Introduction

Older adults who smoke are a key focus for tobacco cessation efforts due to their higher mortality rates compared to both younger smokers and older non-smokers or those who have quit [1]. Research shows that elderly individuals who stop smoking can significantly lower their risks of coronary heart disease, lung cancer, and chronic obstructive pulmonary disease [2]. However, studies indicate that older smokers often receive less support from healthcare providers for quitting, possibly due to concerns about managing treatments given age-related physiological changes and potential side effects [3,4]. Moreover, while numerous studies have investigated smoking cessation rates and influencing factors in smokers, there remains a shortage of research specifically targeting the elderly.

Phillips highlighted the necessity of customizing health education and cessation strategies to meet the unique needs of older smokers [5]. Nevertheless, it remains uncertain which strategies are most effective for this demographic or how varied factors might influence cessation success among different age groups within the older population. To effectively address the age-specific requirements of tobacco control, interventions must be appropriately tailored. It is important to note that resources, impacts, and cessation approaches can vary significantly across different age groups [6]. Additionally, they pointed out the distinction between preventative measures, which are more effective among youth, and the need for more resource-intensive and complex strategies to address late-stage addiction in older smokers. It is therefore essential to identify the factors most critical to successful cessation efforts among middle-aged and older smokers. Health professionals are called to deliver interventions specifically designed for older smokers.

Globally, smoking prevalence has declined in many high-income countries but remains substantial in low- and middle-income regions, particularly in the Western Pacific, where population aging and smoking overlap significantly [7]. Taiwan represents a distinctive case in this context. Since 2012, the government has implemented the Second-Generation Tobacco Cessation Program, a nationwide initiative designed to reduce financial barriers and broaden access to cessation services. The program allows smokers to receive up to two treatment courses per year, each combining pharmacotherapy and counseling, with substantially lowered copayments. It also extends service delivery beyond outpatient clinics to include inpatient, emergency, and pharmacy-based care, while providing subsidies for follow-up and case management to improve adherence and treatment quality [8]. This comprehensive system, integrated within Taiwan’s National Health Insurance, enables accessibility across socioeconomic groups and facilitates large-scale monitoring of cessation outcomes [9].

Understanding the determinants of cessation success within such a policy framework offers valuable insights for countries facing similar aging populations and health system challenges. Therefore, this study seeks to explore the factors contributing to successful smoking cessation among older smokers receiving services in Taiwan and compare the corresponding contributing factors for middle-aged smokers.

Materials and methods

Results

Table 1 displays demographic characteristics for middle-aged and older smokers. Of those, 263,641 middle-aged patients received 442,133 treatment sessions, while 42,650 older patients accounted for 67,372 sessions. The average ages were 50.8 ± 6.9 for middle-aged and 71.0 ± 5.3 for older smokers. Older individuals had a higher proportion of males and tended to have smoked for longer durations with a medium to high FTND level.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 1. Characteristics of participants who received smoking cessation treatment.

https://doi.org/10.1371/journal.pone.0342345.t001

Middle-aged smokers achieved a six-month success rate in quitting smoking of 39.6%, while older smokers had a rate of 45.2%. Table 2 reveals the differences in success rates across various patient and institution characteristics, noting no significant difference with the use of bupropion (p = 0.2445). However, after adjusting for covariates, significant differences in smoking cessation success emerged between the two age groups, influenced by factors such as smoking duration, NRT, varenicline, and bupropion medications, health education counseling, and the urbanization level of the institution’s location.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 2. Overall and correlate-specific six-month smoking cessation success rate between middle-aged and older smokers.

https://doi.org/10.1371/journal.pone.0342345.t002

Separate regression analyses for middle-aged and older smokers are detailed in Table 3. We found that older smokers were more likely to quit if they had been smoking for less than 10 years (aOR=1.35, 95% CI = 1.22–1.50) and if they received medication treatment alongside health education counseling (aOR=1.10, 95% CI = 1.06–1.14). Conversely, middle-aged individuals benefited significantly from treatments involving varenicline (aOR=1.33, 95% CI = 1.26–1.40) and bupropion (aOR=1.24, 95% CI = 1.19–1.30), particularly in highly urbanized institution locations (aOR=1.29, 95% CI = 1.26–1.33).

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 3. Covariate-adjusted odds ratios of successful smoking cessation between middle-aged and older smokers.

https://doi.org/10.1371/journal.pone.0342345.t003

Fig 1 illustrates how different variables explain variances in smoking cessation success. The type of institution, FTND levels, and the duration of smoking had a more significant impact than other factors, similarly observed in both middle-aged and older smokers. The combination of medication with health education counseling notably influenced the success of smoking cessation among older patients than in middle-aged smokers.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Fig 1. Degree of explanation of the associated between the factor and smoking cessation success.

