A common virus may be one contributing cause of multiple sclerosis

Enlarged particles of the common human Epstein-Barr Virus (EBV) shown in bright green, spiky blue, orange, and pink against a dark blue background

Discovering the cause of a disease is not easy. One reason is that the vast majority of diseases do not have a single cause. Instead, most diseases occur because multiple factors combine to cause the disease.

One factor is genes. Some people are born with one or more genes that make them vulnerable to a disease. Other factors come from your environment and behavior: what you eat, the air you breathe, the amount of physical activity you engage in, and habits such as smoking. Recent research finds that certain viruses may also be important contributing factors in causing multiple sclerosis (MS).

Multiple sclerosis harms cells in the brain and spinal cord — but why?

Multiple sclerosis is a disease of the brain and spinal cord that can cause many neurological symptoms, including arm and leg weakness, loss of vision, and difficulty thinking, as well as severe fatigue. Over the past 50 years we’ve learned that MS is an autoimmune disease: in various ways, the immune system attacks the brain and/or the spinal cord, leading to the symptoms of the illness.

However, we haven’t figured out why:what causes the immune system to go on the attack? Over the years, several viruses have been proposed as causes of MS, only to have subsequent research show that they were not. That led some MS doctors and scientists to discount viruses as possible causes.

Yet growing evidence in recent years points to several viruses that may be triggers of MS. The strongest evidence is for Epstein-Barr virus (EBV). This virus infects most people in developed nations like the US in their teen or young adult years.

Once a person is infected, the virus quietly remains alive in the body for the rest of a person’s life. In most people, it causes no health problems. But, rarely, it can cause certain cancers. Now, it has been linked to multiple sclerosis.

Delving deeper into a link between Epstein-Barr virus and MS

A large, long-term study from Harvard, published in the prestigious journal Science, attracted a lot of attention. Blood samples were repeatedly collected from 10 million US military personnel over 20 years. The samples were tested for evidence of infection with EBV.

Over the 20 years, some people in the study developed MS. The researchers compared two groups: people who were not infected with EBV when they entered military service, but then became infected later on; and people who remained uninfected by the virus. Those in the first group were 32 times more likely to develop MS than those in the second group. On average, symptoms of MS began about five years after a person became infected with EBV.

What do these findings tell us? The study provides strong evidence that a new infection with EBV is one important factor — maybe even a necessary factor — in causing MS. But the story is more complicated than that. Think about this: About 95% of all humans become permanently infected with EBV by early adulthood, but fewer than 1% of people develop MS. So, just being infected with EBV doesn’t mean a person will get MS — far from it. Indeed, other factors besides EBV infection also must be involved in causing MS.

Those other factors almost certainly include being born with certain genes that make you vulnerable to getting MS. Being infected with other viruses, as well as EBV, also may be important factors.

But which viruses? In my opinion, growing evidence indicates that a “cousin” of EBV, called human herpesvirus-6A, also may be important in triggering MS. And the genes of endogenous retroviruses also may be factors.

What are endogenous retroviruses?

About 8% of the genes that we are born with come from ancient viruses called retroviruses. These viral organisms successfully inserted their genes into the genes of the animals that preceded, and led to, humans. Some of those genes can be turned on to make proteins that affect our immune systems. Finally, there is evidence that each of these viruses — EBV, human herpesvirus-6A, and endogenous retroviruses — can activate one another, and gang up to cause a disease.

Going forward: New research may offer new leads for prevention

If the Epstein-Barr virus is one important factor in causing multiple sclerosis, then it is possible that vaccines against EBV might lead to fewer cases of MS. Indeed, several scientific groups around the world are working on such vaccines.

One company that made the mRNA vaccine for COVID-19 is working on an mRNA EBV vaccine. The National Institutes of Health also is developing a vaccine. However, it is unlikely we will know if they are effective against EBV, or against the development of MS, for at least a decade. Still, the linkage with this virus may prove to be an important milestone in ultimately conquering multiple sclerosis.

