Evidence Hub

Estimation of level of serum cotinine: A simple, rapid and sensitive biomarker in cigarette smokers

Sangeeta Singh, A. Vishwakarma, Basant Joshi, T. Mohapatra

Asian Journal of Medical Sciences, 2026

Abstract

Background: Cigarette smoking remains the leading preventable cause of morbidity and mortality worldwide. Cotinine, a metabolite of nicotine, serves as a reliable biomarker of tobacco exposure due to its longer half-life (18–20 h) compared to nicotine (2–3 h).

Aims and Objective: The present study aimed to measure serum cotinine levels in cigarette smokers and examines their relationship with smoking duration and intensity, thereby validating smoking status.

Materials and Methods: This case–control study was conducted at a tertiary care center in the Kumaon region of Northern India, including 284 healthy cigarette smokers (cases) aged 18–60 years and 284 age- and sex-matched non-smokers (controls). Detailed smoking histories were obtained, and participants were categorized into four groups based on cigarettes/day and duration: Very mild (Group I: 1–10/day, 10 years). Serum cotinine was quantified using high-pressure liquid chromatography.

Results: Smokers were predominantly male, with a mean age of 41.68±11.52 years. Serum cotinine levels were significantly higher in smokers compared to non-smokers (P<0.05), with values increasing proportionally to smoking duration and intensity.

Conclusion: This study demonstrates a strong positive correlation between serum cotinine levels and smoking behavior, supporting its utility as a biomarker for identifying and validating smoking status. Routine measurement of cotinine in serum or urine may aid in detecting both active and passive…

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free