Copyright 1992 by the American Psychological Association, Inc.
Psychology and Aging 1992, Vol. 7, No. 1,83-88
Factors Related to Sleep Quality in Healthy Elderly Women
This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Nancy Gourash Bitwise Pacific Graduate School of Psychology Elderly women in subjectively good health—free of acute illness and major sleep pathologies—who were self-identified as good (n = 22) and poor (n = 16) sleepers were compared on measures of physical health, psychological symptoms, psychosocial status, and life-style. Poor sleepers reported longer sleep latencies, less total sleep time, more nonrestorative sleep, and more daytime fatigue than did good sleepers. Sleep recordings confirmed subjective reports, with shorter total sleep times and trends for lower sleep efficiency, longer sleep latencies, and more wake-after-sleep onset among women with subjective poor sleep. Poor sleepers also were more frequent users of sedativehypnotic medications in the past. Current medication use, alcohol and caffeine use, daytime napping, and exercise were equivalent in both groups. Psychosocial status failed to discriminate groups. Poor sleepers reported significantly more psychological symptoms than did good sleepers. The levels of both psychological symptoms and sleep disturbance were mild.
expected to lead to earlier bedtimes, earlier awakenings, and more wakefulness during the sleep period. Menopause involves physiological changes that have been linked to poor sleep (Ballinger, 1976). Often overlooked as factors in poor sleep are health conditions such as cardiovascular disease, diabetes, and arthritis and their corresponding medication treatments (Prinz, Vitiello, Raskind, & Thorpy, 1990). A large literature has related poor sleep to psychological factors such as dysphoria, anxiety, somatization, and a tendency to internalize psychological conflicts (Kales, Caldwell, Preston, Healey, & Kales, 1976; Kales, Caldwell, Soldatos, Bixler, & Kales, 1983; Pailhous, Benoit, Goldenberg, Bouard, & Payant, 1988). It is uncertain whether the relevance of these findings increases (Kales et al, 1983), decreases (Roehrs, Lineback, Zorick, & Roth, 1982), or remains essentially unchanged (Bliwise, Bliwise, & Dement, 1985; Morin & Gramling, 1989) for insomnia in the elderly. Psychosocial stressors common among or unique to elderly women may make them more likely to experience sleep disturbance. Differential mortality makes the loss of a spouse more likely for elderly women than for elderly men, and bereavement has been linked to self-reported sleep disturbance (Breckenridge, Gallagher, Thompson, & Peterson, 1986). Another psychosocial stressor for elderly women in our society is divorce. Older divorcees are more likely to report a sense of alienation and to have greater difficulties with adjustment than older widows (Kitson, Lopata, Holmes, & Meyerling, 1980). Life-style factors as predictors of poor sleep must also be considered. Substance use, particularly long-term use of sedatives, hypnotics, and alcohol, can lead to insomnia as tolerance and physical dependence increase over time (Kales & Kales, 1984). Elderly women are disproportionate users of sedativehypnotic medication (Mellinger et al., 1985). In addition, elderly men and women are more likely to take daytime naps and lead sedentary lives than are younger men and women (McGhie & Russell, 1962). Finally, two specific sleep pathologies, sleep apnea and periodic leg movements, common in the aged have received much
Estimates of the proportion of elderly women with complaints of poor sleep range between 20% and 35% (CornoniHuntley, Brock, Ostfeld, Taylor, & Wallace, 1986; Karacan et al., 1976). Many studies have documented that significantly more older women than older men report sleep problems (Cornoni-Huntley et al., 1986; Mellinger, Baiter, & Uhlenhuth, 1985). The reasons why older women are particularly prone to poor sleep, however, are complex and not easily understood given what is known about age-related changes in human sleep patterns. For instance, increases in sleep fragmentation and Stage 1 sleep, both of which usually indicate less restful sleep, are seen in sleep laboratory studies of both elderly men and women without sleep complaints (Webb, 1982; Williams, Karacan, & Hursch, 1974). Another age-related change in sleep observed in both men and women is decreased deep, slow-wave sleep (Stages 3 and 4; Williams et al., 1974). Paradoxically, some studies even suggest that elderly women have more Stage 3 and Stage 4 sleep than do elderly men (Webb, 1982; Williams et al., 1974), which would lead one to predict fewer sleep complaints among elderly women. Age-related changes in sleep architecture do not appear to account for the greater prevalence of sleep complaints among elderly women. Thus, other factors that predispose the elderly, particularly women, to poor sleep must be sought. Theorists of adult development and aging argue that the biological, psychological, and social context of the lives of the elderly must be examined to define and explain age-related changes (Birren & Birren, 1990; Riegel, 1975). Among biological factors, age-related changes in circadian rhythms could produce insomnia (Richardson, 1990), and elderly women appear particularly susceptible to a phase advance in their body temperature cycles (Campbell, Gillin, Kripke, Erikson, & Clopton, 1989; Vitiello, Prinz, Larsen, & Marks, 1990), which would be
Correspondence concerning this article should be addressed to Nancy Gourash Bliwise, Pacific Graduate School of Psychology, Professional Doctoral Studies, 935 East Meadow Drive, Palo Alto, California 94303-4233.
