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Changes in Child Exposure to Environmental Tobacco Smoke (CHETS)

A pre- post- repeat cross-sectional study to detect changes in exposure to second-hand smoke (SHS) among primary school children and displacement of adult smoking from enclosed public places into the home or cars.

A study undertaken by CAHRU (Child and Adolescent Health Research Unit) formerly of The University of Edinburgh and subsequently (2011) relocated to The University of St Andrews.

Principal Investigator: Professor Candace Currie

Lead Researcher: Patricia Akhtar

Study Aims

  • Detect any change in exposure to second-hand smoke (SHS) among Primary school children after implementation of smoke-free legislation in Scotland.
  • Determine if there was displacement of adult smoking from enclosed public places into the home or cars after implementation of the legislation.

Study Design

  • Repeat cross-sectional school survey of national representative samples of 2,500 primary 7 children pre- and 2,500 primary 7 children post-legislation. Data were collected by self-complete questionnaire. Samples of saliva were also collected for testing to cotinine - a biomarker of second-hand smoke (SHS) exposure in non-smokers.
  • Main outcome measures: salivary cotinine concentrations, reports of parental smoking, and exposure to tobacco smoke in public and private places before and after legislation.

Research Instruments & Protocols

Main Outcomes

  • The geometric mean salivary cotinine concentration in non-smoking children fell from 0.36 ng/ml to 0.22 (0.19 to 0.25) ng/ml after the introduction of smoke-free legislation in Scotland - a 39% reduction.
  • The extent of the fall in cotinine concentration varied according to the number of parent figures who smoked, but was statistically significant only among pupils from households in which neither parent figure smoked (51% fall) or only the father figure smoked (44% fall).
  • Pupils reported lower exposure in cafes and restaurants and in public transport after legislation.
  • However, there was little change in reported exposure to second-hand smoke in pupils´ own homes or in cars, but a small decrease in exposure in other people´s homes was reported.
  • There was no evidence of displacement of smoking from public to private places after the legislation was implemented.
  • See also additional papers: Find publications from the Changes in Child Exposure to Environmental Tobacco Smoke (CHETS) study

Updated 17th July 2014

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