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Dr. Roach: How dangerous is secondhand vape smoke?

Keith Roach
To Your Health

        Dear Dr. Roach: I am a nonsmoking woman living with a smoker. He smoked cigarettes outside. Now he is vaping, but inside. How dangerous is secondhand vape smoke? I am having a problem finding any information on the subject. Could you please inform me?

-- H.D.

                 Dear H.D.: You can't find much because there is little known. It is known that vape "smoke" contains nicotine, and evidence for nicotine exposure can be found in the blood of people who are around those who vape. Other compounds that are released from vaping and can be found in the air include small aerosol particles and volatile organic compounds, although at a lower level than in cigarette smokers.

                   Until better information is available, I would say that secondhand vape exposure has health concerns, and although they are likely not as bad as secondhand tobacco smoke, the magnitude of the harms are not well known.

                        Dear Dr. Roach:I am a 79-year-old male who had a stent placed three years ago because of an 80% blocked left anterior descending coronary artery. Ever since then, I have been watching my diet carefully with the help of a hospital dietitian, trying to walk about a mile a day, three to four days per week, and doing cardiac rehab two days per week.

                   My fasting blood sugar (glucose) level for the past year is in the high 90s. My A1C has varied from 6.2 to 6.7 over the past three years (taken at six-month intervals) with the most recent at 6.5. It has been in this range for the past nine years with a peak reading of 6.8 in 2011. My family doctor insists I am diabetic and wants to put me on metformin; my cardiologist feels as long as I keep my A1C at current levels he would hold off on the medication.

                   I am confused about which advice I should follow and if there is any downside to taking the metformin. What is the A1C really measuring? I have been told the A1C is measuring my blood sugar over an extended period of time. With blood sugar levels like I have, is there a conflict between the two measurements? What average instantaneous blood sugar reading would equate to an A1C below 6?

-- L.M.G.

                   Dear L.M.G.: There is disagreement about the optimum blood glucose level in a person with diabetes, and my opinion is that there is no one answer that is right for everyone.

                   You are diabetic, by definition, having had two A1C readings of 6.5 or above. The diagnosis of diabetes is considered stable; that is, once diabetic, you are always considered diabetic, even if your blood sugar becomes normal due to diet, exercise, weight loss, medication or some combination.

                   The ACCORD study looked at people at high risk for heart attack, such as those who had existing heart disease. In that group, medicine to lower the A1C below 6% resulted in a higher risk of heart disease than those who had an A1C goal of about 7%. Based on this study, and considering your known blockages in the heart, I would tend to agree with the cardiologist that medication is unlikely to help you live longer, and your A1C level right now is well controlled with the healthy lifestyle choices you've made.

                   An A1C of 6% is an average glucose level of 126 mg/dL, or 7.0 mmol/L.

                   Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.