Analysis of Assessment Methods for Detecting Nicotine Residue and Its Impact on Humans: A Systematic Review

Area of Science:

• Environmental Health
• Toxicology
• Public Health

Background:

• Thirdhand smoke (THS) comprises toxic nicotine residues persisting on surfaces post-tobacco use.
• Exposure occurs via skin contact or inhalation, with children and infants being particularly vulnerable.
• THS poses a significant, yet often underestimated, public health risk.

Purpose of the Study:

• To systematically review and assess the effectiveness of various methods for measuring nicotine THS residues.
• To evaluate the accuracy of different measurement techniques across diverse human populations.
• To identify gaps and inform future research directions in THS assessment.

Main Methods:

• A comprehensive literature search was conducted across five major databases (ProQuest, Medline, Embase, Scopus, Cochrane Library) from 1999 to 2024.
• Studies involving human populations exposed to THS residue were included; animal studies were excluded.
• Data extraction and screening were performed independently by two reviewers, with the protocol registered on PROSPERO.

Main Results:

• Out of 394 initially retrieved studies, 36 were selected for full review after screening.
• Methods were categorized into analysis of human secretions (saliva, urine), cellular analysis (cellulose substrates), environmental assessments (surfaces, fabrics), and epidemiological assessments (surveys).
• Non-invasive biomarkers like saliva and urine were frequently used, alongside diverse tools including surveys and machine learning.

Conclusions:

• Various selective testing methods for detecting THS nicotine residues exist, each with distinct advantages and limitations.
• Further research is crucial to refine and validate these assessment techniques.
• Improved THS measurement methods will enhance understanding of its impact on human health.