Dear Doctor: Our family is worried; my 18-year-old grandson won’t give up vaping. How many people have gotten sick? We just read about something called popcorn lung. What is that?

Dear Reader: Ever since the first cases of vaping illness were made public last August, the outbreak has made front-page news. The Centers for Disease Control and Prevention, one of several federal agencies monitoring the outbreak, publishes regular updates about the number of cases of vaping illness, as well as the deaths it has caused. As of December, at least 2,400 hospitalizations due to lung injuries associated with vaping have been reported to the CDC from all 50 states, Puerto Rico and the U.S. Virgin Islands. At least 52 people in 26 states and the District of Columbia have died. Doctors and surgeons compare the lung injuries they’re seeing to the kinds of chemical burns usually associated with industrial accidents.

But statistics can be a hard sell, particularly for teenagers. Maybe the case of a 17-year-old boy in Detroit, who recently underwent a double lung transplant after falling ill from vaping, will help make the risks seem more real.

One of the striking things about the outbreak is the number of rare lung conditions doctors are now diagnosing. One of these is hard-metal pneumoconiosis, commonly referred to as “cobalt lung.” It’s a form of pneumonia usually seen in people with long-term exposure to the airborne particulates caused by metal grinding.

Another is bronchiolitis obliterans, or “popcorn lung,” which is the disease you’re asking about. The nickname arises because the disease is linked to a butter-flavored chemical called diacetyl, which was once used in the manufacture of microwave popcorn. This rare form of bronchitis causes the tiny airways within the lungs, known as bronchioles, to become inflamed. This results in tissue damage, including scarring, which thickens and blocks the airways.

Symptoms of popcorn lung include a persistent dry cough and shortness of breath, which become more pronounced during exertion. Additional symptoms can include fatigue and wheezing that are not associated with asthma or illness. Diagnosis often begins with tests to determine lung function. Since chest X-rays can often appear normal in the early stages of the disease, high-resolution imaging tests such as a chest CT scan are often used. There is no cure at this time, so treatment focuses on managing symptoms to slow the progression of the disease. Depending on the individual case, this can include medication to lessen the body’s immune response and to ease inflammation. Antibiotics, cough suppressants and supplemental oxygen may also be used. In extreme cases, a lung transplant may be necessary.

Fortunately, there is also good news. Statistics show that the pace of the vaping illness outbreak is slowing. In addition, research now points to black-market vape products as a source of many of the lung injuries. Still, very little is known about the long-term effects of any kind of vaping. Unless they’re using legitimate products in order to stop smoking, we recommend that our patients don’t vape. The risks of this as a recreational practice are just too great.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Hello, dear readers! We hope this new year is finding you happy and healthy, and that the expectations of the holiday season didn’t take their toll. Whether it’s a moment of meditation, a quiet cup of tea, or a romp with the family dog, always remember to take some time for yourselves. And now, onward to your letters.

-- In response to a column about an inflammatory condition known as polymyalgia rheumatica, or PMR, several of you wondered if changes to diet may be helpful. This condition causes pain and stiffness in the muscles and joints, most often in the neck and shoulders, but also the hips, thighs and lower back. Treatment includes corticosteroids, such as such as prednisone, and pain meds, such as ibuprofen and aspirin.

Research shows that lifestyle changes, including a diet to lower inflammation, can also help ease symptoms. One of the goals in this type of eating is to stabilize insulin levels. That translates to a diet low in added sugars and simple carbohydrates and rich in a variety of colorful, nonstarchy vegetables. Steer clear of alcohol, processed foods, fried foods and processed meats. Harness the anti-inflammatory properties of omega-3 fatty acids with fish such as mackerel, sardines and salmon, and flax seeds, chia seeds and leafy greens.

The good news is that this condition is usually temporary. Most people see relief in about a year, although in some cases, it can take longer to resolve.

-- We heard from several of you regarding the column about frozen shoulder. This is a condition in which pain and stiffness in the shoulder joint gradually makes movement difficult or even impossible.

One reader found relief after seeing a chiropractor. “I had one session, and it fixed my frozen shoulder for good,” she wrote. “That was eight years ago, and my shoulder is still fine. Really works!”

Another reader, whose doctor proposed a surgical fix, sought acupuncture instead. “After one treatment, I could lift (my arm) straight up as high as ever with no pain,” he wrote. “It would save a lot of people a lot of pain if everyone knew about acupuncture.”

-- A recent column in which we discussed the benefits of breathing through the nose rather than the mouth prompted this question from a reader: “What about people who sleep with their mouths wide open?” she asked. “They don’t have any control over how they are breathing.” Many people breathe through their mouths at night due to mild sinus blockage. Blowing one’s nose before bed, using a neti pot or saline nasal spray, adjusting sleep position, elevating the head, and using over-the-counter nasal or mouth strips can each be helpful. In some cases, mouth breathing can be a symptom of obstructive sleep apnea. This is a serious sleep disorder, and it requires medical care.

As always, thank you for your letters. We’re so glad you enjoy the column and find it useful. We love that you keep our mailboxes -- both snail mail and email -- full, and we look forward to hearing from you next month.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I just heard about a study that says if you own a dog, you’ll do better after having a heart attack. Is that real, or is it an urban legend?

Dear Reader: We understand your skepticism, but, yes, it’s true that researchers recently had some good health news for dog owners. It arrived in a pair of studies published last October in Circulation, the American Heart Association’s journal.

According to the findings, people who kept a dog as a pet had measurably better health outcomes following a heart attack or a stroke than those who didn’t live with a canine companion. The studies also found that the dog owners in the study lived longer than nonowners. And though we hate to rain on the puppy parade, it turns out there’s an important caveat. The researchers made statistical adjustments for a number of factors, including income, age and geographic location. However, smoking, which is a serious risk factor in both heart disease and stroke, was not among them.

Even without that particular variable, the researchers concluded that dog owners fare better after a heart attack or a stroke. This means a smoother recovery with fewer complications and fewer additional hospitalizations. These benefits were more pronounced for people who lived alone -- that is, without other humans -- and for those whose heart attack or stroke was a repeat event. The study found that dog ownership decreased the risk of death by 15% for people recovering from a heart attack who shared a home with a partner or a child. That number rose to 33% for heart attack survivors who lived alone.

This association between dog ownership and improved health outcomes continued in the second study, which evaluated the general health data of 3.8 million people. The risk of death from any cause was 24% lower among dog owners, and their risk of developing cardiovascular disease dropped by 65%, the study found.

Why do dogs help us in this way? Studies have long shown that interacting with an animal lowers levels of the stress hormone cortisol, improves blood pressure and boosts mood. If you’ve ever been in a hospital when a therapy dog is present, you’ve seen the beneficial effects firsthand. And it’s not just the patients who line up for a moment of patting and paw-holding, but the nurses, doctors and support staff as well.

It’s also a fact that people with dogs stay more active. A Canadian study found that dog owners walked an average of 300 minutes per week, almost double the 168 minutes per week logged by nonowners. Social interaction is an important factor in good health, and dogs are great catalysts in that regard. It’s the rare dog owner who can complete a walk without at least a smile or hello from fellow pedestrians. The researchers mentioned all these benefits and said they look forward to future research on the subject. As dog lovers, so do we.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)