Intended for healthcare professionals


Changes in exposure of adult non-smokers to secondhand smoke after implementation of smoke-free legislation in Scotland: national cross sectional survey

BMJ 2007; 335 doi: (Published 13 September 2007) Cite this as: BMJ 2007;335:549
  1. Sally J Haw, principal public health adviser1,
  2. Laurence Gruer, director of public health science2
  1. 1NHS Health Scotland, Edinburgh EH12 5EZ
  2. 2NHS Health Scotland, Glasgow G3 7LS
  1. Correspondence to: S Haw Sally.Haw{at}
  • Accepted 22 August 2007


Objective To measure change in adult non-smokers' exposure to secondhand smoke in public and private places after smoke-free legislation was implemented in Scotland.

Design Repeat cross sectional survey.

Setting Scotland.

Participants Scottish adults, aged 18 to 74 years, recruited and interviewed in their homes.

Intervention Comprehensive smoke-free legislation that prohibits smoking in virtually all enclosed public places and workplaces, including bars, restaurants, and cafes.

Outcome measures Salivary cotinine, self reported exposure to smoke in public and private places, and self reported smoking restriction in homes and in cars.

Results Overall, geometric mean cotinine concentrations in adult non-smokers fell by 39% (95% confidence interval 29% to 47%), from 0.43 ng/ml at baseline to 0.26 ng/ml after legislation (P<0.001). In non-smokers from non-smoking households, geometric mean cotinine concentrations fell by 49% (40% to 56%), from 0.35 ng/ml to 0.18 ng/ml (P<0.001). The 16% fall in cotinine concentrations in non-smokers from smoking households was not statistically significant. Reduction in exposure to secondhand smoke was associated with a reduction after legislation in reported exposure to secondhand smoke in public places (pubs, other workplaces, and public transport) but not in homes and cars. We found no evidence of displacement of smoking from public places into the home.

Conclusions Implementation of Scotland's smoke-free legislation has been accompanied within one year by a large reduction in exposure to secondhand smoke, which has been greatest in non-smokers living in non-smoking households. Non-smokers living in smoking households continue to have high levels of exposure to secondhand smoke.


  • We thank Ruth Gosling, Sally Malam, and staff at BMRB Social Research, who conducted the health education population survey and prepared the database; Sonnda Catto of NHS Health Scotland who managed the commissioning of the health education population survey; and Colin Fereyabend, Mira Doig, and staff at ABS Laboratory, who advised on and performed the cotinine assays. We also thank Patricia Akhtar and Dorothy Currie of Child and Adolescent Health Research Unit, University of Edinburgh, and Rob Elton, independent consultant, for support with the analysis and presentation of results.

  • Contributors: SH contributed to the design of the study, undertook data analysis, and wrote the paper. LG contributed to the design of the study and the writing of the paper. SH is guarantor.

  • Funding: NHS Health Scotland and the Scottish Executive.

  • Competing interests: None declared.

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

  • Accepted 22 August 2007
View Full Text