Margaret A.WinkerMD, Senior EditorIndividualAuthorPhil B.FontanarosaMD, Senior EditorIndividualAuthor
To the Editor.— Dr Howard and colleagues1 report a greater rate of progression of atherosclerosis in people exposed to tobacco smoke who had diabetes compared with those who did not. However, some of the participants placed in the "without diabetes" category may have diabetes that has not been diagnosed. According to the study, participants were defined as having diabetes if they reported having diabetes, if they were taking blood glucose–lowering medications, or if they had an 8-hour fasting glucose level of at least 11.1 mmol/L (200 mg/dL). Although the chosen value of 11.1 mmol/L for an 8-hour fasting glucose level is specific, it is not sensitive enough to accurately classify participants in the "with diabetes" or "without diabetes" categories that were used clinically. Current clinical practice recommendations call for a diagnostic value of 7.0 mmol/L (126 mg/dL) for an 8-hour fasting glucose level.2 The accepted value during the course of the study was 7.8 mmol/L (140 mg/dL) for an 8-hour fasting glucose level with 11.1 mmol/L reserved for random samples only.
Duenas MR. Tobacco Smoke and Atherosclerosis Progression. JAMA. 1998;280(1):32-33. doi:10-1001/pubs.JAMA-ISSN-0098-7484-280-1-jbk0701