Relationships of Cotinine and Self-Reported Cigarette Smoking With Hemoglobin A1c in the U.S. Results from the National Health and Nutrition Examination Survey,

OBJECTIVEdWhether nicotine leads to a persistent increase in blood glucose levels is not clear. Our objective was to assess the relationship between cotinine, a nicotine metabolite, and glycated hemoglobin (HbA1c), an index of recent glycemia. RESEARCH DESIGN AND METHODSdWe used cross-sectional data from the Na-tional Health and Nutrition Examination Survey (NHANES) from 1999 to 2008. We limited our analysis to 17,287 adults without diabetes. We created three cotinine categories:,0.05 ng/mL, 0.05–2.99 ng/mL, and $3 ng/mL. RESULTSdUsing self-report, 25 % of the sample were current smokers, 24 % were former smokers, and 51 % were nonsmokers. Smokers had a higher mean HbA1c (5.36 % 6 0.01 SE) compared with never smokers (5.31%6 0.01) and former smokers (5.31%6 0.01). In a similar manner, mean HbA1c was higher among participants with cotinine $3 ng/mL (5.35 % 6 0.01) and participants with cotinine 0.05–2.99 ng/mL (5.34 % 6 0.01) compared with participants with cotinine,0.05 ng/mL (5.29 % 6 0.01). In multivariable-adjusted analysis, we found that both a cotinine $3 ng/mL and self-reported smoking were associated with higher HbA1c com-pared with a cotinine,0.05 ng/mL or not smoking. People with a cotinine level$3 ng/mL had