A systematic review and meta-analysis study was performed to investigate the effectiveness of the existing smoking cessation services in the Thai primary health care setting. Mixed automated and manual search strategies were employed. The databases from January 1993 to June 2018 were used: CINAHL, PubMed, ScienceDirect, SpringerLink, and PUBMED. A combination of the constructs “smoking cessation”, “tobacco control”, “tobacco cessation”, “intervention”, “counseling”, “motivational interviewing”, “quit”, “stop”, “abstinence” and related keywords were searched in order to certify comprehensive coverage of published papers.

We determined the eligible studies to catch both meaningful and methodological attributes. The coding emphasized the research design, purpose of the study, factor associated with the attributes of study participants, nature of the ordinary implementation and comparison, follow-up, intensity, and outcome assessment. The risk of bias was assessed by The Cochrane Collaboration tool [11] to investigate the quality of the selected papers. Then, we conducted meta-analyses using Review Manager (RevMan5.3, The Cochrane Collaboration, Oxford, England) [11].

The findings revealed that the effectiveness of the existing smoking cessation services in the Thai primary health care setting was limited. Previous studies have shown that only 10% of smokers were able to quit smoking after six months overall [12]. In other words, the effectiveness of existing smoking cessation services was assessed for each setting using a six-month quit rate as an indicator: 1) 18% for smoking cessation clinics in the hospitals [13], 2) 1% for Quit for King project [12], 3) 24.5% for The SMART Quit Clinic (Pharsai Clinic) in Ubon Ratchathani University [14] and 4) 37% for Thailand National Quitline (TNQ) [15]. Therefore, it is believed that primary healthcare providers' tobacco cessation services should be better promoted, remarkably increasing usage of existing smoking cessation services.

Approximately three-fourths of Thai smokers have not used tobacco cessation services [1], particularly in the primary healthcare setting. Additionally, the TNQ [15] reported that less than 10% of Thai smokers received smoking cessation services by the TNQ. Furthermore, approximately two-fifths of clients living in Bangkok and the central region of Thailand and most smokers were referred by the secondary and tertiary hospitals. Also, only 0.29% of customers were recognized by the TNQ's services information from sources of primary healthcare. The findings reflected that most smokers living in rural areas had not accessed the smoking cessation service provided by the TNQ. Because there are numerous hurdles to smoking cessation services for smokers in the community. As a result, barriers to smoking cessation service use in primary care-the smoking cessation service system was not blatant-should be found to raise the number of smokers using the existing services, notably the referral system to the TNQ. The meta-analyses demonstrated that smoking cessation advising utilizing multisession proactive stage-matched telephone counseling directing was the best procedure for smoking cessation on 7-day Point Prevalence of Abstinence (PPA) when contrasted and no treatment or regular consideration. Alternately, different intercessions brought about nonsignificant contrasts between the trial and control gatherings. In synopsis, phone counseling was the most appropriate methodology for working with smoking suspension in grown-up smokers in the primary care setting. More research is needed to determine the optimal intervention length, force, and frequency for assisting smokers in quitting in primary care [16].

In the second procedure, quit rate outcomes were determined in the prior procedure as well as the practical goals were drawn to realize these outcomes. Then, we compared each of the practical goals between the most crucial and variable elements extracted in the former procedure, and a matrix of change goals was created by intersecting practical goals with the determinants. Finally, quasi-experimental research was selected as a research design in this study. The goal of the intervention is to see how an integrated smoking cessation service model affects smoking status in community smokers by comparing the experimental and control groups' 7-day PPA scores at six months.

The SEM is a social and environmental theory [7]. It involves systems of individual and environmental relationships, complex relationships between individuals living in the system, and interdependent relationships between members or system components. If any part of the system changes, it affects other parts of the system as well. Applying this idea to health promotion classifies the environmental factors influencing health behavior into five levels: intrapersonal, interpersonal, organizational, community, and public policy.

From past projects, it was found that the SEM was used to describe health behaviors and to implement health problem-solving work with different models. With links between biological factors, behavior, and sociology, the importance of using the SEM for promoting the appropriate health behavior focuses on modifying individual factors and social environments by implementing five levels of modifications that require a wide variety of strategies and operations. It is an inclusive and complete health promotion model that can be used both to describe behavior and guide management and practice.

