Rhythm In Women Research Articles

Relationship between HOMA-IR and melatonin secretory rhythm in women with metabolic syndrome

Relationship between HOMA-IR and melatonin secretory rhythm in women with metabolic syndrome

Functional mobility and lumbopelvic rhythm in women with and without stress urinary incontinence: An observational pilot study

ObjectiveTo examine the functional mobility and lumbopelvic rhythm of the continent and incontinent women. DesignAn observational pilot study was performed with two groups of women, who never experienced falls. MethodsParticipants were 27 women with urinary incontinence and 27 matched controls. The incontinent group had urinary incontinence assessed by the International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF) (score ≥1); and the continent group had an ICIQ-SF score equal to 0. The functional mobility and lumbopelvic rhythm were assessed using G-Sensor® gadget wireless system. With the G-sensor® at the second lumbar vertebra, the participants performed the Walk-Test (functional mobility), Time Up and Go (TUG) (functional mobility), and lumbopelvic rhythm. Student T test, Chi-Square, and Mann-Whitney test were applied to compare continuous variables between groups. p < 0.05 for significance level. Hegdes'g statistic and R2 [Z2/(total n)] were used to effect size. ResultsWalk-test was not different between groups. TUG was different between groups: the continent group (11.0 ± 2.1s) was faster than the incontinent group (12.5 ± 3.3s) (p = 0.03). The sitting-to-standing position knee flexion angle was larger in the continent group (45.0 ± 17.2°) than in the incontinent (34.1 ± 18.8°) (p = 0.03). ConclusionThe incontinent group showed a decrease in functional mobility according to the TUG test. Limiar differences in the flexion angle from sitting to standing suggest incontinent women might have a lower potential for hip flexor moment during hip lifting.

Disturbances in melatonin, leptin and ghrelin rhythms in women with metabolic syndrome with and without polycystic ovary syndrome

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Effects of exogenous melatonin on sleep and circadian rhythms in women with premenstrual dysphoric disorder.

We previously found normal polysomnographic (PSG) sleep efficiency, increased slow-wave sleep (SWS), and a blunted melatonin secretion in women with premenstrual dysphoric disorder (PMDD) compared to controls. Here, we investigated the effects of exogenous melatonin in five patients previously studied. They took 2 mg of slow-release melatonin 1 h before bedtime during their luteal phase (LP) for three menstrual cycles. At baseline, patients spent every third night throughout one menstrual cycle sleeping in the laboratory. Measures included morning urinary 6-sulfatoxymelatonin (aMt6), PSG sleep, nocturnal core body temperature (CBT), visual analog scale for mood (VAS-Mood), Prospective Record of the Impact and Severity of Menstrual Symptoms (PRISM), and ovarian plasma hormones. Participants also underwent two 24-hour intensive physiological monitoring (during the follicular phase and LP) in time-isolation/constant conditions to determine 24-hour plasma melatonin and CBT rhythms. The same measures were repeated during their third menstrual cycle of melatonin administration. In the intervention condition compared to baseline, we found increased urinary aMt6 (p < 0.001), reduced objective sleep onset latency (p = 0.01), reduced SWS (p < 0.001), and increased Stage 2 sleep (p < 0.001). Increased urinary aMt6 was correlated with reduced SWS (r = -0.51, p < 0.001). Circadian parameters derived from 24-hour plasma melatonin and CBT did not differ between conditions, except for an increased melatonin mesor in the intervention condition (p = 0.01). Ovarian hormones were comparable between the conditions (p ≥ 0.28). Symptoms improved in the intervention condition, as measured by the VAS-Mood (p = 0.02) and the PRISM (p < 0.001). These findings support a role for disturbed melatonergic system in PMDD that can be partially corrected by exogenous melatonin.

Peculiarities of Respiratory Rhythm in Healthy Young Men and Women under Different Conditions

