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Do you have a health or medical question for Dr. Manny? Email him at Ask Dr. Manny and he may answer your question on the air or in this space.

Dear Dr. Manny: Is it true that even occasional smoking can increase the risk for certain cancers? I enjoy smoking a cigar once or twice a month.

"Occasional smoking" is a misnomer. You either smoke or you don't. But, getting to your question, there really has not been a very clear relation between health risks and smoking a cigar once a month. However, smoking a cigar daily, or two or three times a week, is associated with oral cancer.

There is also a fundamental difference between how people think about cigars and cigarettes. Cigars have 17 grams of tobacco and 400 milligrams of nicotine, compared with cigarettes that have less than one gram of tobacco and 8 milligrams of nicotine. You smoke a cigar for two hours, not 10 minutes like a cigarette, so the exposure is longer. Again, the health risks are oral cancer, cardiac disease, and the effects of second hand smoke are sometimes problematic--even with just an occasional cigar.

Dear Dr. Manny: When is a cold most contagious? At what point in a cold are you no longer contagious?

Over 200 bugs are associated with the common cold. You are most contagious 24 hours before symptoms present and five days into symptoms. But the big ticket item here is direct contact. If you have a cold, stay home! You can really contaminate alot of people.

We teach children not to use their hands when they cough and sneeze, to use their elbows. This is a good idea for adults too. Don't use your hands to cover your mouth, use your elbow. Wash your hands constantly, and wipe off telephones and those types of things so you don't contaminate other people.

Dear Dr. Manny: What is the daily reading of sugar levels for "borderline" diabetics?

Normal glucose levels in the morning are less than 100. Levels between 100 and 126 are considered "borderline" diabetic, and anything over 126 perhaps indicates a diabetic state. Check with your doctor. There are other tests that confirm diabetes.

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FOX News medical contributor Dr. Manny Alvarez is the Chairman of the Department of Obstetrics and Gynecology and Reproductive Science at Hackensack University Medical Center in Hackensack, N.J., and is Adjunct Professor of Obstetrics and Gynecology at New York University School of Medicine in New York City. He appears on FNC's daytime programs FOX & Friends and FOX News Live.