LC-MS/MS Tracks Cotinine in Saudi Women

Smoking tobacco continues to be one of the top preventable causes of illness and death around the world. In Saudi Arabia, cultural stigma around smoking, along with reliance on people's self-reported answers, makes it hard to get an accurate picture of how many women smoke or are exposed to secondhand smoke. Cotinine, a stable substance the body produces when breaking down nicotine, offers a more objective way to measure both direct smoking and secondhand exposure, since it can be measured in urine. Saudi Arabian researchers therefore conducted a study with four main goals: (1) to get a clearer picture of tobacco smoke exposure among Saudi women by combining survey answers with actual biomarker testing; (2) to confirm the reliability of liquid chromatography-tandem mass spectrometry (LC-MS/MS) for measuring urinary cotinine; (3) to establish a cotinine level specific to this population that could reliably separate smokers from nonsmokers; and (4) to explore smoking habits and the factors that influence them through survey questions. A paper based on this study was published in the journal PLOS One.¹

Why Is More Cotinine Research Needed Specifically for Saudi Women, Given What's Already Known from Other Populations?

Ongoing research continues to improve how urinary cotinine is used to measure tobacco smoke exposure and to refine how that exposure gets classified. One large study involving multiple groups of pregnant women used statistical analysis to figure out specific cotinine cutoff levels that could distinguish between active smoking, exposure to smoke in the environment, and exposure to residual smoke particles that linger on surfaces—showing that these cutoff levels need to be tailored to the specific population being studied.² Similarly, a nationwide study in Vietnam used urinary cotinine testing to assess smoking and secondhand smoke exposure in a lower-income population, revealing that exposure patterns can vary quite a bit depending on demographics.³ Recent reviews of the research have also pointed to ongoing efforts worldwide to standardize cotinine cutoff levels for distinguishing active smokers from those only exposed secondhand, across different populations.⁴ Even so, according to the Saudi Arabian researchers, little data currently exists on appropriate cotinine cutoff levels specifically for Saudi women, especially considering how cultural and social factors may affect whether they are honest about their smoking habits, hence the motivation for this research.¹

How Did Objective Urine Testing for Tobacco Exposure Compare to Saudi Women's Self-Reported Smoking Habits?

For this study, researchers surveyed a single group of 133 Saudi women at one point in time, recruiting them between May and December 2024. Each woman gave a urine sample and answered questions about her smoking habits and any exposure to secondhand smoke. The urine samples were then analyzed using LC-MS/MS. The researchers detected cotinine (a byproduct the body produces when exposed to nicotine) in the urine of 48 out of the 133 women, at levels ranging from very low to just under 8 nanograms per milliliter (a tiny fraction of a gram, showing just how sensitive the test was). Interestingly, even though nearly 89% of participants said they didn't smoke, almost half reported being exposed to secondhand smoke at home. Using statistical analysis, the researchers determined a specific cotinine level that could reliably separate smokers from nonsmokers. Overall, the research team believes that this validated laboratory method offers doctors and researchers a dependable, objective way to measure tobacco exposure in Saudi women rather than relying solely on self-reported smoking habits, which are not always accurate.¹

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References

1. Alansari, A. A.; Aljohar, H. I.; Alotaibi, G. et al. Biomarker-Based Assessment of Tobacco Smoke Exposure in Saudi Females via Analysis of Urinary Cotinine Level. PLOS One 2026, 21 (8), e0355166. DOI: 10.1371/journal.pone.0355166
2. Ni, Y.; Dearborn, L. C.; Szpiro, A. A. et al. Urinary Cotinine Cut-Offs for Tobacco Smoke Exposure in Pregnancy and Associations with Child Intelligence Quotient: A Multi-Cohort Analysis. Int J Hyg Environ Health 2026, 272, 114744. DOI: 10.1016/j.ijheh.2026.114744
3. Le, H. T.; Tran, T. T. T.; Ta, B. T. et al. Urinary Cotinine Concentration as a Biomarker of Environmental Exposure to Nicotine in Vietnam: Results from a Nationwide Survey in 2024. PLOS One 2026, 21 (1), e0338434. DOI: 10.1371/journal.pone.0338434
4. Sayed Mohamed Zain, S. M.; Abdul Shukor, I. H.; Mohamad, N. et al. Urinary Cotinine Cut-Off Concentrations in Children Under 5 Years for Assessing Environmental Tobacco Smoke Exposure: A Systematic Review and Meta-Analysis Protocol. BMJ Open. 2025, 15 (5), e094077. DOI: 10.1136/bmjopen-2024-094077