Snooze more, eat less? Sleep deprivation may hamper weight control

Couple asleep in bed with multicolored striped pillow case and quilt, morning light coming through window; one has arm over the other

Weight loss once was considered a simple calculation: eat less and move more to create a calorie deficit. Now, basic differences between people — in genetics, health conditions, body type, and more — are also thought to play a role in how challenging it is to lose weight. Yet research suggests that some factors may help set the stage for success.

Sleep more to eat less? New research boosts this premise, suggesting that adults who are better rested consume significantly fewer calories than those who are chronically sleep-deprived.

This short-term study of 80 overweight people drives home just how integral slumber — or lack of it — is to our propensity to put on excess pounds, says Dr. Beth Frates, director of lifestyle medicine and wellness in the department of surgery at Massachusetts General Hospital.

“Working to find ways to clean up sleep hygiene may help people to extend sleep time to the recommended seven to nine hours per night,” Dr. Frates says. “This could, in turn, lead to consuming fewer calories and even weight loss in people who are in the overweight category by BMI.”

Sleep shortfall linked to chronic diseases

The new study, published in JAMA Internal Medicine, reinforces earlier findings indicating that people who sleep less consume more calories — and even crave higher-calorie foods — compared with those who sleep for longer periods.

About one-third of Americans don’t sleep the recommended seven to nine hours each night, Dr. Frates notes, and this shortfall is linked to many chronic diseases, including high blood pressure, heart disease, diabetes, and obesity. Sleep, she says, is one of the six pillars of lifestyle medicine — a list that also includes exercise, nutritious eating, stress reduction, social connection, and avoiding risky substances.

“Most people focus on exercise and diet when it comes to weight management and a healthy heart, but few focus on sleep,” she says.

Tracking sleep cycles, calories, and weight

The study participants were adults ages 21 to 40 with a BMI between 25.0 and 29.9, which is considered overweight. All of them routinely slept less than 6.5 hours each night. For the first two weeks, all maintained normal sleep patterns.

For the second two weeks, participants were randomly split into two equal groups. With the aim of lengthening sleep times to 8.5 hours, one group received individualized counseling pointing out ways to alter sleep-busting factors relating to bed partner, children, and pets.

“The advice wasn’t generalized,” Dr. Frates notes. “It was specific to the person, and then there was a follow-up visit with more counseling.” The second group of participants continued their typical sleep habits.

All were told to keep up daily routines without changing diet or exercise habits. Each wore a wrist device that tracked their sleep cycles, and they weighed themselves each morning. Sophisticated lab tests teased out the difference between the number of calories each participant consumed and expended each day.

Balancing appetite-regulating hormones

Researchers found participants who received sleep hygiene counseling slept for more than an hour longer each night than those continuing their prior sleep habits. Extended-sleep participants also consumed an average of 270 fewer calories each day and lost about a pound compared to control group participants, who gained just under a pound on average.

The findings are exciting, because they reveal the power of education and counseling on behavior change — in this case sleep, Dr. Frates says. Significant extra slumber time can help people feel like they’re thriving rather than just surviving, she adds.

But why might extra sleep matter? Sleep duration has long been linked to the body’s production of appetite-regulating hormones. Insufficient sleep is associated with higher levels of the hormone ghrelin, which increases appetite, and lower levels of the hormone leptin, which leads to feeling less full. This sets people up to gain weight. By contrast, sleeping more could alter these hormones and bring them back to balance.

“People might also feel more alert, energized, and happier with more sleep,” Dr. Frates adds. “This could lead to more activity, even if it isn’t exercise. It may lead to less sitting and more socializing.”

It’s worth noting that the study didn’t reveal whether the extended sleep pattern was maintained after the two-week intervention period, or what types of food participants ate and when.

