Dear Doctor: Could you please tell me about peripheral artery disease? I have it and recently underwent angiograms of both legs, including insertion of one stent. One leg is now normal, but the other is back to square one. Do I just suffer through the sleepless nights of pain while waiting for the inevitable stroke or heart attack?

Dear Reader: Think of peripheral artery disease as being like any other arterial disease. Arteries transfer oxygenated blood from the heart throughout the body. The carotid arteries provide blood to the brain, the coronary arteries provide blood to the heart, and the iliac and femoral arteries provide blood to the legs. The inside of each of these arteries is lined with a thin layer of cells called the endothelium. This smooth layer allows blood to move freely within the artery without sticking or clotting.

Injury to the lining of the arteries leads to a mixture of cholesterol and fibrous plaques accumulating on the walls of the artery. This buildup is known as atherosclerosis and, over time, causes the arteries to narrow. In peripheral artery disease of the legs, the narrowing causes decreased blood flow to the legs. The first sign is cramps, usually in the calves, with walking. As the narrowing increases, the cramps can occur simply while lying down, because blood flow decreases without the benefit of gravity. Your worries about strokes and heart attacks are understandable. As with other arterial disease, such plaques can break off and lead to those potentially fatal conditions.

Smoking cigarettes is the biggest risk factor for peripheral artery disease. In fact, chronic smoking is a risk factor for all arterial disease. Other risk factors include diabetes, high blood pressure, kidney disease, high LDL cholesterol and the unavoidable risk factor of being older than 70.

The first course of action should be controlling any risk factors. If people smoke, they should stop. If they have diabetes, they should make sure to keep their blood sugar low. And if they have high cholesterol, they should lower it with medication and diet.

Second, taking a blood thinner, such as aspirin or clopidogrel, will lower the likelihood of clots forming within the blood vessels.

Third, a gradual course of exercise therapy can improve blood flow and decrease calf pain with walking. People without access to a supervised exercise program should walk three days per week for 30 to 45 minutes. A slow start is fine; a more rapid pace can come later.

Fourth, the medication Cilostazol, which works by dilating the blood vessels and not allowing platelets to clot in the arteries, has been shown to increase the distance that people with peripheral artery disease can walk without pain.

As you have experienced, when symptoms are severe or when blood flow to the foot is severely compromised, surgery may be advised. This can be done by angioplasty and stenting, as you had, or, if symptoms are still unrelieved or if the blockage is too long, a bypass graft can be created to skirt the blocked area so that blood can move through unimpeded.

All that said, speak to your doctor. It's possible that not all your pain at night is related to peripheral artery disease. But if it is, controlling your risk factors, using the medications described above and possibly a bypass procedure (if you are a candidate) may help your symptoms. Your physician is in the best position to recommend next steps.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I'm 12 years old, and I really want to get a dog. Can you help me find some studies to convince my mom and dad about the benefits of having a dog?

Dear Reader: First, we think it's terrific that you're going for a fact-based approach to persuade your parents to get a family pet. The good news is that plenty of scientists share your enthusiasm and, to that end, have amassed quite a body of research about the benefits of having a dog in your life.

We're going to begin by assuming no one in the family has pet allergies. It'll be a game-changer if they do. But if there's no sneezing, coughing, itching, asthma or other adverse reaction among the people in your home, then let's get to what science has to say.

Many studies suggest that dogs help their owners in many realms: emotionally, physically and mentally. That's because pet owners tend to walk more, get emotional support and comfort from their pets, suffer less depression, are more social thanks to regular dog walks, and may even get a protective effect against allergies. This last point is thanks to the constant low-grade exposure to the dander, dirt and pollen that an active indoor-outdoor dog brings into the house.

One study showed that older adults who had dogs and walked them regularly had a lower body mass index, had fewer visits to the doctor, and generally spent more time interacting with people than those without dogs. Other studies have shown that being around a dog can reduce stress, which translates to lower blood pressure and better sleep patterns. Several studies have found a link between having a dog in the home and lower rates of asthma and certain allergies among the young children who grow up with the dog.

A study that your parents might like looked at 240 married couples. The couples with a pet in the home had lower blood pressure and heart rates than those without a pet. This applied to when they were just sitting around, as well as while undergoing the rigors of a stress test. And when something did cause them to feel stress, the pet owners' physical responses were less extreme, and their recoveries were faster.

If a list of the many benefits of dog ownership isn't working, try some amazing facts about dogs themselves, like that dog noses are so sensitive they can sniff out certain types of cancer more accurately than actual lab tests.

To be fair, we have to address some potential drawbacks. One is that dogs tend to get ticks and fleas, each of which is associated with disease. Dogs that are not properly trained (and even some that are) may bite. And pets getting underfoot are responsible for some of the up to 8 million visits to the ER for falls each year.

As pet lovers ourselves, we have heard from our own patients about how much their dogs mean to them. We wish you a happy outcome when you talk to your mom and dad.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: French fries are absolutely one of my favorite foods, but because of their calorie content, I try to limit them to twice a week. Now I just read that eating them even that rarely is linked to a higher risk of death. Just how problematic are a couple of servings of fries each week?

Dear Reader: In my younger days, I also loved french fries. It didn't take me long to figure out that potatoes fried in oil were not the healthiest of foods, so I gave them up. I didn't rely on any studies to make this decision, but the research to which you're referring raises some interesting questions about the potential risks of potatoes, especially fried potatoes.

The study, published recently in the American Journal of Clinical Nutrition, assessed 4,400 people who were at high risk of osteoarthritis of the knees. All participants filled out a food questionnaire; two of the questions were about consumption of fried potatoes and un-fried potatoes. Fried potatoes included french fries, hash browns and tater tots.

Participants were then divided into sub-groups, depending on how often they ate potatoes: less than once a month, two to three times a month, once a week, twice per week or, lastly, three or more times per week. Over the eight years of the study, 236 people died. People who ate fried potatoes twice a week had almost double the risk of death, compared to people who ate fried potatoes less than once a month. Those who ate fried potatoes three or more times per week had more than twice the risk of death, compared to the group who ate the fewest fried potatoes. The authors did not find a correlation between death risk and un-fried potatoes.

Note that there were significant limitations to this study. One is that it was relatively small. Second, the authors did not make mention of other foods that participants ate, such as processed meats, trans fats or sodas. So to take fried potatoes in isolation -- and then draw conclusions -- is difficult. Lastly, the groups who ate the fewest fried potatoes included a greater proportion of women, who have a lower death rate within any given time frame as compared to men.

That said, let's assume the data are reliable. If so, why are fries so risky? A 2016 study combined data from three large trials with a total of 199,181 people. In that analysis, three servings per week of french fries correlated with a 19 percent increased risk of diabetes. This increased rate of diabetes was also seen in two other studies. Further, a 13-year Swedish study found a 22 percent increase in the cardiovascular death rate among people who ate fries -- not other fried potatoes -- three days per week. Something to consider: At the time of these studies, fries may have contained greater amounts of trans fats, which have been associated with increased death rates.

The research correlating fries and death rate is not perfect, but there does appear to be a correlation. I would recommend decreasing your intake. Now I have to convince my kids to do the same.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)