83
This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
84
NANCY GOURASH BLIWISE
attention (Ancoli-Israel, Kripke, Mason, & Kaplan, 1985). The possible role of these two conditions in poor sleep, however, has been the subject of much debate among sleep disorders specialists (Aldrich, 1990; Hoelscher, Edinger, Marsh, Radtke, & Erwin, 1990). Some studies suggest a relationship (Edinger et al., 1989; Jacobs, Reynolds, Kupfer, Lovin, & Ehrenpreis, 1988), and others do not (Ancoli-Israel et al., 1985; Dickel & Mosko, 1990; Phillips, Berry, Schmitt, Patel, & Cook, 1989). In the present study, groups of elderly women with good and poor sleep patterns were compared on a range of biological (selected chronic illnessand hormone replacement), psychological (psychological symptoms), psychosocial (divorce or widowhood), and life-style (substance use, exercise, napping, typical bedtimes, and wake-up times) factors thought to be related to poor sleep. In addition, the groups of good and poor sleepers are compared on polysomnographic sleep data. Elderly women with sleep apnea or periodic leg movements are excluded from the sample.
Method
Participants Participants were 38 elderly (mean age = 67.9 years, SD = 9.3) women who were members of a larger cohort of elderly volunteers being studied longitudinally as a part of the Sleep and Aging Program at the Sleep Disorders Center at Stanford University Medical School. None were sleep clinic patients. These individuals were selected retrospectively from the cohort on the basis of criteria for absence of apnea and nocturnal myoclonus (periodic leg movements). Participants were recruited from the Palo Alto, California community from advertisements for good and poor sleepers placed in senior centers, in churches, on bulletin boards in university buildings, and in local circulation newspapers. All gave informed consent. Fifty-three percent were college graduates, and only 9% did not graduate from high school. Over half of the women (56%) were married, 18% were widowed, 21% were divorced, and 5% were single. None of the widowed women had lost a spouse in the past year, and none of the divorced women were divorced within the year before the study. The health status of the women varied, but all were noninstitutionalized, fully ambulatory, had no history of cancer, and were free from acute illness when studied. All reported subjectively good health. None were diabetic, suffered from congestive heart failure or thyroid disease, or were demented. Only 1 smoked. None had ever been hospitalized for psychiatric reasons or had a history of attempted suicide. Only 1 woman had used antidepressant medication in the past. Seven of the 38 participants used sedative-hypnotic medication at the time of the study. Participants were self-identified as good (n = 22) and poor (n = 16) sleepers and were categorized on the basis of their response to recruitment for good or poor sleepers. Self-reported total sleep time (TST) in minutes, /(36) = 1.75, p < .10, tended to be lower for poor sleepers (M = 378.2, SD = 57.1) than for good sleepers (M = 419.0, SD = 73.8). Time to fall asleep was significantly longer, f(36) = 2.41, p < .05, in poor (M = 24.3, SD = 20.3) compared with good (J/= 9.7, SD = 6.1) sleepers. Precise data on duration of disturbed sleep in the poor sleepers were not available. These subjects were followed over time, and none reported marked changes in their subjective steep over follow-up intervals. Thus, a conservative estimate is that the poor sleepers experienced disturbed sleep for at least 5 years. The poor sleepers (M = 68.4, SD = 8.7; range: 49-82) were not significantly older than good sleepers (M= 67.5, SD = 9.9; range: 52-95).
