Day-to-Day Dynamics of Associations Between Sleep, Napping, Fatigue, and the Cortisol Diurnal Rhythm in Women Diagnosed as Having Breast Cancer

Abstract

OBJECTIVES To examine whether day-to-day variations in sleep behaviors, ongoing sleep disturbance and fatigue predict the cortisol diurnal rhythm in women recently diagnosed with early stage breast cancer. Methods Women (N=130, age=55. 6±9.4 years) collected saliva 5×/day/2 days for cortisol. Diaries were used to assess prior-day nap duration, nocturnal awakenings, sleep latency, and morning restfulness. Ongoing fatigue and sleep disturbance were measured using the Multidimensional Fatigue Symptom Inventory and the Pittsburg Sleep Quality Inventory. Data were analyzed using multilevel growth curve modeling. Results Greater ongoing fatigue (b=0.035, p = .032), or sleep disturbance (b=0.026, p = .006) predicted a slower cortisol decline. Greater ongoing fatigue also predicted higher awakening cortisol (b=0.154, p = .030) and lower cortisol awakening response (CAR) (b=−0.146, p = .005). Longer prior-day naps predicted higher CAR (b=0.042, p=.050), and a steeper cortisol decline (b=−0.035, p = .003). Longer sleep latency predicted both a greater cortisol linear decline (b=−0.013, p < .001), and a greater quadratic slope curvature (b=0.0007, p < .001). Feeling less rested in the morning predicted lower awakening cortisol (b=−0.187, p= .004), higher CAR (b=0.124, p=.016) and a slower cortisol decline (b=0.023, p=.042). CONCLUSIONS Both daily variations in sleep behaviors and ongoing sleep disturbance and fatigue associated with a disrupted cortisol rhythm. In contrast, prior-day napping associated with a more robust cortisol rhythm. These findings are particularly relevant to women with breast cancer who often experience sleep disturbance and fatigue. Additional research is needed to determine causal pathways between sleep disturbance and dysregulation of the hypothalamic-pituitary-adrenal axis in patients with breast cancer.

Cancer-related fatigue shows a stable association with diurnal cortisol dysregulation in breast cancer patients

“…To our knowledge only two studies specifically investigated this issue in breast cancer patients (n=29 and n=130, respectively) and results are still inconclusive [12][13][14]. Therefore, we investigated the association between diurnal cortisol pattern and the different dimensions of fatigue in a large sample of breast cancer patients (n=265) undergoing chemo-or radiotherapy.…”

Sleep Quality in Women with Breast Cancer: An Integrative Review

“…These sleep problems were characterized by prolonged sleep onset latency (M= 54.3, SD= 49.2 minutes) and frequent nighttime awakenings, despite 40% of the patients using sleep medications three or more times a week [16]. Greater ongoing fatigue or sleep disturbance predicted a slower cortisol decline, and longer sleep latency predicted both a greater cortisol linear decline and slower cortisol decline [9]. Several studies elucidate how the sleep quality changed during cancer treatments such as chemotherapy or radiotherapy.…”

“…Studies using the PSQI documented poor sleep quality for 65% to 70% of the participants [4,28] and, actigraphy verified that up to 87% of the sample had an excessive number of awakenings.13Moreover, sleep diary records identified that difficulty maintaining sleep was evident by the higher than normal (2-6) number of awakenings per night (6)(7)(8)(9)(10)(11)(12) [27].…”

“…When sleep disturbances become chronic, nurses need to make recommendations and referrals [9]. Because the sleep disturbances are common among breast cancer survivors, even after completion of active cancer treatment [10].…”

Depression in cancer: The many biobehavioral pathways driving tumor progression

“…Additionally, sleep disturbances appear to be associated also with a disrupted cortisol rhythm. For instance, in women with breast cancer, sleep disturbances and feeling less rested in the morning predicted lower awakening cortisol and a slower cortisol decline, suggesting an association between a dysregulation of the HPA axis and sleep dysfunction 204 .…”