Tobacco use remains one of the largest public health threats globally, with over 8 million deaths annually due to tobacco-related diseases (1), placing a substantial burden on both economic and healthcare systems. In China, over 300 million people smoke, and tobacco-related diseases account for more than 1 million deaths annually and are projected to reach 2 million by 2030 (2). Epidemiological data indicate that 49.7% of Chinese current smokers exhibit severe nicotine dependence (3), creating significant challenges for smoking cessation initiatives and public health interventions.

Nicotine, the principal psychoactive component in tobacco products, functions as the key mediator of addiction through its interactions with neurochemical pathways (4). Nicotine dependence plays a pivotal role in shaping smoking behavior and influencing cessation outcomes, with highly dependent smokers facing greater challenges in quitting and experiencing higher relapse rates (5, 6). The Fagerström Test for Nicotine Dependence (FTND) has been validated as a standardized instrument for nicotine dependence assessment (7). Time to First Cigarette (TTFC), the initial component of FTND, quantifies the time interval between awakening and the first cigarette consumption. TTFC serves as a reliable indicator of physiological nicotine dependence severity and correlates significantly with cessation difficulty, relapse probability, and smoking-related health risks (8–10). Additionally, genetic studies have supported the utility of TTFC as an independent measure of nicotine dependence. A previous genetic study on nicotine dependence has demonstrated associations between FMO3 gene polymorphisms and extended TTFC duration, while these genetic variations showed no correlation with daily cigarette consumption (11). This independent nature of TTFC highlights its value as a key indicator in nicotine dependence research (12).

Health literacy (HL) has emerged as a critical research focus in public health studies. The concept encompasses an individual’s abilities to obtain, process, and utilize health-related information (13). Health literacy demonstrates significant associations with both health-related decision-making processes and measurable health outcomes (14–16). Enhanced health literacy may facilitate individuals’ comprehension of smoking-related health risks, potentially modifying their smoking behavior patterns (17, 18).

Despite its recognized importance in health promotion, the specific relationship between health literacy and nicotine dependence remains inadequately explored, particularly regarding physiological indicators such as TTFC. As a robust marker of nicotine dependence severity, TTFC offers a unique opportunity to investigate how cognitive factors (such as health literacy) might interact with the physiological and behavioral aspects of addiction. Understanding these connections could reveal novel pathways for developing more effective, targeted smoking cessation interventions, especially for highly dependent smokers in high-prevalence settings such as China.

This study aims to investigate the association between health literacy and TTFC among daily smokers in China. We hypothesize that higher health literacy levels are linked to a longer TTFC duration, indicating a lower level of nicotine dependence. The findings will provide empirical evidence for developing targeted smoking cessation interventions and contribute to the broader understanding of health literacy’s role in nicotine dependence.

This study provides novel evidence of the complex relationship between health literacy and nicotine dependence among daily smokers in China. By examining time to first cigarette (TTFC ≤30 min) as an indicator of high nicotine dependence, our findings reveal both continuous and threshold effects in this association. In the continuous analysis, each one-point increase in health literacy score was associated with a 1% reduction in high nicotine dependence risk (OR = 0.99, 95%CI: 0.98–0.99, p < 0.001). More importantly, we identified a significant threshold effect at 53 points—the established standard for adequate health literacy in China (19)—with individuals scoring above this threshold showing a substantial 34% lower likelihood of high nicotine dependence compared to those with below basic literacy (OR = 0.66, 95%CI: 0.50–0.87, p = 0.003). Additionally, our analysis revealed a clear dose–response relationship across health literacy categories, with protective effects emerging at intermediate levels and strengthening at adequate levels (P for trend<0.001). These associations remained consistent across various demographic subgroups, suggesting the generalizability of our findings within the smoking population in Zhejiang Province.

Previous research has extensively examined the association between health literacy and smoking behavior. A study based on the CHLS found that health literacy is associated with reduced smoking behavior and enhanced intention to quit smoking (17, 26). For daily smokers, research indicates that individuals with higher levels of health literacy are more likely to quit smoking or reduce their smoking frequency (18), while lower health literacy is associated with greater nicotine dependence. These findings are consistent with the associations observed in our study, further confirming the pivotal role of health literacy in influencing smoking behavior. Our study extends this literature by focusing specifically on nicotine dependence, as measured by TTFC, providing a more granular understanding of how health literacy relates not just to smoking status but to the severity of addiction among daily smokers.

While we did not directly measure the underlying mechanisms, several theoretical frameworks may help explain the observed associations. Individuals with higher health literacy are better positioned to understand smoking-related harms and to navigate health information, which may be linked to more effective smoking-control behaviors. From a cognitive perspective, the Health Belief Model offers a conceptual basis for how health literacy could relate to smoking behavior. Higher health literacy may be associated with greater perceived risk of immediate and long-term smoking harms (18, 27). Such perceptions could plausibly relate to less urgency to smoke after waking, reflected in a longer TTFC.