Introduction.The functioning of physiological systems in the body occurs in certain rhythms with its own variability, which reflects the complex interaction of regulatory mechanisms. The nature of therespiratory rhythm in humans, both at rest and under load, has certain features that are manifested in the duration of spirocycles (phases and their ratio), their variability, manifestation and direction of reactions, which may depend on gender.Purpose.Carrying out of the comparative analysis of variability of a respiratory rhythm at rest and reactions of its characteristics in the conditions of orthoprobe and psychoemotional load inhealthy young men and women.Methods.The measurements involved 88 men and 30 women aged 17-23 years under conditions close to the state of basal metabolism, in the supine position, in orthoprobe and performing the test of psycho-emotional load.The obtained pneumograms, which were recorded using a piezoelectric sensor, were analyzed using a computer program developed by us.The duration of the spirocycle and its phases were defined as the distance between the corresponding points ofthe pneumogram. Studies of respiratory rhythm (breath-to-breath) were performed by the method of temporal analysis on the following indicators: the average value of the respiratory cycle (M), its mode (Mo), the average values of the phases of inspiration (In), exhalation (Exp), their ratio (In / Exp), variation of spirocycle duration (dX), standard deviation (SDNN) and coefficient of variation (SV). The reactivity of changes in indicators was calculated in % relative to baseline at rest.Results. The pattern of respiratory rhythm in people of different sexes differs significantly both at rest and under the influence of dosed loads. At rest, the sexual features of the respiratory rhythm were revealed, which were manifested by slower breathing with less variability in men compared with the group of women.Under conditions of orthostasis, greater changes in respiratory rhythm were found in women who were characterized by slow breathing, mainly due to the active phase of inspiration, together with its relatively greater variability. Psycho-emotional load contributed to the acceleration of respiration in subjects of different sexes, against which the variability of rhythm in men decreased, while in women the changes were multidirectional.Originality. Peculiaritiesof respiratory rhythm in persons of different sexes are shown. Significant gender differences in the duration of the respiratory cycle and its variability at rest have been established. Peculiarities of manifestation and direction of reactions according to indicators of respiratory rhythm variability under the influence of orthoprobe and psychoemotional load in men and women are revealed.Conclusions.Establishing gender differences in the duration of the spirocycle and indicators of its variability indicate the need to take into account this factor to increase the diagnostic and prognostic value of the method of temporal analysis of respiratory rhythm variability in assessing the functional state of the human body. It is necessary to find out the peculiarities of the respiratory rhythm in women, takinginto account the phases of the ovarian-menstrual cycle.Keywords:respiratory rhythm, variability of spirocycle duration, deceleration of breathing, inspiratory phase, orthoprobe, psycho-emotional load.

Evidence for disruption of normal circadian cortisol rhythm in women with obesity

Hyperactivity of the hypothalamic–pituitary–adrenal (HPA) axis may play a role in the pathogenesis of comorbidities encountered in obesity, including the relative hypogonadotropic hypogonadism that we and others have observed. We sought to examine serum cortisol profiles throughout the day and evening in a sample of normal weight women and women with obesity. In this cross-sectional study, regularly cycling obese (n = 12) and normal weight (n = 10) women were recruited. Mean serum cortisol was measured by frequent blood sampling for 16 h (8am–midnight) in the luteal phase of the menstrual cycle. Women with obesity had significantly higher overall cortisol levels when compared to normal weight women (6.2 [4.3, 6.6] vs. 4.7 [3.7, 5.5] ug/dl, p = .04). Over the two-hour postprandial period, obese women displayed an almost two-fold greater (7.2 [6.5, 8.6] ug/dl) rise in cortisol than normal weight controls (4.4 [3.7, 6.2] ug/dl, p < .01). In addition, obese women demonstrated a sustained evening cortisol elevation compared to normal weight women, who displayed the typical decline in cortisol (3.2 [2.3, 4] vs. 2 [1.5, 3.2] ug/dl, p < .05). Changes in the HPA axis in the setting of obesity may be related to risks of obesity-associated metabolic comorbidities and reproductive dysfunction often seen in these women.

うつ・リズム・女性(シンポジウム1「高齢社会と女性」, 第42回日本女性心身医学会学術集会報告)

うつ・リズム・女性(シンポジウム1「高齢社会と女性」, 第42回日本女性心身医学会学術集会報告)

