Dear Doctor: I've suffered with migraines for years, and my doctor wants to give me a daily medication to prevent them. I'm reluctant to rely too heavily on drugs. Aren't there any vitamins or non-prescription medications I can take to prevent migraines?

Dear Reader: The short answer is yes: You can reduce your risk of migraines through non-prescription methods -- and you're not alone in trying to do so. Migraines affect about 12 percent of people in the United States, occurring more often in women, in people between the ages of 30 and 39, and within families.

The headaches can last for hours or up to three days, causing an inability to focus and significant lost productivity. A retrospective analysis of migraine sufferers found that emotional stress was a trigger for 80 percent of them, missing a meal was a trigger for 57 percent, and lack of sleep was a trigger for 50 percent.

When it comes to behavioral interventions, relaxation techniques, cognitive therapy, consistent aerobic exercise and good sleep hygiene can all decrease the frequency of migraines. Now let's look at the data on nutritional supplements.

We'll start with coenzyme CoQ10. In a small 2005 study, patients who experienced migraine headaches two to eight times per month were randomly assigned to take either a placebo or 100 milligrams of CoQ10 three times per day for at least three months. The authors measured success as a greater than 50 percent reduction in the frequency of migraines. Only 14.4 percent of those who took the placebo showed this level of reduction, but 47.6 percent of those who took CoQ10 reduced their frequency of migraines by that amount.

Then there's the B vitamin riboflavin. A small 1998 study found that 59 percent of people who took a daily dose of 400 milligrams had a greater than 50 percent reduction in the frequency of migraines, compared to 15 percent of those who took a placebo. However, it took three months for riboflavin to show this benefit.

Knowing that sleep problems increase the risk of migraines, researchers in a 2016 study compared the effects of 3 milligrams of melatonin to the effects of the anti-depressant amitriptyline or of a placebo. After three months, 54.4 percent of people who took melatonin had a 50 percent or greater reduction in frequency of headaches compared to 39.1 percent in the amitriptyline group and 20 percent in the placebo group. That seems promising, but note that a 2010 study of people who took 2 milligrams of melatonin for a two-month period did not show significant benefit when compared with a placebo.

Now let's move on to botanicals. Small studies have suggested that the root of the butterbur plant, Petasites hybridus, can decrease migraine frequency, but the plant can be toxic to the liver and, in animal studies, has led to genetic changes that could lead to cancer.

Feverfew is another potential treatment. A combined analysis of six trials of the herb yielded conflicting results. Overall, the studies showed that feverfew can decrease the frequency of migraines by 0.6 times per month compared to placebo. Note that it can cause rebound headaches if abruptly stopped, however.

In short, more studies are needed. That said, CoQ10, riboflavin and melatonin all seem like reasonable approaches to help prevent migraines.

(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: My sister-in-law read that sandboxes are full of germs, and now she won't let her kids play with my sons in our backyard. I can see how a public playground might be less than clean, but isn't she overreacting by putting my yard off-limits?

Dear Reader: It's possible that your sister-in-law is reacting to the results of a small study from Spain, which made a bit of a splash last summer. Researchers in Madrid tested the sand in 20 public sandboxes for children and 20 public sandboxes for dogs (who knew?) and found that both types of sandboxes were hosting a nasty bacterium called C. difficile, or C. diff.

Nine of the 20 children's sandboxes contained the pathogen, and 12 of the 20 dog sandboxes had it as well. Most commonly seen in nursing homes and hospitals, where it can spread from patient to patient, C. diff causes an intestinal infection that sometimes leads to severe diarrhea. Some of the C. diff strains in the Spanish sandboxes showed increased toxin production, and some were resistant to antibiotics, which are the primary form of treatment.

But this study isn't the first to point out the risks of sandboxes. By their very nature -- exposed to the potentially dirty hands, feet and bottoms of multiple children, and available to insects and animals -- sandboxes are a likely breeding ground for all sorts of unpleasantness. This includes bacteria left behind by human contact, as well as common parasites like roundworm eggs and hookworm larvae from the feces of infected animals.

