Abstract
Background: Smoking is prevalent among people in China. In this study, we examined the association between smoking and cognitive function in a representative sample of adults aged 45 years and older in China.
Methods: We analyzed the baseline data of 16,892 participants from the China Health and Retirement Longitudinal Study. We measured smoking based on smoking status (never, former, and current smokers) and pack years (one pack year equals 20 cigarettes per day for 1 year). We assessed cognitive function for visuospatial ability, episodic memory, orientation/attention, and overall cognitive function. Multivariate linear and logistic regressions were used to examine the independent association between smoking and cognitive function, controlling for sociodemographic factors, domestic partner status, physical health status, and depressive symptoms.
Results: The study participants were, on average, 60 years old. The prevalence of former and current smoking in this population was 8.4% and 28.8%, respectively. Compared with nonsmokers, former and current smokers had better cognitive function (p < .0001). After controlling for covariates, only former smokers, compared with nonsmokers, have better orientation and attention (p = .04) and overall cognitive function (p = .01). Moreover, pack years are positively associated with orientation, attention (p = .04), and overall cognitive function among all participants (p = .02).
Conclusions: This study identified that, among middle-aged and older Chinese adults, former smokers had the highest cognitive function, especially attention and orientation, followed by never smokers and current smokers. When screening for cognition impairment among Chinese middle-aged and older adults, we should encourage them to quit smoking.