Hello dear readers, and welcome to another monthly letters column. We’d like to begin by revisiting a recent column about valsartan, a blood pressure medication that is the subject of a Food and Drug Administration recall. The recall is due to impurities found in certain lots of the drug. Since this was a selective recall associated with specific manufacturers only, we included websites where readers can check whether their own prescriptions are affected. Apparently, these sites didn’t make it into every print edition of the column, so we’re repeating the information here today. In the time since our column ran, the valsartan recall has spread to include additional manufacturers of the drug.

Find the list of recalled valsartan drugs at: www.fda.gov/downloads/Drugs/DrugSafety/UCM615703.pdf.

For a list of valsartan meds not part of the recall, visit: www.fda.gov/downloads/Drugs/DrugSafety/UCM615704.pdf.

-- After a column about chicken pox, quite a few of you weighed in to urge anyone who has had chicken pox to get the shingles vaccine. As we’ve written before, we heartily agree. Unfortunately, there is presently a shortage of the new vaccine, Shingrix, which provides better protection than the older one. For local availability, check vaccinefinder.org and Shingrix.com.

-- We recently wrote about post-operative cognitive dysfunction, a condition that can arise in some patients, particularly older ones, following surgery under general anesthesia. A nurse from Lincoln, Nebraska, asked us to point out that among the risk factors for this condition, in which patients experience post-surgical disruption to memory and cognition, are alcohol use and abuse. Patients and caretakers should make the medical team aware of alcohol consumption prior to surgery.

-- Asthma has come up in several recent columns. A case worker who visits families wondered whether the essential oil diffusers she sees in some homes might play a role in asthma flares. The answer is yes. Studies have shown that some diffused essential oils, including eucalyptus, lavender and others, release volatile organic compounds (VOCs) into the air. These, like tobacco smoke, dust, pet dander and other airborne irritants, are environmental components that can act as triggers for bronchospasm.

-- We’ve had several letters in which, for reasons relating to menopause or hysterectomy, women wonder whether they should try hormone replacement therapy (HRT). Hormone replacement therapy has always been -- and, we suspect, always will be -- controversial. This is due to a range of potential side effects, which can be dangerous. Up to 80 percent of women experience menopausal symptoms such as hot flashes, night sweats, weight gain, low energy, mood changes and depression. In a quarter of those women, symptoms are severe enough to warrant therapy. Usually this consists of lifestyle interventions, behavioral interventions and nonhormonal treatments such as Paxil or Effexor.

Only in severe cases should HRT be recommended. In our opinion, HRT should never be used in menopausal women who are asymptomatic. A free and useful app that we recommend to patients dealing with the effects of menopause is MenoPro.

Thank you, as ever, for not only reading the column but for engaging with us as well. Whether it’s a question, correction or kind words, we love hearing from you.

(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: How does prostate cancer happen? And what are the symptoms? I’m only 43, but I worry that I wouldn’t recognize the signs if I had it.

Dear Reader: Prostate cancer is one of the most common cancers among men in the United States. It occurs in the prostate gland, a male reproductive organ that sits between the penis and the rectum, just beneath the bladder. The prostate, which is about the size of a golf ball, wraps around the urethra, which is the duct through which urine and semen exit the body. One of the roles of the prostate is to produce fluids that nurture and support sperm, and to propel these fluids into the urethra when needed.

When normal cell division goes awry, the chaotic and uncontrolled growth that results is what we know as cancer. In prostate cancer, the rogue cells use hormones known as androgens, which include testosterone, to fuel their growth. Although prostate cancers begin within the gland, they can spread to nearby regions of the body, including the lymph nodes. Some prostate cancers are slow to grow and can take years to be detected. When slow-growing cancers are identified, the risk they pose may be low enough that physicians recommend careful monitoring, often referred to as "watchful waiting." Other prostate cancers are more aggressive and require swift treatment.

