Monthly Archives: August 2017

How Your Heights Can Affect Increase Your Blood Clot Risk

Your height may be linked to your risk of blood clots: A new study from Sweden found that taller men and women were more likely to develop blood clots in their veins than their shorter counterparts were.

Compared with men who were taller than 6 feet 2 inches (190 centimeters), men who were shorter than 5 feet 3 inches (160 cm) were 65 percent less likely to develop a blood clot in their veins, according to the study. And compared with women taller than 6 feet (185 cm), woman who were shorter than 5 feet 1 inch (155 cm) were 69 percent less likely to develop a venous blood clot.

Venous blood clots, or “venous thromboembolisms,” are blood clots that start in a person’s veins, according to the American Heart Association(AHA). One type of venous blood clot is called a deep vein thrombosis (DVT), and it often forms in the vein of a person’s leg. If a DVT breaks free from a person’s vein, it can travel to the individual’s lungs and get stuck, causing the second type of venous blood clot, a pulmonary embolism. These embolisms can be deadly. [5 Surprising Ways to Be Heart Healthy]

Venous blood clots affect up to 600,000 Americans each year and are the third-leading type of blood vessel problem, after heart attack and stroke, the AHA says.

In the new study, published yesterday (Sept. 5) in the journal Circulation: Cardiovascular Genetics, the researchers looked at data on more than 2.5 million Swedish adult siblings who didn’t have a venous blood clot when the study began. Using the Swedish Hospital Register, a national database that includes information on hospital patients’ medical diagnoses, the researchers identified who had a blood clot during the 30- to 40-year study period.

By including siblings in the study, the researchers could account, in part, for genetic factors that may increase a person’s risk of blood clots, the study said. The researchers found that among same-sex sibling pairs, the risk of venous blood clots was significantly lower in siblings at least 2 inches (5 cm) shorter than their taller siblings.

The study didn’t look into why height was linked to risk of venous blood clots.

“It could just be that because taller individuals have longer leg veins, there is more surface area where problems can occur,” lead study author Dr. Bengt Zöller, an associate professor of internal medicine at Lund University in Sweden, said in a statement.

Gravity may also play a role in the possible link: There’s more gravitational pressure in the leg veins of taller individuals, and that can increase the risk of blood flow slowing or temporarily stopping, Zöller said.

The researchers noted that the study had several limitations. For example, the researchers didn’t account for lifestyle factors — such as smoking, diet and physical activity — that could increase a person’s risk for venous blood clots. In addition, the research was done in Swedish adults, and the results may not apply to Americans or other nationalities, the researchers said.

Zöller acknowledged that a person can’t do anything to change their height. However, he suggested that health care workers take height into consideration when looking at a person’s risk of developing venous blood clots.

PSA Playback Can Reduce Deaths of Prostate Cancer

For men approaching 50 years old, deciding whether or not to be screened for prostate cancer can be confusing: Information about a screening test — called the prostate-specific antigen (PSA) test — is riddled with conflicting advice.

The test measures the blood level of the protein PSA, which is produced by cells in the prostate gland. Abnormally high levels of PSA can mean that a man has prostate cancer, but not always. Some organizations, such as the U.S. Preventive Services Task Force (an expert panel that advises the government) do not recommend that men undergo routine screenings with the PSA test. But others, including the American Cancer Society, recommend that men discuss the test with their doctor.

Now, a new analysis of conflicting findings from two of the largest prostrate screening trials conducted suggests that PSA testing does lead to a lower risk of death from prostate cancer. These results should reduce uncertainty in an area of medicine where patients, doctors and policymakers have many questions, and could help raise awareness about who is best-suited for the blood test, said senior study author Ruth Etzioni, a biostatistician at the Fred Hutchinson Cancer Research Center in Seattle. [5 Things You Should Know About Prostate Cancer]

“They’ll feel more confident that this is a beneficial test with the caveat that a beneficial test doesn’t save everybody. Screening is only one of our tools to save lives with cancer,” Etzioni told Live Science

The analysis was published yesterday (Sept. 4) in thejournal Annals of Internal Medicine.

In the new analysis, the investigators found no evidence that results of PSA screening differed between the two clinical trials, but found strong evidence that getting screened lowered the risk of dying from cancer up to 32 percent, compared with not getting screened.

“The trials aren’t as different as they appear,” Etzioni said.

