Relationship between psychosocial stress dimensions and salivary cortisol in military police officers 1

Abstract Objective: to analyze the relationship between psychosocial stress dimensions and salivary cortisol in military police officers. Method: cross-sectional and analytical study with 134 military police officers. The Effort-Reward Imbalance (ERI) Model scale has been used to assess psychosocial stress. Salivary cortisol was collected in three samples. The following tests were used: Student's t-test, Mann-Whitney, ANOVA, Bonferroni, Kruskal-Wallis and Dunn. Pearson and Spearman correlation methods were used, as well as multiple linear regression. Cortisol at night showed an ascending statistical association with the psychosocial reward (p=0.004) and a descending association with the effort-impairment scores (p=0.017). Being part of the Special Tactical Operations Group (GATE) and the diastolic blood pressure explained 13.5% of the variation in cortisol levels on waking up. The sectors GATE, Special Patrol of the Elite Squad of the Military Police and Motorcyclists explained 21.9% of the variation in cortisol levels 30-minute after awakening. The variables GATE sector and Effort Dimension explained 27.7% of the variation in cortisol levels at night. Conclusion: it was evidenced that salivary cortisol variation was influenced by individual, labor and psychosocial variables.

for the diagnosis of stress has become routine, due to the easy of collection and the low cost, when compared to other methods (7) .
Regarding stress, some studies that have assessed stress in the Brazilian (11) and Swiss military police officers (12) and in the elite squad of the Italian military police (2) are highlighted. As for salivary cortisol levels, these were investigated in German (3) , American (13) and Dutch (14)(15)(16) police officers. However, these studies assessed separately the self-perception of stress or the salivary cortisol curve, which allow identifying a gap in the knowledge about the health of the police officers.
In this context, it was established as study problem:  Figure 1 shows the CIAs, subdivisions within each CIA, work shift and tasks.
The study population consisted of 416 BOE military police officers, of which 317 were in active service. The subjects in active service were included in the sample, with age range from 18 to 65 years. The exclusion criteria were: police officers who had worked less than one year in the corporation (54 police officers); female police officers, since they represent less than 5% of the BOE population and develop a different cortisol response in comparison with male sex; and those on corticosteroids (7) . Based on these criteria, the eligible population of this study was 263 military police officers.
Of these, 258 answered the data collection instrument and 134 collected the three samples of saliva.
The sample size calculation was performed using G*Power software Version 3. 1.2 (2009) (6) . Dr. Johannes Siegrist's research group shortened the scale in order to facilitate its use.
In this study, the recommendations of its creators were followed, with the removal of 16 questions from the long version validated in Brazil (5) . The short version validated in Brazil (18) was considered reliable (α=0.703).

Reward
In this study, cortisol levels at night, in turn, in addition to being negatively related to waist circumference, showed the highest scores for nonsmokers police officers and for those without reports of health problems. The low variation of cortisol levels during the day, that is, low cortisol levels in the morning and high at night, may be associated with flattening of the cortisol curve, which indicates signs of chronic stress (25) . These findings lead to inferring that police officers with the lowest abdominal circumferences, who did not smoke and without health problems were possibly more active and committed to work, finding it difficult to "disconnect" from work at night. On the other hand, stress and hyperactivation of HPA axis can influence the increase of adipose tissue and vice versa, so that obesity can contribute to the consolidation of a state of chronic stress (23) . As such, increased cortisol levels on waking up may be related to their affinity for work, and increased cortisol levels at night may be to assure readiness, since even if they do not work daily on the night shift, they may be requested at any time, remaining in state of readiness.
High cortisol levels on waking up were also identified among firefighters assessed after exposure to a highly stressful and potentially traumatic event, and associated with physiological reactivity for tasks involving high demand and fear conditioning (27) .
Thus, although all sectors of BOE have the mission of maintaining public safety and face the same working conditions, the work at GATE, Kennel and Motorcyclists sectors is quite different and is a reference for the entire state, which may allow a closer identity thereof.
The weekly workload was negatively related to cortisol on waking up, ie, the higher the workload, the greater the overload, the more frequent the exposure to stressors at work, the less cortisol response on awakening. However, police officers who considered the number of people on the job scale as sufficient had the highest average of cortisol levels at night Tavares JP, Lautert L, Magnago TSBS, Consiglo AR, Dal Pai D.
when compared to those who rated it as insufficient.
This data may be intrinsic to the mobilization of these workers towards work, surpassing their physical and mental capacity, without noticing that the overload may be due to the lack of employees and the excessive overtime worked. For some professionals working in/ with dangerous activities, such as the police officers, a certain amount of stress is positive and necessary so that the work is achieved (1) . This is a characteristic of these professionals, who face, in addition to the direct demands of the work, hierarchy and discipline, other demands related to the organization of the work in view of the expectations of the society (11) .
However, many suffer from such work regime. In the opinion of the military police officers who patrol the streets, having two jobs, working night and day, spending 12 hours on the street, on alert, working under pressure and sleeping little, affect their quality of life and health in a counterproductive way (26) .
In addition to the association between cortisol levels and individual and work variables, some studies have experimentally identified alterations in salivary cortisol levels in stress situations (3,13) and reported that well-conducted simulations can help to improve worker performance and reduce stress. In a simulation of school shootout conducted by the German police, cortisol levels were higher at the beginning of training and decreased subsequently (3) . In the assessment of the decision-making capacity of US police officers, in a simulated work-stress situation, the higher cortisol variation was associated with a lower number of errors (better performance) to armed targets and with a better perception of stimuli related to threat and surveillance (13) .
The association between cortisol at night and the   (14) . Both in the present study and in the Dutch one, salivary cortisol variation was influenced by individual and labor variables, but the salivary cortisol levels of BOE police officers was also altered by the effort-impairment psychosocial variable. which exposes only a single view of the assessment of physiological and labor stress and does not allow establishing a cause-effect relationship. In this context, those who were on sick leave or away from work may constitute a relevant portion of the police officers exposed to stress and its complications.
This study represents a gain in knowledge since it identified an association between psychosocial stress dimensions and a biological stress marker in military police officers. Furthermore, it is highlighted the peculiarity of the Special Tactical Operations Group (GATE) as the sector most exposed to stress, which allows inferring that this job specifications have implications on the health of these military police officers.

Conclusion
It was concluded that the effort-impairment