Procedure All participants underwent two consecutive nights of polysomnography, using conventional techniques for recording and scoring sleep stages (Rechtschaffen & Kales, 1968). Bedtimes were established by reference to each woman's customary bedtime at home. Alcohol intake was prohibited the day preceding and the days of the 1st and 2nd laboratory night. Sedative-hypnotic medications were prohibited on both laboratory nights and for a week before the study. Caffeine intake was limited to one cup of coffee, tea, or cola on the day before each laboratory night. Recordings of sleep apnea and periodic leg movements used standard techniques (Guilleminault, 1982). Participants were selected from the sleep and aging cohort because they had a respiratory disturbance index (RDI) of fewer than 10 events (apneas and hypopneas) per hour of sleep and a periodic leg movement index (PLMI) of fewer than 10 movements (including both movements with and without arousal) per hour of sleep. These requirements were met for both laboratory nights because of known variability in sleep apnea and periodic leg movements (Mosko, Dickel, & Ashurst, 1988). Mean RDIs for Nights 1 and 2 were 2.44 and 1.95, respectively, and mean PLMIs for Nights 1 and 2 were 1.52 and 2.17, respectively. The following data were analyzed from the all-night polysomnograms: TST in minutes, sleep efficiency (TST/time in bed X100), sleep latency in minutes (minutes to first epoch of sleep), time awake after sleep onset, number of awakenings, rapid eye movement (REM) latency in minutes (minutes from first epoch of sleep to the first epoch of REM sleep with intervening wakefulness included), and the percentages of Stage 1, Stage 2, Stages 3 and 4, and Stage REM (all calculated as a percentage of TST). Mean values for Nights 1 and 2 were calculated for each of these variables and used in statistical analyses. Participants completed a modified version of the Sleep Questionnaire and Assessment of Wakefulness (SQAW) developed by Miles (1982). The SQAW collects detailed information about typical bedtimes and wake-up times, frequency of alcohol and caffeine intake, frequency of daily exercise, use of sedative and hypnotics and other medications currently and in the past, and number of daily naps. Participants rated the severity of sleepiness, fatigue, and nonrestorative sleep using a 5-point Likert scale (1 = none, 2 = slight, 3 = moderate, 4 = considerable, and 5 = very great). Alcohol use was quantified by classifying participants as infrequent drinkers (those who reported never using alcohol, n = 15, and who reported using alcohol less than once a week, n = 4) and frequent drinkers (those who reported using alcohol at least once a week but less than once a day, n = 4, and those who reported using alcohol at least once per day, n - 15). Caffeine use was quantified as the number of cups of caffeinated beverages (coffee, tea, or cola) consumed per day. Estimates of dairy exercise were based on responses to the question "How many times in a usual week do you participate in a sport or some other form of physical exercise?" Chronic illnesses and physiological sequela of menopause were identified by classifying frequently used medications into the following categories: cardiovascular medications (diuretics, antihypertensives, beta blockers, calcium channel blockers, and angiotensin inhibitors), antiinflammatory medications (steroidal and nonsteroidal), and medications for menopausal symptoms (estrogen and progesterone). All participants completed the revised Symptom Checklist—90 (SCL-90-R) developed by Derogatis (1977) and the Geriatric Depression Scale (GDS; Yesavage et al., 1983). The SCL-90-R is a checklist of 90 symptoms on which individuals rate the extent to which they have been distressed by each using a 5-point scale. The list yields scores on nine separate dimensions, none of which include reference to sleep disturbance. The GDS is a 30-point self-report depression scale that was developed and validated for the elderly. It contains no somatic items and is best considered a measure of depressed mood (Yesavage et
85
SLEEP QUALITY IN ELDERLY WOMEN al, 1983). The SCL-90-R and the GDS were completed with a 1-week time frame. Data were analyzed by first examining the frequency distribution of each variable using the Kolmogorov-Smirnov single sample test of normal distribution. Normally distributed data were analyzed with t tests comparing good and poor sleepers. Data not following a normal distribution were analyzed with Mann-Whitney U tests. Chi-square tests of independence were used to compare good and poor sleepers on dichotomous variables.
