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Sleep disturbance and its correlates among elderly Japanese
Archives of Gerontology and Geriatrics 30 (2000) 85 – 100 www.elsevier.com/locate/archger
Sleep disturbance and its correlates among elderly Japanese Yuko Ito a,*, Akiko Tamakoshi b, Kenichi Yamaki a, Kenji Wakai b, Takashi Kawamura b, Kenzo Takagi c, Tetsuo Hayakawa a, Yoshiyuki Ohno b a
Second Department of Internal Medicine, Nagoya Uni6ersity School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 -8550, Japan b Dpartment of Pre6enti6e Medicine, Nagoya Uni6ersity School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 -8550, Japan c Department of Medical Technology, Nagoya Uni6ersity School of Health Sciences, 65 Tsurumai-cho, Showa-ku, Nagoya 466 -8550, Japan Received 4 October 1999; received in revised form 7 December 1999; accepted 8 December 1999
Abstract Although sleep disturbance is a major public health problem in the elderly, few studies have examined the association between sleep disturbance and other related factors in Japan. We examined correlates of sleep disturbance among Japanese elderly. Participants in this cross-sectional study (255 men and 263 women) were those enrolled in a population-based health examination for 65 year-old residents in N City, Japan in 1996 and 1997. Epidemiological data were collected by a self-administered questionnaire. Sleep disturbances were assessed by three common symptoms: difficulty in falling asleep, frequent awakening at night and not feeling rested in the morning. The mean sleep duration was longer in men than in women (7.2 vs 6.8 h, PB0.01), and women reported difficulty in falling asleep more frequently than men (22.4 vs 15.3%, PB 0.05). Sleep disturbances were associated with low educational attainment, retirement from work, higher body mass index (BMI), irregular bedtime, history of cardiovascular disease, arthritis or joint pain and prostatic hypertrophy, and lower subjective well-being in men, and the use of sleeping pills and depression in both genders, but not with marital status, residential status, smoking habits, exercise, limited instrumental activity of daily living, and past episode of such chronic diseases as hyperten -
* Corresponding author. Tel.: +81-52-7442167; fax: + 81-52-7442175. E-mail address: [email protected] (Y. Ito) 0167-4943/00/$ - see front matter © 2000 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 1 6 7 - 4 9 4 3 ( 9 9 ) 0 0 0 5 4 - 0
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sion and stroke. Our study suggests a close association of sleep disturbances among elderly Japanese with several medical/psychiatric health problems that are usually more prevalent in such an age group. Our findings emphasize the realistic need for clinicians to take underlying health problems into consideration when their patients complain of sleep-related symptoms. © 2000 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Sleep disturbances; Health habits; Medical and psychiatric health problems; Japanese elderly
1. Introduction Sleep disturbances are common and clinically important in elderly people. Several epidemiological and clinical studies have demonstrated that the prevalence rate of insomnia among the elderly varies from 17 to 45% (Habte-Gabr et al., 1991; Hays et al., 1996; Lindberg et al., 1997; Newman et al., 1997), with a higher rate in women (Mellinger et al., 1985; Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Quera-Salva et al., 1991; Lindberg et al., 1997; Newman et al., 1997). Sleep disturbances increase with advancing age (Mellinger et al., 1985; Habte-Gabr et al., 1991; Hays et al., 1996; Newman et al., 1997). Previous studies have also suggested that sleep disturbances are usually associated with the presence of cardiovascular diseases (Newman et al., 1997), respiratory diseases (Habte-Gabr et al., 1991; Foley et al., 1995), stroke or arthritis (Newman et al., 1997), lower socioeconomic status (Habte-Gabr et al., 1991), limited physical functions (HabteGabr et al., 1991; Foley et al., 1995; Newman et al., 1997), depression (Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Foley et al., 1995; Newman et al., 1997), anxiety (Mellinger et al., 1985; Quera-Salva et al., 1991; Newman et al., 1997) and sleeping-pill use (Habte-Gabr et al., 1991; Foley et al., 1995). In addition, sleep duration is linked to an increased total mortality risk (Wingard and Berkman, 1983), and the use of sleeping pills is known to be associated with an increased risk of nocturnal death and poor health (Rumble and Morgan, 1992). It is, therefore, important to understand the relationship between sleep disturbances and their correlates. In Japan, however, neither gender-specific prevalence of sleep disturbances nor epidemiological factors related to sleep disturbances have been examined in detail among elderly populations. In this study, we examined the prevalence rate of self-reported sleep disturbances and their associations with demographic characteristics, lifestyle, medical history, and physical and psychological status. The population sample studied consisted of 518 inhabitants aged 65 years (255 men and 263 women), who participated in a health check-up program in N City, Japan.
