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Thirdhand smoke contamination in hospital settings: assessing exposure risk for vulnerable paediatric patients
  1. Thomas F Northrup1,
  2. Amir M Khan2,
  3. Peyton Jacob III3,
  4. Neal L Benowitz4,
  5. Eunha Hoh5,
  6. Melbourne F Hovell6,
  7. Georg E Matt7,
  8. Angela L Stotts8
  1. 1Department of Family and Community Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, Houston, Texas, USA
  2. 2Department of Pediatrics, UTHealth Medical School; Medical Director Level III NICU, Children's Memorial Hermann Hospital, Houston, Texas, USA
  3. 3Departments of Medicine and Psychiatry, University of California San Francisco; Division of Clinical Pharmacology, San Francisco General Hospital Medical Center, San Francisco, California, USA
  4. 4Departments of Medicine and Bioengineering & Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA
  5. 5Division of Environmental Health, Graduate School of Public Health, San Diego State University, San Diego, California, USA
  6. 6Center for Behavioral Epidemiology and Community Health, Graduate School of Public Health, San Diego State University, San Diego, California, USA
  7. 7Department of Psychology, San Diego State University, San Diego, California, USA
  8. 8Department of Family and Community Medicine, Department of Psychiatry and Behavioral Sciences, UTHealth Medical School, Houston, Texas, USA
  1. Correspondence to Dr Thomas F Northrup, Department of Family and Community Medicine, The University of Texas Health Science Center at Houston (UTHealth) Medical School, 6431 Fannin, JJL 328, Houston, TX 77030, USA; Thomas.F.Northrup{at}


Background Tobacco has regained the status of the world's number two killer behind heart/vascular disease. Thirdhand smoke (THS) residue and particles from secondhand smoke (SHS) are suspected health hazards (eg, DNA damage) that are likely to contribute to morbidity and mortality, especially in vulnerable children. THS is easily transported and deposited indoors, where it persists and exposes individuals for months, creating potential health consequences in seemingly nicotine-free environments, particularly for vulnerable patients. We collected THS data to estimate infant exposure in the neonatal ICU (NICU) after visits from household smokers. Infant exposure to nicotine, potentially from THS, was assessed via assays of infant urine.

Methods Participants were mothers who smoked and had an infant in the NICU (N=5). Participants provided surface nicotine samples from their fingers, infants’ crib/incubator and hospital-provided furniture. Infant urine was analysed for cotinine, cotinine's major metabolite: trans-3′-hydroxycotinine (3HC) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of the nicotine-derived and tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).

Results Incubators/cribs and other furniture had detectable surface nicotine. Detectable levels of cotinine, 3HC and NNAL were found in the infants’ urine.

Discussion THS appears to be ubiquitous, even in closely guarded healthcare settings. Future research will address potential health consequences and THS-reduction policies. Ultimately, hospital policies and interventions to reduce THS transport and exposure may prove necessary, especially for immunocompromised children.

  • Carcinogens
  • Cotinine
  • Environment
  • Nicotine
  • Priority/special populations

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  • Contributors TFN and ALS conceptualised, designed and oversaw the study in consultation with AMK, PJ, NLB, EH, MFH and GEM. Specifically, AMK, as the Medical Director of the Children’s Memorial Hermann Hospital neonatal ICU, provided expertise in this area during the conduct of the study. PJ and NLB provided oversight and expertise related to infants’ urine collection, analyses and interpretation. EH, MFH and GEM provided oversight and expertise related to the surface nicotine collection, analyses and interpretation. TFN was the primary writer with all authors providing edits/revisions across several drafts of the manuscript.

  • Funding This work was supported by the National Heart, Lung and Blood Institute (R01 HL107404, PI=ALS; R01 HL103684–02, PI=MFH), and the National Institute on Drug Abuse (P30 DA012393; PI=Reese T Jones) at the US National Institutes of Health, and Department of Health and Human Services. This work was also supported by the California Consortium on Thirdhand Smoke, California Tobacco-Related Disease Research Programme (20PT-0184; PIs=NLB and PJ), and the California Tobacco-Related Disease Research Programme (TRDRP) for ‘Certifying Smoke-Free Used Cars: Effects on Value and Consumer Behaviour’ (21RT-0142; PI=GEM).

  • Competing interests None declared.

  • Ethics approval UTHealth Medical School, Committee for the Protection of Human Subjects.

  • Provenance and peer review Not commissioned; externally peer reviewed.