Effects of menopausal status on sleep in midlife women

The Relationship Between Mood and Sleep in Different Female Reproductive States

Mood and sleep are tightly interrelated. Mood and sleep symptoms and disorders are more common in women than in men and often associated with reproductive events. This article reviews the current literature on the reciprocal relationships between mood and sleep across reproductive phases in women, such as menstrual cycle and related disorders, pregnancy, climacteric, and use of hormonal contraception and hormone replacement therapy. Mood and sleep symptoms seem to covary in relation to physiologic and pathologic reproductive conditions, although the relationship seems more clear for subjective than objective sleep.

Disturbed sleep is associated with reduced verbal episodic memory and entorhinal cortex volume in younger middle-aged women with risk-reducing early ovarian removal

Introduction

Women with early ovarian removal (<48 years) have an elevated risk for both late-life Alzheimer's disease (AD) and insomnia, a modifiable risk factor. In early midlife, they also show reduced verbal episodic memory and hippocampal volume. Whether these reductions correlate with a sleep phenotype consistent with insomnia risk remains unexplored.

Methods

We recruited thirty-one younger middleaged women with risk-reducing early bilateral salpingo-oophorectomy (BSO), fifteen of whom were taking estradiol-based hormone replacement therapy (BSO+ERT) and sixteen who were not (BSO). Fourteen age-matched premenopausal (AMC) and seventeen spontaneously peri-postmenopausal (SM) women who were ~10y older and not taking ERT were also enrolled. Overnight polysomnography recordings were collected at participants' home across multiple nights (M=2.38 SEM=0.19), along with subjective sleep quality and hot flash ratings. In addition to group comparisons on sleep measures, associations with verbal episodic memory and medial temporal lobe volume were assessed.

Results

Increased sleep latency and decreased sleep efficiency were observed on polysomnography recordings of those not taking ERT, consistent with insomnia symptoms. This phenotype was also observed in the older women in SM, implicating ovarian hormone loss. Further, sleep latency was associated with more forgetting on the paragraph recall task, previously shown to be altered in women with early BSO. Both increased sleep latency and reduced sleep efficiency were associated with smaller anterolateral entorhinal cortex volume.

Discussion

Together, these findings confirm an association between ovarian hormone loss and insomnia symptoms, and importantly, identify an younger onset age in women with early ovarian removal, which may contribute to poorer cognitive and brain outcomes in these women.

Optimizing sleep across the menopausal transition

Women frequently experience sleep disturbances, particularly night-time awakenings, as they transition menopause and enter postmenopause. Sleep is essential for optimal functioning and health. Persistent and distressing sleep disturbances across menopause can negatively impact daytime functioning and productivity, and increase risk for mental and physical health conditions. While multiple factors can disturb sleep, two unique factors in the context of menopause are vasomotor symptoms and the changing reproductive hormone environment. Vasomotor symptoms are associated with sleep disturbances and contribute significantly to awakenings and amount of time spent awake during the night. Even after accounting for vasomotor and depressive symptoms, lower estradiol and higher follicle stimulating hormone levels, indicative of menopause, are associated with sleep disturbance, particularly awakenings, suggesting that the hormone environment may directly affect sleep. Management strategies for clinically significant menopausal sleep disturbances include cognitive behavioral therapy for insomnia, which is effective and durable in treating menopausal insomnia. Hormone therapy alleviates sleep disturbances, particularly in the presence of disruptive vasomotor symptoms. Sleep disturbances have a significant impact on women's functioning and health, and there is a need for further research of the underlying mechanisms to advance effective preventative and treatment strategies that ensure optimal health and well-being of midlife women.

