Prevalence of nicotine dependence among smokers aged 40 years and older in China

Background Nicotine dependence, also known as tobacco dependence, is a common chronic disease and a major risk factor for chronic respiratory diseases. The present study was designed to determine the prevalence of nicotine dependence and its changes among smokers aged 40 years and older in China, to analyze the characteristics of nicotine dependence among smokers, and to provide a reference for smoking cessation interventions. Methods The data were sourced from nationally representative large-sample surveys conducted during 2014–2015 and 2019–2020 in the Chinese population, covering 125 counties (districts) in 31 provinces, autonomous regions and municipalities. Variables related to smoking and nicotine dependence among residents ≥40 years old were collected in face-to-face interviews. A total of 20,062 and 18,975 daily smokers were included in the 2014–2015 and 2019–2020 surveys, respectively. The severity of nicotine dependence was evaluated according to the Fagerström Test for Nicotine Dependence and Heaviness of Smoking Index. The level and change in nicotine dependence among daily smokers aged ≥40 years were estimated using a complex weighted sampling design, and their influencing factors were analyzed. Results Levels of nicotine dependence among daily smokers aged ≥40 years in China could be divided into very low, low, medium, high, and very high, accounting for 31.1%, 27.9%, 13.4%, 20.5%, and 7.1% of the total, respectively. The average Fagerström Test for Nicotine Dependence score was 3.9 (95% confidence interval [CI]: 3.8–4.0), with the prevalence of medium–high nicotine dependence being 41.0% (95% CI: 39.0–42.9%) and that of high and very high nicotine dependence being 27.6% (95% CI: 26.0–29.3%), both of which were significantly higher in men than in women (both P < 0.001). Among daily smokers, those with a low education level, age at smoking initiation <18 years, and with smoking duration of ≥20 years had a higher degree of nicotine dependence. In terms of geographic region, the level of medium–high nicotine dependence in South China was higher than in other areas, and the decline in the prevalence of high nicotine dependence was the greatest in Northwest China (P < 0.001). The prevalence of medium–high and high and very high nicotine dependence was significantly higher in men with chronic respiratory symptoms, chronic obstructive pulmonary disease (COPD), and/or chronic respiratory diseases than in men without these conditions (all P < 0.05). The prevalence of high and very high nicotine dependence in women with chronic respiratory symptoms and chronic respiratory diseases was significantly higher than that in women without these conditions (both P < 0.05). Compared with that during 2014–2015, the prevalence of high nicotine dependence among daily smokers decreased during 2019–2020 by 4.5 percentage points in the total population (P < 0.001) and by 4.8 percentage points in men (P < 0.001), with no significant change seen in women (P > 0.05). Additionally, the prevalence of high nicotine dependence in men with chronic respiratory symptoms and COPD decreased by 6.7 and 4.7 percentage points, respectively (P < 0.05), but showed no significant change in women with these conditions (P > 0.05). Multivariate logistic regression analysis showed that the risk of medium-high nicotine dependence was higher among daily smokers who were male; 50–59 years old; unmarried/divorced/widowed/separated; engaged in agriculture, forestry, husbandry, fishery and water conservancy; had a low education level; started smoking before the age of 18 years; and smoked for more than 20 years. Conclusions The past few years have seen a slight decline in the prevalence of high (severe) nicotine dependence among smokers aged ≥40 years in China. However, 41.0% of daily smokers had medium-high nicotine dependence, and 27.6% had high or very high nicotine dependence, with notable differences in population and geographic distributions. Development of tailored interventions, optimization of smoking cessation service systems, and integration of smoking cessation into the management of chronic diseases will effectively reduce the burden of nicotine dependence in China.