1. Introduction
The electronics industry was estimated to employ 18 million workers worldwide in 2010 [
1], and East Asian countries including Japan, South Korea, and Taiwan contributed to over 50% of the global export values. Contrary to the high-tech, clean image of the industry, the work environment may contain chemical hazards (i.e., irritants, allergens, metals, fiberglass), physical hazards (i.e., low humidity, noise, nonionizing radiation), and ergonomic hazards (i.e., repetition, lighting, standing posture) [
2,
3,
4]. Chronic exposure to these hazards has been linked to possible adverse outcomes such as systematic toxicity, issues in reproductive health, and increased risk of cancer [
3]. Electronic manufacturing often takes place in clean rooms, where employees are required to be fully covered in protective suites [
5]. When the workers remain fully suited during the entire work shift, these head-to-toe garments can cause inconvenience and discomfort. In addition, the industry is known for rapid technological innovation, global competition, operating on shift work, high job demands, and performance-based pay systems [
3,
6]. All of the aforementioned factors may negatively affect the mental health of the employees. However, work-related mental problems are often overlooked due to the high confidentiality requirement and the great economic importance of the industry.
Mental disorders are associated with occupational dysfunction, long-term sickness absence, loss of productivity, poverty, social isolation, and economic burden (i.e., the payment of disability benefits) [
7]. Workers with mental disorders are likely to experience a range of emotional symptoms that can impair their performance at work and increase the risk of accidents [
8]. Chronic work-related strains are known risk factors of mental disorders. A longitudinal, prospective cohort study found that job strain arising from high job demands was associated with mental disorders among London based civil servants [
9]. Analysis of the national workers’ compensation database in Australia showed that the most common reasons for work-related mental health claims (41%) were work responsibilities, job demands, interpersonal conflicts in the workplace, etc. [
10]. Bromet et al. [
11] found that high job demands combined with lack of social support at work increase the risk of depression and anxiety. In addition to work-related factors, the risk factors for mental disorders or emotional symptoms also include non-work-related factors such as gender, lifestyle, etc. Women have a higher prevalence of depression than men, and this gender difference may be explained by genetic, neurohormonal, psychobiological, and social factors [
12,
13]. Alcohol drinking and cigarette smoking are associated with major depression and other emotional symptoms [
14]. In addition, regular exercise is a protective factor to depression or anxiety [
15]. It is crucial to identify early signs of mental distress to prevent the severe consequences of mental illnesses at the levels of the individual and the society.
East Asian countries such as Taiwan and Japan are reported to have a lower prevalence rate of depressive and anxiety disorders than do western societies [
16]. The lifetime prevalence of major depression in Taiwan (1.14%) is lower than that in the United States (5.15%) [
17], and the 12-month prevalence rate of major depression is 0.8% in Taiwan [
18]. However, “cultural stoicism” in Taiwanese adults may result in high diagnosis thresholds and low help-seeking behavior s compared with that of the adult population in western countries [
19]. Individuals in Taiwan with mental problems sometimes complain only of physical symptoms (i.e., pain) [
20]. Thus, proactive surveillance is likely necessary to identify the individuals who are at risk. However, few existing reports studied the prevalence of mental problems or emotional symptoms in the electronics industry in Taiwan or other Asian countries. Studies found that high job demands were associated with unhealthy mental states (such as depressive disorders) for this industry [
21,
22,
23], but how clean rooms as a work environment affects the workers’ mental health is still not well understood. A Chinese study found that male clean-room workers had higher work stress than their women counterparts, and clean-room workers had higher work stress than non-clean-room workers [
5], but more studies are necessary to validate the findings. Taken together, it is critically important to understand the emotional symptoms among electronics workers in Taiwan, especially considering unique characteristics of the industry and culture. As a proof-of-concept study, the aim of this study is to analyze potential risk factors to determine whether they have an independent influence on the emotional symptoms of Taiwanese workers in a representative electronics factory.
4. Discussion
In the present study, we explored the mental conditions in two different types of work environments in an electronics manufacturing factory: the office environment and the clean room environment. For office workers, working under high pressure, working long hours, a high workload, and an imbalance between physical and mental job demands and the worker’s abilities were strongly associated with emotional symptoms. For clean room workers, regular exercise was a protective factor, which is similar to the findings of the following two studies: Sugisawa et al. [
30] who found that both work load and health practices (i.e., exercise) had a significant independent influence on mental health after adjusting for age and marital status, and Nomura et al. [
15] who showed that healthy behaviors (regular exercise, a calorie-focused diet, or both) were negatively associated with higher job demands (OR = 0.69, 95% CI = 0.53–0.89) after adjusting for age, lifestyle, and health beliefs.
We noticed that for clean room workers, working under high pressure, facing conflicting demands, and social isolation at work were significantly associated with emotional symptoms after adjustment for age, gender, and other job demands, whereas no such correlations were disclosed in office workers. In the present study, the characteristics of clean room workers were young age, high proportion of men workers, high proportion of smoking, and many workers with shift work or night work, compared with that of office workers (
Table 5). These discrepancies may account for the different association with emotional symptoms between office workers and clean room workers. The finding regarding working under high pressure was consistent with a previous report which found that the risk of stress in clean workshops was higher than that in ordinary workshops in an electronics company [
5]. The high percentage of conflicting demands in the clean room environment may be associated with the fast-changing nature of the work, which often requires the workers to learn new knowledge or skills to adapt to new manufacturing processes in this constantly evolving industry. Workers in the clean room environment had to wear clean caps, protective suits, masks, gloves, and shoes [
5]. These clothing and protective gears may increase the difficulty of interpersonal communication, which may explain the social isolation of these workers.
We explored the gender differences in emotional symptoms and the associated factors and found that the women workers suffered more emotional symptoms than their male counterparts. The emotional symptoms in women workers were significantly associated with working under high pressure and conflicting demands after adjustment for age, lifestyle, and other job demands. This finding was similar to that of a previous study that showed women workers reporting more conflicting demands than men workers [
31].
There are several potential limitations to the present study, mostly due to the characteristics of the electronics industry. First, the participants in this study were recruited from one electronics enterprise. Although the enterprise was selected based on its representative characteristics of the general electronics industry, it is nonetheless a potential bias of this study. Second, because the requirement of confidentiality is high in the electronics industry, long-term follow-up of workers with mental problems was not possible, leading to the cross-sectional design of the present study. Thus, we could not monitor the progression of emotional symptoms or deduce the direction of cause for the emotional symptoms assessed. Third, although we adjusted for potential confounders including age, gender, lifestyles, etc., information regarding job control and support, personality, coping, long-term emotional symptoms, financial difficulties (i.e., low salary), living alone, negative life events [
24], as well as mediating appraisals (i.e., stress and job satisfaction) were not examined in this study. Fourth, because of the time constraints due to a tight production schedule, the instruments for diagnosing mental disorders and assessing job demands had to be simplified. Although using emotional symptoms as outcomes may reveal early warning signs of later disease development, the workers with symptoms of depression may or may not have depressive disorder. It is worth noting that, in the present study, 25% of the workers reported depression symptoms, which was close to the previously reported depression rates for clean workshop (24.8%) and ordinary workshop (23.8%) workers of a Chinese electronics factory assessed by the Center for Epidemiologic Studies Depression Scale (CES-D) [
5]. This result suggests that our survey likely represents a valid estimation of the real situation, and may be used as evidence to persuade industrial owners and the government to comply and support a large-scale, long-term study in the future.