DEAR DR. ROACH: I have a good friend who is almost 77 years old. He was a heavy smoker until about 14 years ago. He decided to quit smoking and used nicotine gum to help with this process. It’s my ...

After a few vigorous puffs of a burning cigarette, a smoker’s lungs will be filled with a toxic cloud of more than 5,000 different substances. Their combined effects on health are well known: cancer, ...