Aims: To examine the correlation between the Fagerström Test for Nicotine Dependence (FTND) score and smoking prevalence across countries.
Design: Cross-sectional study.
Setting: Fifteen studies from 13 countries with FTND score data.
Participants: Samples of smokers were identified through systematic literature searches, web queries and colleagues. Smokers were considered representative of their country's smoking population if they were drawn from population-based sources, were not seeking smoking cessation treatment and did not have significant comorbidities. Smoking prevalence data were derived from the study itself or the country's population rate of daily smoking for the study year.
Measurements: A Pearson correlation coefficient was used to examine the direction and magnitude of the correlation between FTND score and smoking prevalence across countries.
Findings: FTND scores ranged from 2.8 to 4.6. Smokers in Germany and Norway had the lowest FTND scores, while smokers in Sweden and the United States had the highest FTND scores. The prevalence of daily smoking in these countries was very different: 37% and 30% in Germany and Norway, 19% and 16% in the United States and Sweden, respectively. An inverse correlation towards higher FTND scores in countries with lower smoking prevalence was found (r=-0.73, P=0.001). Current smokers had higher FTND scores than former smokers.
Conclusions: The significant inverse correlation between FTND score and smoking prevalence across countries and higher FTND score among current smokers supports the idea that remaining smokers may be hardening. Less dependent smokers may quit more easily and remaining dependent smokers may need more intensive treatment.