This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Results Polysomnographic data were consistent with self-identification as good and poor sleepers (Table 1). The good sleepers had significantly longer sleep times and trends for higher sleep efficiencies, shorter sleep latencies, and greater wake time after sleep onset than the poor sleepers. The number of awakenings, however, did not distinguish the groups, perhaps because women with the two conditions typically causing frequent awakenings in the elderly (sleep apnea and periodic leg movements) were excluded from the sample. There were no significant differences in sleep stage percentages between good and poor sleepers. Subjectively, poor sleepers described significantly (z = 2.49, p < .05) more nonrestorative nocturnal sleep (M = 2.8, SD = 1.3) than good sleepers (M = 1.7, SD = 1.0). Poor sleepers also reported significantly (z = 2.05, p < .05) greater difficulty with daytime fatigue (M = 3.2, SD = 1.2) than good sleepers (M= 2.3, SD =1.1), but no statistically significant differences in ratings of the amount of daytime sleepiness were found. Chi-square analysis suggested that chronic illnesses were unrelated to the sleep difficulties of this sample of elderly women without sleep pathology. No differences between good and poor sleepers on the number of individuals receiving antiinflammatory medications (5% vs. 7%) or cardiovascular medications (14% vs. 21%) were found. In addition, no differences in
Table 1 Nocturnal Polysomnography in Elderly Women With Good and Poor Sleep
estrogen replacement (20% vs. 36%) were found between good and poor sleepers. Poor sleepers consistently reported more psychological symptoms than good sleepers on a number of scales (Table 2). Significant differences were found for somatic symptoms and symptoms of phobic anxiety, paranoid ideation, and psychoticism. Trends were observed for obsessive-compulsive, general anxiety, and depressive symptoms. Psychosocial factors failed to discriminate the two groups. Poor sleepers were no more likely to be divorced or widowed than were good sleepers; however, none of the women in the study were recently widowed or divorced. There were no differences in age or education between the good and poor sleepers; approximately 58% of the good sleepers and 47% of the poor sleepers had a college degree. No statistically significant differences between good and poor sleepers were found on any of the behaviors typically associated with insomnia. Good sleepers reported consuming alcohol at least once a week more often (59%) than poor sleepers (31%), but this difference was not statistically significant. As expected, poor sleepers tended more often to be at least occasional users of sedatives or hypnotics in the past (25% vs. 5%), x2 (1, N= 34) = 3.18, p < .10, but there were no differences in the proportions of poor and good sleepers currently using hypnotic medications (21 % vs. 20%), x2 (1, N= 34) = .01, ns. The number of days with physical exercise was virtually identical between the two groups (good sleepers: Af = 3.8, SD = 2.6; poor sleepers: M = 3.9, SD = 2.3). There was a trend, t(36) = 1.74, p
Psychology and Aging 1992, Vol. 7, No. 1,83-88
Factors Related to Sleep Quality in Healthy Elderly Women
This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Nancy Gourash Bitwise Pacific Graduate School of Psychology Elderly women in subjectively good health—free of acute illness and major sleep pathologies—who were self-identified as good (n = 22) and poor (n = 16) sleepers were compared on measures of physical health, psychological symptoms, psychosocial status, and life-style. Poor sleepers reported longer sleep latencies, less total sleep time, more nonrestorative sleep, and more daytime fatigue than did good sleepers. Sleep recordings confirmed subjective reports, with shorter total sleep times and trends for lower sleep efficiency, longer sleep latencies, and more wake-after-sleep onset among women with subjective poor sleep. Poor sleepers also were more frequent users of sedativehypnotic medications in the past. Current medication use, alcohol and caffeine use, daytime napping, and exercise were equivalent in both groups. Psychosocial status failed to discriminate groups. Poor sleepers reported significantly more psychological symptoms than did good sleepers. The levels of both psychological symptoms and sleep disturbance were mild.