(223) Circadian activity rhythms in women with fibromyalgia

(223) Circadian activity rhythms in women with fibromyalgia

Abstract 262: Women Are Less Likely to Be Resuscitated than Men

Background: There is a gender disparity in utilization of and benefit from health care. In various fields of medicine, women underuse the health care system and seem to benefit less when accessing health care than men. We aimed to study whether access to and outcome after out-of-hospital cardiopulmonary resuscitation (CPR) differs between men and women. Methods: We performed a population-based cohort study of non-traumatic out-of-hospital cardiac arrest (OHCA) cases before EMS arrival between 2006 and 2012. By using death certificate data of the national statistics service, we identified all cardiac out-of hospital deaths in the same period. Persons aged &lt;20 years were excluded. First, we calculated the Mantel-Haenzel odds ratio (OR-MH) for gender and chance of a resuscitation attempt, while weighing the number of persons per age-category. Second, neurologically intact survival (NI-survival) after resuscitation attempt was regressed on gender in the total group and stratified according to score on resuscitation parameter. Third, multivariable logistic regression was used to assess the independent association between gender and shockable initial rhythm. Results: We identified 22,443 OHCAs (52.8% male), and recorded 6,038 CPR attempts after OHCA of cardiac cause (72.5% male). Men have a significantly higher chance of receiving a resuscitation attempt than women (pooled OR-MH 1.63, 95%CI 1.52-1.75, p&lt;0.001). Women benefited less from CPR than men; NI-survival was higher in men compared to women (20.4% vs. 13.0%, OR 1.71, 95%CI 1.46-2.01, p&lt;0.001). The gender gap in survival was explained by a lower incidence of a shockable initial rhythm in women (48.8% vs. 34.4%). Gender was independently associated with presence of a shockable initial rhythm (OR 1.83, 95%CI 1.60-2.09, p&lt;0;001); so were CPR parameters. Conclusions: Women are less likely than men to receive CPR by EMS in case of OHCA. When women do receive CPR, they have lower chance of survival. The survival disparity is gender related and can only partly be explained by CPR circumstances.

Day-to-day dynamics of associations between sleep, napping, fatigue, and the cortisol diurnal rhythm in women diagnosed as having breast cancer.

To examine whether day-to-day variations in sleep behaviors, ongoing sleep disturbance, and fatigue predict the cortisol diurnal rhythm in women recently diagnosed as having early-stage breast cancer. Women (N = 130, mean [standard deviation] 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 a multilevel growth curve modeling. 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). Both daily variations in sleep behaviors and ongoing sleep disturbance and fatigue are associated with a disrupted cortisol rhythm. In contrast, prior-day napping is 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.

151. Day-to-day dynamics of associations between childhood adversity and cortisol diurnal rhythm in women diagnosed with breast cancer

A dysregulated cortisol diurnal rhythm is associated with a poorer prognosis for women with metastatic breast cancer. The purpose of this study was to investigate whether adversity experienced during childhood influences the dynamics of the cortisol rhythm in women newly diagnosed with early stage breast cancer. Women ( N = 98) were evaluated after their diagnosis but before surgery. Women completed the Perceived Stress Scale and the Childhood Trauma Questionnaire to assess their levels of psychological stress and the degree of exposure to childhood adversity, respectively. Over two consecutive days, women collected saliva five times per day for cortisol measurement, while also completing sleep diaries to assess prior-night sleep quality, including nocturnal awakenings, and morning restfulness. Multilevel growth curve modeling was used to examine whether childhood adversity contributed to the day-to-day variations in the cortisol diurnal rhythm. Emotional and physical abuse were significant predictors of the cortisol quadratic slope, indicating that women who reported greater exposure to such childhood adversity had greater levels of cortisol at bedtime. These effects were independent of daily variation in prior-night sleep quality, perceived stress levels, as well as demographic and cancer disease factors. These findings demonstrate childhood adversity to be a preexisting risk factor for dysregulation of the cortisol diurnal rhythm in women experiencing the stress associated with breast cancer diagnosis. Such dysregulation may negatively impact cancer control.

Dyspnoea related to pre-excitation during sinus rhythm as a new indication for catheter ablation

Patients with pre-excitation without arrhythmic symptoms are diagnosed as Wolff-Parkinson-White (WPW) pattern. To evaluate the efficacy of radiofrequency ablation (RFA) in patients with a WPW pattern and reported dyspnoea. Five patients (four adults and one adolescent, all female, age 33 ± 15 years) with a WPW pattern were referred due to dyspnoea and exercise intolerance. None had a history of paroxysmal syncope, pre-syncope, dizziness or palpitation. Before and after RFA, additional tests were used to exclude organic diseases of the pulmonary vessels, heart and lung, as well as bronchial hyperreactivity and metabolic diseases. Cardiopulmonary exercise test (CPET), echocardiography, time of forced expiration, baseline dyspnoea index (BDI), and transition dyspnoea index (TDI) were included into an objective evaluation of breath pattern. In all investigated patients, no arrhythmia was inducible during the electrophysiology study. The time of forced expiration increased immediately after RFA from 15.8 ± 2.9 to 29.2 ± 4.4 s (p < 0.001). The BDI score before RFA was 6.7 ± 1.9 and the TDI score after RFA showed a significant improvement: 8.0 ± 1.2 (p < 0.05). CPET revealed significant improvement in cardiopulmonary capacity after RFA in all cases: peak oxygen consumption [mL/kg/min]: 31.1 ± 7 vs. 42.6 ± 9.6 (p = 0.014); peak exercise minute ventilation [L/min]: 60.0 ± 19.9 vs. 82.0 ± 27 (p = 0.006); peak exercise tidal volume [L]: 1.56 ± 0.25 vs. 2.04 ± 0.24 (p = 0.002); ratio dead space/tidal volume at the end of exercise: 28 ± 2.6 vs. 25 ± 2.3 (p = 0.005). Dyspnoea during sinus rhythm in women with pre-excitation may be considered to be an evaluation criterion before RFA.

