Dear Doctor: Do hospitalized patients really get better care from female doctors compared to men, as a new study -- and now many headlines -- claim?

Dear Reader: My initial reaction when I saw this study was one of denial. As a man, I viewed the study -- and the host of media articles reporting on it -- with something like hostility; it seemed no less than an attack on my gender. After I calmed down a bit, I read through the research.

The study, published recently in JAMA Internal Medicine, looked at a random sample of data -- totaling more than 1.5 million hospitalizations -- from four years of hospitalizations among Medicare patients being cared for by general internists. The authors separated the patients into two groups based on the gender of their physicians, then evaluated quality of care by the death rates of these patients within a 30-day period after hospitalization and also by the rates of readmission to the hospital after being discharged.

The authors found that the death rates of patients cared for by female internists were slightly lower than the death rates of patients cared for by male internists: 11.07 percent versus 11.49 percent. This was not a staggering difference -- amounting to one fewer death in 233 patients -- but still, it was a difference. Further, readmission rates were lower for patients of female doctors compared to patients of male doctors: 15.02 percent versus 15.57. This means one fewer readmission in 182 patients.

Even as a man playing devil's advocate, I can't blame confounding factors -- differences in patient characteristics -- for the findings. Female doctors took care of more female patients, slightly fewer patients with heart disease, lung disease and diabetes, but slightly more patients with kidney disease. But these were only minimal differences, and the authors took those differences into account, making adjustments for them in their findings.

Yet there were two differences between the female and male doctors that may be of substance: the physicians themselves. Female physicians in the study were on average 5 years younger than their male counterparts (42.8 years versus 47.8 years). Not to be ageist, but younger doctors may have a greater ability to use hospital computer systems, may be more likely to utilize social services for their patients, and may be more willing to alter their practices based on the latest studies.

Another important aspect is that female physicians on average took care of fewer hospitalized patients than their male counterparts, with female internists taking care of an estimated 132 hospitalized patients per year versus male internists' 181. The busier schedule of the male internists may increase the chances that some aspects of care will be negatively affected. The authors tried to correct for both the age and patient load issues, but that's not easy to do.

As provocative as this new study is, it's far from conclusive. A 2013 study in the Journal of the American Board of Family Medicine found no differences in care between male and female physicians in the rates of death, hospitalizations or health care expenditures.

In summation, this research does nonetheless offer a reminder to all physicians, regardless of gender or age, that many factors affect patient death rates and readmissions -- and we can't afford to let any of them fall through the cracks.

Tomorrow, my colleagues Dr. Glazier and Dr. Ko will cover this study.

(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: One of my resolutions for the new year was to become a vegan, and now my girlfriend is saying I'll have to take supplements to get enough vitamin B12. Why can't I get B12 in my diet, and what will happen if I fall short?

Dear Reader: Your girlfriend has done her homework -- vitamin B12 is a nutrient that is essential to human health. And while it occurs naturally in a wide range of animal foods, B12 is not found in any plant foods. As a vegan, you're now going to have to rely on supplements to be sure you get enough B12.

Why is it so important?

Vitamin B12 is a bit of a workhorse. Not only does it play a key role in the proper functioning of the brain and the nervous system, it's crucial to the production of red blood cells in the bone marrow. As though that wasn't enough, B12 also aids in DNA and RNA synthesis, and is involved in the metabolism of carbohydrates, fats and proteins. Research shows that B12 also has a hand in maintaining mood and memory.

The body does not store B12, so you need to ingest it every day. Beef liver and clams have the highest concentrations of the nutrient. It is also present in varying quantities in red meat, eggs, poultry, shellfish, milk and milk products. Many breakfast cereals and some dairy products are fortified with B12. For vegans, there are non-dairy milks, meat substitutes and nutritional yeast products to which B12 has been added. Dietary supplements are widely available.

What happens when B12 is in short supply?

Considering all the roles the nutrient plays in health and well-being, the list of symptoms is long and sometimes quite serious. People with a B12 deficiency may feel weak and tired, the result of the vitamin's role in producing the red blood cells that carry oxygen throughout the body. Since B12 helps maintain the protective sheath around your nerves, a lack of the vitamin can lead to strange sensations like numbness or tingling, as well as problems with balance or walking. Mood and memory may also suffer.

In extreme cases, B12 deficiency can lead to megaloblastic anemia, a blood disorder in which the red blood cells produced in the bone marrow are unusually large, malformed and immature.

And while your girlfriend is right about your need for vigilance in getting enough B12, she may do well to examine her own B12 status. Recent studies suggest that up to 40 percent of the population, vegan or not, may be flirting with B12 insufficiency. Due to physiological changes associated with aging, the elderly are at increased risk of vitamin B12 deficiency. Individuals who have undergone weight-loss surgery must also make a special effort to get enough of the nutrient.

As for you, a newly minted vegan, we recommend that you seek professional advice, preferably from your family doctor, to be certain that you forge a wise nutritional course.

(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.)

Dear Doctor: Many doctors in my area recommend CoQ10 in conjunction with statin drugs to reduce or eliminate muscle pain. It has worked for my wife, and we have heard lots of anecdotal evidence from friends who use it. What's the evidence behind the use of CoQ10 with statins?

Dear Reader: First, let's take a look at statins. These drugs have been repeatedly shown to lower cholesterol levels -- leading to decreased rates of atherosclerosis, heart attacks and strokes -- but they can have side effects. The most common side effect I've seen among my patients is muscle pain, which is the reason that most people stop these very beneficial drugs.

Now let's look at CoQ10. This coenzyme is needed for energy production within muscle cells. Some studies have shown that statins decrease the concentration of CoQ10 in both muscle tissue and in the bloodstream. The hypothesis is that, if you decrease the CoQ10 levels, you reduce the production of energy in muscle cells and they won't function as well, leading to muscle aches, weakness or inflammation.

In extremely severe cases -- I've seen this in very few of my patients -- statins can lead to the death of muscle cells, and a decrease in muscular CoQ10 may be one of the reasons. Massive cell death can also lead to acute kidney failure, but fortunately, in most cases, after stopping the statin and getting intravenous fluids, the patient's symptoms will quickly improve.

As for whether taking CoQ10 can prevent the side effects of statins, the studies of CoQ10 supplementation with statins are small and not conclusive. A 2007 study in the American Journal of Cardiology showed a 40 percent decrease in pain among statin users who took 100 milligrams of CoQ10 daily versus those who took 400 international units (IU) of vitamin E daily. However, there were only 18 people in the group that took CoQ10, so it's difficult to make an overarching conclusion about CoQ10's benefits. Other small studies have not shown any benefit from supplementation.

A combined analysis of six studies published in 2015 in Mayo Clinical Proceedings found a slight decrease in pain among statin users who took CoQ10, but the decrease was not clinically significant. The authors concluded that a larger study was needed.

Based on these studies, and the lack of a large study to evaluate CoQ10, it would be difficult to recommend CoQ10 to prevent muscle pain. However, judging by some of my patients' experiences and by your wife, some statin users have found significant pain relief with CoQ10.

My general thought on the matter is, if you have muscle symptoms with a statin, you should probably change the type of statin you're getting. Some types, such as rosuvastatin and pravastatin, don't concentrate in the muscles as much as others, causing fewer muscle problems. Switching to them may have benefit. Taking 100 milligrams of CoQ10 may also have benefit, but again, a large trial will be necessary to further evaluate this.

(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.)