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Feb 21 (Reuters) - Welcome to Health Rounds! For the first time, researchers have been able to restore hand and arm movements years after a paralyzing stroke. A separate team reported on Monday that a staggering number of kids worldwide show signs of being at risk for serious eating disorders. Also, a review of data from one of the largest clinical databases for COVID-19 research has found that heart problems after infection with SARS-CoV-2 were less common in people who had been vaccinated against the virus.

In breaking news, see these stories from our Reuters journalists: Merck & Co's pill for treating COVID-19 does not prevent infection when taken by a patient's household members; tens of thousands of junior doctors in England have voted to strike next month; U.S. to select 10 costliest drugs for Medicare pricing negotiation.

Harmful eating behaviors affect 20% of kids

Roughly one-in-five children and adolescents worldwide suffers from harmful eating behaviors that could put them at risk for serious disorders, with girls particularly affected, a new review of published studies suggests.

Researchers analyzed 32 studies published since 2000 involving more than 63,000 children and teens between the ages of 6 and 18 from 16 countries. All participants, about half of whom were girls, were considered to be physically and mentally healthy, and all had completed a widely-used five-item screening questionnaire for identifying eating disorders.

The questionnaire asked: (1) Do you make yourself sick because you feel uncomfortably full? (2) Do you worry you have lost control over how much you eat? (3) Have you recently lost more than 14 pounds (6.4 kg) in a 3-month period? (4) Do you believe yourself to be fat when others say you are too thin? (5) Would you say that food dominates your life?

On the basis of "yes" answers to at least two of the questions, 22% were characterized as having "disordered eating," a term used to describe harmful eating behaviors that may not qualify as an eating disorder, which is considered a form of mental illness.

Rates of disordered eating were significantly higher in girls than in boys and rose in parallel with age and body mass index, the research team reported on Monday in JAMA Pediatrics.

Disordered eating can lead to eating disorders with harmful consequences, the authors noted. They said the high proportion of disordered eating found in this study reinforces the importance of screening for eating disorders by primary care clinicians.

Arm and hand movement restored years after stroke

Years after suffering severe strokes, two patients who underwent electrical stimulation of specific spinal cord regions could once against move their arms and hands, researchers reported on Monday in Nature Medicine.

Currently, no treatments are effective for treating post-stroke paralysis of the arms and hands once it becomes chronic.

In the new study, funded by the U.S. National Institutes of Health, some of the improvements persisted for weeks after the stimulation device was switched off, the researchers also found.

In each patient, thin metal electrodes resembling strands of spaghetti were implanted on the surface of the spinal cord along the neck to stimulate so-called neural circuits, which are populations of interconnected nerve cells that can carry out specific functions when activated.

Similar technology is already being used to restore movement to the legs after spinal cord injury, but the wide range of motion of the arms and hands has made restoring that movement more challenging, the researchers said.

After the treatment, the two patients could perform tasks of varying complexity, such as grasping common household objects and opening a lock.

"By stimulating these sensory nerves, we can amplify the activity of muscles that have been weakened by stroke," study coauthor Douglas Weber of Carnegie Mellon University said in a statement. "Importantly, the patient retains full control of their movements: The stimulation is assistive and strengthens muscle activation only when patients are trying to move."

The researchers are enrolling additional trial participants to understand which stroke patients can benefit most from this therapy and how to optimize stimulation protocols for different severity levels.

COVID vaccines linked with lower heart risks

Vaccination against COVID-19 was associated with fewer heart attacks, strokes, and other cardiovascular issues among people who were infected with the coronavirus, researchers have found.

Researchers used a large U.S. database to study the outcomes of more than 1.9 million COVID-19 patients, including 217,843 who had received mRNA vaccines from Pfizer/BioNTech or Moderna or the viral vector vaccines from Johnson & Johnson.

Full vaccination was associated with a 41% lower risk of major adverse cardiac events after SARS-CoV-2 infection, the researchers found. Even partial vaccination was associated with a 24% lower risk.

The research team could not identify the variants that caused patients' infections, and the study cannot prove that vaccination protected against cardiac events.

Still, this study and others have found that particularly among individuals with pre-existing health conditions that put them at higher risk, COVID vaccines are linked with a lower risk of complications if people do become infected with the virus, said study leader Dr. Girish Nadkarni of the Icahn School of Medicine at Mount Sinai in New York City.

"While we cannot attribute causality, it is supportive evidence that vaccination may have beneficial effects on a variety of post-COVID-19 complications," Nadkarni said in a statement.

The work was supported, in part, by funds from the National Institutes of Health and the National COVID Cohort Collaborative. The data were released on Monday in the Journal of the American College of Cardiology and will be presented on March 5 at the ACC’s 72nd Annual Scientific Session in New Orleans. (Reporting by Nancy Lapid; Editing by Bill Berkrot)