The Perimenopausal Years Are Associated with a Sharp Increase in the Frequency of Sleep Complaints

THE PERIMENOPAUSAL YEARS ARE ASSOCIATED WITH A SHARP INCREASE IN THE FREQUENCY OF SLEEP COMPLAINTS BY WOMEN.1,2 Although the exact prevalence of self-reported sleep problems varies widely across studies,3-5 perimenopausal women typically cite insomnia, disturbed sleep, and fatigue as some of their most frequent and pressing health concerns. The initiation of these sleep difficulties is usually attributed to the presence of hot flashes and related perimenopausal symptoms.2 This hypothesis is supported by laboratory sleep studies,6,7 though there is at least one contradictory report.8 Perimenopausal women experiencing hot flashes have more arousals during sleep and more sleep stage changes compared with women of equivalent age and hormonal status who are not experiencing hot flashes.7 Estrogen replacement therapy (ERT) has been widely prescribed for the alleviation of hot flashes and consequent sleep disruption. Numerous studies have shown that ERT reduces hot flashes and improves self-reported sleep quality (e.g., 9). Only a few of these studies examined ERT effects on objective sleep measures (e.g., polysomnography). These studies found that ERT could reduce wakefulness6,10 and movement arousals,11 and increase REM sleep.10,12 Collectively these studies suggest that estrogen may be of use in alleviating the sleep complaints of older women, especially those who are experiencing hot flashes.13,14 Sleep complaints do not subside after the menopausal transition years. Many older postmenopausal women continue to report significant sleep disturbance, including nighttime awakenings, long sleep onset latencies, and overall poor sleep quality.1 Little is known about the impact of ERT on the sleep of older, postmenopausal women who are not experiencing hot flashes. Previous studies using polysomnography to assess ERT effects were typically based on women experiencing hot flashes. One purpose of this study was to examine the effect of long-term oral ERT on objective and subjective sleep measures in postmenopausal women who were not experiencing hot flashes and who were well past the hormonal fluctuations that occur during the three to four years on either side of menopause.15,16 The other purpose of this study was to determine whether long-term oral ERT might ameliorate the impact of stress or environmental disruption on the sleep of older women. Sleep quality can be negatively affected by a variety of stressors or environmental disruptions: noise,17 change in ambient temperature,18 sleeping in a novel environment,19 and periodic blood sampling through an intravenous catheter.20 However, the sleep impact of these circumstances varies significantly among individuals. This