Sleep, fatigue, depression, and circadian activity rhythms in women with breast cancer before and after treatment: a 1-year longitudinal study.

Sleep disturbance, fatigue and depression are common complaints in patients with cancer, and often contribute to worse quality of life (QoL). Circadian activity rhythms (CARs) are often disrupted in cancer patients. These symptoms worsen during treatment, but less is known about their long-term trajectory. Sixty-eight women with stage I-III breast cancer (BC) scheduled to receive ≥4cycles of chemotherapy, and age-, ethnicity-, and education-matched normal, cancer-free controls (NC) participated. Sleep was measured with actigraphy (nocturnal total sleep time [nocturnal TST] and daytime total nap time [NAPTIME]) and with the Pittsburgh Sleep Quality Index (PSQI); fatigue with the Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF); depression with the Center of Epidemiological Studies-Depression (CES-D). CARs were derived from actigraphy. Several measures of QoL were administered. Data were collected at three time points: before (baseline), end of cycle 4 (cycle 4), and 1year post-chemotherapy (1year). Compared to NC, BC had longer NAPTIME, worse sleep quality, more fatigue, more depressive symptoms, more disrupted CARs, and worse QoL at baseline (all p values <0.05). At cycle 4, BC showed worse sleep, increased fatigue, more depressive symptoms, and more disrupted CARs compared to their own baseline levels and to NC (all p values <0.05). By 1year, BC's fatigue, depressive symptoms, and QoL returned to baseline levels but were still worse than those of NC, while NAPTIME and CARs did not differ from NC's. Additional research is needed to determine if beginning treatment of these symptoms before the start of chemotherapy will minimize symptom severity over time.

Serum Melatonin in Women with Polycystic Ovary Syndrome

There has been a surge of interest in recent years in studying the changes of serum melatonin concentrations in disorders that are associated with insulin resistance such as diabetes mellitus type 2 and polycystic ovary syndrome (PCOS). The present study was designed to investigate the day-time and night-time levels of serum melatonin and the cortisol rhythm in women with PCOS and compare them with those of healthy women. This is a case-control study which included 30 women with PCOS and 25 healthy women. All hormonal measurements in both the study group and controls were carried out between days 3 and 5 counted from the beginning of the last regular menstrual cycle; they included serum levels of melatonin and cortisol at 03:00 a.m and 08:00 a.m, total testosterone (T), dehydroepiandrosterone sulfate (DHEA-S), luteinizing hormone (LH), follicle stimulating hormone (FSH), and immunoreactive insulin at 08:00 a.m. Women with PCOS were found to have a significantly higher melatonin level at 08:00 a.m. and smaller mean night-day difference in the concentrations of melatonin in comparison with those of healthy women (natural log (Ln) night-day difference 0.60 +/- 0.10 pg/ml versus 1.15 +/- 0.14, p < 0.002). Melatonin to cortisol ratios at 03:00 a.m. and 08:00 a.m. showed no statistically significant differences between the two groups (Ln melatonin/cortisol 03:00 a.m., 1.01 +/- 0.06 versus 1.05 +/- 0.05; Ln melatonin/cortisol at 08:00 a.m., 0.62 +/- 0.01 versus 0.56 +/- 0.03, p > 0.05). The results we obtained about the changes of melatonin in women with PCOS could help in elucidating the complex pathophysiological pattern of this disease.