The study had other limitations, too. “Were the people in the sleep extension intervention making healthier choices?” Dr. Frates asks. “Calories are important, but what makes up those calories is equally important. Measuring hunger levels, cravings, and stress levels would also provide important information.”

Takeaway tactics to improve your sleep

A few key tactics from the study could help you improve how long you sleep — and possibly help you take in fewer calories:

  • Keep a sleep log
  • Monitor sleep times with wrist actigraphy devices such as smartwatches
  • Evaluate bedtime routines to tweak factors influencing sleep duration
  • Limit use of electronic devices at least an hour before bed.

Constantly clearing your throat? Here’s what to try

Man in front of lap top at office with uncomfortable look on his face as he tries to clear his throat; he is touching his throat with one hand

Ahem! Ahem! Ever feel the need to move the mucus that annoyingly sits all the way at the back of your mouth? Most of us do at one time or another. The sensation usually lasts for just a few days when dealing with symptoms of a common cold.

But what happens if throat clearing lingers for weeks or months? That nagging feeling may be uncomfortable for the person who has the problem, and might also bother friends and family who hear the characteristic growling sound.

So what causes all that throat clearing? There are many causes, but I’ll focus here on four of the most common culprits. It’s important to know that throat clearing lasting more than two to three weeks deserves an evaluation from a medical professional.

Post-nasal drip

Post-nasal drip is probably the most common cause of throat clearing.

Your nose makes nasal mucus to help clear infections and allergens, or in response to irritants such as cold weather. A frequently runny nose can be quite disturbing. Just as mucus can drip toward the front of the nose, some mucus may also drip from the back of the nose toward the throat, sometimes getting close to the vocal cords. If the mucus is too thick to swallow, we try to force it out with a loud AHEM!

Solutions: The best solution to this problem is to treat the cause of post-nasal drip. An easy way to do it without medications is to try nasal irrigation with a neti pot. If you notice no improvement, different types of nasal sprays may help. It is best to discuss these options with a health professional, because some sprays may cause your symptoms to worsen. The key is to understand what is causing excess mucus production.


Another common cause of throat clearing is laryngopharyngeal reflux (LPR). Acid in your stomach helps digest food. But excess stomach acid sometimes flows backward up the tube called the esophagus that links throat to stomach. This may splash on the vocal cords or throat, causing irritation and throat clearing.

Not everyone with acid reflux experiences a burning sensation in the throat. Nor does everyone have heartburn, which is a classic sign of a related condition called gastroesophogeal reflux disease (GERD). Some people merely feel an urge to clear their throat or have a persistent cough.

Solutions: Eating an anti-reflux diet and not lying down shortly after eating may help in some cases. Often, people have to use medications for several weeks or months to lower stomach acid production.


A common class of heart and blood pressure medicines can also cause throat clearing. These are called ACE inhibitors. The funny thing is that these medications can trigger the urge even after years of people taking them daily without experiencing that symptom. If that’s the cause there is an easy fix. The sensation would be completely gone after stopping the medication, although in some cases it can take several weeks to abate. It is very important to talk to your doctor before stopping a prescribed medicine, so you can switch to something else.

Nerve problems

Damaged nerves responsible for sensation around the throat area is another possible cause. These issues are more difficult to treat, and are usually diagnosed after most of the other possibilities are ruled out. People often have this type of throat clearing for many years.

Solutions: A multidisciplinary team with ear, nose, and throat doctors (otolaryngologists) and neurologists may need to investigate the problem. Medicines that change how a person perceives sensation can help.

There are many other reasons for throat clearing. Some people, for instance, just have a tic of frequently clearing their throat. Noticing any clues that point to the root cause can help. Maybe constant throat clearing happens only during spring, pointing toward allergies, or perhaps after drinking coffee, a reason to consider reflux.

An observant eye and jotting notes in a diary may help shine a light on the problem and its possible solutions. Very often, when the cause remains elusive, your primary care doctor may recommend a trial of treatment as a way to diagnose the problem.