Normal A1C remains the same for all ages
DEAR DR. ROACH: Do you find in your practice that “normal” A1C for non-diabetics changes with age? — D.D.
ANSWER: The hemoglobin A1C is a measure of how much sugar is on a hemoglobin molecule. Blood sugar will attach to hemoglobin, and the more sugar in the blood, the more that will become bound to hemoglobin over the lifetime of a red blood cell. The A1C then provides a very good (but not perfect) guide to blood sugar over the past two to three months. The A1C is not reliable in people with abnormal or unusual hemoglobin types, or in people with a condition of increased breakdown of blood cells.
As people get older, their ability to respond to a sugar load decreases. For a person without diabetes, this relative inability to metabolize sugar has little significance, but it does make the average A1C increase somewhat with age.
Even though the average A1C increases with age, the normal A1C remains as defined, independent of age: less than 5.7%. Clearly, more people will be diagnosed with diabetes (nearly all Type 2 diabetes) as they age.
DEAR DR. ROACH: Can a viral infection produce a heart murmur? — J.K.
ANSWER: Yes, though not in the way you may be thinking.
A heart murmur can be normal (physiologic) or abnormal, usually due to a problem with a heart valve. In a person with a damaged heart valve, a trained listener can clearly hear abnormal, turbulent blood flow across the valve, and we can usually discern which valve is affected. One professor I had was able to very precisely estimate the size of a valve that wasn’t open fully and was consistently proven right by the echocardiogram.
A physician can sometimes hear blood flowing through a structurally normal valve. This is more common in people who are thin, young and high cardiac output, such as after exertion. A viral infection produces an increase in cardiac output, so it will make a physiologic (one old term is “innocent,” which I still enjoy) heart murmur more noticeable.
One bacterial infection, rheumatic fever, can damage the heart valves. Fortunately, rheumatic fever is very uncommon now in the age of antibiotics, but rheumatic heart disease is still a major cause of valvular heart disease in older patients, and creates the most dramatic heart murmurs.
DEAR DR. ROACH: My urologist put me on finasteride for enlarged prostate. What are the side effects? — R.G.
ANSWER: Finasteride blocks the conversion of testosterone (T) to dihydrotestosterone (DHT). DHT has two known effects: It enlarges the prostate, and it causes loss of hair in a typical male pattern. Thus, finasteride is used in men with enlarged prostate and in both men and women with hair loss. The usual dose for enlarged prostate is 5 mg, but only 1 mg when used for male pattern hair loss.
Adverse effects to finasteride are uncommon, but the most common are sexual side effects, specifically erectile dysfunction, decreased libido and ejaculatory dysfunction. At the higher 5 mg dose, these occurred in about 5% of men. At the lower dose for hair loss, these occurred in about 1.5% of men in a large review of clinical trials. Side effects are more likely with older men.
There have been conflicting reports about the risk of depression in men taking finasteride, but depression should certainly be looked for in a man being treated.