Prolactin secretory rhythm in women: immediate and long-term alterations after sexual contact

Prolactin (PRL) is one of the most versatile hormones in the mammalian body, affecting reproductive, sexual and other functions. In rats, mating or vaginocervical stimulation activates a characteristic PRL secretory pattern for several days, which is essential for successful reproduction. Although the underlying mechanisms appear to be different, PRL is also crucial for human fertility. We have detected a PRL increase in women induced by sexual intercourse. Extending these findings, the current study aimed at analyzing the PRL secretory rhythm after sexual contact, in order to elucidate whether human females also show long-term alterations of the PRL secretory pattern. In a pilot study, serial blood samples were taken from women (n= 7) in mid-cycle to assess changes in PRL secretory rhythm induced by sexual intercourse, during a period of 32 h. Compared with control condition, sexual intercourse with orgasm induced not only the well-established immediate PRL increase of ~300% but also an additional PRL elevation around noon of the next day (P< 0.05). These fluctuations were measured on top of the regular circadian rhythm of PRL, manifested as a surge early in the morning. We are able to demonstrate a long-term change in the PRL secretory rhythm after sexual intercourse with orgasm in females, suggesting memory effects. We hypothesize that the additionally secreted PRL could be beneficial for decidualization and implantation. Further studies with more participants are required to investigate in detail the implications of such effects on reproductive success in humans.

Vagal Regulation, Cortisol, and Sleep Disruption in Women with Metastatic Breast Cancer

To determine the relationship between hypothalamic pituitary axis (HPA) dysregulation, vagal functioning, and sleep problems in women with metastatic breast cancer. Sleep was assessed by means of questionnaires and wrist actigraphy for 3 consecutive nights. The ambulatory, diurnal variation in salivary cortisol levels was measured at 5 time points over 2 days. Vagal regulation was assessed via respiratory sinus arrhythmia (RSA(TF)) during the Trier Social Stress Task. Ninety-nine women (54.6 +/- 9.62 years) with metastatic breast cancer. Longer nocturnal wake episodes (r = 0.21, p = 0.04, N=91) were associated with a flatter diurnal cortisol slope. Sleep disruption was also associated with diminished RSA(TF). Higher RSA baseline scores were significantly correlated with higher sleep efficiency (r = 0.39, p = 0.001, N=68) and correspondingly lower levels of interrupted sleep (waking after sleep onset, WASO; r = -0.38, p = 0.002, N=68), lower average length of nocturnal wake episodes (r = -0.43, p < 0.001, N=68), and a lower self-reported number of hours of sleep during a typical night (r = -0.27, p = 0.02, N=72). Higher RSA AUC was significantly related to higher sleep efficiency (r = 0.45, p < 0.001, N=64), and a correspondingly lower number of wake episodes (r = -0.27, p = 0.04, N=64), lower WASO (r = -0.40, p = 0.001, N=64), and with lower average length of nocturnal wake episodes (r = -0.41, p = 0.001, N=64). While demographics, disease severity, and psychological variables all explained some portion of the development of sleep disruption, 4 of the 6 sleep parameters examined (sleep efficiency, WASO, mean number of waking episodes, average length of waking episode) were best explained by RSA. These data provide preliminary evidence for an association between disrupted nocturnal sleep and reduced RSA the subsequent day, confirming an association between disrupted nocturnal sleep and flattened diurnal cortisol rhythm in women with metastatic breast cancer. They suggest that the stress-buffering effects of sleep may be associated with improved parasympathetic tone and normalized cortisol patterns during the day.

Circadian rhythms, sleep, and the menstrual cycle

Women with ovulatory menstrual cycles have a circadian rhythm superimposed on the menstrual-associated rhythm; in turn, menstrual events affect the circadian rhythm. In this paper, we review circadian rhythms in temperature, selected hormone profiles, and sleep–wake behavior in healthy women at different phases of the menstrual cycle. The effects on menstrual cycle rhythmicity of disrupted circadian rhythms, for example, with shiftwork and altered circadian rhythms in women with menstrual-related mood disturbances, are discussed. Compared to the follicular phase, in the post-ovulation luteal phase, body temperature is elevated, but the amplitude of the temperature rhythm is reduced. Evidence indicates that the amplitude of other rhythms, such as melatonin and cortisol, may also be blunted in the luteal phase. Subjective sleep quality is lowest around menses, but the timing and composition of sleep remains relatively stable across the menstrual cycle in healthy women, apart from an increase in spindle frequency activity and a minor decrease in rapid eye movement (REM) sleep during the luteal phase. Disruption of circadian rhythms is associated with disturbances in menstrual function. Female shiftworkers compared to non-shiftworkers are more likely to report menstrual irregularity and longer menstrual cycles. There also is accumulating evidence that circadian disruption increases the risk of breast cancer in women, possibly due to altered light exposure and reduced melatonin secretion. Further investigations into the biological consequences of circadian disruption in women will offer insight into some menstrual-associated disorders, including mood changes, as well as reproductive function and possible links with breast cancer.

