Dear Doctors: My ex-husband had a certain musty smell before he was diagnosed with Parkinson’s disease. Now my current husband has that same smell, and I’m worried he has Parkinson’s, too. Radon is a problem here in Tennessee, and I’ve heard it’s connected to Parkinson’s. Why isn’t this public knowledge?

Dear Reader: In recent columns, we have written about the health risks of exposure to radon gas, some unusual symptoms of Parkinson’s disease, and the biochemistry behind a distinct and musty scent that sometimes occurs in the skin of older adults. Your letter intrigued us with a discussion of all three.

Parkinson’s disease is a progressive neurodegenerative disorder. It changes the region of the brain associated with muscle movement and other functions. These result in a deficit of dopamine, a neurotransmitter crucial to smooth, sustained and deliberate movement. The steady decrease in dopamine production causes the primary symptoms of Parkinson’s. These include muscle rigidity, slowed movement, tremors, balance problems, difficulty swallowing and slurred speech.

Like many neurodegenerative conditions, there is no specific test for Parkinson’s disease, which often makes it difficult to diagnose. That’s why, when a woman in Scotland told researchers in 2009 that her husband’s scent changed several years before he was diagnosed with Parkinson’s and that she could recognize that scent in others with the disease, they were intrigued. A decade later, researchers had isolated four compounds specific to the skin secretions of people living with Parkinson’s. The hope is someday these can be used as biomarkers for early diagnosis of the disease.

In a recent column, we explored the age-related changes that can lead to a musty, dusty smell on the skin of older adults. Because the compound that causes the scent is not water-soluble, it can’t be washed off, so it can become quite noticeable. The compound is also easily aerosolized and can infiltrate an entire room. A significant portion of older adults emit this musty smell. By contrast, the number of adults over age 60 with Parkinson’s is far smaller -- about 10 out of every 1,000. A musty scent in older adults does not automatically indicate Parkinson’s disease.

That brings us to radon. A colorless, odorless and radioactive gas, it results from the decay of uranium and radium found in rocks and soil. Radon can seep into buildings through cracks and openings in foundations. Exposure poses health risks, primarily lung cancer. Some regions, including the area in Tennessee you are writing from, are radon hotspots. That makes it particularly important to use a reliable radon detector.

The results of some research have suggested a possible connection between radon gas exposure and neurodegenerative disease, including Parkinson’s. However, a definitive link has not been established. To ease your mind, discuss your concerns with your husband and his health care providers. At the very least, they can perform a baseline assessment to measure against for future neurological changes.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: Cannabis is legal where I live. I’m not a heavy user, but I do enjoy it now and then. I just heard about a study that ties using cannabis to heart disease. There’s not a lot of information about how using cannabis affects your health, and I would like to know more about that study.

Dear Reader: We should begin with the fact that, despite changes to regulations in a growing number of states, cannabis remains illegal at the federal level. Commonly known as marijuana, it is classified as a Schedule I substance under the Controlled Substances Act. Possession or distribution of cannabis is a federal offense. At the state level, a complex patchwork of laws allows cannabis use for medical or recreational use. Limits vary on the types and amounts of cannabis products allowed, as well as the legal age for their use.

It’s true we don’t know much about the health effects of cannabis. Federal drug laws have limited research opportunities for a long time. Now, the loosening of restrictions in the United States and other nations is providing more data from national surveys, epidemiological studies and clinical research. We are in a steep learning curve about the drug’s possible health effects.

Last spring, the journal Heart published a study from researchers in France. The focus of the study was how regular cannabis use may affect the cardiovascular system. The researchers looked at health data collected from 24 studies. The data covered 200 million adults from ages 19 to 59. They separated the data into two groups, regular users of cannabis and nonusers. Analysis found that cannabis users had a 29% higher risk of a heart attack and a 20% higher risk of a stroke.

As with all observational studies, this research can only point to a possible link between cannabis use and cardiovascular events. It doesn’t prove or explain the connection. But it does echo previous research noting the burden cannabis use places on the heart. This includes heart arrhythmia, high blood pressure and increased heart rate. This applies to smoking the drug and edibles as well. A study from researchers at the University of California, San Francisco, published last spring, found that regular users of edibles had reduced vascular function, by more than 55%, compared to nonusers.

Cardiovascular disease continues to be the leading cause of death in the U.S. With cannabis use growing (around 15% of adults by current estimates), these newest findings are concerning. Older adults and those with existing heart conditions are at particular risk of adverse outcomes. All of this makes it important to consider the potential risks before using cannabis. At the very least, discuss cannabis use when you see your health care provider.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Kansas City, MO 64106; 816-581-7500

Hello, readers! Welcome to a bonus letters column. We are happy to report that you are keeping our inboxes busy, so we’ll dive right in.

-- We recently wrote about collagen peptides, a protein abundant in collagen, skin and bone. It is available as a nutritional supplement, which is the subject of one reader’s question: “I have read that collagen supplements can increase bone mineral density, and have even had a doctor suggest that I use them,” she wrote. “Is there any evidence to support this?”

Bone health is an important concern for women who have gone through menopause. Estrogen plays a key role in maintaining bone health. A decline in estrogen during menopause can lead to a net loss of bone mineral density. Several small studies found that, after a year of daily collagen peptides supplementation, some women measurably increased bone mineral density in the lower spine and upper leg. They also had higher levels of a blood biomarker that indicates bone formation. The results were affirmed in a follow-up study. As we noted in that column, these were small studies, so further research is needed. However when used as recommended on the product packaging, collagen peptide supplements are generally well-tolerated. It may be helpful to follow your doctor’s recommendation.

-- We’ve written about the challenges of long COVID, a collection of symptoms that can persist after an initial COVID-19 infection resolves. These include brain fog, loss of taste or smell, heart arrhythmia, extreme fatigue, shortness of breath, dizziness, digestive issues, poor sleep and depression. We continue to hear from people struggling with the debilitating effects of this condition, including a reader from Washington. “I was skeptical of claims about long COVID until I contracted COVID-19 for the third time. Since then, I have had almost daily incidents of debilitating fatigue that can last hours,” he wrote. “Can you share more information about the trials you described in your newspaper column so that my primary care physician and I can see if I might be a good candidate to join one of them?”

Long COVID continues to be a serious problem, with an estimated 20 million people in the United States struggling to recover. You and your physician can learn about clinical trials currently recruiting patients at clinicaltrials.gov. Search “long COVID” and look for studies that are still recruiting. Your doctor may also find it useful to read the capsule descriptions of the ongoing studies, which shed light on the various approaches and treatments now being considered.

We thank you, as always, for your interest in this column. We love hearing from you. As a reminder, we can’t make a diagnosis, offer a second opinion or comment on treatment plans. If you don’t mind sharing, we love to know what state or city you’re writing from. It’s always so interesting to know where these columns are reaching you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Kansas City, MO 64106; 816-581-7500