Association Between Obesity and Sleep Disorders in Postmenopausal Women

Maria Fernanda Naufel, MSc; Cristina Frange, MSc; Monica Levy Andersen, PhD; Manoel João Batista Castello Girão, MD, PhD; Sergio Tufik, MD, PhD; Eliane Beraldi Ribeiro, PhD; Helena Hachul, MD, PhD

Disclosures

Menopause. 2018;25(2):139-144. 

In This Article

Abstract and Introduction

Abstract

Objective: To investigate the relationship between obesity and sleep architecture in postmenopausal women.

Methods: One hundred seven postmenopausal women from the Ambulatory of Integrative Treatment for Female Sleep Disorders were invited by telephone to participate in this study. Fifty-three completed the study. We included women aged 50 to 70 years, and excluded women on hormone therapy or missing data. The study consisted of two meetings, including a full-night polysomnography. Menopause status was confirmed by amenorrhea for at least 1 year. Anthropometric measurements included: body mass, height, body mass index (BMI), waist circumference, hip circumference, waist-to-hip ratio (WHR), and neck circumference. Participants were allocated into two groups according to BMI: nonobese group (BMI <30 kg/m2) and obese group (BMI ≥30 kg/m2).

Results: The obese group had significantly (P < 0.01) increased values of BMI, neck circumference, waist circumference, and hip circumference. WHR was similar between the groups (P = 0.77). Obese participants had significantly increased values of respiratory disturbance index (16.4 vs 9.3 n°/h) and apnea-hypopnea index (14.2 vs 5.6 n°/h). Rapid eye movement sleep latency was positively correlated to body mass (r = P < 0.01), BMI (P < 0.01), and hip circumference (P = 0.01). WHR was negatively correlated to sleep efficiency (P = 0.03). The linear regression model showed that BMI (P < 0.01) and WHR (P < 0.01) were positive predictors of rapid eye movement sleep latency.

Conclusion: In postmenopausal women, high BMI and abdominal obesity are sources of sleep disturbances, decreasing deep sleep, and sleep efficiency, while increasing the risk of obstructive sleep apnea.

Introduction

Menopause is defined as the permanent cessation of menstruation, resulting from the loss of ovarian and follicular activity. Although postmenopause begins at that time, it is not recognized until after 12 months of amenorrhea. With the average life expectancy close to 80 years, women may spend one-third or more of their lives in the postmenopausal stage.[1–3] At the postmenopausal stage, sleep disturbances and weight gain are major health concerns, affecting the quality of life.[4–10]

Postmenopausal women present with sleep difficulties with a higher frequency than younger women. Insomnia and obstructive sleep apnea (OSA) seem to be the most prevalent sleep disorders after menopause. The early diagnosis and treatment of them is important in improving postmenopausal women's quality of life.[9–11] Estrogen deficiency can lead to sleep instability, and hormone therapy has been found to correct sleep disorders in some postmenopausal women.[12]

Sleep is classified into rapid eye movement (REM) sleep and non-REM (NREM) sleep; the latter being further subdivided into stage 1 (N1), stage 2 (N2), and stage 3 (N3). Stage 3 is also known as slow wave sleep or deep sleep. In normal individuals, NREM sleep predominates in the first half of the night, whereas REM sleep is more frequent in the second half of the night.[13] Each sleep cycle lasts for about 90 to 120 minutes, and a night has four to six different sleep cycles; it shifts between the different sleep stages (such as NREM and REM sleep stages), as well as arousal and wakefulness.

Deep sleep has been associated with body and brain restitution (eg, daytime function or feeling rested or energetic upon awaking), and REM sleep has been associated with promotion of emotional and/or mental functions, including memory.[11] Sleep can be monitored by subjective (questionnaires), objective (polysomnography [PSG] or actigraphy), or multimodal ways. PSG is the gold-standard method for respiratory sleep disorder diagnosis.[11]

The prevalence of overweight and obesity is proportionally higher in postmenopausal women when compared with premenopausal women.[14] Changes in reproductive hormone levels are important factors contributing to this positive association.[14] There is also evidence that estrogen withdrawal affects fat distribution, leading to an increased proportion of abdominal fat in postmenopausal women.[15–17] Although weight gain and abdominal obesity may be attenuated by estrogen therapy, hormone therapy is of limited use as it has been linked to various health risks.[15–17]

In the general population, the association between obesity and sleep disturbances has been shown to be harmful, favoring the development of type 2 diabetes, hypertension, cardiovascular disorders, metabolic syndrome, stroke, and some cancers.[18]

There are few studies about the association between obesity and sleep disorders in postmenopausal women, and in the majority of these previous studies, the sleep disorder has been assessed on the basis of self-report only (questionnaires). When they were assessed by PSG, most of the studies focused only on OSA and not sleep architecture.[19–22] In this context, the aim of the present study was to investigate the relationship between obesity and sleep architecture in postmenopausal women.

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