DEAR DR. ROACH: Several months ago, I developed a case of a bigeminy heartbeat. My cardiologist prescribed metoprolol. At about the same time, I had reduced my intake of magnesium from about 50% of the daily value (DV) to 35%. (This may have preceded the bigeminy onset.)

Quite by accident, I read an article recommending magnesium for a heart arrhythmia. Within a week or so of reading the article, I started magnesium gluconate at 100% of the DV. I have been taking this and metoprolol for about a month, and my condition has improved about 95%.

The question is: How can we tell if the magnesium shorting down to 35% was actually the cause and increasing it to 100% was the cure? — L.R.

ANSWER: Bigeminy, more precisely ventricular bigeminy, is a term most people probably haven’t heard of, but most people have heard of a premature ventricular contraction (PVC). Ventricular bigeminy is when every other beat is a PVC and alternates with regular beats.

While this rhythm can happen in people without any heart disease or risk factors, your cardiologist will have considered many underlying causes, such as excess alcohol use, anemia, low oxygen levels, and thyroid disease. A beta blocker like metoprolol is usually the first drug that is used as beta blockers reduce adrenalin levels, reduce the oxygen needs of the heart, and are proven to be effective at reducing the number of PVCs.

A low magnesium level is another risk factor for PVCs and ventricular bigeminy, and there are case reports of the rhythm going away completely with magnesium. So, while we can’t be sure whether your bigeminy was caused by a low magnesium level, the story is suggestive that it’s a real possibility.

I don’t recommend taking magnesium except in people who have low levels, but 100% of the DV of magnesium is quite safe to take.

DEAR DR. ROACH: I am a 76-year-old female who weighs 112 pounds. I am 5 feet, 4 inches tall, and in good health. I walk 40 minutes to 1 hour over a very hilly course five days a week and do strength training two days a week. I was just diagnosed with osteoporosis, with my risk of a major osteoporosis fracture being 12.6% and my risk of a hip fracture being 3.8%, according to FRAX.

I have Barrett’s esophagus that is monitored every three years and take 20 mg of omeprazole for it. I also take 2,000 IU of vitamin D daily and try to eat a high-calcium diet. My only other medication is 50 mg of trazodone for sleep. I have no other medical problems.

My primary doctor wants to put me on medication for osteoporosis. Given my situation, which medication would you recommend? — P.C.

ANSWER: The FRAX score is a way of combining a person’s measured bone density with clinical risk factors like age, sex and weight to provide an estimate of the fracture risk. Most authorities recommend treatment when the risk of a major osteoporotic fracture is greater than 20% or the risk of a hip fracture is greater than 3%. Your primary doctor is following the published literature. (I will note that a revised calculator called the FRAXplus includes additional risk factors and can be found at www.FRAXplus.org/calculation-tool/.)

Omeprazole, the medicine you take for Barrett’s, protects your esophagus but can cause poor absorption of calcium, which may be an additional risk factor for you. Because of your Barrett’s, the normal first-line treatments (oral bisphosphonates) are not recommended. Instead, intravenous bisphosphonates such as zoledronic acid once a year are the standard recommendation.

Denosumab is another option, but people need to stay on this medication long-term because, unlike bisphosphonates, bone loss occurs rapidly after stopping it.

DEAR DR. ROACH: As I amble past middle age and try to take note of my functioning as a male, I wonder if I could benefit from taking one of these testosterone supplements that I see advertised on TV. But I don’t know how much they would improve my health or sexual function. Does the recommended dosage on the bottle apply to everybody? Or should I ask me doctor to recommend me one? I am confused. — R.G.

ANSWER: Unfortunately, the “testosterone supplements” you see in ads are misleading since they don’t contain testosterone. They are advertised to “support testosterone” and are made from vitamins (usually B vitamins), minerals (like magnesium and zinc), and a variety of supplements. One of these supplements is “horny goat weed,” which has estrogen-like characteristics and has never been proven to be effective for humans. It does contain a substance that works similarly to sildenafil (Viagra), but it is only about 1% as effective.

I absolutely recommend that you speak to your doctor. If the issue is erectile function, which does decrease with age in most men, then there are effective treatments that can be used once an evaluation is done looking for any possible cause. Causes can include low testosterone or a blockage in the artery to the penis.

Testosterone itself is a controlled substance that is appropriate for men with symptoms of low testosterone and who have repeatedly low blood levels of testosterone. If this includes you, then prescription testosterone and repeat blood tests are appropriate and should help your symptoms. I recommend that you stay away from these supplements.

DEAR DR. ROACH: I live in a large apartment complex that still allows smoking, and some people here are extremely heavy smokers. Tenants must smoke in their units or in two designated areas that I avoid. Am I in danger of secondhand smoke?

I live in a wooded area two blocks away from the beach to enjoy fresh air, but the cigarette smell in my enclosed hallway is overwhelming at times. On many days, it can be smelled from the street outside the complex! Do I have a concern or just a super sensitive nose? I’ve never smoked. — N.H.

ANSWER: The term “thirdhand smoke” is sometimes used to describe not the danger of smoking (firsthand), nor the danger of being around a person who is actively smoking (secondhand), but the residue of tobacco smoke left on surfaces and dust.

This residue can be found on the fingers of people who have moved into homes where smokers previously lived. There is even a little bit in the air as what has been left from smoking gets re-aerosolized. This is the biggest concern when people are living in a contaminated home. (Regular cleaning won’t get rid of all the residual chemicals from tobacco smoke.)

So, there is a concern, but the risk to your health, given that you are walking through a corridor, is small. Not touching the surfaces of the enclosed hallway is wise, and washing your hands when you come in is also a good idea. Some airflow from opening the windows in the corridor, if possible, would reduce the small risk.

Your nose may be sensitive, but what you are picking up is potentially harmful. From a long distance in the outside air, I suspect the risk is negligible.

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