In this study, 53.1% of our subjects reported suffering from dysmenorrhea. The prevalence of dysmenorrhea among women younger than 30 was 73.8%, which is consistent with the results of previous studies [24],[25].
Both factors of emotional labor, emotive effort and emotive dissonance, were significantly associated with dysmenorrhea among all workers. Emotional labor induces stresses [8],[26],[27] that can cause disorders in the secretions of pulsatile follicle-stimulating hormone and luteinizing hormone and can then impair follicle development [28]. Impaired follicle development induces the synthesis and secretion of progesterone, thus causing an increase in the synthesis of prostaglandin F2-alpha and prostaglandin E2 as well as the binding of prostaglandin to myometrium receptors [29],[30]. Therefore, dysmenorrhea has been thought to result from an imbalance of prostaglandin, which controls the tone of the myometrium and the blood vessels [29]. In addition, an increased synthesis of prostaglandin F2 in the myometrial cells due to the stress-related hormone cortisol has been suggested to induce dysmenorrhea [31]. In short, emotional labor might be one of the psychosocial stressors causing dysmenorrhea.
However, the association between emotional labor and dysmenorrhea varied according to occupational type. Both emotive effort and emotive dissonance were significantly associated with having dysmenorrhea among call center workers. Among sales workers, emotive effort was associated with having dysmenorrhea, but with borderline statistical significance. However, there was no statistical significance in the association between emotional dissonance and dysmenorrhea.
A number of factors may explain these results. First, the frequency, period, and intensity of interactions with customers were not investigated in this study. According to a study by Park et al. regarding the frequency of customer interactions, sales workers were found to meet with an average of 32 customers throughout 5.4 hours of work per day, while call center workers were found to speak with an average of 125 customers throughout 5 hours of work per day [32]. Kim et al. found that sales workers meet an average of 100 customers in a typical weekend day, and sales workers were found to spend three to five minutes responding to one customer. In addition, sales workers were found to face double the number of customers during the weekend as compared to the total number of customers they face during the weekdays [33]. However, call center workers receive an average of 550 calls per day [33]. Park et al. reviewed the frequency of emotional events to examine factors related to the intensity of emotional labor in the workplace [32]. They reported that sales and call center workers experienced unreasonable requests from customers 3.6 and 3.9 times, lost face (due to a customer’s rude comments) 1.6 and 3.7 times, and endured violent comments from customers (insulting and cursing) 0.6 and 2.7 times, respectively, during a two-month period [32]. In addition, call center workers experienced sexual harassment an average of 1.1 times over the two-month period [32]. Therefore, call center workers interact with customers more frequently and intensely than sales workers do. Our finding of a stronger association between emotional labor and dysmenorrhea among call center workers supports their findings.
Second, while sales workers communicate with customers face-to-face, call center workers communicate only voice-to-voice; therefore, nonverbal communication is only applicable to sales workers. Nonverbal communication including gestures, eye contact, and touch accounts for two-thirds of typical communication [34]. When there is a lack of nonverbal communication, emotive effort or emotive dissonance can increase. Nonverbal communication in itself can also be a stressor that causes dysmenorrhea. As a result, the lack of nonverbal communication among call center workers can confound and affect the association between emotional dissonance and dysmenorrhea. Third, different job requirements between these two types of jobs could be a reason for the difference in the effect of emotive dissonance on dysmenorrhea between the two groups. Although job decision latitude for call center workers is low [35], sales workers who sell clothing in large-scale outlet stores examined in the present study possessed some job decision latitude. Furthermore, sales workers tend to be people who enjoy working with the public and selling items/services. Thus, the effect of emotive dissonance on dysmenorrhea might be lower among sales workers.
No significant difference in the distribution among the high-risk emotive effort group was found by occupational type; however, the call center workers comprised a higher proportion of workers at a high risk of emotive dissonance. Among the general and occupational characteristics considered in this study, we found no factors related to being at a high risk of emotive dissonance (data not shown). As mentioned above, emotional difficulty, caused by a lack of nonverbal communication, may be an important cause of emotive dissonance.
The limitations of this study are as follows. First, causality between emotional labor and dysmenorrhea cannot be determined due to the cross-sectional design of this study. Second, the participants worked in one area in Seoul; thus, there are limitations to the generalizability of our findings to other sales and call center workers in South Korea. However, we think that the characteristics of the sales workers in our study might be applicable to other sales workers in South Korea because our investigation was conducted on workers from large-scale outlet stores. In addition, because the working processes of call center workers are comparatively similar nationwide, regional variation is not expected to vary widely among different call center workers. Third, we were not able to investigate how many inbound or outbound calls the call center workers received. An inbound call involves responding to a previously submitted inquiry, while an outbound call is assumed to occur without a previous inquiry from the customer. For call center workers, the type of calls, inbound and outbound, may affect their working conditions, types of emotional labor, negative events, and work processes after events [32]. Fourth, severe menstrual pain could be caused by secondary dysmenorrhea due to another primary disease (organopathy or another disease); however, this factor was not excluded from this study.