DEAR DR. ROACH: A recent column advised readers to wear masks. Please print a study that shows masks work. I can show you 10 studies from the CDC that say they don’t. You should not encourage your readers to do something without proof. — C.W.
ANSWER: Although some authorities were hesitant to recommend masks at the beginning of the pandemic, the evidence has become strong that masks are effective at protecting both the wearer and (especially) others from getting sick. A study in July showing masks to be ineffective was retracted by the authors, noting their experimental data were unreliable and, therefore, “our findings are uninterpretable.” The best type of study, a clinical trial, is not yet available, although at least two are ongoing, despite concerns about the ethics of such a trial.
The Centers for Disease Control and Prevention affirmed shortly thereafter that “cloth face coverings are a critical tool in the fight against COVID-19 that could reduce the spread of the disease, particularly when used universally within communities.” Because medical face masks, particularly the high-quality N95 masks, remain in short supply to health care providers in some parts of the country, members of the public are encouraged to use cloth masks, particularly those with two or more layers of washable, breathable fabric.
I am posting links to a few studies and editorials about mask effectiveness on my page at Facebook.com/keithroachmd.
DEAR DR. ROACH: My doctor said that an ultrasound and blood tests show that I have fatty liver. I drink wine and a beer occasionally. What is fatty liver? How did I get it, and what can I do about it? — E.M.
ANSWER: Fatty liver is a catch-all term for abnormal fat depositions in the liver. These can come about in people with heavy alcohol use: Only about 1% of people who have two to four drinks per day will develop alcoholic fatty liver disease, but 6% of those who have eight drinks per day will.
For nondrinkers, or people who drink only occasionally, the major risks are older age, diabetes, being male and being overweight or obese, especially when the weight is predominantly around the abdomen. Nonalcoholic fatty liver disease is extremely prevalent in the United States: 10% to 46% of people have it. It is now among the leading causes of cirrhosis in the U.S.
The major treatments for nonalcoholic fatty liver disease are lifestyle changes. Alcohol abstinence is recommended, even modest alcohol use like you. If you are overweight, weight loss is the primary treatment. One authority recommends a goal of 5% to 7% of body weight (so, 10-14 pounds if you weigh 200 pounds, for example). Regular physical activity was found to reduce overall mortality rates in people with NAFLD as well, independent of the effect on body weight.
Because viral hepatitis can be much more severe in a person with fatty liver, you should be sure you are immune to hepatitis A and hepatitis B (your doctor can do blood tests to be certain, and can give the appropriate vaccines if you are not immune). If you have diabetes, careful control of diabetes is essential. Because people with NAFLD are at increased risk of heart disease, other risk factors, especially blood pressure and cholesterol levels, should be more aggressively treated, including with medication therapy if lifestyle changes are not enough.
* * *
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.

Comments are not available on this story.