Role of Ovarian Hormones in the Modulation of Sleep in Females Across the Adult Lifespan

Ovarian hormones, including 17β-estradiol, are implicated in numerous physiological processes, including sleep. Beginning at puberty, girls report more sleep complaints than boys, which is maintained throughout the reproductive life stage. Sleep problems are exacerbated during the menopausal transition, evidenced by greater risk for sleep disorders. There is emerging evidence that menopause-associated hormone loss contributes to this elevated risk, but age is also an important factor. The extent to which menopause-associated sleep disturbance persists into postmenopause above and beyond the effects of age remains unknown. Untreated sleep disturbances have important implications for cognitive health, as they are emerging as risk factors for dementia. Given that sleep loss impairs memory, an important knowledge gap concerns the role played by menopause-associated hormone loss in exacerbating sleep disturbance and, ultimately, cognitive function in aging women. In this review, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining the sleep-wake cycle in younger and middle-aged females, with evidence implicating 17β-estradiol in supporting the memory-promoting effects of sleep. Sleep physiology is briefly reviewed before turning to behavioral and neural evidence from young females linking 17β-estradiol to sleep-wake cycle maintenance. Implications of menopause-associated 17β-estradiol loss is also reviewed before discussing how ovarian hormones may support the memory-promoting effects of sleep, and why menopause may exacerbate pathological aging via effects on sleep. While still in its infancy, this research area offers a new sex-based perspective on aging research, with a focus on a modifiable risk factor for pathological aging.

Role of menopause and hormone replacement therapy in sleep-disordered breathing

There are suggestions that the loss of female sex hormones following menopause is critical for the development or progression of sleep-disordered breathing (SDB). We conducted a review of the literature on the role of menopause and hormone replacement therapy (HRT) in SDB risk. There is an increase in SDB during the menopausal transition period, but data on an effect beyond that of increasing age and changes in body habitus are weak or absent. Early community-based, observational studies reported a protective effect by HRT on SDB prevalence, but this could possibly be explained as a healthy user effect. Interventional studies of the effect of HRT on SDB are sparse, with only a few randomized placebo-controlled studies, often performed on small samples of women without clinically significant SDB. HRT regimens have varied and all the studies are fairly old. They do not definitely assure the alleviation of SDB and HRT cannot thus be recommended as treatment for SDB. It is concluded that there is no evidence that female sex hormone changes during menopause per se are able to explain the increase in SDB in midlife women and conclusions on the effect of HRT on SDB cannot be drawn from the current literature.

Onset of the Menopause Transition: The Earliest Signs and Symptoms

Although more than 80% of women experience some degree of psychological or physical symptoms around menopause, both women and clinicians have misconceptions about how hormonal changes relate to menopausal symptoms and psychological conditions. Recently, several large-scale, longitudinal studies have been conducted to better characterize symptoms and changes that occur around menopause. This article offers current evidence for symptoms that occur in the early menopause transition, including vasomotor symptoms, mood changes, sleep problems, and changes in sexual functioning.

Sleep problems during the menopausal transition: prevalence, impact, and management challenges

A substantial number of women experience sleep difficulties in the approach to menopause and beyond, with 26% experiencing severe symptoms that impact daytime functioning, qualifying them for a diagnosis of insomnia. Here, we review both self-report and polysomnographic evidence for sleep difficulties in the context of the menopausal transition, considering severity of sleep complaints and links between hot flashes (HFs) and depression with poor sleep. Longitudinal population-based studies show that sleep difficulties are uniquely linked with menopausal stage and changes in follicle-stimulating hormone and estradiol, over and above the effects of age. A major contributor to sleep complaints in the context of the menopausal transition is HFs, and many, although not all, HFs are linked with polysomnographic-defined awakenings, with HF-associated wake time contributing significantly to overall wakefulness after sleep onset. Some sleep complaints may be comorbid with depressive disorders or attributed to sleep-related breathing or movement disorders, which increase in prevalence especially after menopause, and for some women, menopause, age, and environmental/behavioral factors may interact to disrupt sleep. Considering the unique and multifactorial basis for sleep difficulties in women transitioning menopause, we describe clinical assessment approaches and management options, including combination treatments, ranging from cognitive behavioral therapy for insomnia to hormonal and nonhormonal pharmacological options. Emerging studies suggest that the impact of severe insomnia symptoms could extend beyond immediate health care usage and quality of life issues to long-term mental and physical health, if left untreated in midlife women. Appropriate treatment, therefore, has immediate benefit as well as advantages for maintaining optimal health in the postmenopausal years.