2. Materials and methods
2.1. Population sample A population-based health examination of 65 year-old residents commenced in 1996. All inhabitants aged 65 years (530 in 1996 and 614 in 1997) were eligible for
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health examination and encouraged to participate by postcard and a notice in local newspapers. A total of 253 inhabitants (47.7%) participated in the examination in 1996 and 266 (43.3%) in 1997. A postal questionnaire was mailed to those who participated. Approval of this study was obtained from the institutional review board, and informed consent from each subject. Excluded from this study was only one individual who did not give informed consent for the study. A total of 518 respondents (255 men and 263 women) completed the questionnaire, i.e. an overall response rate of 45.3%. At entry, information on the study subjects was collected by a self-administered questionnaire, which inquired about demographic characteristics, lifestyle, prior medical history, socio-psychological status, and others. Clinical and physical examinations were given to all subjects at entry. Educational status was dichotomized by the highest educational attainment: completion of junior high school or less, and some higher education beyond junior high school. Marital status included never married, married, widowed, divorced or separated. Smoking status was categorized as current smokers or others. Body weight and height were reported, and BMI (body mass index) was calculated as body weight in kg/(height in meter)2. Prior and present illnesses such as hypertension, cardiovascular diseases (angina pectoris/myocardial infarction), stroke, respiratory diseases, arthritis or joint pain and prostatic hypertrophy were reported. Instrumental activities of daily living (IADL) was measured by a multidimensional 13-item index of functional capacity according to the Tokyo metropolitan institute of gerontology (TMIG) index of competence (Koyano and Shibata, 1991). Limitation of IADL was defined as a score of 12 or less. Depression was assessed using the short form of the geriatric depression scale (GDS) (Brink, 1982; Yesavage et al., 1982; Sheikh and Yesavage, 1986; Niino, 1991). Depression was defined as a score of six or more (Burke et al., 1991). Subjective well being was evaluated using life satisfaction index K (LSIK) (Koyano and Shibata, 1994). This scale is composed of a nine-item index including satisfaction with life as a whole, psychological stability, and evaluation of own aging (Koyano and Shibata, 1994). The range of score is zero to nine points, and a high score indicates high subjective well being.
2.2. Sleep questionnaire Sleep disturbances were assessed by a self-administered questionnaire that included the following questions and answers: 1. How many h do you sleep at night on an average?; 2. How long does it take from going to bed to falling asleep? (answer: B 10 min, 10 – 30 min, 30 – 60 min, or \60 min); 3. How many times do you usually wake up at night? (answer: never, once , twice, or three times or more); and 4. How do you feel when you wake up in the morning? (answer: good or bad). Three major types of sleep disturbance (difficulty in falling asleep, frequent awakening at night and feeling not rested in the morning) were defined as follows.
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Falling asleep was judged as difficult when the difference between bedtime and time of falling asleep exceeded 30 min. Frequent awakening at night was defined when the reported number of awakenings was more than twice, and feeling not rested in the morning when felt bad in the morning. The questionnaire also inquired about the use of sleeping pills with frequency of usage per week.
2.3. Statistical analysis All statistical analyses were performed using statistical analysis system (SAS) (SAS Institute, 1990). Chi-square test was used to evaluate differences in categorical variables, and t-test was applied when examining continuous variables. Trends were examined by the Mantel-extension test for categorical variables with adjustment for year of examination (Mantel, 1963). Associations of sleep disturbances with demographic characteristics, lifestyle, medical history, and physical and psychological status were assessed. All variables significantly associated with any one of the sleep disturbances in the bivariate analyses were considered for inclusion in a logistic regression model. All analyses were conducted separately for men and women. P values of B0.05 was considered statistically significant.
