Objective
The aim of the present study was to investigate whether there is an association between serum cortisol and work-related stress, as defined by the demand–control model in a longitudinal design.
Methods
One hundred ten women aged 47–53 years completed a health questionnaire, including the Swedish version of the Job Content Scale, and participated in a psychological interview at baseline and in a follow-up session 2 years later. Morning blood samples were drawn for analyses of cortisol.
Results
Multiple stepwise regression analyses and logistic regression analyses showed that work demands and lack of social support were significantly associated with cortisol.
Conclusions
The results of this study showed that negative work characteristics in terms of high demands and low social support contributed significantly to the biological stress levels in middle-aged women. Participation in the study may have served as an intervention, increasing the women's awareness and thus improving their health profiles on follow-up.
Over the last decade, there has been a substantial increase in long-term sick leave in Sweden. Work-related stress and work overload are considered to be the major underlying causes, and it is middle-aged women who are affected the most [1]. Several studies showed that women not only report more symptoms but also actually suffer physically and mentally more than men do [2], [3] and [4]. Most studies in stress research have been conducted on men; thus, results cannot automatically be generalized to women [5] and [6]. Women may also experience different stressors, have different perceptions of stress [6] and [7], and display different patterns of neuroendocrine reactivity to stress compared to men [8], [9] and [10]. Midlife, entailing biological and psychosocial changes, has been shown to be a vulnerable phase of life for women [11] and [12]. Studies of middle-aged women are scarce, and there is an urgent need to elucidate the possible association between the negative aspects of the psychosocial work environment and stress-related conditions among women of this age group.
The demand–control model has been widely used as an instrument to explain work-related stress. The model identifies job demands and job control as two crucial dimensions of the work environment and proposes that work strain is caused by the combination of high psychological demands and low decision latitude [13]. The third dimension of the model, social support, accounts for a potential moderating or buffering effect against stress. Furthermore, social support has been shown to promote health [14], [15] and [16].
An elevation of cortisol levels has been considered as an indicator of stress, which, in turn, has been linked to detrimental effects on health [17] and [18]. The results concerning the association between cortisol and job strain are still contradictory. Ohlsson et al. [19] were unable to show a significant correlation between job strain and cortisol among workers in a mainly female sample employed in human service organizations: on the other hand, their study indicated an association between high emotional strain and increased levels of prolactin, a hormone affected by stress [20]. Steptoe et al. [21] found that job strain was correlated with elevated cortisol concentrations early in the working day among male and female teachers. Luecken et al. [22] showed that cortisol levels measured during the working day in a sample of women were unrelated to job strain but were greater among those reporting high strain at home due to domestic responsibilities. Perceived stress among male and female teachers was found to correlate with increased cortisol levels during the first hour after awakening [23]. Thus, results concerning the association between stress and cortisol are still contradictory, and there is paucity in research concerning work stress and cortisol levels among middle-aged women.
Stressful working conditions have been shown to influence both physical and psychological health by acting as important mediating factors in the development of, for example, cardiovascular and musculoskeletal disorders [24], [25] and [26], and symptoms of depression and anxiety [27]. High demands at work were found to be related to increased symptoms of poor health among middle-aged women [15]. A recent study suggests a link between work stress and Type 2 diabetes in middle-aged women [28]. Psychosocial stressors may also affect health-related behaviors such as smoking, alcohol consumption, food intake, and exercise habits [29]. Thus, it is important to consider lifestyle variables and their influence on stress reactions in women.
The present study, using a longitudinal design, aims to investigate whether there is an association between serum cortisol and work-related stress, as defined by the demand–control model, in terms of high demands, lack of control, and social support in middle-aged women.
