Changes in environmental tobacco smoke (ETS) exposure over a 20-year period: cross-sectional and longitudinal analyses.
OBJECTIVE
To examine long-term changes in environmental tobacco smoke (ETS) exposure in British men between 1978 and 2000, using serum cotinine.


METHODS
Prospective cohort: British Regional Heart Study.


METHODS
General practices in 24 towns in England, Wales and Scotland.


METHODS
Non-smoking men: 2125 studied at baseline [questionnaire (Q1): 1978-80, aged 40-59 years], 3046 studied 20 years later (Q20: 1998-2000, aged 60-79 years) and 1208 studied at both times. Non-smokers were men reporting no current smoking with cotinine < 15 ng/ml at Q1 and/or Q20.


METHODS
Serum cotinine to assess ETS exposure.


RESULTS
In cross-sectional analysis, geometric mean cotinine level declined from 1.36 ng/ml [95% confidence interval (CI): 1.31, 1.42] at Q1 to 0.19 ng/ml (95% CI: 0.18, 0.19) at Q20. The prevalence of cotinine levels < or = 0.7 ng/ml [associated with low coronary heart disease (CHD) risk] rose from 27.1% at Q1 to 83.3% at Q20. Manual social class and northern region of residence were associated with higher mean cotinine levels both at Q1 and Q20; older age was associated with lower cotinine level at Q20 only. Among 1208 persistent non-smokers, cotinine fell by 1.47 ng/ml (95% CI: 1.37, 1.57), 86% decline. Absolute falls in cotinine were greater in manual occupational groups, in the Midlands and Scotland compared to southern England, although percentage decline was very similar across groups.


CONCLUSIONS
A marked decline in ETS exposure occurred in Britain between 1978 and 2000, which is likely to have reduced ETS-related disease risks appreciably before the introduction of legislation banning smoking in public places.
Jefferis
Barbara J
BJ
British Regional Heart Study, UCL Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London, UK. b.jefferis@pcps.ucl.ac.uk
Thomson
Andrew G
AG
Lennon
Lucy T
LT
Feyerabend
Colin
C
Doig
Mira
M
McMeekin
Laura
L
Wannamethee
S Goya
SG
Cook
Derek G
DG
Whincup
Peter H
PH
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003367:Cotinine / Q000097:blood*; D003430:Cross-Sectional Studies; D004739:England; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011633:Public Facilities / Q000331:legislation & jurisprudence; D012606:Scotland; D012907:Smoking / Q000331:legislation & jurisprudence*; D014028:Tobacco Smoke Pollution / Q000032:analysis*; D014852:Wales
D015415:Biomarkers; D014028:Tobacco Smoke Pollution; D003367:Cotinine