Respir Physiol Neurobiol. 2015 Apr;209:17-22.
Cotinine as a marker for risk prediction in the Ludwigshafen Risk and Cardiovascular Health Study.
- 1Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany.
- 2Drug Regulatory Affairs, Pharmaceutical Institute, Bonn University, Bonn, Germany.
- 3Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany; Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria; Synlab Academy, Synlab Services GmbH, Mannheim, Germany.
- 4Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany. Electronic address: Marcus.firstname.lastname@example.org.
Cotinine is one of the major metabolites of nicotine. The aim our study was to investigate cotinine as a marker for individual risk prediction in the Ludwigshafen Risk and Cardiovascular Health study.
840 samples had detectable cotinine measured using a radioimmunoassay (RIA nicotine metabolite, DPC Biermann GmbH). The distribution of risk factors across quartiles of cotinine or pack-years was analyzed by ANOVA and the association of cotinine and pack-years with mortality by Cox regression.
Cotinine and pack-years both showed significant association with mortality in adjusted models with HRs (95% CI) of 1.30 (1.17-1.44) and 1.26 (1.13-1.42) comparing the third to the first tertile for cotinine and pack-years, respectively. Either cotinine or pack-years or self-reported smoking increased the area-under-the-curve significantly as compared to a basic model including other risk factors.
Cotinine is a strong predictor of mortality in non-smokers as well as in smokers. As objectively measurable parameter cotinine would be preferable for risk prediction. Copyright © 2014 Elsevier B.V.
KEYWORDS: Cotinine; Mortality; Nicotine; Smoking
The consumption of tobacco originated in the Americas, probably for use in shamanistic rituals and for medical purposes. In the late 15th century Europeans arrived and brought plant and smoking habit to Europe were consumption, cultivation, and trading quickly spread.
Today, cigarette smoking is highly prevalent worldwide and it is well known that it represents an important and preventable cause for common diseases like cancer and cardiovascular disease. A major compound of cigarette smoke is nicotine. On average about 1 mg of nicotine per cigarette is absorbed by the human body where it is rapidly metabolized, mainly by the liver. The most important metabolite is cotinine which has a biological half-life of 19 to 40 hours and is therefore well suited to determine the amount of cigarette smoke that somebody inhaled. This does not only apply to the smokers themselves but also to people in their surrounding who are exposed to “second-hand smoke”. Therefore, the measurement of cotinine may also allow assessing the risk associated with passive smoking.
In our study we included 840 study participants in whose blood samples we could detect cotinine. Of these, 123 reported to be ex-smoker or non-smoker. We divided our patients in three groups according to the cotinine concentration in their blood and found that the group with the highest cotinine concentrations had a 1.3 times higher risk of dying as compared to the group with the lowest cotinine concentrations. Furthermore, we found that the inclusion of cotinine into risk prediction models lead to a significant improvement of risk prediction. In conclusion, we found that plasma cotinine concentration represents a suitable and objectively measurable marker for the risk associated with cigarette smoking, also including passive smokers.