The SEM and the theory of behavior change procedures were applied to develop an integrated smoking cessation model for the primary health care system. There are different levels of development:

2.3.2. Individual and Interpersonal Levels

Consisted of 1) delivering brief advice to promote the smokers quit through home visits, 2) referring the smokers’ information for receiving the intensive staged-based [17] proactive telephone counseling for smoking cessation by the TNQ counselors via the mobile application, and 3) providing follow-up for preventing relapse. An overview of the application of the SEM is shown in Table 1.

The TTM [9] has been practicing behavioral change, especially smoking cessation. This model helps the researchers understand how to provide the specific intervention in each stage. People could use different techniques to change their behaviors in each stage depending on the surrounding context. Generally, the TTM has been used to explain changing behaviors, serving the specific technique to change unexpected behaviors [17]. Ten processes of change can be divided into two higher factors labeled cognitive/experiential and behavioral. Also, self-efficacy and decisional balance (i.e., pros and cons) are crucial components of the TTM [18], and these elements appear to help clarify why health behavior changes occur. Moreover, decisional balance is is associated with the perceived “pros” (merits) and “cons” (demerits) between ongoing current behaviors and changing behaviors. Decisional balance demonstrates weighing the advantage and disadvantages of changing through vigorous behaviors and is essential for beginning phase movement [9].

Table 1. Application of an ecological model framework to develop an integrated smoking cessation model in a primary health care system.

S.No	Level	Intervention
1	Community, organization, and policy	1. Developing the potential capacity of the CHWs to help quit smoking through brief smoking cessation advice, referring the smokers’ information for receiving intensive counseling for smoking cessation by the TNQ, and home visits to prevent relapse.   2. Developing the potential capacity of nurses working in the HPHs in supervising the CHWs following the study protocol.   3. Providing intensive counseling for smoking cessation by the TNQ counselors
2	Individual and interpersonal	1. The CHWs provide brief advice to quit smoking to raise motivation to quit smoking   2. The TNQ counselors provide intensive counseling for smoking cessation by phone, and the CHWs visit home to prevent relapse.

Finally, the TTM [9] was used as the theoretical support for the outcome identification-smoking status. The study participants were asked about their quit attempts 7, 30, 90, and 180 days after the quit date. Additionally, 7-day PPA at 180 days after the quit date was used to identify smoking status using self-report. On the one hand, smokers participating in the program can stop smoking for seven consecutive days at 30, 90, and 180 days after quitting tobacco use.

Fig. (2). The study protocol.

We designed the smoking cessation program's significant components in accordance with the literature review and set a meeting with stakeholders, including two sessions:

After the ECNP approved the study proposal, the researchers contacted the related organizations in the selected areas for reviewing participant’s data and data collection. Then, the researchers contacted the nurses working in the selected HPHs to screen the participants who met the name lists' criteria. The community smokers and the CHWs who meet the inclusion criteria from the name lists reported by the Health-promoting hospital were assigned to the study participants.

The participants were smokers from four communities, selected from one province in the central region of Thailand, Nakhon Pathom Province. It was because the smoking prevalence in this province [19] had still been higher than the indicator of Thailand National Strategic Plan for Tobacco control. Moreover, this province could represent all provinces since it was combined with urban and rural areas. Nakhon Pathom comprised seven districts. The Mueng Nakhon Pathom district was specifically be selected for consideration in this study. Moreover, this area is a good representative of the current smoking situation. It consists of eighteen HPHs. The HPHs were selected by a simple random sampling technique. Finally, two HPHs were randomly chosen to represent HPHs. Then, the selected HPHs were randomly assigned into experimental and control groups, with two communities in each group. To avoid the threats of validity, the experiment and control group participants were divided into two groups using a matched-pairs design at the beginning.

The research instruments consist of two parts:

Firstly, the intervention instrument, which is a Smoking cessation program, includes 1) study protocol, 2) Smoking cessations handbook for the Community nurses and the CHWs are composed of: 2.1) knowledge associated with smoking cessation service includes Tobacco hazard and impact on individual health, second hand, third-hand smoker, smoking cessation process, smoking cessation treatment, helping smokers base on staged match intervention starting by brief intervention and relapse prevention and 2.2) smoking cessation service skill.

