Prevalence of tobacco smoking in Switzerland: do reported numbers underestimate reality?

QUESTION UNDER STUDY: Surveys on tobacco consumption represent an important decision aid for public health policy related to smoking. Although Switzerland's tobacco control policies and regulations are among the weakest, its reported smoking prevalence is among the lowest in Europe. However, there appears to be a discrepancy between reported prevalence and aggregate data on national cigarette consumption. Our purpose was to closely look at this discrepancy and study its significance. METHODS: Calculation of national aggregate tobacco consumption by Switzerland's resident population for the years 2012 to 2015 and comparison with reported consumption derived from survey results on smoking prevalence and intensity. Comparison with similar data for France for year 2014. Evaluation of several hypotheses to explain the discrepancy between survey results and national aggregate consumption data. RESULTS: There was a large discrepancy of about 45% between reported smoking consumption implied by survey results and estimated actual consumption derived from aggregate data on sales. Whereas survey results suggest smoking prevalence in Switzerland to be around 25% and rather stable during the period 2012 to 2015, true prevalence could be greater than 31%. CONCLUSION: The results of surveys aiming to estimate smoking prevalence and intensity in Switzerland may substantially suffer from underreporting, misreporting and sampling bias. Survey methodology needs to be examined to see whether such reporting discrepancy can be reduced.