expected to lead to earlier bedtimes, earlier awakenings, and more wakefulness during the sleep period. Menopause involves physiological changes that have been linked to poor sleep (Ballinger, 1976). Often overlooked as factors in poor sleep are health conditions such as cardiovascular disease, diabetes, and arthritis and their corresponding medication treatments (Prinz, Vitiello, Raskind, & Thorpy, 1990). A large literature has related poor sleep to psychological factors such as dysphoria, anxiety, somatization, and a tendency to internalize psychological conflicts (Kales, Caldwell, Preston, Healey, & Kales, 1976; Kales, Caldwell, Soldatos, Bixler, & Kales, 1983; Pailhous, Benoit, Goldenberg, Bouard, & Payant, 1988). It is uncertain whether the relevance of these findings increases (Kales et al, 1983), decreases (Roehrs, Lineback, Zorick, & Roth, 1982), or remains essentially unchanged (Bliwise, Bliwise, & Dement, 1985; Morin & Gramling, 1989) for insomnia in the elderly. Psychosocial stressors common among or unique to elderly women may make them more likely to experience sleep disturbance. Differential mortality makes the loss of a spouse more likely for elderly women than for elderly men, and bereavement has been linked to self-reported sleep disturbance (Breckenridge, Gallagher, Thompson, & Peterson, 1986). Another psychosocial stressor for elderly women in our society is divorce. Older divorcees are more likely to report a sense of alienation and to have greater difficulties with adjustment than older widows (Kitson, Lopata, Holmes, & Meyerling, 1980). Life-style factors as predictors of poor sleep must also be considered. Substance use, particularly long-term use of sedatives, hypnotics, and alcohol, can lead to insomnia as tolerance and physical dependence increase over time (Kales & Kales, 1984). Elderly women are disproportionate users of sedativehypnotic medication (Mellinger et al., 1985). In addition, elderly men and women are more likely to take daytime naps and lead sedentary lives than are younger men and women (McGhie & Russell, 1962). Finally, two specific sleep pathologies, sleep apnea and periodic leg movements, common in the aged have received much
Estimates of the proportion of elderly women with complaints of poor sleep range between 20% and 35% (CornoniHuntley, Brock, Ostfeld, Taylor, & Wallace, 1986; Karacan et al., 1976). Many studies have documented that significantly more older women than older men report sleep problems (Cornoni-Huntley et al., 1986; Mellinger, Baiter, & Uhlenhuth, 1985). The reasons why older women are particularly prone to poor sleep, however, are complex and not easily understood given what is known about age-related changes in human sleep patterns. For instance, increases in sleep fragmentation and Stage 1 sleep, both of which usually indicate less restful sleep, are seen in sleep laboratory studies of both elderly men and women without sleep complaints (Webb, 1982; Williams, Karacan, & Hursch, 1974). Another age-related change in sleep observed in both men and women is decreased deep, slow-wave sleep (Stages 3 and 4; Williams et al., 1974). Paradoxically, some studies even suggest that elderly women have more Stage 3 and Stage 4 sleep than do elderly men (Webb, 1982; Williams et al., 1974), which would lead one to predict fewer sleep complaints among elderly women. Age-related changes in sleep architecture do not appear to account for the greater prevalence of sleep complaints among elderly women. Thus, other factors that predispose the elderly, particularly women, to poor sleep must be sought. Theorists of adult development and aging argue that the biological, psychological, and social context of the lives of the elderly must be examined to define and explain age-related changes (Birren & Birren, 1990; Riegel, 1975). Among biological factors, age-related changes in circadian rhythms could produce insomnia (Richardson, 1990), and elderly women appear particularly susceptible to a phase advance in their body temperature cycles (Campbell, Gillin, Kripke, Erikson, & Clopton, 1989; Vitiello, Prinz, Larsen, & Marks, 1990), which would be
Correspondence concerning this article should be addressed to Nancy Gourash Bliwise, Pacific Graduate School of Psychology, Professional Doctoral Studies, 935 East Meadow Drive, Palo Alto, California 94303-4233.
83
This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
84
NANCY GOURASH BLIWISE
attention (Ancoli-Israel, Kripke, Mason, & Kaplan, 1985). The possible role of these two conditions in poor sleep, however, has been the subject of much debate among sleep disorders specialists (Aldrich, 1990; Hoelscher, Edinger, Marsh, Radtke, & Erwin, 1990). Some studies suggest a relationship (Edinger et al., 1989; Jacobs, Reynolds, Kupfer, Lovin, & Ehrenpreis, 1988), and others do not (Ancoli-Israel et al., 1985; Dickel & Mosko, 1990; Phillips, Berry, Schmitt, Patel, & Cook, 1989). In the present study, groups of elderly women with good and poor sleep patterns were compared on a range of biological (selected chronic illnessand hormone replacement), psychological (psychological symptoms), psychosocial (divorce or widowhood), and life-style (substance use, exercise, napping, typical bedtimes, and wake-up times) factors thought to be related to poor sleep. In addition, the groups of good and poor sleepers are compared on polysomnographic sleep data. Elderly women with sleep apnea or periodic leg movements are excluded from the sample.
