There is a broad body of background data to show that teaching is a profession practiced well beyond established pedagogical hours in educational centers. In this sense, teachers continue their jobs within their homes when they perform different job-related activities, such as class planning, reviewing homework, tests and projects, preparing class material, and seeking out new teaching strategies (1, 2). Therefore, work overload among teachers can lead to different afflictions or diseases linked with the physical realm such as voice disorders (3), musculo-skeletal disorders and/or obesity (1, 4, 5), as well as a deteriorated mental health (6–11), and decreased quality of life (QoL) among teachers (5, 12–15). In this context, the WHO defines quality of life as an individual’s perception of their cultural environment and their values concerning specific goals, standards, and expectations. This is coupled with mental and physical well-being, state, level of independence, interpersonal relationships, surroundings, and individual convictions (16). Furthermore, apart from work overload, it has been shown that long working hours and long commutes to educational centers cause QoL problems for teachers (2, 17) as they lack the time to perform other types of activities, such as spending time with their families (2, 13). In Chile, several studies have been carried out on the quality of life of teachers, and a significant deterioration has been observed, mainly among women and young teachers (4, 5, 12, 15).

It has also been reported that a habit used by teachers to reduce their stress levels is TC (18) since it boost energy and reduces anxiety (19). Additionally, a considerable prevalence of CT has been found in younger and female teachers (6, 20). TC is a major cause of death worldwide, with around 7 million people dying annually due to direct TC (21). TC is related with different non-transmissible diseases, including cardiovascular diseases. A large part of the deaths (70%) related with cardiovascular diseases were attributed to modifiable risk factors including TC (22). TC has also been related with different types of cancer, including in the lungs, larynx, mouth, and esophagus, as well as chronic respiratory diseases and diabetes (23). TC has been related with deficient mental and physical health as well (24–27) since TC leads to premature skin aging, tooth loss, and increased gum disease risk, along with making wounds take longer to heal (23). TC can be related with mental illnesses too, since nicotine acts on neurotransmitter pathways, affecting serotonin release, which can cause depression (21). Reports indicate that people presenting some type of mental illness have a higher probability of TC, as it has been observed that an important of the mentally ill population smokes (25, 28–31).

Across Latin America, Chile has the highest rate of TC, reaching 38.7% in 2015, compared to Argentina at 22.6% and Brazil with a 14.3% rate (32). While the National Health Survey (ENS 2016–17) indicated a TC rate of 33.3% (33), this is still a high figure and must be considered. At the gender level, men have a higher TC rate than women (43.4% men, 36.5% women) while in the age group breakdown, the age groups of 20–29 years and 30–49 years have the highest TC rate (41.1 and 41.4%) compared to other groups (33), meaning that Chile has a sustained high TC rate. In this sense, few studies have reported the prevalence of TC in Chilean teachers. Thus, a prevalence between 31.96 and 35.9% has been described in Chilean teachers (6, 20, 34).

TC has been reported as having a negative effect on QoL, as different studies have observed that smokers have a lower QoL compared with nonsmokers (35–39). Additionally, studies on teachers report a strong relationship between mental health and CT. However, there remains a reasonable doubt whether a CT affects the mental health of teachers or whether low teacher mental health increases the risk of CT. Therefore, we set out three objectives for the following research. (1) To describe the prevalence of Chilean teachers who smoke, (2) to evaluate a bidirectional association between tobacco use and mental component of QoL.

Table 1 presents the sociodemographic characteristics analyzed by participants’ gender. A total of 647 teachers were analyzed of which 465 were women (71.8%) and 182 were men (28.1%). 63.2% of participants were in the first age category (<45 years). There is a significant association between marital status and participants’ gender (p < 0.005), with a higher rate among the category for men with a spouse or partner, reaching 53.8%. No significant association was observed between gender and age, having any children, work contract type, and the type of school where the participants worked.

The association between sociodemographic characteristics and MSD with teachers’ QoL appears in Table 2. The PHC on QoL has a significant association with the p50 of MSD (p = 0.023). On the other hand, in the MHC of QoL, there are significant associations in age, contract type, and p50 category (p < 0.01). Significant associations allow us to observe that most teachers below the T-Score for MHC are those age 44 or less and indicating that they had 6 or more body regions with MSD. Teachers with indefinite work contracts also had better mental health (87%).

