Dear Dr. Roach: My wife smoked for many years and finally quit with the help of nicotine gum that is 4 milligrams each. Since quitting almost 20 years ago, she continues to use about 12 pieces of nicotine gum per day. Does ingesting this much nicotine in this manner put her at risk for developing some type of cancer from the nicotine? — T.D.

Answer: No, nicotine is not carcinogenic, that is to say cancer-causing. In large doses, it is dangerous, but the doses she is taking are not — at least, for a person used to them. Early signs of nicotine toxicity are excess salivation, nausea and vomiting.

There are many toxic substances in tobacco, some of which are cancer-causing. The tobacco does not need to be burned; chewing tobacco and snuff increase the risk of oral cancer. About half of all people who smoke will die because of smoking-related illness. Even one cigarette a day has significant long-term health risks.

Although it’s not ideal that she continues to use nicotine gum, there is no doubt the gum is much, much safer for her than continuing to smoke.

Dear Dr. Roach: I had a left hip replacement five years ago. I had severely reduced range of movement and pain. I have not been happy with the results of the first replacement. I walk daily, but some days I can hardly lift my left leg. The right hip now is bone on bone, according to X-rays. It does not cause me any pain or loss of movement.

Two doctors have recommended replacement of my right hip. Will delaying the replacement of the hip and the continued bone on bone movement cause more damage, or can I continue to hold off on the surgery until the pain becomes worse? — J.M.

Answer: Most people are very satisfied with the results of their joint replacement surgeries, both knee and hip. Over 90 percent of patients continue to work, and have no pain or complications 15 years postoperatively, but that leaves some people with worse outcomes.

Delaying surgery does not make surgery appreciably more difficult. However, the most common feedback I get from my patients who have undergone hip replacement surgery is that they wish they had had it done sooner. Almost 60 percent of hip replacements last 25 years. A less than perfect result on one side does not necessarily mean you will have a bad outcome on the second side as well.

© 2020, King Features Syndicate