Method
Participants Participants were 38 elderly (mean age = 67.9 years, SD = 9.3) women who were members of a larger cohort of elderly volunteers being studied longitudinally as a part of the Sleep and Aging Program at the Sleep Disorders Center at Stanford University Medical School. None were sleep clinic patients. These individuals were selected retrospectively from the cohort on the basis of criteria for absence of apnea and nocturnal myoclonus (periodic leg movements). Participants were recruited from the Palo Alto, California community from advertisements for good and poor sleepers placed in senior centers, in churches, on bulletin boards in university buildings, and in local circulation newspapers. All gave informed consent. Fifty-three percent were college graduates, and only 9% did not graduate from high school. Over half of the women (56%) were married, 18% were widowed, 21% were divorced, and 5% were single. None of the widowed women had lost a spouse in the past year, and none of the divorced women were divorced within the year before the study. The health status of the women varied, but all were noninstitutionalized, fully ambulatory, had no history of cancer, and were free from acute illness when studied. All reported subjectively good health. None were diabetic, suffered from congestive heart failure or thyroid disease, or were demented. Only 1 smoked. None had ever been hospitalized for psychiatric reasons or had a history of attempted suicide. Only 1 woman had used antidepressant medication in the past. Seven of the 38 participants used sedative-hypnotic medication at the time of the study. Participants were self-identified as good (n = 22) and poor (n = 16) sleepers and were categorized on the basis of their response to recruitment for good or poor sleepers. Self-reported total sleep time (TST) in minutes, /(36) = 1.75, p < .10, tended to be lower for poor sleepers (M = 378.2, SD = 57.1) than for good sleepers (M = 419.0, SD = 73.8). Time to fall asleep was significantly longer, f(36) = 2.41, p < .05, in poor (M = 24.3, SD = 20.3) compared with good (J/= 9.7, SD = 6.1) sleepers. Precise data on duration of disturbed sleep in the poor sleepers were not available. These subjects were followed over time, and none reported marked changes in their subjective steep over follow-up intervals. Thus, a conservative estimate is that the poor sleepers experienced disturbed sleep for at least 5 years. The poor sleepers (M = 68.4, SD = 8.7; range: 49-82) were not significantly older than good sleepers (M= 67.5, SD = 9.9; range: 52-95).
Procedure All participants underwent two consecutive nights of polysomnography, using conventional techniques for recording and scoring sleep stages (Rechtschaffen & Kales, 1968). Bedtimes were established by reference to each woman's customary bedtime at home. Alcohol intake was prohibited the day preceding and the days of the 1st and 2nd laboratory night. Sedative-hypnotic medications were prohibited on both laboratory nights and for a week before the study. Caffeine intake was limited to one cup of coffee, tea, or cola on the day before each laboratory night. Recordings of sleep apnea and periodic leg movements used standard techniques (Guilleminault, 1982). Participants were selected from the sleep and aging cohort because they had a respiratory disturbance index (RDI) of fewer than 10 events (apneas and hypopneas) per hour of sleep and a periodic leg movement index (PLMI) of fewer than 10 movements (including both movements with and without arousal) per hour of sleep. These requirements were met for both laboratory nights because of known variability in sleep apnea and periodic leg movements (Mosko, Dickel, & Ashurst, 1988). Mean RDIs for Nights 1 and 2 were 2.44 and 1.95, respectively, and mean PLMIs for Nights 1 and 2 were 1.52 and 2.17, respectively. The following data were analyzed from the all-night polysomnograms: TST in minutes, sleep efficiency (TST/time in bed X100), sleep latency in minutes (minutes to first epoch of sleep), time awake after sleep onset, number of awakenings, rapid eye movement (REM) latency in minutes (minutes from first epoch of sleep to the first epoch of REM sleep with intervening wakefulness included), and the percentages of Stage 1, Stage 2, Stages 3 and 4, and Stage REM (all calculated as a percentage of TST). Mean values for Nights 1 and 2 were calculated for each of these variables and used in statistical analyses. Participants completed a modified version of the Sleep Questionnaire and Assessment of Wakefulness (SQAW) developed by Miles (1982). The SQAW collects detailed information about typical bedtimes and wake-up times, frequency of alcohol and caffeine intake, frequency of daily exercise, use of sedative and hypnotics and other medications currently and in the past, and number of daily naps. Participants rated the severity of sleepiness, fatigue, and nonrestorative sleep using a 5-point Likert scale (1 = none, 2 = slight, 3 = moderate, 4 = considerable, and 5 = very great). Alcohol use was quantified by classifying participants as infrequent drinkers (those who reported never using alcohol, n = 15, and who reported using alcohol less