Ovarian hormones, sleep and cognition across the adult female lifespan: An integrated perspective

Loss of ovarian function in women is associated with sleep disturbances and cognitive decline, which suggest a key role for estrogens and/or progestins in modulating these symptoms. The effects of ovarian hormones on sleep and cognitive processes have been studied in separate research fields that seldom intersect. However, sleep has a considerable impact on cognitive function. Given the tight connections between sleep and cognition, ovarian hormones may influence selective aspects of cognition indirectly, via the modulation of sleep. In support of this hypothesis, a growing body of evidence indicates that the development of sleep disorders following menopause contributes to accelerated cognitive decline and dementia in older women. This paper draws from both the animal and human literature to present an integrated view of the effects of ovarian hormones on sleep and cognition across the adult female lifespan.

Sleep and Menopause

Sleeping problems are a serious public health problem, imposing a substantial burden on individuals and society. Although sleeping problems occur throughout the lifespan, and in both sexes, menopause can be considered as one important milestone of increasing occurrence in sleeping problems. However, to determine whether sleeping problems are caused by the menopause or merely occur by coincidence during the menopause is not always easy because several, particularly age-related, changes take place at the same time. The most important factors are general diseases, medications, weight changes and mood symptoms. According to women's own judgment, hormone therapy significantly improves sleep quality. Hormone therapy can thus be considered as a first-line treatment for climacteric sleeping problems. If sleeping problems are accompanied by other disorders, hormone therapy should be kept in mind as an adjuvant therapy. According to worldwide consensus on hormone therapy, the main indication of hormone therapy is alleviation of climacteric symptoms, including climacteric sleeping problems. However, when choosing hormone therapy for a patient, contraindications and possible long-term side effects should be individually considered. This review illustrates the effect of menopause on sleep and evaluates different treatment options, especially hormone therapy, in alleviation of symptoms.

Sex differences in sleep: impact of biological sex and sex steroids

Men and women sleep differently. While much is known about the mechanisms that drive sleep, the reason for these sex differences in sleep behaviour is unknown and understudied. Historically, women and female animals are underrepresented in studies of sleep and its disorders. Nevertheless, there is a growing recognition of sex disparities in sleep and rhythm disorders. Women typically report poorer quality and more disrupted sleep across various stages of life. Findings from clinical and basic research studies strongly implicate a role for sex steroids in sleep modulation. Understanding how neuroendocrine mediators and sex differences influence sleep is central to advancing our understanding of sleep-related disorders. The investigation into sex differences and sex steroid modulation of sleep is in its infancy. Identifying the mechanisms underlying sex and gender differences in sleep will provide valuable insights leading to tailored therapeutics that benefit each sex. The goal of this review is to discuss our current understanding of how biological sex and sex steroids influence sleep behaviour from both the clinical and pre-clinical perspective.

Poor sleep in relation to natural menopause: a population-based 14-year follow-up of midlife women

OBJECTIVE

This study aims to estimate the prevalence and predictors of moderate/severe poor sleep in relation to the final menstrual period (FMP) in midlife women.

METHODS

Annual assessments were conducted in a population-based cohort of 255 women. All were premenopausal at cohort enrollment and reached natural menopause during the 16-year follow-up. The outcome measure was severity of poor sleep, as reported by participants in annual interviews for 16 years and as evaluated in relation to the FMP.

