A cross-sectional analytical study was conducted among 588 Sugarcane Factory Workers in Northeast of Thailand. Data were collected from December 2017 to April 2018. The sample size was calculated based on Hsieh FY et al., for multiple logistic regression formula [16] which was used to identify the correlation in the multivariable analysis by using multilevel logistic regression. The approximate sample size was 327 which were further adjusted to control the over-fitting using the rho (ρ) of 0.50 and Variance Inflation Factor (VIF) equal to 2.00. Therefore, the total number of the sample was 588. Data sampling processes were used as a multistage sampling technique. Firstly, 4 factories in the North-east of Thailand were randomly selected. Then 3 departments facing high concentrations with bagasse dust at the working area were drawn. Then, 588 samples were selected from the total 7,965 sugarcane factory workers registered at the department of industrial work by applying systematic random sampling technique among those 3 departments in proportion to size of the population. The inclusion criteria of the respondents were workers who were 18 years of age or older, Thai nationality, willing to participate in the study, having no communication problems with the research. Those suffering from the respiratory diseases including allergies, asthma, and emphysema, were excluded.

Structured questionnaire was developed based on the research questions. The content validity of questionnaire was tested by 3 experts and had a Cronbach’s alpha coefficient of 0.86. The questionnaire consisted of 3 parts as follows: 1) Demographic characteristics include sex, age, education, marital status, income, type of RPE used and information on the usage of RPE; 2) HBM include Perceived susceptibility; refers to one’s perception of the risk or the chances of contracting a health disease or condition (had 5 questions), Perceived severity; refers to a person’s feelings on the seriousness of contracting an illness or disease (had 5 questions), Perceived benefits; refers to a person’s perception of the effectiveness of various actions available to reduce the threat of illness or disease (had 5 questions) and Perceived barriers; refers to a person’s feelings on the obstacles to performing a health action (had 5 questions) and was interpreted as good level (18.4-25 scores), moderate level (11.7-18.3 scores) and poor level (5-11.6 scores). 3) The behavioural usage of the RPE, behaviour of using RPE before working, while working and after work, had 15 questions and was interpreted as good level (35.4-45 scores), moderate level (25.2-35.3 scores), poor level (15-25.1scores).

Ethical approval for this study was obtained from the Khon Kaen University Ethics Committee for Human Research (HE602331). The research participants were enrolled in the study after written informed and voluntary consent.

Descriptive and analytical statistical data were analysed with STATA® (version.13; College Station, TX, USA: Stata Corp). Demographic characteristics of the participants were described as frequency and percentage for categorical data; mean and standard deviation for continuous data. Inferential statistics, a simple logistic regression, was used for bivariate analysis to identify individual factors associated with good behaviours for the usage of RPE. All statistically significant variables in bivariate logistic regression having p-value less than 0.25 were processed into the multiple logistic regressions. Crude Odds Ratios (ORs) and Adjusted Odds Ratio (AORs) were calculated and reported with a 95% confidence intervals. All statistical tests were two-sides and p-value less than 0.05 were considered statistically significant.

The result in this study indicated, 71.94% of SWF were males with an average age of 38 years and average income of 10,146 Thai baht (THB) per month. The most common type of RPE used was cotton masks 94.56%. The information on the usage of RPE as obtained from the safety officers was 77.89%, from supervisors was 70.41% and knowledge boards in factories was 37.24% [Table/Fig-1].

A moderate level of perceived susceptibility was found among 83.16% (95% CI 80.13-86.20), good level 10.37% (95% CI 7.90-12.84) and poor level 6.47% (95% CI 4.47-8.46).

A good level of perceived severity was observed among 54.80% (95% CI 50.04-58.12), moderate level 42.82% (95% CI 39.52- 47.56) and poor level 2.38% (95% CI 1.14-3.62).

About 89.46% (95% CI 86.97-91.94) of SFW noticed a good level of perceived benefits, moderate level 10.20% (95% CI 7.75-12.66) and poor level 0.34% (95% CI 0.13-0.81).

A max of 67.00% (95% CI 63.20-70.82) identified a moderate level of perceived barriers, poor level 20.41% (95% CI 17.14-23.68) and good level 12.59% (95% CI 9.90-15.27) [Table/Fig-2].