than once a week, n = 4) and frequent drinkers (those who reported using alcohol at least once a week but less than once a day, n = 4, and those who reported using alcohol at least once per day, n - 15). Caffeine use was quantified as the number of cups of caffeinated beverages (coffee, tea, or cola) consumed per day. Estimates of dairy exercise were based on responses to the question "How many times in a usual week do you participate in a sport or some other form of physical exercise?" Chronic illnesses and physiological sequela of menopause were identified by classifying frequently used medications into the following categories: cardiovascular medications (diuretics, antihypertensives, beta blockers, calcium channel blockers, and angiotensin inhibitors), antiinflammatory medications (steroidal and nonsteroidal), and medications for menopausal symptoms (estrogen and progesterone). All participants completed the revised Symptom Checklist—90 (SCL-90-R) developed by Derogatis (1977) and the Geriatric Depression Scale (GDS; Yesavage et al., 1983). The SCL-90-R is a checklist of 90 symptoms on which individuals rate the extent to which they have been distressed by each using a 5-point scale. The list yields scores on nine separate dimensions, none of which include reference to sleep disturbance. The GDS is a 30-point self-report depression scale that was developed and validated for the elderly. It contains no somatic items and is best considered a measure of depressed mood (Yesavage et
85
SLEEP QUALITY IN ELDERLY WOMEN al, 1983). The SCL-90-R and the GDS were completed with a 1-week time frame. Data were analyzed by first examining the frequency distribution of each variable using the Kolmogorov-Smirnov single sample test of normal distribution. Normally distributed data were analyzed with t tests comparing good and poor sleepers. Data not following a normal distribution were analyzed with Mann-Whitney U tests. Chi-square tests of independence were used to compare good and poor sleepers on dichotomous variables.
This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.
Results Polysomnographic data were consistent with self-identification as good and poor sleepers (Table 1). The good sleepers had significantly longer sleep times and trends for higher sleep efficiencies, shorter sleep latencies, and greater wake time after sleep onset than the poor sleepers. The number of awakenings, however, did not distinguish the groups, perhaps because women with the two conditions typically causing frequent awakenings in the elderly (sleep apnea and periodic leg movements) were excluded from the sample. There were no significant differences in sleep stage percentages between good and poor sleepers. Subjectively, poor sleepers described significantly (z = 2.49, p < .05) more nonrestorative nocturnal sleep (M = 2.8, SD = 1.3) than good sleepers (M = 1.7, SD = 1.0). Poor sleepers also reported significantly (z = 2.05, p < .05) greater difficulty with daytime fatigue (M = 3.2, SD = 1.2) than good sleepers (M= 2.3, SD =1.1), but no statistically significant differences in ratings of the amount of daytime sleepiness were found. Chi-square analysis suggested that chronic illnesses were unrelated to the sleep difficulties of this sample of elderly women without sleep pathology. No differences between good and poor sleepers on the number of individuals receiving antiinflammatory medications (5% vs. 7%) or cardiovascular medications (14% vs. 21%) were found. In addition, no differences in
Table 1 Nocturnal Polysomnography in Elderly Women With Good and Poor Sleep
estrogen replacement (20% vs. 36%) were found between good and poor sleepers. Poor sleepers consistently reported more psychological symptoms than good sleepers on a number of scales (Table 2). Significant differences were found for somatic symptoms and symptoms of phobic anxiety, paranoid ideation, and psychoticism. Trends were observed for obsessive-compulsive, general anxiety, and depressive symptoms. Psychosocial factors failed to discriminate the two groups. Poor sleepers were no more likely to be divorced or widowed than were good sleepers; however, none of the women in the study were recently widowed or divorced. There were no differences in age or education between the good and poor sleepers; approximately 58% of the good sleepers and 47% of the poor sleepers had a college degree. No statistically significant differences between good and poor sleepers were found on any of the behaviors typically associated with insomnia. Good sleepers reported consuming alcohol at least once a week more often (59%) than poor sleepers (31%), but this difference was not statistically significant. As expected, poor sleepers tended more often to be at least occasional users of sedatives or hypnotics in the past (25% vs. 5%), x2 (1, N= 34) = 3.18, p < .10, but there were no differences in the proportions of poor and good sleepers currently using hypnotic medications (21 % vs. 20%), x2 (1, N= 34) = .01, ns. The number of days with physical exercise was virtually identical between the two groups (good sleepers: Af = 3.8, SD = 2.6; poor sleepers: M = 3.9, SD = 2.3). There was a trend, t(36) = 1.74, p