Table 2 shows participants in different TC categories (non-smoker, ex-smoker, and smoker), analyzed against the participants’ sociodemographic traits. We observed a significant association between the participants from the first age category of <45 yrs. and the smoker-type TC category (68.7%, p < 0.05).

Table 3 compares the scores from each of the eight dimensions and the two summary measurements from the SF-36 QoL survey, analyzed with each participant TC category. The results showed significant differences between the role limitations dimensions due to emotional problems, mental health and on the MCS measurement (p < 0.05), observing that smoking teachers had a lower score on the aforementioned dimensions than non-smoking participants.

Table 4 is a logistic regression model, evaluating the association between the QoL summary measurements (PCS and MCS; low PCS and MCS are values under 50) and TC (smokers). Smoking teachers have a higher risk of low MCS scores (OR: 1.74; p < 0.05). Teachers who were < 45 years old presented a greater risk of significantly lower PCS scores (OR: 1.86; p < 0.01), while for teachers <45 yrs. age granted a protective factor, as they had a lower risk of low MCS scores (OR: 0.56; p < 0.01).

Table 5 contains a logistic regression with the TC category (smokers) as a dependent variable, and QoL adjusted by gender and age. Teachers with low MCS scores for QoL had a higher risk of being smokers (OR: 1.77; p < 0.01). This model also shows that the TC risk factor is independent of participants’ age and gender.

The main results show that TC prevalence among teachers considered in this study was 34.2%. This is lower than other studies, such as one from 2003 where the TC rate among Chilean teachers reached 35.9% (34). The decreasing TC rate appears not only among teachers, but also across Chile, falling from 39.8% in the 2009–2010 National Health Survey (ENS), to 32.5% in the 2016–2017 (33, 44). Across South America, Chile has one of the highest TC rates compared with other countries, such as Argentina at 22.5% and Colombia with 9.5% (19). However, in other countries, TC among teachers is notably lower than in Chile. TC among Turkish teachers stood at 20.1%22, while in Botswana it was only 3.2% (45).

The age of teachers in the sample mainly fell into the first age category, i.e., between 25 and 44 years old (63.21%) (Tables 1, 2). These data align with those reported by the Education Ministry in the 2020 teachers’ variation, which reported that 62.9% of teachers recorded in the Chilean school system fell within the <45 year age range (10). Our results also indicate a significant association between TC and teachers being <45 years old (p < 0.05). These results are similar to the data from the 2016–2017 ENS, where participants from the 25–44 year age group had a higher TC rate (33). Young teachers have been reported as being exposed to different problems related with teaching work, such as job instability, a situation which negatively impacts young teachers’ mental health given its concomitant financial uncertainty (11). We should add that young teachers are more likely to have negative mental health impacts as well since they have high anxiety and depression rates (6, 10) which could be related with the aforementioned problems.

It is widely documented that smokers tend to have a lower QoL than nonsmokers (36–38). With regards to our results, we can observe that smoking teachers tend to score lower on the role limitation dimensions due to emotional problems, mental health, and on the MCS measurement (p < 0.05). We also reported that teachers who smoke have a higher risk of lower MCS scores (OR: 1.74; p < 0.02) and that those with a low MCS score for QoL have a higher risk of being smokers (OR: 1.77; p < 0.01); we can thus indicate that TC can be related with mental health problems among Chilean teachers. These findings mesh with prior studies indicating that many people with mental health problems or diseases are smokers (25, 28, 29) and that TC also doubles of probability of suffering mental health issues (46).

