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Rapid response to:

Papers

Educational differences in smoking: international comparison

BMJ 2000; 320 doi: https://doi.org/10.1136/bmj.320.7242.1102 (Published 22 April 2000) Cite this as: BMJ 2000;320:1102

Rapid Response:

Time series analysis may have been more informative

Dear Editor,

We are writing in response to Cavelaars et al paper concerning the
prevalence of smoking among high and low educated groups in twelve
European countries.

The authors have identified several limitations regarding the
comparability of the international data used. One limitation that they
have overlooked is that the data were collected over eight years, whereas
the application of these data to the smoking epidemic model implies the
study of a single point in time ("around 1990"). Adjustments could have
been made for the year of collection, sampling source and interview method
to improve the validity of the results. In particular, the Swiss data were
collected by telephone which could create significant bias against the
inclusion of the lower educated group.

The smoking epidemic model is a linear one, describing the trends of
smoking prevalence among a population over time. The use of cross-
sectional data is, therefore, not an ideal way of demonstrating it. We
suggest that it would be more useful to analyse time series data from each
country. This could then be used to chart the smoking prevalence in the
population and the ratio of smoking rates between the two educational
groups over time. In countries found not to correlate with the four stage
model it would be interesting to look at factors which may account for
this, such as cigarette pricing, advertising restrictions, health
education and awareness of health risks. This may give some insight into
prevention strategies, especially in low socioeconomic groups and women.

Yours sincerely,

Claire Dobson, Fiona Craig, Jenny Brown, Susannah McLean

Claire.Dobson@ncl.ac.uk

Stage 3 Medical students

Department of Epidemiology and Public Health,
The Medical School,
University of Newcastle upon Tyne

Competing interests: No competing interests

11 May 2000
Claire Dobson
Medical Student
Newcastle University Medical School