Dear Doctor: I just read your column about bone density tests and want to know your thoughts on medications for osteoporosis. Is it better to take calcium and vitamin D and engage in exercise or to risk the medications’ side effects?

Dear Reader: Yours is one of a number of letters we received about treatment for osteoporosis. It’s a subject of great importance to all women, particularly as they reach perimenopause and menopause. The increased risk of osteoporosis at that time of life is due to the drop in estrogen production by the ovaries. Estrogen plays a key role in the ongoing cycle of bone deposit and bone loss and keeps the balance in favor of bone strength. As estrogen levels drop, bone loss speeds up. That’s why the bone density tests we wrote about recently are necessary. They give each woman an idea of the changes her skeleton is undergoing and point to the appropriate treatment.

As a reminder, bone density test results include a scale known as a T-score, which is a comparison to the bone density of a healthy 30-year-old adult. The lower the number in someone’s T-score, the lower their bone density. A T-score of -1 and above is considered to be normal. Scores of -1 to -2.4 equal low bone density, also known as osteopenia. The tipping point into osteoporosis is a score of -2.5 and lower. (Because the scores are rendered in negative numbers, the larger numbers actually equal a lower score.) Guidelines suggest that when someone’s T-score indicates osteoporosis, a class of medications known as bisphosphonates should be considered. They work by inhibiting the breakdown of minerals, including calcium, which help give bone its strength.

Several readers mentioned concerns about the potential side effects of these medications, which have made news in recent years. Bisphosphonates are available in pill form and as an IV infusion. Side effects of both forms of this medication can include pain in the bones, muscles and joints. People who take the drug in tablet form have reported difficulty swallowing, nausea, heartburn, irritation to the esophagus and gastric ulcer. A condition known as osteonecrosis of the jaw, in which the jaw bone becomes exposed and fails to heal properly, has been reported in some cases. However, this is rare -- we’ve never seen this in our own practices -- and research suggests it’s more common among patients receiving high doses of IV bisphosphonates. We have many patients on bisphosphonates, and in our experience, they are generally very well-tolerated.

To decide what’s right for you, we think you should begin by sharing your concerns about these medications with your doctor. Your T-score, along with your medical history, will help guide the direction your treatment should take.

Bisphosphonates are typically prescribed along with calcium and vitamin D, both of which help to preserve and protect bones. We also recommend that our patients engage in weight-bearing and high-impact exercise, which has been shown to strengthen and preserve bone. Be sure to check with your doctor for guidance on the specific exercise and intensity level that’s right for your specific needs.

(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: What can you tell me about the new saliva test for Parkinson’s disease? My older sister just learned she might have Parkinson’s, but her doctors aren’t sure. Why is it so hard to diagnose?

Dear Reader: Parkinson’s disease is a progressive disorder of the nervous system that leads to a deficit of dopamine, which is a neurotransmitter. Neurotransmitters help nerve cells communicate with each other, and dopamine plays a crucial role in our ability to produce smooth, deliberate and sustained movement. It’s the loss of dopamine that gives rise to some of the symptoms of Parkinson’s, which include difficulties with walking and balance, tremors, slurred speech and rigidity. The disorder also affects sleep, smell and blood pressure.

Diagnosing Parkinson’s disease can be difficult because the symptoms and their onset vary from person to person and are similar to other neurodegenerative disorders. There is no specific test for Parkinson’s disease, so emerging research into chemical changes in the saliva of Parkinson’s patients has drawn a lot of interest. While it’s true that some of this research shows promise in the area of diagnosis, at this time there is no saliva test for the disease.

Several studies have examined a range of biomarkers that are present in the saliva of people living with Parkinson’s. Many of them found significant differences when compared to the saliva of people without the disease. In a newer study, published earlier this year, researchers in India examined saliva samples taken from 76 patients living with Parkinson’s disease and samples from 37 healthy people, who served as controls. They found certain metabolic compounds in the Parkinson’s group saliva that suggest the disease process may be linked to an imbalance in the makeup and functioning of neurotransmitters, as well as to certain changes in the makeup of the gut microbiome.

This isn’t the first research to look into the potential role of the gut microbiome in neurodegenerative diseases such as Parkinson’s. The intestine is among the first organs affected by Parkinson’s disease, and health care professionals have long noted that symptoms such as constipation and gastrointestinal distress often precede the onset of neurological symptoms.

Recent research has also highlighted the gut-brain connection. One study tracked patients who had portions of their vagus nerve surgically removed. Five years after the surgery, the group had a 40% lower incidence of Parkinson’s disease than patients whose vagus nerve remained intact. This is significant because the vagus nerve runs from the brainstem to the colon, a direct link between the brain and the gut.

In another study, mice bred to be susceptible to Parkinson’s disease developed symptoms when they were implanted with fecal samples from Parkinson’s patients. The same type of mice implanted with fecal samples from healthy adults did not develop similar symptoms.

All of this has led to increasing interest in the idea that Parkinson’s disease originates in the gut and then spreads to the brain. Each new study sets the stage for further research into gut-based therapies, and even to a potential cure.

(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 healthy and active 42-year-old, but I’ve been noticing a change in my periods lately. They’re not as regular as before, and they’re a lot shorter. Could this be perimenopause? What’s going on, and what else is going to happen?

Dear Reader: Perimenopause is the transitional time that leads up to a woman’s final menstrual cycle. For some women, perimenopause can last for as little as a few months or a year. More often, it lasts for several years. In some instances, the changes associated with perimenopause can take place over the course of a decade. Although the symptoms can differ from woman to woman, they arise from the same cause. That is, certain hormonal changes within the body that precede the end of a woman’s reproductive years.

Perimenopause is the period of time during which a woman’s ovaries gradually begin to produce less estrogen, which is one of the hormones involved in the complex process that signals the uterus and the breasts to prepare for possible pregnancy. Although this shift in estrogen production is most common when a woman is in her mid-40s, it can happen earlier, when she is in her 30s. Perimenopause ends when a woman has gone a full year without a menstrual cycle, which is the start of menopause.

The symptoms that you mention are consistent with perimenopause. Many women experience changes to their menstrual cycles during this time, including fluctuations in flow, duration and regularity. These can be erratic because estrogen levels often diminish at an uneven pace, both rising and falling. However, it’s important to distinguish the normal changes that accompany the transition to menopause and symptoms that may signal other causes. If the changes that you see become extreme, such as persistent heavy bleeding, the presence of blood clots, spotting between periods or after sex, or an increase in frequency of menstruation, please check with your doctor. Other conditions such as fibroids, endometriosis or, rarely, cancer may be the cause.

The final phase of perimenopause sees the sharpest drop-off in estrogen production. This is a time during which additional symptoms often appear. These can include fatigue, breast tenderness, changes to mood, hot flashes, a worsening of the symptoms of PMS, urinary incontinence, night sweats, sleep disruption, vaginal dryness and changes to sex drive. This decline in estrogen leaves women at risk of osteoporosis, a disease in which bones gradually become porous and, thus, more fragile. Women also begin to lose the protective heart effects of estrogen, which is believed to help keep blood vessels more flexible.

Considering your age, along with the symptoms that you mentioned, it’s possible that you are experiencing perimenopause. However, due to the ongoing fluctuations in hormone levels, no one test can provide a definitive diagnosis. Instead, your health care provider will evaluate your symptoms, along with your age and menstrual history. If your symptoms begin to interfere with quality of life, they may offer treatment that can include lifestyle changes, hormone replacement therapy or antidepressants. Each has risks and benefits, so be sure to have these explained to you in detail.

(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.)