Original ArticlePsychosocial correlates of sleep quality and architecture in women with metastatic breast cancer
Introduction
Women diagnosed with breast cancer have high rates of sleep disruption [1], [2], [3], [4], [5]. Sleep disturbance often begins before or during treatment and may continue long after treatment completion, often worsening for women with metastatic breast cancer (MBC) [6], [7], [8]. One recent study demonstrated that those with breast cancer had the highest number of sleep quality complaints among cancer patients [9]. The majority of studies examining sleep in women with breast cancer have relied on self-report or indirect measurement [10]. Relatively few studies have used polysomnography (PSG), the gold standard for objectively assessing sleep [10], to examine sleep patterns in individuals with breast cancer. Of the studies that utilized PSG, dysregulation of sleep architecture in cancer patients was evidenced by lower sleep efficiency (SE) [11], more time in lighter nonrapid eye movement (NREM) sleep (stages 1 and 2), and less time in deep NREM or slow-wave sleep (SWS) (stages 3 and 4), as well as less rapid eye movement (REM) sleep than experienced by the general population [12]. However, another study found little change in PSG-assessed sleep before and after completion of chemotherapy [13]. Evidence regarding objective changes in sleep architecture of women with MBC is inconclusive and further study is warranted.
There is a well-described correlation between depression and sleep disturbance in the general population [14], [15]. Among women with breast cancer, nearly 20–30% experience depression [2], [16], [17], a higher prevalence than that seen in the general population. Depression further increases as breast cancer advances [18], [19]. Palesh et al. [8] found that higher baseline and worsening depression among women with MBC predicted progressive sleep problems and that sleep disruption was associated with autonomic dysregulation during the day, particularly loss of vagal tone [20]. Although many precipitating factors may engender sleep disturbance and depression in MBC (e.g., stress, pain) the physiologic or psychological changes underlying these phenomena are unknown.
In addition, the relationship of marriage and sleep quality in women with breast cancer has been understudied, with investigations primarily focusing on healthy adults. Studies have demonstrated that divorced women have higher rates of sleep disturbance and insomnia [21]. Further there is evidence that marital happiness is related to improved sleep quality in women, relative to those experiencing marital discord [22]. Spousal sleep problems also negatively affect sleep and mood as well as the health of their partners [23]. Thus marriage appears to be an important variable affecting sleep quality in cancer patients. We aimed to examine the relationship of marital status to sleep among metastatic breast cancer patients. Our study examined the relationship of depression and marital status with sleep parameters assessed by two nights of consecutive at-home PSG and one night of laboratory PSG. Our a priori hypothesis was that higher depression scores among women with MBC would be related to significantly greater sleep disturbance. Exploratory aims were to examine the role of a potential moderator, marital status, in relation to sleep quality and architecture. We explored potential interactions between depression and marital status as they related to sleep in women with MBC.
Section snippets
Participants
Predominately white women (88.2%) with MBC (N = 103) were recruited and consented to participate (Fig. 1). The women were postmenopausal and were between the ages of 45–75 years (mean age, 57.8 ± 7.7 years) (Table 1). They also had documented metastatic or recurrent breast cancer, with Karnofsky Performance Status Scale ratings of at least 70% (physical ability measure for medically ill patients) [24]. Participants were at least 2 months postchemotherapy or hormonal treatment. Women were excluded if
Home PSG
Consistent with our hypothesis regarding depression and sleep disruption, significant effects of depression emerged for REM sleep. Women who reported more symptoms of depression on the CES-D (score of ⩾8) spent less time in REM sleep (i.e., minutes of REM sleep divided by minutes of TST) and had fewer minutes of REM sleep than those reporting fewer symptoms of depression. Table 2 presents the CES-D means and standard deviations, and Table 3 shows the standardized regression coefficients and
Discussion
Women with MBC who had more depressive symptoms had more disturbed sleep at home and in the laboratory. Single women with MBC had worse sleep quality at home and worse SE than married women. We also found that marriage was protective of sleep quality in women with high depressive symptoms. At home women with MBC averaged 6.5 h of sleep and had low SE of 74.0% (i.e., normal efficiency ⩾85%) [34], [35]. Our sample had considerably longer sleep-onset latency [34], [36], extended REM sleep latency,
Conclusion
Our findings demonstrate that depressed or single women with MBC have disturbed sleep, including increased light NREM sleep, reduced SWS and REM sleep, and poor sleep quality. Marriage seemed to protect sleep quality and normalize sleep architecture in the presence of depression, even when women slept alone in the laboratory. Depressed and single women with MBC appear to be at the highest risk for objective sleep disturbances and may derive greater benefit from clinical interventions. Future
Conflict of interest
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2013.07.012.
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