My 16-year-old son plays football at school. He gets a lot of bumps on the head. It worries me that this kind of playing may cause harm to his brain. Am I being overly protective and nervous, or is there danger? C.R., Pittsburgh, Pennsylvania, US.

Judy Siegel-Itzkovich replies:

In fact, playing such contact sports as teenagers can pose harm, according to a new study at the University of California at Berkeley, Duke University and the University of North Carolina at Chapel Hill.  Playing high school football changes the teenage brain, said the researchers, who found in an MRI (magnetic resonance instrument) study that repeated blows to the head – even during a single season of football or soccer – can cause microscopic changes in the brains of young players.

The researchers used a new type of MRI scanner to take brain scans of 16 high school players aged 15 to 17, before and after a season of football. They found significant changes in the structure of the grey matter in the front and rear of the brain, where impacts are most likely to occur, as well as changes to structures deep inside the brain. All participants wore helmets, and none received head impacts severe enough to constitute a concussion.

The study, which is the cover story of the November issue of the journal Neurobiology of Disease, is one of the first to look at how impact sports affect the brains of children at this critical age, the researchers said.

“It is becoming pretty clear that repetitive impacts to the head, even over a short period of time, can cause changes in the brain,” noted study senior author electrical engineering and computer sciences Prof. Chunlei Liu of Berkeley. “This is the period when the brain is still developing, when it is not mature yet, so there are many critical biological processes going on, and it is unknown how these changes that we observe can affect how the brain matures and develops.”

One bang to the head may be nothing to sweat over, they continued. But mounting evidence shows that repeated blows to the cranium – such as those racked up while playing sports like hockey or football or through blast injuries in military combat – may lead to long-term cognitive decline and increased risk of neurological disorders, even when the blows do not cause concussion.

Over the past decade, researchers have found that an alarming number of retired soldiers and college and professional football players show signs of a newly identified neurodegenerative disease called chronic traumatic encephalopathy (CTE) in which there is a buildup of pathogenic tau protein in the brain. Though still not well understood, CTE is believed to cause mood disorders, cognitive decline and eventually motor impairment as a patient gets older. Definitive diagnosis of CTE, however, can be made only by examining the brain for tau protein during an autopsy.

These findings have raised concern over whether repeated hits to the head can cause brain damage in youth or high school players and whether it is possible to detect these changes at an early age, the researchers added.

“There is a lot of emerging evidence that just playing impact sports actually changes the brain, and you can see these changes at the molecular level in the accumulations of different pathogenic proteins associated with neurodegenerative diseases like Parkinson’s and dementia,” Liu said. “We wanted to know when this actually happens – how early this occurs,”

The brain is built of white matter, long neural wires that pass messages back and forth between different brain regions, and grey matter, tight nets of neurons that give the brain its characteristic wrinkles. Recent MRI studies have shown that playing a season or two of high school football can weaken white matter, which is mostly found nestled in the interior of the brain. Liu and his team wanted to know if repetitive blows to the head could also affect the brain’s gray matter.

“Grey matter in the cortex area is located on the outside of the brain, so we would expect this area to be more directly connected to the impact itself,” Liu said.

The researchers used a new type of MRI called diffusion kurtosis imaging to examine the intricate neural tangles that make up gray matter. They found that the organization of the gray matter in players’ brains changed after a season of football, and these changes correlated with the number and position of head impacts measured by accelerometers mounted inside players’ helmets.

The changes were concentrated in the front and rear of the cerebral cortex, which is responsible for higher-order functions like memory, attention and cognition, and in the centrally located thalamus and putamen, which relay sensory information and coordinate movement.

“Although our study did not look into the consequences of the observed changes, there is emerging evidence suggesting that such changes would be harmful over the long term,” Liu said. Tests revealed that students’ cognitive function did not change over the course of the season, and it is yet unclear whether these changes in the brain are permanent, the researchers say.

“The brain microstructure of younger players is still rapidly developing, and that may counteract the alterations caused by repetitive head impacts,” said first author Nan-Ji Gong, a postdoctoral researcher at Berkeley. However, the researchers still urge caution – and frequent cognitive and brain monitoring – for youth and high schooler pupils engaged in impact sports.

“I think it would be reasonable to debate at what age it would be most critical for the brain to endure these sorts of consequences, especially given the popularity of youth football and other sports that cause impact to the brain,” Liu concluded.

I am a 71-year-old man. I have been a geologist for 50 years and spent every year outdoors in Canada’s Arctic looking for diamonds, uranium and gold. I don’t smoke; I am overweight. I weigh 185 pounds. I exercise, walking in the winter and biking in the summer for abut 40 minutes a day. I drink wine only very moderately, but I have had pre-diabetes for many years.

I was just told this month by my doctor that this has developed into fully fledged type-2. I have been to a dietitian, but it didn’t help. My doctor has given metformin for many years to prevent pre-diabetes from turning into diabetes, and I have also been on Januva for a few months.

My wife says that one is born with a set number of heartbeats, so why use them up exercising? But I would still like to know what other diabetes drugs could help me. P.P., Brampton, Ontario, Canada

Israel Diabetes Council chairman Prof. Itamar Raz replies:

The best kind of drug for this condition is sodium-glucose co-transporter 2 (SGLT-2 inhibitor, which is also called gliflozin. This is a new class of diabetic medications for the treatment of type 2 diabetes that have also been found to benefit the heart and functioning by reducing the absorption of glucose via the kidneys.

The medication, commercially known as Forxiga, works by initiating glycosuria – excretion of glucose into the urine. Normally, urine contains no glucose because the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream. Glycosuria is nearly always caused by high blood glucose levels, most commonly due to untreated diabetes. SGLT-2 inhibitors reduce blood glucose levels in patients with type-2 diabetes mellitus by inhibiting the glucose reabsorption pathway which results in glucosuria.

The effect of the drug will begin in several days. But you must continue to exercise regularly, eat a proper diet and go to your personal physician or diabetologist for consultation and prescription of the drug if it is suitable for you.

If you want an Israeli expert to answer your medical questions, write to Breaking Israel News health and science senior reporter Judy Siegel-Itzkovich at judy@israel365.com with your initials, age, gender and place of residence and details of the medical condition, if any.