(A) Middle-aged adults. (B) Older adults.

https://doi.org/10.1371/journal.pone.0342345.g001

Discussion

Middle-aged (ages 40–64) and older (ages 65+) smokers achieved six-month smoking cessation success rates of 39.6% and 45.2%, respectively. We found that older smokers were more likely to quit if they had smoked for less than 10 years and received medication combined with health education counseling. In contrast, middle-aged smokers had higher success rates with varenicline and bupropion medications, particularly when treated at institutions in highly urbanized areas. Better to compare the factors contributing to successful quitting between the two groups:

“Middle-aged and older smokers essentially shared similar factors that contributed to the success of smoking cessation, with shorter duration of smoking associated with more in older smokers than in middle-aged smokers. On the other hand, both varenicline and bupropion, as well as higher urbanization, were associated more with successful quitting in middle-aged than in older smokers.”

Our six-month smoking cessation success rate for older smokers was higher than the 35.1% rate reported in Turkey by Çetinkaya et al. for patients aged 60 and over who participated in a smoking cessation outpatient clinic program [13]. Our older smokers also showed a higher six-month smoking quit success rate than middle-aged smokers, which is consistent with previous studies [14,15]. For example, the six-month follow-up quit rates for smokers aged 45–64 were 33.2%, and 47.1% for those 65 and older in primary health care centers [14]. Older smokers may have a stronger motivation to quit smoking than middle-aged smokers, likely due to health concerns [16–18]. Health-related factors, such as taking more medications or having chronic conditions [17,18], were positively associated with smoking cessation in smokers aged 60 years or older. In addition, a newly diagnosed chronic health condition might appear to motivate older smokers to quit smoking but did not motivate middle-aged smokers [17].

Older smokers are more likely to quit if they have smoked for fewer years. This observation is supported by literature indicating that a shorter smoking duration increases the likelihood of successful cessation [19–21]. Additionally, studies have shown that individuals who start smoking at an older age have higher quit rates compared to those who begin at younger age [22,23]. Al-Dahshan et al found that individuals who began smoking after the age of 18 had a significantly higher quit rate than those who started at or before 18 years old [14], suggesting that an early onset of smoking complicates cessation efforts. However, Chang et al. found that among smokers aged 60 and above, the duration of smoking does not differ significantly between those who quit and those who continue [21].

The effectiveness of varenicline and bupropion was significantly different according to age groups [24]. Those findings were similar to our findings that varenicline and bupropion were more effective for successful smoking cessation in middle-aged than older smokers. Chang et al. proposed an explanation of the adverse effects of varenicline that may cause physicians to be more willing to prescribe varenicline to younger smokers than older smokers [25]. It is plausible that adherence to varenicline was poorer in older smokers, but this remains uncertain and warrants further investigation. Scholz et al. showed the success rates for older groups using NRT were equal to or better than those of older groups using bupropion and varenicline, which was also consistent with our present findings [24].

We also found that medication therapy, along with health education counseling, played a more significant role in contributing to smoking cessation among older smokers. The findings are consonant with those of Kim et al., who found that higher odds of smoking cessation for 6 months were positively associated with higher levels of behavioral counseling sessions, but this study did not investigate the age stratification for counseling association with quit rate [16]. Huang et al. also showed that effective counseling is an essential factor for successful smoking cessation [26]. Cohen-Mansfield et al. also observed that more social contact or support may be associated with smoking cessation for older people [18].

Smokers treated in urbanized areas appear to benefit more from quitting programs, particularly middle-aged smokers; however, this benefit was less obvious in older smokers. The urban clinics likely offer advantages due to superior resources and accessibility [27]. Nonetheless, these advantages might not be as effective for older smokers, potentially due to socioeconomic factors. Kim et al. noted that socioeconomic status (SES) inequalities in cessation rates increase among young and middle-aged individuals but begin to diminish after the age of 60 [16]. In contrast, data from the China Health and Retirement Longitudinal Study (CHARLS) suggest that the urban or rural location of residents was not significantly associated with smoking relapse [28].

The strengths of our study included the highlighting of differences in factors that affect smoking cessation between middle-aged and older smokers in a large, population-based sample in a clinical setting. We performed regression modeling to adjust for important confounding factors (including smoking years and type of medication) by separating the age-specific groups. In addition, our study was population-based, which covered all smokers who sought treatments from the Second-Generation Tobacco Cessation Program. The study sample was therefore considered representative. The present study has several limitations. In our study, first, we don’t consider the individual’s health condition since such information was not routinely collected in the national Second-Generation Tobacco Cessation Program. The omission of these data may have introduced unmeasured confounding, as older adults’ health status could affect both their motivation to quit and cessation success. Second, we don’t have socioeconomic status information that may have led to additional residual confounding, given that access to cessation resources and treatment affordability often differ by socioeconomic background.

This study suggests that while the basic mechanisms of smoking cessation are similar across different populations, the success of specific interventions may be influenced by the middle-aged or older context due to differences in duration of smoking, medication, health education counseling, and urbanization of the institution’s location. These findings imply that Taiwan’s Tobacco Cessation Program could further improve its impact by tailoring intervention strategies to meet the distinct needs of each age group. For example, emphasizing medication adherence and continuous counseling support for middle-aged smokers, while prioritizing accessibility and comorbidity management among older adults.

Future research should examine the long-term health outcomes of smoking cessation across age groups and incorporate socioeconomic indicators to identify disparities in cessation success. Such evidence would provide valuable guidance for optimizing cessation services and ensuring their effectiveness among both middle-aged and older populations.

Supporting information