The two trials in question are the European Randomized Study of Screening for Prostate Cancer (ERSPC), which was conducted in the Netherlands, Belgium, Sweden, Finand, Italy, Spain and Switzerland, and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO), which was conducted in the United States. The ERSPC trial found PSA screening was associated with a 21 percent lower risk of dying from prostate cancer. The PLCO trial, however, found no link between PSA screening and the reduced risk of death from prostate cancer.

But the different results may stem from the different ways and the different countries in which the two trials were conducted, the researchers said. For example, men in the two trials were screened at different frequencies (annually versus every two to four years). They were also told to get a biopsy when their PSA level reached different thresholds (4.0 micrograms per liter [μg/L] versus 3.0 μg/L). And screening was stopped at different times. [5 Myths About the Male Body]

In the PLCO trial, only 40 percent of those recommended for a biopsy actually had one within one year, Etzioni added.

Both PSA trials had two main groups, or “arms,” being studied — an arm receiving PSA testing and a control arm that was not receiving PSA testing. But in the PLCO trial, more than three-fourths of the control group had at least one screening test during the trial, the authors said.

“It’s called ‘contamination,’ and there were very high levels in the U.S. study,” said Andrew Vickers, an attending research methodologist at Memorial Sloan Kettering Cancer Center in New York City. Vickers was not involved in the new analysis, but wrote an editorial that was published alongside the new analysis in the Annals of Internal Medicine.

Adding to the contradictory results of these trials are medical considerations around prostate cancer that can muddy a decision about whether to have the test. For instance, a test can help detect cancer early, but prostate cancers are generally slow-growing and many never spread. This means the test may not well serve men over age 70, who may die from other causes long before their prostate cancer becomes dangerous, Vickers told Live Science.

Prostate cancer is easy to treat, according to the Mayo Clinic, but the treatment can produce side effects, such as urinary incontinence, erectile dysfunction or bowel dysfunction. PSA tests aren’t perfect. Protein levels can be elevated even if there’s an infection and cancer isn’t present. As a result, tests can produce unnecessary anxiety and fear.

“The question is, Does it do more good than harm,” Vickers said.

To get a better idea of whether early detection itself is effective, Etzioni and her team used computer modeling to summarize the different factors that impacted the amount of early detection on each arm of the two trials and put them on an even playing field. Then, they compared each of the four arms to a historical population of men that had never undergone PSA screening to create a score that represented the amount of early detection of prostate cancer.

“It takes all of the influences and turns it into one score that means the same thing for the four different arms,” Etzioni said.

Next, they correlated the four scores with the number of men who died of prostate cancer in each arm. They found a strong correlation, and no evidence of differences in screening benefit between the trials after accounting for the scores, Etzioni said.

“The modeling study essentially shows is that if the rates of screening in the US trials had been similar to the European studies, they would have had similar results,” Vickers said.

Although mathematical models are standard in medicine, when it comes to deciding whether a cancer-screening test is effective or not, they all depend on a huge number of assumptions, Vickers said. Ideally, large clinical trials would be done in ways that are identical to each other, but this is virtually impossible.

Vickers also said that other, smaller studies have shown that PSA testing was effective at finding prostate cancer.

“If [Etzioni’s study] was just one modeling study, that would not be very good evidence,” he said. “But the fact that this is congruent with other evidence … makes it a compelling study.”

How Zika Virus Can Help Combat Brain Cancer

The Zika virus can be a serious health threat, especially to unborn children, but now researchers say the virus itself could help treat another devastating illness — brain cancer.

A new study suggests that the same properties that make Zika a dangerous virus for unborn children could be useful in treating brain cancer in adults. The study was done in lab dishes and animals, and much more research is needed before it could be tested in humans.

It’s thought that the Zika virus naturally targets and kills brain stem cells, which are abundant in fetal brains during development. As a consequence, women infected with Zika virus during pregnancy are at increased risk of giving birth to children with neurological problems. But adults have fewer active stem cells in their brains, and as a result, the effect of Zika on adult brains is usually much less severe, the researchers said.

What’s more, the growth of certain brain cancers — including often-lethal glioblastomas — may be driven by cancer stem cells that divide and give rise to other tumor cells. These glioblastoma stem cells are typically resistant to therapies such as chemotherapy and radiation, and may fuel the return of the cancer after treatment. The researchers hypothesized that the Zika virus could target these cancer stem cells. [5 Facts About Brain Cancer]

“We wondered whether nature could provide a weapon to target the cells most likely responsible” for the return of glioblastoma after treatment, study co-author Milan Chheda of Washington University School of Medicine in St. Louis, said in a statement.

