the Health Improvement Network, a U.K. primary care research database.

Their analysis included 504,206 patients ages 20 and older from 371 practices. All of the patients had recorded serum bilirubin levels but no evidence of hepatobiliary or hemolytic disease.

Median bilirubin levels were 0.64 mg/dL in men and 0.53 mg/dL in women.

Through a median follow-up of eight years, there were 1,341 incident cases of lung cancer, 5,863 incident cases of COPD, and 23,103 all-cause deaths. The corresponding rates per 10,000 person-years were 2.5, 11.9, and 42.5.

For men, the rate of lung cancer per 10,000 person-years dropped from 5.0 in the lowest decile of bilirubin levels to 3.0 in the fifth decile. Similar declines were seen for COPD (19.5 to 14.4) and death (51.3 to 38.1).

The findings were similar for all outcomes in women, and the declines in both sexes remained significant after adjustment for age, body mass index, systolic blood pressure, smoking, alcohol intake, and a measure of social deprivation.

The authors acknowledged some limitations of the study, including possible residual confounding by unmeasured environmental exposures or race/ethnicity and the inability to establish causality for the observed relationships.

Marijuana Users at Risk for Early Psychosis

Data on more than 22,000 patients with psychosis showed an onset of symptoms almost three years earlier among users of cannabis compared with patients who had no history of substance use.

The age of onset also was earlier in cannabis users compared with patients in the more broadly characterized category of substance use, investigators reported online in Archives of General Psychiatry.

“The results of this study provide strong evidence that reducing cannabis use could delay or even prevent some cases of psychosis,” Dr. Matthew Large, of the University of New South Wales in Sydney, Australia, and co-authors wrote in conclusion.

“Reducing the use of cannabis could be one of the few ways of altering the outcome of the illness because earlier onset of schizophrenia is associated with a worse prognosis and because other factors associated with age at onset, such as family history and sex, cannot be changed.”

Psychosis has a strong association with substance use. Patients of mental health facilities have a high prevalence of substance use, which also is more common in patients with schizophrenia compared with the general population, the authors wrote.

Several birth cohort and population studies have suggested a potentially causal association between cannabis use and psychosis, and cannabis use has been linked to earlier onset of schizophrenia. However, researchers in the field remain divided over the issue of a causal association, the authors continued.

Attempts to confirm an earlier onset of psychosis among cannabis users have been complicated by individual studies’ variation in methods used to examine the association. The authors sought to resolve some of the uncertainty by means of meta-analysis.

A systematic search of multiple electronic databases yielded 443 potentially relevant publications. The authors whittled the list down to 83 that met their inclusion criteria: All the studies reported age at onset of psychosis among substance users and nonusers.

The studies comprised 8,167 substance-using patients and 14,352 patients who had no history of substance use. Although the studies had a wide range of definitions of substance use, the use was considered “clinically significant” in all 83 studies. None of the studies included tobacco in the definition of substance use.

The studies included a total of 131 patient samples.

Substance use included alcohol in 22 samples, cannabis in 41, and was simply defined as “substance use” in 68 samples.

Alcohol use was not significantly associated with earlier age at onset of psychosis.

On average, substance users were about 2 years younger than nonusers were. The effect of substance use on age at onset was greater in women than in men, but not significantly so. Heavy use was associated with earlier age at onset compared with light use and former use, but also not significantly different, the authors reported.

Substance users were two years younger at the onset of psychosis compared with nonusers. Age at onset was 2.7 years earlier among cannabis users compared with nonusers.

Acknowledging limitations of the study, the authors cited the lack of information on tobacco use and its association with earlier age at onset of psychosis, and the lack of data on individual patients inherent in all meta-analyses.

Despite the limitations, the authors said the findings have potentially major clinical and policy implications.

“This finding is an important breakthrough in our understanding of the relationship between cannabis use and psychosis,” they wrote in conclusion. “It raises the question of whether those substance users would still have gone on to develop psychosis a few years later.”

“The results of this study confirm the need for a renewed public health warning about the potential for cannabis use to bring on psychotic illness,” they added.

Walking Helps Heart and Brain

Regular aerobic exercise such as walking may protect the memory center in the brain, while stretching exercise may cause the center — called the hippocampus — to shrink, researchers reported.

In a randomized study involving men and women in their mid-60s, walking three times a week for a year led to increases in the volume of the hippocampus, which plays an important role in memory, according to Dr. Arthur Kramer, of the University of Illinois Urbana-Champaign in Urbana, Ill., and colleagues.

On the other hand, control participants who took stretching classes saw drops in the volume of the hippocampus, Kramer and colleagues reported online in theProceedings of the National Academy of Sciences.

