Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 44 4 2015 04 15 495 500 Huijie Li Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Yunping Zhou Zibo Center for Disease Control and Prevention, Zibo, P.R. China. Suyun Li Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Qiang Wang Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Lulu Pan Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Xiaorong Yang Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Nan Zhang Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Fan Jiang Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Mingkui Han Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. Chongqi Jia Dept. of Epidemiology and Biostatistics, Shandong University, Jinan, P.R. China. 2015 10 14 Background: A recent study indicates that the incidence of smoking cessation varies with age. Although nicotine dependence (ND) has been regarded as one of the most significant barriers of successful smoking cessation, few researches have focused on the relationship between nicotine dependence and age. Methods: A cross-sectional study (conducted in 2013) with 596 Chinese rural male current smokers was performed to study the relationship between ND and age. The ND level was assessed using the Fagerström Test for Nicotine Dependence (FTND) scale. The univariate two-degree fractional polynomials (FPs) regression was used to explore the relation of ND to age. Results: The mean of FTND scores in the middle-aged group (45-64 yr old) was higher than that in the younger (<45 yr old) and older groups (≥65 yr old). The FPs regression showed an inverse U-shaped relationship between ND and age. Conclusion: The middle-aged current smokers had higher degree of ND than the younger and the older groups, which showed an inverse U-shaped relationship between ND and age. This finding needs to be confirmed by further researches. https://ijph.tums.ac.ir/index.php/ijph/article/view/3598 https://ijph.tums.ac.ir/index.php/ijph/article/download/3598/3273