The physical and mental health problems associated with TC in the smoking population are a widely documented situation, but they still cause alarm. Reports show that smokers who consume 1 to 3 cigarettes per day are 3 times likelier to die from lung or heart disease (26) and that having 1 to 4 cigarettes per day is associated with doubling smokers’ mortality risks, compared with nonsmokers (27). Yusuf et al. (22) reported that around 70% of deaths related with cardiovascular disease in middle-income countries, which includes Chile, were attributed to modifiable risk factors including TC. This shows the odds of improving smokers’ QoL if they quit smoking, as they would avoid generating TC-related cardiovascular diseases. It is noted that quitting smoking improves QoL (19, 24, 25) and that behavioral interventions involving both physical activity and quitting smoking simultaneously improve QoL better than only doing one of these interventions at once. Nduaguba et al. noted that ex-smokers who did physical activity had between 70 and 160% better odds of presenting higher QoL than ex-smokers who did no physical activity (39). In this sense, the relationship between TC and mental health is influenced by various factors ranging from nicotine addiction to social and environmental determinants. In that sense, addiction to nicotine, one of the main components of tobacco, has been reported to exacerbate or contribute to the development of mental health problems (29). TC can cause changes in the nervous system and interactions with psychiatric medications, complicating existing mental treatments and having critical effects on people’s QoL (30). In addition, it has been observed that people with mental problems present a high prevalence of TC (28). In this sense, teachers who are exposed to greater factors that may affect their mental health could suggest a bidirectional influence, in which mental health problems may increase tobacco use. Tobacco use, in turn, may exacerbate mental health conditions (31). In this context, it has been observed that in a bidirectional manner, teachers with high emotional exhaustion consume more tobacco, and conversely, teachers with high TC also present a higher risk of emotional exhaustion (6). Therefore, the evidence shows that health strategies in teachers cannot be treated as individual factors but must be addressed in a comprehensive manner.

The teaching profession has one of the highest workloads, as the work continues beyond the classroom, leading to physical and mental health problems for teachers (1, 7, 10, 12). When comparing teaching with other professions regarding engagement and work exhaustion, we observed that teachers had lower engagement and higher exhaustion than other professionals (8). It is thus important to apply methods and strategies to help teachers with their mental health (9) and TC (47). In this sense, the social environment and support systems are essential in TC and cessation. The presence of a supportive social network can facilitate smoking cessation efforts, whereas a lack of support can hinder them. In addition, social cues and reinforcement of smoking behavior through peer networks and the media can influence smoking (48, 49). Therefore, initiatives involving smoke-free (TC-free) environments within educational establishments involving teachers could be an opportunity to improve self-care and prevent TC-associated risks in teachers. In this sense, Chile has national plans involving the entire educational community to prevent TC (50). In the coming years, there should be an evaluation of the policies applied. In addition, intervention strategies aimed at teachers could be applied (47). However, interventions in teachers should be more comprehensive because the evidence in this work shows that the factors cannot be treated in isolation.

The present study has various limitations which must be considered. The first limitation is common to all cross-sectional studies, in that it provides a momentary snapshot of the teachers involved and does not allow us to carry out a cause-effect relation. The second limitation was the study sample. While the teacher sample was representative, as it covered the three national macrozones of Chile (north, center, and south), this only provides a general nationwide vision of teachers’ TC and QoL. The third limitation is that the data obtained for the study were gathered before the COVID-19 pandemic, which has negatively impacted teachers’ QoL due to lockdowns and the fact of adjusting to a reality which has affected both their mental and physical health (10–13). Therefore, if a study similar to ours was done today after the height of the pandemic, it is likely that QoL values would be lower, and TC would be higher.

The objective of this study was to analyze TC among Chilean teachers and observe the effects of TC on teachers’ QoL. The present study reported that approximately one-third of the school teachers TC. In addition, we observed that TC negatively affects Chilean teachers’ QoL, as we can observe lower scores in various QoL dimensions including mental health and role limitations due to emotional problems, along with MCS among teachers who smoke. We reported a bilateral association between MCS and TC where teachers with TC had a higher risk of low MCS while teachers with low MCS also had a greater risk of smoking. Our results thus describe a negative effect of TC on QoL. Programs and public policies should be implemented to help teachers quit smoking, by showing the benefits which arise once they quit, along with reducing the risk factors which affect teachers’ mental health.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by Ethics Committee at Pontificia Universidad de Valparaíso, Chile (n°BIOEPUCV-H 160-2017). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

PL: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Supervision, Writing – original draft, Writing – review & editing. VV-G: Investigation, Writing – original draft, Writing – review & editing. LB: Investigation, Writing – original draft, Writing – review & editing. LL: Data curation, Formal analysis, Investigation, Methodology, Supervision, Writing – original draft, Writing – review & editing.