RESULTS

The annual prevalence of moderate/severe poor sleep largely ranged from about 28% to 35%, with no significant differences in any year relative to the FMP for the sample overall. When sleep status was stratified at premenopausal baseline, premenopausal sleep status strongly predicted poor sleep around the FMP. Women with moderate/severe poor sleep in premenopause were approximately 3.5 times more likely to have moderate/severe poor sleep around menopause than those with no poor sleep at baseline in adjusted analysis (odds ratio, 3.58; 95% CI, 2.50-5.11; P < 0.0001), whereas mild poor sleepers in premenopause were approximately 1.5 times more likely to have moderate/severe poor sleep around menopause (odds ratio, 1.57; 95% CI, 0.99-2.47; P = 0.053). There was no significant association between poor sleep and time relative to the FMP among women who had no poor sleep at premenopausal baseline. Hot flashes were significantly associated with poor sleep (odds ratio, 1.79; 95% CI, 1.44-2.21; P < 0.0001 in adjusted analysis) but had no interaction with baseline sleep severity (interaction P = 0.25), indicating that hot flashes contributed to poor sleep regardless of baseline sleep status.

CONCLUSIONS

Findings show a high prevalence of moderate/severe poor sleep in midlife women, with only a small "at-risk" subgroup having a significant increase in poor sleep in relation to the FMP. Sleep status at premenopausal baseline and concurrent hot flashes strongly and consistently predict poor sleep in the menopausal transition. Overall, poor sleep does not increase around the FMP and frequently occurs in the absence of hot flashes, indicating that sleep difficulties in the menopausal transition in generally healthy women are not simply associated with ovarian decline.

Magnitude of the impact of hot flashes on sleep in perimenopausal women

OBJECTIVE

To quantify the impact of objectively recorded hot flashes on objective sleep in perimenopausal women.

DESIGN

Cross-sectional study. Participants underwent 1-5 laboratory-based polysomnographic recordings for a total of 63 nights, including sternal skin-conductance measures, from which 222 hot flashes were identified according to established criteria. Data were analyzed with hierarchical mixed-effect models and Spearman's rank correlations.

SETTING

Sleep laboratory.

PATIENT(S)

Thirty-four perimenopausal women (age ± SD: 50.4 ± 2.7 years).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Perceived and polysomnographic sleep measures (sleep quality, amount of time spent awake after sleep onset, and number of awakenings). Subjective (frequency and level of bother) and objective (frequency and amount of hot flash-associated awake time) hot-flash measures.

RESULT(S)

Women had an average of 3.5 (95% confidence interval: 2.8-4.2, range = 1-9) objective hot flashes per night. A total of 69.4% of hot flashes were associated with an awakening. Hot flash-associated time awake per night was, on average, 16.6 minutes (95% confidence interval: 10.8-22.4 minutes), which accounted for 27.2% (SD 27.1) of total awake time per night. Hot flash-associated time awake, but not hot flash frequency, was negatively associated with sleep efficiency and positively associated with waking after sleep onset. In addition, self-reported wakefulness correlated with hot flash-associated waking, suggesting that women's estimates of wakefulness are influenced by the amount of time spent awake in association with hot flashes during the night. Having more perceived and bothersome hot flashes was correlated with more perceived wakefulness and awakenings and more objective hot flash-associated time awake and hot-flash frequency.

CONCLUSION(S)

The presence of physiological hot flashes accounts for a significant proportion of total objective time awake during the night in perimenopausal women.

Sleep and sleep disorders in menopausal women

Sleep disorders in the menopause are common. Although these disorders may be due to the menopause itself and/or the associated vasomotor symptoms, the etiology is multifactorial and includes a number of other associated conditions. They may simply arise as part of the aging process and not be specifically related to the decrease in estrogen levels or, alternatively, because of breathing or limb movement syndromes, depression, anxiety, co-morbid medical diseases, medication, pain and/or psychosocial factors. The most commonly encountered sleep disorders in menopausal women include insomnia, nocturnal breathing disturbances and the associated sleep disorders that accompany the restless leg syndrome, periodic leg movement syndrome, depression and anxiety. This review article addresses sleep and the sleep disorders associated with menopause and briefly the role that hormone therapy may play in alleviating these disorders.

