With the decline of reproductive hormones in the menopausal transition period, a substantial number of women experience physiological and psychological changes. Sleep disturbance is one of the major complaints of menopausal women with advancing age. Menopausal women also frequently experience other typical menopausal symptoms, including hot flashes (HFs), night sweats, palpitations, mood changes, anxiety, and depression, which also increase the risk of developing sleep problems
[1]. Indeed, various sleep problems, such as decreased sleep duration, poor sleep quality, and early morning awakenings, commonly begin in the menopausal period
[2]. It is reported that women in menopausal transition or menopause suffer from sleep disturbance or insomnia, ranging from 35% to 60%, and a significant number of women experience severe symptoms that impair daytime functioning
[3]. Sleep disturbance can cause fatigue, somnolence, mood disorders, memory impairment, lack of attention, and even accidents, which can lead to behavioral, occupational, and social problems
[4]. Recent studies revealed that insomnia is also associated with significant medical problems, such as cardiovascular disease, diabetes, and an increased risk of mortality
[5]. In addition to menopause, it has been reported that women have specific periods related to vulnerability to sleep disorders, such as the menstrual cycle and pregnancy, suggesting a link between sleep disorders and female hormones
[6,7][6][7]. As such, insomnia is closely related to hormonal changes and, although it is a major menopausal symptom, there are currently no universal guidelines for treating insomnia in menopausal women.
2.Definition of Insomnia and Sleep Disorders
Insomnia is defined as difficulties falling asleep or maintaining sleep, which result in daytime impairment, despite adequate opportunity and circumstances to sleep. Chronic insomnia disorder is defined when it occurs at least three times per week for three months, according to the International Classification of Sleep Disorders, Third Edition (ICSD-3). Insomnia was traditionally approached as a primary or secondary (comorbid) disorder, provoked by physical problems or psychosocial factors, etc. (as will be discussed later in the Insomnia Etiology Section), but there were issues of uncertainty with the nature of the associations and the direction of causality in comorbid insomnia cases; thus, all insomnia diagnoses were consolidated under chronic insomnia disorder
[9][8].
3. Sleep Disturbance across Menopause: Epidemiology
Middle-aged women have increasing complaints of sleep disorders as they enter menopausal transition and the menopausal period. The incidence rates of sleep problems show 39–47% in peri-menopausal and 35–60% in postmenopausal women, compared to 16–42% in premenopausal women
[3]. Although sleep deteriorates with age and is affected by many physical problems (lower back pain, musculoskeletal disorders, urinary symptoms, hot flushes (HFs), etc.), mood disorders and psychosocial factors, socioeconomic, and racial/ethnic factors
[10[9][10],
12], an independent relationship between menopausal stages and sleep disturbance, controlled for the effects of aging and other confounders, was shown in a meta-analysis of 24 cross-sectional studies
[13][11].
Meanwhile, women who had undergone surgical menopause and were not taking hormone therapy had the highest prevalence of sleep disturbance compared with natural menopausal transitional women, independent of age or years since surgery. The most common sleep complaint in these women was reported as frequent awakenings during sleep in the longitudinal analysis of the Study of Women’s Health Across the Nation (SWAN)
[3].
4. Pathogenesis and Etiology of Insomnia and Menopause
Sleep disturbance in postmenopausal women is pathophysiologically multifactorial (
Table 1). Physiologically, it may be strongly associated with menopause symptoms, such as HFs and night sweats that can be experienced along with female hormonal changes
[16][12], and psychiatrically, with mood disorders, anxiety, and depression
[10][9]. In addition, family/economic/social stress, obesity, ill health, and drug and alcohol intake are common causes of sleep problems in middle-aged women, and commonly encountered comorbid diseases with sleep disorders include OSA, RLS, and periodic leg movement syndrome. After menopause, the prevalence of OSA increases due to weight gain and changes in fat distribution from increased testosterone production and decreased female hormones, and the incidence of RLS increases
[14,17][13][14].
Table 1.
Etiology of sleep disorders in menopause.
Physiologic/Physical |
Age Circadian rhythm modifications Decreased melatonin secretion Female sexual hormone changes Decreased estrogen and progesterone, increased FSH Menopausal symptoms Hot flushes, night sweats Others Bladder problems, Ill health, chronic pain—musculoskeletal disorders, osteoarthritis, fibromyalgia, cancer, etc. Poor sleep hygiene/circumstances Medication, coffee, smoking |
Psychiatric/Psycho-social |
Mood disorder—depression Anxiety Illegal drugs, alcohol intake Others—familial/economic/social problem: stress, bereavement, divorce, unemployment, finances, etc. |
Comorbid diseases with sleep disorders |
Obstructive sleep apnea Restless legs syndrome Periodic limb movement syndrome |
Others |
Circadian rhythm sleep–wake disorder Narcolepsy, idiopathic hypersomnia Parasomnias |