A Meta-Analysis of Urinary Cotinine Cut-Off Concentrations in Children Under Five Years for Assessing Environmental Tobacco Smoke Exposure.

Background: Environmental tobacco smoke (ETS) exposure is a preventable risk factor for adverse health outcomes in early childhood. Urinary cotinine is widely used as a non-invasive biomarker of ETS exposure; however, variation in reported cut-off concentrations limits comparability across studies....

Full description

Bibliographic Details
Published in:Tobacco Use Insights Vol. 19; pp. 1 - 18
Main Authors: Sayed Mohamed Zain, Sharifah Mazrah, Mohamad, Nadia, Anual, Zurahanim Fasha, Abdul Shukor, Imanul Hassan, Wan Azmi, Wan Nurul Farah
Format: meta analysis research systematic review tables/charts Journal Article
Published: Sage Publications Inc. 7/2/2026
Online Access:View this record in EBSCOhost
fields @attributes:
  recordID: 1
pdfLink:
plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=195095143&site=ehost-live
header:
  @attributes:
    shortDbName: ccm
    uiTerm: 195095143
    longDbName: CINAHL Complete
    uiTag: AN
  controlInfo:
    bkinfo:
    dissinfo:
    jinfo:
      jid:
        1179173X
        B3LD
      jtl: Tobacco Use Insights
      issn: 1179173X
      maglogo: Y
    pubinfo:
      dt: 7/2/2026
      vid: 19
      pid: 344
      pub: Sage Publications Inc.
      place: Thousand Oaks, California
    artinfo:
      ui:
        195095143
        195095143
        195095143
        10.1177/1179173X261459432
        195095143
      ppf: 1
      ppct: 17
      formats:
        fmt:
          – @attributes:
              type: T
          – @attributes:
              type: P
      tig:
        atl: A Meta-Analysis of Urinary Cotinine Cut-Off Concentrations in Children Under Five Years for Assessing Environmental Tobacco Smoke Exposure.
      aug:
        au:
          Sayed Mohamed Zain, Sharifah Mazrah
          Mohamad, Nadia
          Anual, Zurahanim Fasha
          Abdul Shukor, Imanul Hassan
          Wan Azmi, Wan Nurul Farah
        affil: Environmental Health Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health Malaysia, Shah Alam, Malaysia
      sug:
        subj:
          Environmental Exposure Adverse Effects
          Inhalation Exposure Adverse Effects
          Passive Smoking Adverse Effects
          Tobacco Adverse Effects
          Cotinine Urine
          Urinalysis
          Reference Values
          Biological Markers Urine
          Human
          Child
          Meta Analysis
          Systematic Review
          Urine Specimen Collection
          Nicotine Metabolism
          Tobacco Control
          Child Health
          Air Pollution Adverse Effects
          Smoking Prevention and Control
          PubMed
          Embase
          Cochrane Library
          Enzyme-Linked Immunosorbent Assay
          Radioimmunoassay
          Liquid Chromatography-Mass Spectrometry
          Chromatography, Gas
          Air Pollution, Indoor
          Tobacco Products
          Confidence Intervals
          ROC Curve
          Environmental Health
          Preventive Health Care
          Infant, Newborn
          Infant
          Child, Preschool
          Checklists
          Descriptive Statistics
          Data Analysis Software
          Immunoassay
          Creatinine Urine
          Child: 6-12 years
          Infant, Newborn: birth-1 month
          Infant: 1-23 months
          Child, Preschool: 2-5 years
      ab: Background: Environmental tobacco smoke (ETS) exposure is a preventable risk factor for adverse health outcomes in early childhood. Urinary cotinine is widely used as a non-invasive biomarker of ETS exposure; however, variation in reported cut-off concentrations limits comparability across studies. No prior systematic review has quantitatively synthesised urinary cotinine cut-off values for children under five years. This review aimed to systematically summarise and evaluate these cut-off concentrations in early childhood. Methods: A systematic review and meta-analysis were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines and a prospectively published protocol (PROSPERO CRD42024556969). PubMed, Embase, Scopus, and the Cochrane Library were searched from inception to February 2025. Observational and experimental studies reporting urinary cotinine cut-off concentrations to classify ETS exposure among children under five years were included. Study quality was assessed using the Newcastle–Ottawa Scale. Random-effects meta-analyses were performed to estimate pooled urinary cotinine cut-off concentrations for ETS exposure classification, stratified by unit of measurement (ng/mL vs ng/mg creatinine). Results: Twelve studies were included. Reported urinary cotinine cut-off concentrations ranged from 0.05 to 30 ng/mL for unadjusted values and from 2.47 to 120 ng/mg creatinine for creatinine-adjusted values. Meta-analysis yielded pooled reference values of 5.90 ng/mL (95% CI: 5.53–6.27) and 50.36 ng/mg creatinine (95% CI: 47.53–53.20), respectively. Conclusion: Urinary cotinine is a valid biomarker for assessing ETS in young children, but inconsistent cut-off values limit comparability. The pooled estimates may aid interpretation in surveillance and research but should not be used as universal thresholds. Standardized, age-appropriate cut-offs are needed to strengthen exposure assessment and inform child-focused tobacco control policies.
      pubtype: Academic Journal
      doctype:
        meta analysis
        research
        systematic review
        tables/charts
        Journal Article
      ougenre: Article
    language: English
    refInfo:
    holdings:
      @attributes:
        islocal: N