Examining the Relationship Between Subjective Sleep Disturbance and Menopause

A Systematic Review and Meta-analysis

Qunyan Xu, PhD; Cathryne P. Lang, PhD

Disclosures

Menopause. 2014;21(12):1301-1318. 

In This Article

Abstract and Introduction

Abstract

Objective. The purpose of this study was to conduct a systematic review and meta-analysis of the relationship between menopausal stages and sleep disturbance reported using subjective methods. Secondary aims included examining the influence of culture/ethnicity on the relationship between menopausal stages and sleep disturbance.

Methods. Multiple electronic databases were searched from the first available year to November 2013, and a manual search of the reference lists of review articles identified was also conducted. Twenty-four studies with a total of 63,542 midlife women were identified, coded, and analyzed.

Results. The crude and adjusted odds of experiencing sleep disturbance were small but statistically significant for perimenopausal and postmenopausal women, using premenopause as the reference group. The ethnicity of the samples influenced effect sizes; Asian and white women both experienced an increased rate of sleep disturbance at the perimenopausal and postmenopausal stages compared with the premenopausal stage, whereas Hispanic women experienced no change in sleep disturbance across the menopausal transition.

Conclusions. The prevalence of sleep disturbance is higher in perimenopausal, postmenopausal, and surgical menopausal women than in premenopausal women. There is an independent relationship between menopausal stages and sleep disturbance beyond the effects of aging and other confounders, although the magnitude of the relationship is small. Culture, ethnicity, or both might affect the levels of sleep disturbance at various menopausal stages.

Introduction

Many established scales of menopausal symptoms include items that assess sleep quality symptoms. For example, the Greene Climacteric Scale includes the item difficulty in sleeping,[1,2] and the Menopause Rating Scale includes the item sleep problems (difficulty in falling asleep, difficulty in sleeping through, and waking up early) [3]; these are two of the most commonly used scales of menopause symptoms. The inclusion of items assessing sleep quality in such scales was based on clinical observations that women complain of disturbed sleep during the menopausal transition. Clinicians' observations were supported by the results of early research studies, which reported greater sleep disturbance in perimenopausal and postmenopausal women.[4]

A number of review studies —which extensively discuss an overview of sleep disturbance at the menopausal transition, potential risk factors for sleep disturbance, and management strategies—have been published recently.[5,6,7,8] With regard to the prevalence of sleep disturbance and its correlated factors, consensus for several factors was achieved across these reviews. First, there was an approximately 20% increase in sleep disturbance from reproductive stage to menopause, which is likely to have a substantial impact on the population and health services. Sleep is important to quality of life and various other cognitive processes. Sleep deprivation, regardless of duration, is associated with short-term and long-term consequences such as fatigue, impaired memory, cardiovascular disease, and diabetes.[9] Given the rising number of women entering the menopausal transition globally,[10] the population that will be affected by sleep disturbance is considerable.

Second, sleep disturbance at the menopausal transition, as in all other ages, is multifactorial in origin. Vasomotor symptoms (eg, night sweats), mood symptoms (notably anxiety and depression), medical conditions (eg, chronic obstructive pulmonary disease and cardiovascular disease), and lifestyle factors (eg, smoking and alcohol consumption) are frequently identified as risk factors for sleep disturbance, although the causal relationships between these factors and sleep disturbance are difficult to investigate owing to coincidence with the menopausal transition. Vasomotor symptoms are associated with narrowed core body temperature, which is linked with a decreased level of estrogen.[11] Vasomotor symptoms cause sudden perspiration during sleep and necessitate the changing of clothing and bed linen, which may result in sleep disruption (although not every episode of hot flash/night sweat awakens women). More recently, the results of an American study suggested that the severity of vasomotor symptoms, rather than its presence, is the most crucial aspect in evaluating the relationship between vasomotor symptoms and sleep disturbance.[12] Age itself has also been indicated as a causal factor for midlife sleep disturbance. Age impacts on both sleep architecture and circadian rhythm (eg, as people age, the percentage of time of rapid eye movement sleep decreases, whereas that of light sleep increases).[13] For asymptomatic postmenopausal women, sleep disturbance may be a mere effect of aging. Whether sleep disturbance originates from menopause itself or is a result of temporally related factors is not well understood.

Although a number of reviews have indicated that the postmenopausal stage itself poses independent risks for sleep disorders compared with the premenopausal stage,[8] a cursory examination of the literature demonstrated that many published studies undertaken with nonwhite women reported no difference in the report of sleep disorders by women at various menopausal stages[14,15,16,17] or that premenopausal women were at greater risk for sleep disorders.[18] In addition, although it has long been believed that menopausal symptoms (particularly the experience of vasomotor symptoms) are culturally dependent, with Asian women tending to experience fewer vasomotor symptoms than white women,[19] sleep disturbance has not been reviewed cross-culturally in existing reviews. Meanwhile, given the "filing drawer" problem of publication (that nonsignificant findings are much less likely to be published), a systematic examination of all available data and reviews of the risk of bias of publications via a meta-analysis is well advised. Therefore, the aim of the present meta-analysis is to evaluate the relationship between menopausal stages and sleep disturbance and its correlated factors in community midlife women. Sleep disturbance in this study is defined as "subjectively perceived sleep problems that do not necessarily meet criteria for a clinical disorder but are bothersome to the individual."[6] Although a number of polysomnography studies have targeted specific aspects of the diminishing menstrual cycle (eg, Campbell et al[20] and Freedman and Roehrs[21]) in women at midlife or in women with vasomotor symptoms, objective and subjective measures of sleep quality are poorly correlated,[5,8] and we believe that combining subjective and objective measures in a single meta-analysis is not advised.

To achieve this aim, we examined the crude odds of experiencing sleep disturbance at each menopausal stage and the adjusted odds of experiencing sleep disturbance at each menopausal stage, taking into account age and other confounders. Furthermore, the effect of ethnicity as a moderator of these effect sizes was examined.

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