The total 588 sugarcane factory workers, the majority of them has good behavioural usage of RPE in good level (35.4-45 scores) 64.80% (95%CI: 60.92-68.67) than in medium (25.2-35.3 scores) 33.16% and poor level (15-25.1 scores) 2.04% [Table/Fig-3].

Bivariate analysis on the association between each independent variable and good behavioural usage of RPE among SFW was performed by simple logistic regression presenting the crude OR with 95% CI, and p-value. All factors that had p-value <0.25 were proceeded to a multivariable analysis by using multiple logistic regression [Table/Fig-4].

Multiple logistic regression analysis by Backward elimination indicated that SFW who have group of perceived benefits in good level were 2.66 times more likely to have good behaviour in RPE usage when compared with those whose perceived benefits were of a poor level (Adjusted OR=2.66, 95% CI=1.53 to 4.62, p=0.001) [Table/Fig-5].

Our results indicated that most workers had good level of behavioural usage of RPE (64.80%) that about as high as (94.56%) use cotton masks as types of RPE usage. In addition, most of the sources of information on RPE usage provided by safety officers were (77.89%), by supervisors (70.41%) and by knowledge boards in factories (37.24%) respectively. The workers with good level of behavioural usage of RPE might have good practice of using that RPE to protect themselves from their work such as helmet, safety shoes, using boots and ear plug and ear muff depending on different working environment [11,17]. The respiratory protective equipment such as wearing facemasks have significant effects with perceived benefits with one of HBM components to protect from airborne contaminants and some of the infections [15,18,19].

Additionally, workers who had good level of HBM in perceived benefits were 2.67 times more likely to have good behaviour usage of RPE when compared with those who had poor level of HBM in perceived benefits (Adjusted OR=2.66, 95% CI=1.53 to 4.62, p=0.001). In addition, some research also reports the association between HBM and RPE, especially the good impact from the components of HBM (i.e., perceived susceptibility, perceived severity. perceived benefits and perceived barriers) has influence on RPE usage to protect their personal safety at work [15,20,21].

The HBM has been functional to the likelihood of an impressively broad range of health behaviours among a varied range of inhabitants. The HBM focused on two aspects of individuals’ representations of health and health behaviour, perceived susceptibility to illness or health problems [22]. It was consistent to current study and found that the levels of perception of the HBM in perceived benefits were associated with the behavioural usage of RPE in good levels of 89.46% (95% CI: 86.97-91.94).

More interestingly, the results found that the SFW who have a good level of perceived benefits were 2.66 times more likely having a chance in behavioural usage of RPE than those SFW with perceived benefits at a poor level (Adjusted OR=2.66, 95% CI: 1.53 to 4.62, p=0.001). The current study presents a similar result to a previous study on HBM related to self-care behaviour of patients at Sub-District Health Promoting Hospital [23,24]. Moreover, the perceived benefits refer to how effective facemasks are believed to be in preventing the spread of diseases by the community and/or individual [24], this result is consistent with the findings of Sim SW et al., [15]. Although perceived susceptibility seemed to be the most substantial aspect in determining compliance, perceived benefits of mask-wearing were set-up to have significant effects on mask-wearing compliance as well [24].

This study had some limitations. First, current study is focused and carried out in particular factory in a region, therefore it could not represent the whole population of SFW in Thailand. Second, as the curent study was a cross-sectional analytical study, it could not infer causality; therefore, further study with experimental study design by input intervention on significant factors is recommended to provide the better understanding of the causal relationship between HBM and behavioural usage of RPE among SFW in Northeast of Thailand.

This study shows that HBM has an important role to develop a healthy environmental workplace. The good-level of perceived benefits have a strong association with behavioural usage of RPE among SFW in North-eastern of Thailand. Therefore, the HBM in perceived benefits will be a strategy of an incentive for workers to practice with good behaviour in their workplace environment. The current study of cross-sectional design is the first finding of significant factors associated with obvious results. Then, further studies will follow the advice from the evidence that promotes safety behaviour change in real work situations.