Similarly, Social Cognitive Theory suggests that self-efficacy may explain our findings. Some studies have found a significant correlation between self-efficacy and health literacy (28, 29). Consequently, health literacy may enhance self-efficacy, which in turn affects smokers’ nicotine dependence. Increased self-efficacy can bolster individuals’ confidence in managing their health, including resisting the urge to smoke, thereby promoting better self-regulation and enabling smokers to postpone the onset of daily smoking. Furthermore, individuals with strong health literacy may be more adept at seeking social support and fostering a social environment that facilitates smoking cessation (30, 31). The environmental feedback from supportive networks may further reinforce healthy behaviors, creating a positive feedback loop that strengthens smokers’ ability to resist immediate nicotine consumption. It is important to note that we did not directly measure risk perception, self-efficacy, or social support in this study. Therefore, these proposed pathways remain hypothetical and warrant investigation in future research specifically designed to examine these potential mediating mechanisms.

This study identified a nonlinear relationship between health literacy and the risk of high nicotine dependence, providing a novel perspective on the influence of health literacy. The protective pattern appeared more pronounced at scores above 53. This finding is close to the established cut-off for adequate health literacy in China (19), suggesting that individuals with higher literacy levels may be better equipped to process and act upon health information, thereby achieving more effective smoking control behaviors. The stronger protective effect observed at higher health literacy levels may reflect the cumulative benefits of improved knowledge, risk perception, and health-related decision-making. While this pattern is consistent with the idea that sufficient literacy supports better appraisal and use of health information, the underlying mechanisms were not directly assessed in our study. These findings underscore the importance of targeting health literacy improvement as part of tobacco control strategies, particularly for individuals with scores below the identified threshold. Enhancing health literacy in this group could yield substantial public health benefits by reducing nicotine dependence. Future research should explore the mechanisms underlying this relationship, including potential mediators such as risk perception, self-efficacy, and access to health resources.

Our findings offer valuable insights for tobacco control in China, where smoking remains deeply embedded in male social interactions and business relationships (32). The identified threshold effect at 53 points—coinciding with China’s standard for adequate health literacy (19)—suggests that the relationship between health literacy and nicotine dependence is not simply linear. This observation may inform smoking cessation strategies in Zhejiang Province, which, despite implementing various tobacco control policies, continues to struggle with high smoking rates among adult males (33).

This work aligns with China’s evolving health promotion approach, which has increasingly recognized health literacy as foundational to public health improvements. With government initiatives now setting specific targets for health literacy improvement (34), an opportunity exists to incorporate tobacco control objectives within this established framework. Rather than creating isolated cessation programs, integrating nicotine dependence content into broader health literacy efforts may yield greater efficiency. This approach leverages existing infrastructure while potentially enhancing smokers’ ability to comprehend and act upon health information. As our results demonstrate protective effects becoming more pronounced above the 53-point threshold, efforts to improve health literacy among smokers may complement conventional measures such as smoking restrictions. For Zhejiang Province, which has prioritized health promotion yet continues to face substantial smoking-related challenges, this health literacy-oriented approach to tobacco control aligns with existing health policy directions while offering a more targeted pathway to address nicotine dependence among daily smokers.

This study has several strengths, including its use of multi-stage stratified random sampling, which enabled a large and representative sample across Zhejiang Province. Furthermore, TTFC, as the most predictive single item in the FTND, is both simple and quick to measure (12). However, several limitations warrant consideration. First, the cross-sectional design precludes causal inference. While higher health literacy was inversely associated with earlier TTFC, reverse causation and residual confounding from unmeasured variables cannot be ruled out. Second, our measures were based on self-report, which may introduce recall and social desirability biases. Although TTFC is considered a reliable and validated measure, and our sensitivity analysis using a stricter cutoff (TTFC ≤ 5 min) confirmed result robustness, reporting bias cannot be entirely eliminated. Third, because 99.23% of participants were men, findings primarily reflect associations among male daily smokers and should not be generalized to women without caution. Future longitudinal studies with objective measures and balanced sex representation are warranted to establish causality and examine potential sex differences.

In a large, province-wide sample of 3,235 daily smokers in Zhejiang, higher health literacy was inversely associated with high nicotine dependence (TTFC ≤30 min). We observed a clear dose–response relationship and a threshold around 53 points, which is notably close to the national adequacy cut-off. This suggests health literacy as a potentially important and policy-relevant factor in tobacco control strategies. While causality cannot be inferred from self-reported, cross-sectional data, and the predominantly male sample limits generalizability to women, these findings underscore the need for longitudinal and interventional studies to determine whether improving health literacy can delay TTFC and reduce dependence.