Hello, dear readers, and welcome back for our monthly letters column. Warmer weather is here, so please remember to use sun protection, fend off mosquitoes with bug spray and be aware of ticks as you head outdoors. And now, onward to your questions and comments.

-- After a column about osteoporosis, we heard from a reader dealing with the condition. “I was diagnosed three years ago and tried several medications,” she wrote. “They all had side effects, though, especially on the bowels. What about AlgaeCal?”

The product you’re asking about is a plant-based calcium supplement enhanced with vitamins and minerals. A study published in the Journal of the American College of Nutrition in 2016 found that some people using the product did see an increase in bone density and that the product wasn’t associated with adverse health effects. We encourage you to discuss this option with your health care provider, and also to explore nonbisphosphonate treatments, which are delivered via injection or infusion.

Meanwhile, exercise is an important component of bone health, and we’re glad to know you’ve made it part of your daily routine. In addition to aerobic activities, be sure to include resistance and weight-bearing exercises as well.

-- When discussing the importance of adequate sleep, we have referred to melatonin. A reader wondered about potential side effects. “A couple of years ago, I started taking melatonin before bedtime,” she wrote. “After a few months, I started to feel light-headed and unfocused during the daytime. I stopped taking it, and I started to feel better. Have you ever heard of this before?”

Although melatonin tends to be a benign supplement, it’s efficacy as a sleep aid can vary depending on the dose and the individual. So do side effects, which can include the fuzziness and light-headedness you describe. People have also reported daytime sleepiness, short-term feelings of depression and gastric issues. We’ve had a number of letters about poor sleep (no surprise, considering the year we’ve all just had), so we’ll address nonpharmacologic approaches to insomnia in an upcoming column.

-- A reader had a question in response to a column about bronchiectasis, which is when inflammation and infection cause the bronchial tubes of the lungs to become thickened. “My wife was diagnosed with bronchiectasis in 2007 and had three or four flareups per year that were treated in various ways,” he wrote. “Since being treated with a new medication, she’s had almost no mucus and only one minor flareup in six years. Can bronchiectasis go into remission?”

Yes, the good news is that bronchiectasis can go into remission, which is when the signs and symptoms of a disease are reduced or disappear. However, remission is not a cure. Your wife’s bronchiectasis is under control due to her medications and treatment protocols, so it’s important for her to continue to adhere to them.

Thank you, as always, for your questions and kind comments. We love hearing from you. We continue to get a lot of vaccine questions and will devote a column to them soon.

(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’ve been running during the lockdown, and about a month ago, my outer thigh started to feel like it’s clenched up, and the outside of my knee hurts sometimes. My roommate says it’s most likely that my IT band is too tight and needs to be stretched. What does that mean?

Dear Reader: The IT band is a long swath of connective tissue that makes it possible for us to use our legs to travel. It starts at the top of the pelvis, runs along the length of the outer thigh and ends at the shin, just below the knee, connecting a hip flexor muscle and the gluteus maximus with the outside of the shin. It’s made up of a connective tissue called fascia, which is a sheath that surrounds and encloses muscles and also connects them to bone. You’ll hear the IT band referred to by different names -- the iliotibial band or the iliotibial tract. For fellow science nerds, “ilio” derives from the word ilium, which refers to the flank or hip area. “Tibial” refers to the tibia, which is the larger of the two bones in the lower leg, commonly known as the shin bone.

One of the jobs of the IT band, which is the largest piece of fascia in the human body, is to stabilize the knee. It also facilitates movement at the hip. An intriguing study from scientists at Harvard has recently suggested an additional function. The researchers found that, due to its inherent elasticity, the IT band collects and disperses energy, much like a spring. They suspect that in addition to conferring stability to the joints in the knee and the hip, it also plays an important role in humans’ ability for propulsive speed, particularly in running and jumping.

The idea that the feeling of tightness you describe can be alleviated by stretching the IT band is a bit of a misconception. While fascia is inherently elastic, it’s also extremely strong. You can’t actually stretch it to make it looser or longer. What you can do is stretch the muscles of the hip and thigh, which research suggests play a role in the “it’s-too-tight” problem.

With your occasional outer knee pain, you’ve referenced what may be an overuse injury known as IT band syndrome. The pain can become noticeable during weight-bearing movements, such as climbing or descending stairs; in the down stroke of cycling; or while doing lunges. One theory regarding the pain involves repetitive friction during knee flexion. In runners, it has been associated with running in the same direction when on a circular track, excessive mileage and a lot of time spent running downhill. In this case, as well, stretching and strengthening the muscles of the hips and thighs can be helpful.

Someone dealing with IT band issues should first focus on decreasing local inflammation. This can be done with a change in how and how much you exercise, and with nonsteroidal anti-inflammatory medication. Once inflammation is under control, stretching and strengthening exercises can safely be added to your exercise routine.

(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: It seems like every time I turn on the TV, there’s a commercial that talks about mesothelioma. What is it, and how do people get it?

Dear Reader: Mesothelioma is a rare, aggressive and often fatal form of cancer that arises in the mesothelial cells. These are specialized cells that form a thin membrane known as the mesothelium. It covers the majority of internal organs and lines several internal cavities, including in the chest and abdomen. Its main job is to provide a slippery protective surface so when tissues come into contact, they slide and glide rather than adhere. Depending on their specific location, mesothelial cells also secrete fluids, help with fluid transport, and play a role in immune function, inflammation control and tissue repair.

The main cause of mesothelioma is exposure to asbestos, which is a generic term for certain fibrous minerals that can be spun into strong fireproof thread. Awareness of the health hazards of asbestos dates back to 1924, but it took a series of increasingly restrictive laws in the 1970s for it to finally fall out of widespread use. At that time, it became clear that even light or intermittent exposure to asbestos, whether in buildings, products or manufacturing, was risky.

Today, past asbestos exposure, much of it occupational, accounts for up to 80% of all cases of malignant mesothelioma. There is evidence that family members of people who were regularly exposed to asbestos may also have increased risk of developing mesothelioma. The disease has also been linked to a specific X-ray process used in the early-to-mid 20th century, and family history is suspected to play a role in risk.

One of the many challenges of malignant mesothelioma is that it develops decades -- in some cases up to 40 years -- after asbestos exposure. Another is that symptoms often become apparent only when the disease is advanced.

The majority of cases, up to 85%, arise in the tissues of the pleura, which is the two-layered membrane that surrounds each lung. Symptoms can include chest pain, shortness of breath and chronic cough. Some people may develop a mass in the chest wall or areas of lumpy tissue beneath the skin on the chest. For disease located in the membrane around the stomach, abdominal pain, nausea, vomiting, diarrhea, unexplained weight loss and abnormal fluid accumulation can occur. When the disease affects the membrane around the heart, which is rare, symptoms can include heart arrhythmias, chest pain, difficulty breathing and low blood pressure. The disease can also cause general weakness and exhaustion, as well as night sweats.

Treatment, which includes surgery, radiation and chemotherapy, depends on the age and health of the patient, and at what stage the disease has been diagnosed. Some patients find that alternative treatments, such as acupuncture, breath training, and relaxation and mindfulness exercises can help them to cope with breathlessness. In recent years, targeted therapies, which use drugs and other substances to directly attack cancer cells, have begun to show promise. Clinical trials for new and effective treatments are ongoing.

(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.)