Sleep, rhythms, and the endocrine brain: influence of sex and gonadal hormones

While much is known about the mechanisms that underlie sleep and circadian rhythms, the investigation into sex differences and gonadal steroid modulation of sleep and biological rhythms is in its infancy. There is a growing recognition of sex disparities in sleep and rhythm disorders. Understanding how neuroendocrine mediators and sex differences influence sleep and biological rhythms is central to advancing our understanding of sleep-related disorders. While it is known that ovarian steroids affect circadian rhythms in rodents, the role of androgen is less understood. Surprising findings that androgens, acting via androgen receptors in the master "circadian clock" within the suprachiasmatic nucleus, modulate photic effects on activity in males point to novel mechanisms of circadian control. Work in aromatase-deficient mice suggests that some sex differences in photic responsiveness are independent of gonadal hormone effects during development. In parallel, aspects of sex differences in sleep are also reported to be independent of gonadal steroids and may involve sex chromosome complement. This a summary of recent work illustrating how sex differences and gonadal hormones influence sleep and circadian rhythms that was presented at a Mini-Symposium at the 2011 annual meeting of the Society for Neuroscience.

Evaluation and management of sleep disturbance during the menopause transition

Sleep disturbances in midlife women are common and have been associated with the menopause transition itself, symptoms of hot flashes, anxiety and depressive disorders, aging, primary sleep disorders (i.e., obstructive sleep apnea, periodic limb movement disorder), comorbid medical conditions and medications, as well as with psychosocial and behavioral factors. Because there are several common sources of sleep problems in midlife women, the cause of an individual woman's sleep disturbance may be multifactorial. Effective behavioral and pharmacological therapies are available to treat sleep disturbances of different etiologies. This review provides an overview of different types of sleep disturbance occurring in midlife women and presents data supporting the use of hormone therapy, hypnotic agents, and behavioral strategies to treat sleep problems in this population. The review aims to equip clinicians evaluating menopause-age women with the knowledge and evaluation tools to diagnose, engage sleep experts where appropriate, and treat sleep disturbance in this population. Sleep disorders in midlife women should be treated because substantial improvements in quality of life and health outcomes are achievable.

Effects of gabapentin on sleep in menopausal women with hot flashes as measured by a Pittsburgh Sleep Quality Index factor scoring model

OBJECTIVE

The aim of this research was to analyze gabapentin's effect on Pittsburgh Sleep Quality Index (PSQI) scores in menopausal women.

METHODS

Secondary analysis of data from a cohort of menopausal women participating in a randomized, double-blind, placebo-controlled trial of gabapentin 300 mg three times daily (TID) for hot flashes. The outcomes of interest were PSQI global and factor scores at weeks 4 and 12.

RESULTS

Subjects randomized to gabapentin demonstrated improvement in the sleep quality factor score, compared to placebo-treated subjects, at 4 and 12 weeks (p < 0.03). There was also gabapentin-associated improvement in the global PSQI score (p = 0.004) and the sleep efficiency factor score (p = 0.05) at 4 weeks. There was no significant effect of gabapentin on the daily disturbance factor score.

CONCLUSIONS

Gabapentin may improve sleep quality in menopausal women with hot flashes. These results warrant further prospective investigation, with an emphasis on measuring subjective sleep quality and maintenance.

Frequency and severity of hot flashes and sleep disturbance in postmenopausal women with hot flashes

OBJECTIVE

To determine whether greater frequency and severity of hot flashes are independently associated with insomnia symptoms and objective measures of disrupted sleep among healthy postmenopausal women with hot flashes.