The American Cancer Society estimates that more than 174,650 new cases of prostate cancer will be diagnosed this year, and the disease will claim more than 31,000 lives. As you allude to when mentioning your age, the majority of prostate cancers -- about 60 percent -- are diagnosed in men 65 and older. But race plays a role as well. Prostate cancer affects black men at two to three times the rate of white men and at an earlier age. They are also more likely to die from the disease.

Although a screening tool known as a prostate-specific antigen (PSA) test is effective at detecting certain hormonal changes associated with prostate cancer, it has been overused in the past and led to unnecessary treatment. The U.S. Preventive Task Force recommends that for men between the ages of 55 to 69, prostate cancer screening should be a decision made by patients and doctors working together on a case-by-case basis. However, a survey of prostate cancer outcomes by several colleagues at UCLA determined that, due to their elevated risk, black men would benefit from prostate cancer screening guidelines tailored to their unique and specific needs.

When it comes to symptoms, unfortunately prostate cancer is often largely silent in the early stages. As the cancer becomes more advanced and affects the size and shape of the prostate, the gland’s position in the body may lead to symptoms that include:

-- Difficulty urinating.

-- Frequent urination.

-- A diminished stream of urine.

-- Pelvic discomfort.

-- Signs of blood in the semen.

-- Onset of difficulty achieving or maintaining an erection.

-- Discomfort when sitting.

If you develop these symptoms, please talk to your doctor. It doesn’t mean that you have cancer, but you will be taking the first step to finding out what, if anything, may be wrong.

(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’m a 38-year-old man, and because I live in a loud environment, I’ve used soft foam earplugs at night for the past three years. Are they safe to wear for extended periods of time? I’ve lost half the hearing in my right ear and wonder if it could be from wearing earplugs for so long.

Dear Reader: Sleeping in a noisy environment is not only a challenge, but it also affects the quality of the sleep that you manage to get. Sleep is a complex process with multiple stages, each of them equally important. Not only does uninterrupted sleep help you feel rested, but research has shown the quality of the sleep we get affects our physical and mental health as well. A report issued by the Institute of Medicine Committee on Sleep Medicine and Research found that the length and quality of sleep played a role in a wide range of conditions, including hypertension, diabetes, depression, obesity and cardiovascular disease.

Earplugs can be an effective way to deal with a variety of sounds that interrupt sleep. They form a seal around the entrance to the ear canal and physically block the vibrations that would otherwise reach the eardrum and get sent to the brain to be interpreted as sound. Unfortunately, when earplugs are used incorrectly, they can lead to damage to the ears or to hearing.

One of those risks is related to earwax, a waxy oil known as cerumen. It’s produced by glands in our ears and naturally finds its way into and out of the ear canal over the course of the day and night. Earwax protects the skin within the ear canal, has a role in cleaning and lubrication, and serves as a protective barrier against moisture, dust, bacteria, fungi and other unwelcome substances. Long-term use of earplugs can interfere with the self-cleaning flow of earwax; rather than letting it drain, it can result in a buildup. This can lead to tinnitus, which is ringing in the ears, or even to hearing loss. A health care professional can use a device known as an otoscope to look deep into the ear to check whether the ear canal is blocked. He or she will then remove the excess earwax by first softening it with warm water or a special solution, followed by gentle manual extraction.

Another potential risk is infection due to bacterial buildup on the earplug’s surface, which then gets transferred into the ear canal. This can occur when the same pair of earplugs is used repeatedly and can lead to hearing loss. The best way to avoid problems is to be vigilant about practicing earplug hygiene. Pre-molded earplugs, which are reusable, must be cleaned daily. Foam earplugs should be discarded regularly -- daily if at all possible. It’s important to store any earplugs in a ventilated case to prevent bacterial buildup due to moisture.

Reusable earplugs can be uncomfortable for sleeping, and disposables may not be in everyone’s budget. In those cases, consider over-the-ear protection, like noise-canceling ear muffs, which reduce sound without touching the ear canal.

(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.)