The findings suggest that it’s possible to overcome the age-related decline in hippocampal volume with only moderate exercise, Kramer told MedPage Today, leading to better fitness and perhaps to better spatial memory. “I don’t see a down side to it,” he said.

The volume of the hippocampus is known to fall with age by between 1 percent and 2 percent a year, the researchers noted, leading to impaired memory and increased risk for dementia.

But animal research suggests that exercise reduces the loss of volume and preserves memory, they added.

To test the effect on humans, they enrolled 120 men and women in their mid-sixties and randomly assigned 60 of them to a program of aerobic walking three times a week for a year. The remaining 60 were given stretch classes three times a week and served as a control group.

Their fitness and memory were tested before the intervention, again after six months, and for a last time after a year. Magnetic resonance images of their brains were taken at the same times in order to measure the effect on the hippocampal volume.

The study showed that overall the walkers had a 2 percent increase in the volume of the hippocampus, compared with an average loss of about 1.4% in the control participants.

The researchers also found, improvements in fitness, measured by exercise testing on a treadmill, were significantly associated with increases in the volume of the hippocampus.

On the other hand, the study fell short of demonstrating a group effect on memory – both groups showed significant improvements both in accuracy and speed on a standard test. The apparent lack of effect, Kramer told MedPage Today, is probably a statistical artifact that results from large individual differences within the groups.

Analyses showed that that higher aerobic fitness levels at baseline and after the one-year intervention were associated with better spatial memory performance, the researchers reported.

But change in aerobic fitness was not related to improvements in memory for either the entire sample or either group separately, they found.

On the other hand, larger hippocampi at baseline and after the intervention were associated with better memory performance, they reported.

The results “clearly indicate that aerobic exercise is neuroprotective and that starting an exercise regimen later in life is not futile for either enhancing cognition or augmenting brain volume,” the researchers argued.

The study was supported by the National Institute on Aging, the Pittsburgh Claude D. Pepper Older Americans Independence Center, and the University of Pittsburgh Alzheimer’s Disease Research Center. The authors said they had no conflicts.

Painkiller Use Common Among NFL Players

Retired National Football League players who abused opioid painkillers while active were most likely to use and abuse the same drugs after leaving the sport, the results of a telephone survey and analysis found.

The survey found more than half of the retired NFL players interviewed used opioidpainkillers during their career. Of those, 71 percent reported misusing the drugs while playing, and 15 percent said they still abuse the prescription medication, Dr. Linda B. Cottler, of Washington University School of Medicine, and colleagues reported online in Drug and Alcohol Dependence.

The former broadcaster and NY Giants great, Frank Gifford, said, “pro football is like nuclear warfare. There are no winners, only survivors.”

The findings from Cottler’s survey support Gifford’s assessment.

An analysis of survey data showed the rate of opioid misuse while the retired players were active in the NFL was roughly three times greater than the lifetime rate of nonmedical use of opioids in the general population of approximately the same age.

Misuse in the past 30 days in retired players was seven percent, versus less than two percent in adults 26 and older in the general population. Looking only at men in the general population, the abuse rate is about two and half percent.

The final sample included 644 former players listed in the 2009 Retired NFL Football Players Association Directory who had retired from 1979 to 2006 and had at least one phone number listed.

They completed a phone interview that discussed general demographic data, health status, pain, impairment, alcohol use, prescription opioid use, and illicit drug use. Prescription opioid use was measured for while a player was active as well as over the past 30 days. Participants were categorized into users and nonusers. Users were subcategorized as having used the drugs as prescribed, or having misused them.

Misuse was defined as taking more of the drug than prescribed, using it in a way other than prescribed, using it after a prescription ended, using it for a different reason, or using it without a prescription.

When compared against players prescribed opioids while in the NFL and with those who were non-users during their NFL careers, 17 percent of those who misused while playing used as prescribed in the past 30 days, 15 percent misused in the past 30 days, and 68 percent reported no use.

In a multivariate analysis, moderate to severe pain, undiagnosed concussions, and drinking 20 or more alcoholic drinks a week were the strongest predictors of misuse. Undiagnosed concussions were reported by 81 percent of misusers.

“This association might have been due to the fact that those who choose not to report concussions are the same players who choose not to reveal their pain to a physician, thus managing their pain on their own,” the researchers wrote. “They may believe that if they report a concussion, they will be pulled from active play.”

The researchers noted the study may have been limited by lack of detailed pain information from while a player was active, a small sample size, a more inclusive definition of misuse that included abuse of opioids a player was prescribed, and a sample that included potentially more-healthy-than-average retired footballers — the researchers noted interviews with former players not in the Retired Players Association uncovered “multiple examples of serious and heavy opioid abuse.”

They added that future research could measure number of alcoholic drinks and level of pain while active in the NFL against opioid use and abuse.

The study received funding from ESPN and the National Institute on Drug Abuse.