METHODS

A baseline cross-sectional analysis of a multicenter, randomized trial in 217 healthy postmenopausal women aged 40 to 60 years with hot flashes was conducted. Hot flash frequency and severity were recorded in a daily diary; frequency of moderate to severe hot flashes was the primary measure. Insomnia symptoms were assessed with the Insomnia Severity Index (ISI). Hot flash frequency and severity and objective parameters of sleep-wake patterns (using a wrist actigraph) were concurrently measured over an average of seven consecutive 24-hour periods in a subcohort of 112 women.

RESULTS

The mean age of participants was 54 years, and 80% were white; 33% had an ISI score greater than 14, consistent with at least moderate insomnia. In multivariable analysis, the mean ISI score showed a stepwise increase in magnitude with higher frequency of moderate to severe hot flashes (adjusted mean ISI score, 9.5, 11.4, 11.9, and 13.0 for quartiles 1-4, respectively; P for trend = 0.002). Higher frequency of moderate to severe hot flashes was also independently associated in a graded manner with greater nighttime wakefulness (P for trend = 0.028) and a higher number of long wake episodes (P for trend = 0.008) but was not related to sleep efficiency, total sleep time, or sleep latency.

CONCLUSIONS

Among healthy postmenopausal women with hot flashes, frequency of moderate to severe hot flashes was independently associated in a graded manner with severity of insomnia symptoms and objective measures of nighttime wakefulness and sleep fragmentation.

Experience of menopausal symptoms by women in an urban community in Ibadan, Nigeria

OBJECTIVE

The aim of this study was to determine the prevalence and distribution of menopausal symptoms among women in Ibadan in the 4-week period preceding the survey and factors associated with these symptoms.

METHODS

A descriptive cross-sectional, community-based study was carried out on Nigerian women aged 40 to 60 years, using the multistage sampling technique. Quantitative data were collected on sociodemographic, obstetric, and gynecological variables as well as symptom experience in the preceding 4 weeks using a structured questionnaire that included a standardized Menopause Rating Scale (MRS). Eleven symptom groups were scored for each respondent on a scale of 0-4, with increasing severity for each score and a maximal total score of 44. The MRS is made of three subscales (somatovegetative, psychological, and urogenital) with maximal scores of 16, 16, and 12, respectively. Scores for each subscale and the overall total score were calculated for each respondent, and these served as the main outcome measures. The higher the composite score, the greater the severity of menopausal symptoms.

RESULTS

In all, 1,189 women with a mean age of 48.1 +/- 5.9 years were interviewed. Prevalence of any menopausal symptom was 84.5% during the 4-week period studied. Joint and muscular discomfort was the most common reported symptom among all women in this study (59.0%), followed by physical and mental exhaustion (43.0%), sexual problems (40.4%), and hot flashes (39.0%). Factors predicting the total score on the MRS were age of respondent (P = 0.01; 95% CI, 0.02-0.17), menopause status (P = 0.001; 95% CI, 0.33-1.24), and occupational group (P = 0.02; 95% CI, 0.10-1.42). Age of respondent and menopause status also predicted scores on the somatovegetative and urogenital subscales, but not on the psychological subscale. Occupation was the only predictor on the psychological subscale (P = 0.002; 95% CI, 0.16-0.75).

CONCLUSIONS

Prevalence of menopausal symptoms was high among women in this study. Although any woman could face challenges associated with menopausal symptoms, those who were older, perimenopausal, and postmenopausal and who had routine or manual occupations had the highest total MRS scores. All women, especially those in these categories, should receive health information and guidance on possible lifestyle adjustments to ease the disruptions that menopausal symptoms can cause.

Sleep and the menopause - do postmenopausal women experience worse sleep than premenopausal women?

OBJECTIVE

To examine the sleep characteristics in three cross-sectional populations: young, premenopausal and postmenopausal women, and the associations between sleep, menopause, mood and cognitive performance.

