Dear Doctor: I am 72 years old and have bronchiectasis, which I understand is a form of COPD. Can you give me some more information about it? I’ve never been in a smoking environment, but I was raised in a home that used coal and wood for heat.

Dear Reader: Although bronchiectasis and chronic obstructive pulmonary disease, or COPD, are related, they are actually two separate conditions. COPD is an umbrella term for a number of airway diseases, such as chronic bronchitis and emphysema, which obstruct air flow in the lungs and leave the person short of breath. Bronchiectasis causes similar problems, but it is considered a distinct diagnosis of its own.

As the name suggests, bronchiectasis is a disease of the bronchial tubes, or bronchi. These are the main airways into the lungs. When you inhale, the breath moves through the larynx and descends through the trachea, or windpipe. At that point, the airway divides into a pair of bronchi, which are sturdy but flexible mucus-lined tubes made up of cartilage and smooth muscle. These bronchial tubes direct the inhaled breath to the left and right lungs. Each bronchial tube continues to divide and subdivide into ever-smaller structures, the whole of which is referred to as the bronchial tree. As the bronchi become smaller, the proportion of smooth muscle increases and cartilage decreases. This makes them more flexible but less sturdy. The bronchial tree culminates in a variety of tiny tubes, or tubules, and saclike structures, which handle the exchange of oxygen and carbon dioxide.

In someone living with bronchiectasis, chronic inflammation has caused the bronchial tubes to become scarred, thickened and widened. The damage leaves them slack and loose, which interferes with the proper movement of mucus. This leads to the buildup of mucus, as well as buildup of the inhaled particles, dust and bacteria that the mucus is meant to capture and clear away. The result is repeated lung infections, which further damage the structures of the lung and make it more difficult to breathe.

The most common cause of bronchiectasis is damage to the airways. This can be from severe pneumonia, whooping cough, tuberculosis or fungal infections. Cystic fibrosis, a genetic disease that causes a buildup of mucus in the lungs, is related to half the cases of bronchiectasis in the U.S. Allergic reactions to certain fungi and diseases of the connective tissue, including rheumatoid arthritis and Crohn’s disease, are also known to play a role. You mentioned extended exposure to smoke from wood and coal; studies have linked both wood smoke and coal dust to the condition.

Although there is no cure for bronchiectasis at this time, it can be managed. Treatment includes the use of bronchodilators to expand the airways, medications to thin mucus and expectorants to make it easier to cough up. For lung infections, antibiotics are the primary course of treatment. Chest physical therapy, a specific technique that uses percussive force on the chest and back, helps to loosen accumulated mucus. The goals of the combined therapies are to loosen and remove mucus and prevent or cure resulting infections.

(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: Last fall at my annual checkup, my doctor ordered a bone density test. Besides talking to me about osteoporosis in general, she also suggested calcium supplements. I wonder if you have any advice about which supplements are best, and also about maintaining bone health.

Dear Reader: You’ve already taken the first step to protecting bone health by getting a bone density test. This is a simple scan that, as the name suggests, measures bone mineral density.

Although they seem static, our bones are metabolically active organs. They are in constant flux, with old bone being removed and new bone being made. Most of us reach peak bone mass in our late 20s to mid-30s. At that point, the balance of bone metabolism shifts. Bone loss gradually begins to exceed bone creation. Factors such as menopause, inactivity and certain medications can accelerate bone loss. A bone density test gives you an idea of where you are in the process. It does this via a score that compares your bone density to that of a young adult, measuring your bone health on a scale that ranges from normal through low bone mass and to established osteoporosis. It is recommended that all women age 65 and older and men age 70 and older should have a bone density test.

While calcium supplements have their place in keeping our bones strong and healthy as we age, they’re just one part of a broader strategy. To maintain skeletal health and integrity, we also need to focus on a nutritious diet that includes sources of not only adequate calcium, but also potassium, magnesium and vitamin D. That means eating from a wide range of fresh fruits, vegetables, leafy greens, lean meats, dairy products, healthful oils, seeds, beans and legumes.

To help meet their calcium needs, postmenopausal women may need to turn to supplements. Guidelines suggest getting from 1,000 to 1,200 milligrams of calcium daily, with at least half of that coming from dietary sources. Calcium carbonate, at 40% elemental calcium, and calcium citrate, at 21% elemental calcium, are the two main forms of supplements. Newer research has hinted at potential cardiovascular risks linked to the overuse of calcium supplements. With that in mind, we recommend meeting as much of your calcium need as possible through diet, and limiting daily supplements to a maximum of 500 mg per day.

The final piece of the bone-health puzzle is exercise. Specifically, strength training and weight-bearing exercises. Research shows that bone responds to load-bearing exercise by remodeling, which is the complex process that results in the formation of new bone. This includes exercises such as lifting weights, climbing stairs, skipping rope, dancing, running or playing tennis, to name just a few. Regular exercise also improves balance and coordination, which are important to prevent falls. It’s always important to check with your doctor about the type of physical activity that is appropriate for your unique situation. This is particularly true for anyone who is frail or has been diagnosed with thinning bone or osteoporosis.

(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: My big New Year’s resolution was to get my gut into better shape. I’m not talking about a flat stomach -- after having three kids, that ship has sailed -- but about the gut microbiome. Do I need to take probiotics?

Dear Reader: Considering the abundance of foods and drinks with which many of us celebrate the weeks between Thanksgiving and Jan. 1, the new year is a logical and appropriate time for a gut reset. And, yes, we’re talking about the gut microbiome here, which is the collection of trillions of microorganisms that call our digestive tracts home. These include the vast and varied colonies of bacteria, fungi, protozoa, friendly viruses and other microbes that interact with our bodies and, in many cases, help to keep us healthy. Research into the microbiome continues to uncover the many ways in which gut health plays a role in general health, including how it affects processes as varied as the immune system, blood sugar regulation, the cardiovascular system, cholesterol, weight and even mental health.

The good news is that, with several simple lifestyle choices, you can improve your gut health. To understand how, we should define two important terms -- the probiotics that you mention and another equally important piece of the gut microbiome puzzle, prebiotics. Probiotics is the word we use to describe the good microbes living in our guts. A wide variety of types and strains of probiotics are now available as dietary supplements, and in food sources such as yogurt, kefir and naturally fermented foods and drinks. The jury is still out as to whether or not probiotic supplements are actually helpful in achieving and maintaining gut health.

Perhaps more important are prebiotics. These are a type of indigestible carbohydrate that are found in fiber-rich foods, including fruits, vegetables, seeds, beans and legumes. Prebiotics pass through the digestive system and arrive in the colon largely intact. There, they provide a food supply for the all-important probiotics living in our gut. In order to support your microbiome, it’s important to eat a wide range of fresh fruit, vegetables and other prebiotics.

In addition to what you do eat, gut health depends on steering clear of certain foods. Unfortunately for those of us with a sweet tooth, recent studies have shown that a high intake of simple carbohydrates in the diet can tip the balance of gut bacteria to specific types of microbes associated with low-grade inflammation. That’s pretty much the opposite of what you’re trying to achieve. The occasional sweet treat won’t wreak havoc on the gut, but people who regularly eat a lot of sugar or highly processed foods need to rethink their diets.

Gut health isn’t all about food. Studies have found that, just like our hearts, bones, muscles and mood, the denizens of our gut microbiomes respond positively to exercise. A study published in 2017 found a link between exercise and the bacteria that support weight loss. Add in adequate sleep and managing stress, and you’re on your way to a healthier gut in 2021.

(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.)