Tobacco dependence severity, cessation legacy and serial mediation in aging China

Most studies on smoking in China operationalize tobacco use as a binary exposure, obscuring clinically meaningful heterogeneity in dependence intensity. Despite China's status as the world's largest tobacco consumer, limited research has examined gradients in tobacco dependence severity, post-cessation health legacies, or the behavioral-psychological pathways linking nicotine entrenchment to chronic disease in older adults.

This secondary analysis drew on data from the 2020 China Health and Retirement Longitudinal Study (CHARLS). Tobacco dependence severity was classified: as mild (<10 cigarettes/day), moderate (10-20), or severe (>20) using a consumption-based proxy aligned with the Fagerström test for nicotine dependence (FTND) consumption subscale. Analytic samples included current smokers for dependence-chronic disease associations and serial mediation (n=3637) and former smokers for pre-cessation dependence analyses (n=1935). Multivariable logistic regression estimated direct associations. Serial mediation through reduced physical activity and elevated depressive symptoms to chronic disease was tested using path analysis with bias-corrected bootstrapping. All models adjusted for gender, age, education level, hukou type (household registration status), income, employment, and marital status.

Compared with mild dependence, moderate current dependence was associated with higher odds of any chronic disease (AOR=1.22; 95% CI: 1.04-1.42), while severe dependence showed a positive but marginally significant association (AOR=1.24; 95% CI: 0.99-1.54). Among former smokers, moderate and severe pre-cessation dependence predicted elevated hypertension (AOR=1.56 and 1.81) and dyslipidemia (AOR=1.77 and 1.89). Associations appeared more pronounced among agricultural hukou holders, though formal interaction tests were non-significant. Serial mediation identified a statistically significant but substantively trivial indirect pathway through reduced physical activity and elevated depressive symptoms (β=0.001, p<0.05); single-mediator paths were non-significant.

Tobacco dependence severity, as measured by a cigarette consumption-based proxy, shows an overall positive gradient with chronic disease risk among older Chinese adults. Higher pre-cessation dependence is associated with persistent hypertension and dyslipidemia risk after quitting. Descriptive subgroup variation appeared more pronounced among agricultural hukou holders, although interaction tests did not support statistically significant heterogeneity. The findings suggest the value of moving beyond binary smoking classifications toward dependence-stratified screening and post-cessation surveillance. Such considerations may inform tobacco control efforts under Healthy China 2030 for rural populations.