Secondly, instruments for data collection are demonstrated as follows:

Demographic data of participants includes 1) Demographic data of smokers consists of gender, age, educational level, occupation, underlying disease, type of tobacco, and smoking duration, 2) Demographic data of the CHW consists of gender, age, academic level, occupation, the CHW experience, acquiring knowledge regarding cigarettes, and smoking cessation assistance experience.

The heavy smoking index (HSI) [20] includes two questions to examine the level of nicotine dependence. The nicotine addiction level was interpreted by the score as follows: low addiction (0-2), moderate addiction (3-4), and high addiction (5-6).

The staging questionnaire [21] consists of five questions based on the stage of change model, with the goal of determining the smokers' stage of change in the community: “Are you seriously thinking of quitting smoking?” The stage of change was interpreted by the score as follows: 1) No, not at all thinking about quitting (pre-contemplation), 2) Yes, within the next six months (contemplation), 3) Yes, within the next 30 days (preparation), 4) Yes, I quit within the last six months (action), and 5) No, I quit more than six months ago (maintenance).

Quit attempt measurement [22] includes a question that includes a question: “How many times have you stopped smoking for 24 hours or longer?”.

Lastly, the Validity check instrument, two instruments for appraising the CHWs' capacities for offering smoking cessation service, was tested as a validity check as follows:

Knowledge Associated with Smoking Cessation (KASC) includes a set of questions developed by the researcher. It was contained with five dimensions including 1) Tobacco hazard and impact on individual health, second hand, third-hand smoker 2) benefits of smoking cessation, 3) brief advice for smoking cessation process, 4) nicotine withdrawal and solutions, and 5) referring system to the smoking cessation service and arrange to follow up methods. It consisted of 25 items with a dichotomous answer for choosing: “correct or incorrect” (correct = 1 point, incorrect = 0 point). The KASC in the Thai version obtained good content validity; the reliability using Cronbach’s alpha was 0.80 [23]. The content validity index was 0.83-1.00 for item-content validity index (I-CVI), 0.92 for Scale-level CVI/universal agreement (S-CVI/UA), and 0.98 for Scale-level CVI/average proportion (S-CVI/Ave) [23].

Smoking cessation assistance behavior (SCAB) includes a set of questions developed by the researcher. This instrument was used for reporting smoking cessation assistance behaviors among the CHWs by themselves. The procedures for smoking cessation assistance behavior include six steps as follows: 1) building relationships and assessing motivation to quit smoking, 2) convincing smokers to quit by providing brief advice for smoking cessation, 3) referring to TNQ, and 4) offering follow up to prevent relapse among smokers after quitting smoking. The 27 Likert scale items with five categories (Always, Usually, Sometimes, Rarely, and Never) were used; higher scores indicated more frequent smoking cessation services. It was rated on the frequency of determining smoking cessation assistance behavior as a 5-point scale from 0 (Never) to 4 (Always). The SCAB in the Thai version obtained good content validity; the reliability using Cronbach’s alpha was 0.88 [23]. The content validity index was 0.83-1.00 for item-content validity index (I-CVI), 0.93 for Scale-level CVI/universal agreement (S-CVI/UA), and 0.99 for Scale-level CVI/average proportion (S-CVI/Ave) [23].

Smoking cessation assistance capability and knowledge associated with smoking cessation among the CHWs have been validated in this program by questionnaires developed by the researchers. Five experts confirmed content validity. Then, the reliability was tested by data collecting in 30 CHWs working in another sub-district.

This project was a quasi-experimental design that organized the subjects; smokers were randomly allocated into two groups-experimental and control groups. The sample size of smokers was calculated using G*Power Program version 3.1.9.4, with 72 participants in each group.

Propensity Score Matching (PSM) was used to analyze the probability of the outcomes between the experimental and control groups after balancing the covariates from the literature review [24], including age [25], the total number of years for education [26], underlying disease [27], smoking duration [28], and nicotine addiction level (HSI score) [29].