Nationwide tobacco surveys and sales data in Denmark from 1920 to 2010.

INTRODUCTION Tobacco smoking is an important cause of premature death and morbidity in Denmark. It is therefore important to monitor tobacco consumption. In this paper, tobacco consumption in Denmark is illustrated by two methods: sale of tobacco products and smoking habit surveys. MATERIAL AND METHODS Data on sale of tobacco products in Denmark were available for the 1920-2010-period. National smoking habit surveys were found through grey-zone literature, a PubMed search and a report on the Danish population's smoking habits. Ten smoking habit surveys were identified from the 1953-2010-period, three of which have data from multiple years and annual surveys from 1969 onwards. RESULTS The changes in tobacco consumption found by the two methods were not parallel. Furthermore, there were significant differences between the proportions of smokers found in smoking habit questionnaires from the same year. This difference may be due to changes in cross-border trade, smuggling, smokers' willingness to participate in smoking habit studies, recognition of own smoking and actual tobacco consumption, and differences in the composition of participants in the smoking habit studies both over time and between different studies. CONCLUSION Both sales statistics and surveys have advantages and disadvantages. It may therefore be important to use both when estimating tobacco consumption.