Dear Doctors: Can you please do a column about familial hypercholesterolemia? It is my diagnosis, and I would like you to explain it. My LDL is over 500. It is my understanding that there are different kinds of LDL. Is that correct? Any information would be helpful.

Dear Reader: Familial hypercholesterolemia, often shortened to FH, is a condition that interferes with the mechanisms the body uses to manage blood cholesterol levels. In medical terminology, “hyper” means that something is above normal, and “emia” refers to the blood. The word “familial” indicates this condition has a genetic component. More specifically, FH results in very high levels of a type of cholesterol known as low-density lipoprotein, or LDL. This puts people living with FH at increased risk of developing heart disease and of having a heart attack at an early age. To understand how and why, we need a few more details.

Cholesterol is a fatty, waxy substance that is transported throughout the body in the blood. The liver produces about 80% of the cholesterol our bodies use, and 20% comes from our diet. Although the focus is often on cholesterol as a risk factor for heart disease, it is needed by every cell in the body. It is a crucial building block of our cell membranes; is essential for the production of certain hormones, including estrogen and testosterone; and is necessary for the manufacture of vitamin D. That said, high levels of cholesterol, particularly of LDL, can lead to a dangerous buildup of fatty deposits within the blood vessels. This significantly increases the risk of narrowing of the arteries.

Cholesterol is classified into two main types. High-density lipoprotein cholesterol, or HDL, helps move lipids from the blood and into the liver for disposal. This has led to HDL being referred to as “good cholesterol.” But low-density lipoprotein does the opposite. It transports lipids from the liver into the blood for delivery to the cells. You are correct that there are different types of LDL. It is broken down into several subclasses, each of which decreases in size and increases in density. It is those characteristics, the smaller size and higher density, that make an overabundance of LDL particularly dangerous. Some researchers have come to suspect that the subclasses of LDL behave differently from one another, and that each may have a unique role in cardiovascular disease.

The good news is that lifestyle choices, along with medical interventions, can have a positive effect on this condition. These include not just changes to diet and the use of medication, but also regular screenings to monitor blood lipid levels. Due to the genetic component, each case of FH is different and benefits from highly personalized treatment. That makes it important for anyone living with FH to seek out expert medical care. Genetic testing can also shed light on the condition and inform treatment choices. It is recommended that, when possible, someone with FH work with a cardiologist who has experience with the disorder.

(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: I had a COVID-19 vaccine in June 2023, so I’m overdue for another. I’ve heard there’s going to be an updated vaccine coming out in the fall. If possible, I would like to get it at the same time as my flu shot in October. Is the new COVID shot very different from the old one?

Dear Reader: With summer drawing to a close and the autumn months on the horizon, we are easing into the annual trifecta of cold, flu and COVID seasons. Health data show that COVID-19 still surpasses all other infectious respiratory illnesses as a cause of severe illness, hospitalization and, sadly, death. The good news is that the margin by which COVID-19 beats out influenza is the slimmest it has ever been.

More than four years since the start of the COVID-19 pandemic, we have a high degree of population immunity. It is estimated that 98% of people in the U.S. now have at least some degree of protective immunity. This is due, in large part, to the availability of vaccines. Prior infection also plays a role. Another contributing factor in the improved outcomes from COVID-19 infections is the availability of effective treatments, particularly the drug Paxlovid.

You are correct about an updated mRNA COVID-19 vaccine. It was approved by the Food and Drug Administration in August and is now available. The new shots have been adjusted to target the newer variants of the omicron strain, which are driving the most recent surge of infections in the United States. Vaccines protect against infection with the virus. When someone does get COVID-19, being vaccinated reduces the risk of developing severe illness. There is also now evidence that being vaccinated prior to infection cuts the risk of developing long COVID in half.

The fall timing of the updated COVID-19 vaccine is deliberate. It coordinates with the release of this year’s influenza vaccine. As you point out in your letter, this allows people to get both shots at the same time.

The Centers for Disease Control and Prevention continue to recommend the COVID-19 vaccine for anyone age 6 months and older. As in the past, the people at highest risk of severe illness from the virus are adults 65 and older, anyone with a compromised immune system and those with chronic health conditions such as diabetes, heart disease or obesity. Individuals who have not been vaccinated in a year or more, and those who have never been vaccinated, are also at increased risk.

Some people wait to time their vaccines to coincide with the peak months of the respiratory illness season. That is, the colder months that send people indoors, and, thus, into close contact with one another. For those who plan to delay their vaccines, taking additional precautions is recommended. These include avoiding crowds and using a good mask in public places. If you do become ill, seeking medical care may give you access to Paxlovid. And remember to isolate for a few days, which protects the people around 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.)

Hello, dear readers, and welcome to a bonus letters column. We have some interesting questions to address and will get right down to business.

-- A column about a study that found resistance training yields benefits for adults in their 80s and 90s -- and older! -- got quite a bit of interest, including this letter from a reader: “I do wish you had told these folks that lifting weights doesn't have to mean really heavy weights. I imagine a lot of people have an image of weightlifting involving pressing 300 pounds,” he said. “If you write on this subject again, you can do older adults a great service by letting them know that benefits can be had from weights as light as 2 to 5 pounds.” Thank you for making an excellent point. When you begin weightlifting, you want to exercise at your existing level of fitness. Older adults can begin with weights as light as a pound. Through repetition, and with proper form, they can gain strength. If desired, they can gradually move up to heavier weights.

-- We heard from a reader asking about the biopsy she recently underwent. “After a breast biopsy, they installed a titanium marker,” she wrote. “Do I need to worry about that if I get an MRI in the future?” This type of tissue marker, sometimes also known as a clip, is used to identify a specific site from which cells were taken during a biopsy. Its presence allows doctors to locate the precise area in future scans and if treatment is needed. These types of markers are about the size of a sesame seed and cannot be felt. They can safely remain in place during an MRI and will not set off a metal detector.

-- A recent column discussed how the stigma associated with hearing aids can prevent some people from using them. An otolaryngologist in Chicago has shared his approach to the challenge. “In these cases, I often recommend the family try a ClearCast PAL, a personal assistive listening device,” he wrote. “This is an FDA-registered medical device that works really well to help seniors hear conversations and the television clearly without having to rely on hearing aids. In my experience, there is little reluctance to trying this product as it looks like a set of headphones. It is also very easy to put on and take off, so the user can use it when they want.” Thank you for this suggestion. The device you mention falls into the category of assisted listening systems, or ALS. Some people with hearing loss find these easier to use, and also more affordable, than hearing aids. They are not a replacement for hearing aids, but can be a first step to the management of hearing loss.

Thank you, as always, for taking the time to write to us. We love hearing from you. It is time for a reminder that we cannot examine any medical records or data, offer a diagnosis, comment on treatment plans or offer a second opinion.

(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.)