The researchers found that the Zika virus preferentially targeted and killed human glioblastoma stem cells in a lab dish, without having much of an effect on normal adult brain cells.

Next, the researchers tested the Zika therapy on mice with glioblastomas. To do this, they injected a mouse-adapted strain of Zika virus into the glioblastoma tumors. (The strain of Zika virus that infects humans does not infect mice.)

They found that mice treated with Zika showed slower tumor growth and lived longer than those that didn’t get the Zika treatment. All of the untreated mice died after about a month, but close to half of the treated mice were still alive after two months, the researchers said.

Still, much more research is needed to show that the therapy is safe and effective in humans. The researchers plan to genetically modify the Zika virus so that it is weaker and would not be expected to cause disease. A preliminary test of such an “attenuated” Zika strain showed that this virus was still capable of targeting and killing glioblastoma stem cells in a lab dish.

“Our study is a first step towards the development of safe and effective strains of Zika virus that could become important tools in neuro-oncology and the treatment of glioblastoma,” said study co-author Michael Diamond, also of Washington University.

But concerns over the safety of a Zika-based therapy will need to be addressed with further studies in animals before the therapy is tested in humans, Diamond said. Ultimately, the Zika therapy might be used along with other traditional brain cancer therapies to treat glioblastomas, the researchers said.

The new study is published today (Sept. 5) in The Journal of Experimental Medicine.

Zika is not the only virus being considered as a potential treatment for glioblastomas. Other research groups are testing measles, polio and herpes viruses as possible ways to target glioblastomas.

‘Hearing Sound’ in Schizophrenia can Trace Specific Brain Areas

'Hearing Voices' in Schizophrenia May Trace to Specific Brain Region

 

The study involved 59 patients with schizophrenia who said they heard voices that other people could not perceive. The people in the study answered questions about the nature of these voices, including whether the voices were friendly or threatening, happened frequently or only occasionally, or were “internal” (perceived as coming from inside a patient’s head) or “external” (perceived as coming from outside a patient’s head). Based on the participants’ answers, the individuals were given an “auditory hallucinations” score, with higher scores indicating more-severe hallucinations.

The researchers then used a therapy called high-frequency transcranial magnetic stimulation (TMS), which sends magnetic pulses through a person’s scalp to stimulate brain cells. The scientists targeted a specific part of the brain that is linked with people’s understanding and production of language, within an area known as the temporal lobe. [10 Things You Didn’t Know About the Brain]

Patients were randomly assigned to receive either TMS or a “sham” treatment that was not expected to have an effect. Each group underwent two sessions of their treatment a day, for two days.

About 35 percent of patients in the TMS group showed a significant response to the therapy, compared to just 9 percent of patients in the sham group. A significant response was defined as a more than 30 percent decrease in the auditory hallucinations score.

‘Hearing voices’ can be a disturbing symptom of schizophrenia, both for patients and for those close to sufferers,” said study author Sonia Dollfus, a professor of psychiatry at the University of Caen in France, said in a statement. “We have shown that treatment with high-frequency TMS makes a difference to at least some sufferers,” Dollfus said. However, she noted that more research is needed to determine whether TMS is the best way to treat these patients in the long term.

The study was presented Sept. 5 at the European College of Neuropsychopharmacology (ECNP).

Previous studies have suggested that TMS could treat auditory hallucinations in people with schizophrenia, but those studies were less rigorous than the current one. The new study is “the first controlled trial to show an improvement in these patients by targeting a specific area of the brain and using high-frequency TMS,” Dollfus said. (A controlled trial is one that includes a “control group,” i.e., a group that did not get the TMS treatment.)

Andreas Meyer-Lindenberg, director of the Central Institute of Mental Health in Mannheim, Germany, who was not involved in the study, said that the research builds on previous work suggesting that this brain region plays a critical role in the generation of voice hallucinations in schizophrenia. Although the percentage of people whose symptoms improved from the therapy was moderate, “TMS is a welcome addition to the therapeutic repertoire [for schizophrenia patients], especially for patients who do not respond to medication,” Meyer-Lindenberg said in a statement. (Meyer-Lindenberg is a member of the ECNP executive board.)