Validation of self reported smoking by serum cotinine measurement in a community-based study

Abstract

Study objective: The validity of self reported smoking in population surveys remains an important question. An associated question is what would be the value of measuring serum cotinine concentrations in such surveys to obtain validated smoking data. Design: Cross sectional analysis of data on self reported smoking and serum cotinine among a random population sample of 5846 persons aged 25 to 64 years, who participated in the FINRISK-92 survey. Main results: Among self reported regular smokers, 97.2% of men and 94.9% of women had a cotinine concentration of 10 ng/ml or higher in serum. Of those participants who reported to have smoked at any time during their life but not during the previous month, 6.3% of men and 5.2% of women had a serum cotinine concentration of at least 10 ng/ml. Among never smokers 2.5% of men and 2.7% of women had detectable level of cotinine in their serum. The validity of self reporting was similar among subjects from different areas, ages, and socioeconomic groups. Conclusions: In a sample of the general population in Finland the validity of self reported smoking is high, and most of the few self reported non-smokers who had cotinine in their serum had only low or moderate levels.B oth in clinical and in community settings there has been a concern about the validity of self reported smoking. Mainly, three biological measurements have been used to validate self reported smoking: carbon monoxide, thiocyanate, and cotinine. 3 The aim of our paper is to study the validity of self reported smoking in a cardiovascular risk factor population survey by comparing self reports with results of measurements of cotinine levels in serum.Nicotine metabolises rapidly and extensively, primarily in the liver. N-oxidation of nicotine to nicotine-1'-N-oxide occurs in humans. This metabolite has been shown to convert back to nicotine. In humans, the urinary elimination phase of the metabolite parallels that of the parent nicotine, indicating a formation rate limited excretion. It has been estimated that approximately 4% of the nicotine dose is excreted as nicotine-1'-N-oxide. Furthermore, it has been estimated that the quantitative disposition of nicotine is as follows: an average of 9% of the dose seems to be excreted as intact nicotine, and about 70% of nicotine seems to be converted to cotinine. Cotinine is the major plasma metabolite of nicotine and persists for a considerable time period in plasma, with a half life of approximately 16 hours. Only a minor fraction of the generated cotinine is excreted by the kidneys, but cotinine is further metabolised to more polar water soluble substances. According to recent human data the major metabolite found in urine is hydroxylated cotinine.

Linkage of nicotine dependence and smoking behavior on 10q, 7q and 11p in twins with homogeneous genetic background

“…However, earlier studies in Finland have indicated that the current smokers do report their smoking status very accurately. 38 Based on previous studies of the Finnish Twin Cohort, heritability estimates for smoking-related traits in Finland are similar to those reported for other Caucasian populations. 39,40 The smoker phenotype yielded the highest linkage scores in this study (10q25, D10S597, NPL 3.35, LOD 3.12), less than 5 Mb apart from a previously reported linkage locus for the Fagerström Tolerance Questionnaire-(an earlier version of FTND) 41,42 based ND in 130 New Zealand families ascertained for ND, 10 and 37 Mb apart from a locus for smoking quantity recently identified in an AfricanAmerican population.…”

Utilization of Mental Health Services by Minority Urban Adults: Psychosocial Predictors

“…First, the measures used in this study were based on self-report and may include some respondent bias (e.g., individuals with negative affect might over-report depressive symptoms) or the under-reporting of cigarette smoking or doctor visits for a psychological problem. However, self-reported data has been used in a number of survey studies 64,65 and has been found to have adequate reliability and validity. Second, the findings of this study are based on African American and Puerto Rican adults living in an urban area.…”

Putative biases in estimating mortality attributable to obesity in the US population

“…Studies of the validity of such self reports 22,23 have shown them to be relatively reliable. Such self reports would presumably cause only minor misclassification errors, which would only cause slight underestimates of the true impact of reverse causation due to smoking and serious illness.…”