Absence of Circadian Salivary Cortisol Rhythm in Women with Anorexia Nervosa

Study Objective To compare the cortisol levels and 24 hour salivary cortisol rhythm in patients with anorexia nervosa (AN) and normal controls. Design Prospective transversal controlled study. Setting Tertiary-referral University Hospital. Participants Twenty-five patients aged 15 to 35 years, 13 of them with regular ovulatory cycles, and 12 with diagnosis of AN. Interventions Salivary and blood collection for cortisol 24-hour rhythm determination. Main Outcome Salivary cortisol was determined at 9 am, 5 pm, and 11 pm. Seric follicle-stimulating hormone, luteinizing hormone (LH), prolactin, estradiol (E2), progesterone, dehydroepiandrosterone-S (DHEA-S), and cortisol were sampled together with the 9 am salivary sample. Results LH, E2, and DHEA-S levels were reduced in patients with AN. A correlation between salivary and serum cortisol levels was observed in the 9 am sample only in controls (r = 0.67, P = 0.01; AN: r = 0.48, P = 0.12). Cortisol rhythm was present in all control subjects, whereas it was absent in one third of AN patients. The area under the curve for the AN group with preserved rhythm was significantly higher than for the control group (Me = 6811 ng/dl/24h vs 3708 ng/dl/24 h; P = 0.034). Conclusion Patients with AN have higher salivary cortisol levels when compared to normal women and some of them do not present circadian rhythm.

Possible Linkage between the Ability to Change the Period (τ) of the Prolactin and Cortisol Rhythms in Women and Breast Cancer Risk

The 24 h profiles of plasma hormone concentrations are rhythmic. The circadian period (τ) changes in development, with seasons, and in women with different stages of the menstrual cycle. It is known that the rhythms of prolactin and cortisol are sensitive to environmental time cues, such as changes in day length and phase; however, the importance of these changes is not yet understood. This study investigates whether there is a relation between the ability of a subject to respond to external cues that are associated with seasonal changes causing alteration of the rhythm's periods in cortisol and prolactin and the epidemiologically determined susceptibility to breast cancer. It is shown that the rhythmic output pattern of prolactin and cortisol in vivo is generated by more than one oscillator and structured by more than one rhythmic component. Each cohort of American women, classified on an epidemiologic basis as high risk (HR) or low risk (LR) to develop breast cancer, expresses different rhythmic output patterns of both variables, suggesting that the genetic background as defined by the risk state is related to differences in the circadian time structure, including the ability of the subject to change the rhythm's τ. The LR cohort exhibited a statistically significant change between seasons in the rhythm's τ of both the prolactin and cortisol patterns. In contrast, the HR cohort showed no change in the rhythm's τ between seasons for prolactin and cortisol patterns. These results show that in human beings, the presence of a circannual rhythm in the circadian time structure or the ability to adapt the circadian rhythmic pattern of these variables to external cues, such as seasons, is related to the partly genetically determined risk state to develop breast cancer and may be of importance for human health.

Fatigue, sleep, and circadian rhythms prior to chemotherapy for breast cancer

Previous investigations have shown that women undergoing chemotherapy for breast cancer experience both disturbed sleep and fatigue. However, most of the previous research examined women either during or after chemotherapy. This study examined sleep, fatigue, and circadian rhythms in women with breast cancer before the start of chemotherapy. Eighty five women with Stages I-IIIA breast cancer who were scheduled to begin adjuvant or neoadjuvant anthracycline-based chemotherapy participated. Each had sleep/wake activity recorded with actigraphy for 72 consecutive hours and filled out questionnaires on sleep, fatigue, depression, and functional outcome. On average, the women slept for about 6 h a night and napped for over an hour during the day. Sleep was reported to be disturbed and fatigue levels were high. Circadian rhythms were robust, but women who were more phase-delayed reported more daily dysfunction (p<0.01). The data from the current study suggest that the women with breast cancer likely experience both disturbed sleep and fatigue before the beginning of chemotherapy. Although their circadian rhythms are robust, breast cancer patients with more delayed rhythms experience more daily dysfunction secondary to fatigue. These data suggest that strategies to improve disturbed sleep and to phase-advance circadian rhythms prior to initiation of chemotherapy may be beneficial in improving daily function in breast cancer patients.