While this all sounds quite dire, there are steps you can take to make your backyard sandbox safer, and to protect your children in whichever sandbox they use.

For your home:

-- Keep the sandbox covered when not in use. Whether you use a tarp or a wooden cover, it's important that the fit be tight. Cats, rats, mice and raccoons prefer a dry place to do their business.

-- If the sand gets wet during play, be sure to let it dry thoroughly before covering. Molds, yeasts, bacteria and other unhealthy things love a moist environment.

-- Replace sand regularly. Be sure to use play sand rather than construction-grade sand, so it will not contain silica.

-- Rake and sift the sand frequently to check for debris. If you find any scat, you have to assume the entire box is contaminated. Dig it all out and start fresh.

For your kids:

-- Make it a rule that they wash their hands before and after playing in any sandbox.

-- We're sorry, but with younger children you're going to have to keep an eagle eye to make sure hands -- and sand -- don't get into the mouth.

-- Wash and disinfect any and all sand toys your kids use. It just takes a minute and makes a big difference.

-- Clothes that have been in the sandbox should head right into the washer. Shoes should be thoroughly brushed clean.

It sounds like a lot of work, but depending on how your kids feel about the sandbox, it can be worth the effort. And who knows? Your sister-in-law may even relent and let her kids come over.

(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 familiar with hepatitis C's connection to death, but hepatitis A? I had no idea that could be lethal, and now I'm reading about a number of deaths in San Diego. I thought anyone could get hepatitis A.

Dear Reader: You're right, anyone can get hepatitis A. That's what makes the current outbreak alarming, but only if you don't know how, or are unable, to protect yourself. First, some background: Hepatitis A occurs in about 1.4 million people worldwide each year; in the United States, only about 1,200 to 2,500 people are infected per year, primarily in sporadic outbreaks.

The virus is released in the stool of infected people, and from there it can move to their hands. It's resistant to detergents, high temperature and solvents. Frequent handwashing can reduce the risk of transmission, but some of the virus can linger. A significant factor in hepatitis A transmission is that a person can transfer the virus to others even before he or she shows symptoms. In areas of poor sanitation, hepatitis A can easily be transferred among the population. This is why the disease is so prevalent in developing countries. Hepatitis A also can be transferred via contaminated foods, like shellfish, that have come in contact with the virus.

San Diego's hepatitis A outbreak is blamed on poor sanitary conditions, with related contamination of food sources. This has led to more than 400 cases since November 2016; 16 have been fatal. Many of these cases have occurred in the homeless population, which lacks proper sanitation facilities, leading the city to clean many of the streets with bleach and to provide portable handwashing stations in areas frequented by the homeless.

Once ingested, the hepatitis A virus moves into the bloodstream and then into the liver. There, it replicates in the liver, causing the immune system to attack the infected cells. This, in turn, leads to massive liver inflammation. Shortly after infection, patients experience nausea, fever, fatigue, poor appetite and stomach pain. A few days later, 40 to 70 percent of patients will have a yellowish discoloration of the skin and severe itching. For the majority, this is as bad as it gets, and symptoms improve after two weeks. In fact, 85 percent of patients will have full recovery within two to three months, and nearly 100 percent have full recovery at six months.

In contrast, hepatitis C and sometimes hepatitis B cause a chronic low-grade infection that can lead to cirrhosis of the liver and liver cancer. For people who already have chronic hepatitis C or B, hepatitis A can more readily lead to liver failure and death. Also, people over the age of 50 have greater difficulty recovering from hepatitis A, leading to dehydration, other infections and death.

In short, good public sanitation, handwashing and vaccination for hepatitis A can prevent infection. Children now routinely get vaccinated for hepatitis A, which has decreased the incidence of hepatitis A not only in children, but also in the general population. People with chronic hepatitis B or C should also be vaccinated against hepatitis A to reduce their risk of death should they become infected, as should homosexual men and IV drug users.

So, while hepatitis A is rare in the United States, incidents such as the one in San Diego highlight the need to be vigilant against the disease.

(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.)