STUDY DESIGN

Twenty-one premenopausal (45-51 years), 29 postmenopausal (59-71 years) and 11 young (20-26 years, using oral contraceptives) women were recruited. Polysomnography was used to measure objective sleep quality. Subjective sleep quality, sleepiness and mood were assessed using questionnaires. Cognitive performance was investigated by means of three attentional tests.

RESULTS

Total sleep time in pre- and postmenopausal women was similar (404.9 and 384.7 minutes), but shorter than in young women (448.2 minutes, P = 0.030 and <0.003, respectively). Sleep efficiency followed the same pattern, being 84.3% in premenopausal (P = 0.027), 80.2% in postmenopausal (P < 0.003) and 93.4% in young women. Pre- and postmenopausal women had less slow wave sleep (duration or activity) and more wake time after sleep onset (duration or frequency). Insomnia complaints were more frequent after the menopause (P = 0.023). Sleepiness and mood scores were similar in all groups. Reaction speeds slowed with increasing age. After the menopause, better cognitive performance was associated with more rapid eye movement sleep.

CONCLUSION

Objective sleep measures differed significantly between the young and postmenopausal groups. These differences may be more because of the physiology of ageing than the rapid changes across the menopause, since similar sleep characteristics were already present in the premenopausal women. The increase in sleep complaints after menopause was not associated with sleepiness or disturbances in objective sleep quality, mood or cognitive performance.

Beliefs about sleep and perceived sleep quality are associated with quality of life among perimenopausal women

Sleep disturbance is a common complaint among perimenopausal women and is hypothesized to contribute to compromises in their quality of life (QoL). We investigated the degree to which sleep disturbance and QoL were related and whether dysfunctional beliefs and attitudes about sleep were significantly associated with QoL ratings among a community sample of 168 perimenopausal women (88% return rate). Questionnaires included measures of subjective sleep quality, beliefs and attitudes about sleep, and QoL. Subjective sleep quality accounted for a significant amount of variance in both the physical and mental health aspects of QoL. Dysfunctional beliefs and attitudes about sleep significantly accounted for the physical components of QoL but not mental components. The interplay among sleep quality, dysfunctional beliefs and attitudes about sleep, and QoL is discussed, as well as potential clinical implications and ideas for future investigations specific to perimenopausal women.

Hot flashes and sleep in women

Sleep disturbances during menopause are often attributed to nocturnal hot flashes and 'sweats' associated with changing hormone patterns. This paper is a comprehensive critical review of the research on the relationship between sleep disturbance and hot flashes in women. Numerous studies have found a relationship between self-reported hot flashes and sleep complaints. However, hot flash studies using objective sleep assessment techniques such as polysomnography, actigraphy, or quantitative analysis of the sleep EEG are surprisingly scarce and have yielded somewhat mixed results. Much of this limited evidence suggests that hot flashes are associated with objectively identified sleep disruption in at least some women. At least some of the negative data may be due to methodological issues such as reliance upon problematic self-reports of nocturnal hot flashes and a lack of concurrent measures of hot flashes and sleep. The recent development of a reliable and non-intrusive method for objectively identifying hot flashes during the night should help address the need for substantial additional research in this area. Several areas of clinical relevance are described, including the effects of discontinuing combined hormone therapy (estrogen plus progesterone) or estrogen-only therapy, the possibility of hot flashes continuing for many years after menopause, and the link between hot flashes and depression.

Gender differences in sleep and sleep-disordered breathing

Sleep and sleep disorders are different in several important ways between men and women. Because of pregnancy and menopause, women experience changes in sleep that may present as clinical problems. In clinical populations, women are more likely to present with insomnia than are men, although their sleep may be better preserved. The presentation of sleep apnea in women is distinct from that of men and is less likely to include a "classic" history of witnessed ap-nea or heavy snoring. More likely it presents with nonspecific symptoms, such as fatigue or mood disturbance. There are little data on the effects of different treatments for OSA between men and women. OHS is a syndrome that may be as common in women as in men. The role of hormones in its pathophysiology is not well-defined.