3. Results Table 1 shows the demographic characteristics, lifestyle, medical history, and physical and psychological status among elderly men and women aged 65 years. At age 65 years, more women were widowed, divorced or separated than men (PB 0.01), and had a past history of arthritis or joint pain (P B 0.01). More men were still working (P B0.01) and smoking (PB 0.01) than women, and had such past history as respiratory diseases (PB 0.01) and limitation of IADL (PB 0.05) than women. Educational status, residential status, BMI, physical exercise, some medical histories, depression and subjective well being were not different by gender. Fourteen men (5.5%) and 19 women (7.2%) were using sleeping pills. The prevalence of sleep disturbances in our population sample was computed. Women reported difficulty in falling asleep more frequently than men (22.4 vs 15.3%, PB 0.05). Frequent awakening at night (30.2% in men and 28.1% in women), feeling not rested in the morning (15.4% in men and 19.1% in women), and any of three sleep disturbances (43.5% in men and 49.4% in women) did not significantly differ by gender. Mean sleep duration was significantly longer in men (7.2 h) than in women (6.8 h, P B 0.01). Table 2 details the prevalence of sleep disturbances by demographic characteristic and lifestyle. Men with less than high school education reported more frequent awakening at night than those with a higher education (PB 0.05). Not-working men complained more frequently of difficulty in falling asleep than working men (PB0.01). Higher BMI was significantly associated with any of three sleep disturbances (P B 0.05). Men with irregular bedtime complained significantly more
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Table 1 Demographic characteristics, lifestyle, prior medical history, physical and phychological status in men and women aged 65 years old, N city, Japan Men
Women
N (%)
N (%)
N
255
263
Educational attainment Less than high school High school or more
82 (32.5) 172 (67.5)
89 (33.8) 174 (66.2)
NS
Marital status Married Othersa
243 (95.3) 12 (4.7)
207 (78.7) 56 (21.3)
B0.01
Work–retirement status Working Not working
149 (58.4) 106 (41.6)
81 (30.8) 182 (69.2)
B0.01
Residential status With others Alone
236 (92.5) 19 (7.5)
217 (82.5) 46 (17.5)
NS
BMI Lowest 1/4 Second and third 1/4 Highest 1/4 Current smoker
64 (25.1) 126(49.4) 65 (25.5) 95 (37.3)
68 131 64 8
Physical exercise More than once a week One time or more a week
138 (54.1) 117 (45.9)
138 (52.5) 125 (47.5)
Prior medical history Irregular bedtime Hypertension Cardiovascular disease Stroke Respiratory diseases Arthritis or joint pain Prostatic hypertrophy Sleeping pill use
26 66 11 14 46 18 16 14
(10.2) (25.9) (4.3) (5.5) (18.0) (7.1) (6.3) (5.5)
Limitation of IADL (scores of Tmig of competence) 11 71 (27.8) 12 55 (21.6) 13 129 (50.6) Depression (GDS ` 6) Subjecti6e wll being (scores of LSIK) 0–3 4–6 7–9 a b
27 53 4 7 20 46 – 19
(25.9) (49.8) (24.3) (3.0)
(10.3) (20.2) (1.5) (2.7) (7.6) (17.5) (7.2)
55 (20.9) 45 (17.1) 163 (62.0)
P values
B0.01
NS NS NS NS NS B0.01 B0.01 – NS B0.05b
58 (22.7)
52 (19.8)
NS
68 (26.6) 132 (51.8) 55 (21.6)
64 (24.3) 140 (53.2) 59 (22.4)
NS
Others include those never married, widowed, divorced or seperated. Test for trend by Mantel-extention test, others by chi-squared test.
Men Variables
N (%)
89 (33.8)
22.5
32.6
13.5
50.6
40.0
174 (66.2)
22.4
25.9
22.0
48.9
14.5 25.0
43.2 33.3
207 (78.7) 50.0
23.2 56 (21.3)
27.5 20.0
19.4 29.1
48.3 18.2
31.5 28.3
17.6 12.4
43.2 43.8
81 (30.8) 182 (69.2)
20.1 23.1
25.9 29.1
17.5 19.8
46.9 50.6
15.7 (7.5) 10.5
30.9 21.1
15.8 10.5
44.0 36.8
217 (82.5) 46 (17.5)
22.1 23.9
30.0 19.6
18.1 23.9
50.0 49.3
64 (25.1) 126 (49.4)
6.3 22.4
21.9 32.8
9.4 19.4
29.7* 49.2
68 (25.9) 131 (49.8)
17.7 22.9
29.7 46.0
16.2 23.1
47.1 51.9
65 (25.5)
10.6
33.3
13.9
46.2
64 (24.3)
26.6
24.3
14.1
46.9
Work-retirement status Working 149 (58.4) Not work- 106 (41.6) ing Residential status With others 236 (92.5) Alone 19
Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Any of three sleep disturbances
20.7
40.2*
13.4
51.2
12.8
25.6
16.5
14.8 (4.7)
30.5 25.0
10.1** 22.6
N (%)
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Any of three sleep disturbances (%)
Marital status Married 243 Others 12
BMI a Lowest 1/4 Second and third 1/4 Highest 1/4
Women Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Demographic 6ariables Educational attainment Less than 83 high school High school 172 or more
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Table 2 Prevalence of sleep disturbances according to demographic characteristics and lifestyles in men and women aged 65 years old, N city, Japan
Table 2 (Continued)
Variables
N (%)
Lifestyles 6ariables Current smorker Smoking 95 (37.3) Not smoking 160 (62.7) Physical exercise Less than 138 (54.1) once/week Once or 117 (45.9) more/week Irregular bedtime Yes 26 (10.2) No 229 (89.8)
Women Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Any of three sleep disturbances
N (%)
Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Any of three sleep disturbances (%)
16.8 14.5
23.2 34.6
18.1 13.9
39.4 45.9
8 (3.0) 255 (97.0)
12.5 22.8
12.5 28.7
0.0 14.8
12.5 50.6
17.5
27.7
18.4
43.4
138 (52.5)
26.8
26.8
21.9
52.9
12.7
23.1
12.0
43.6
125 (47.5)
17.6
29.6
16.0
45.6
17.4 15.3
34.8 29.7
30.4** 13.7
60.9* 41.4
27 (10.3) 236 (89.7)
12.0 23.7
8.0 28.0
16.7 19.5
44.0 50.0
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Men
a
Trend was testedby Mandel-extension test, others by chi-square test. * PB0.05. ** PB0.01.
91
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frequently of not feeling rested in the morning (PB 0.01) and any of three sleep disturbances (P B 0.05), compared to men with regular bedtime. No significant associations were identified at all in women. In men, sleep disturbances were also found to be unrelated to marital status, residential status, smoking habits and physical exercise. Table 3 shows the relationships between sleep disturbances and past medical history. Men who had suffered from cardiovascular diseases complained more frequently of difficulty in falling asleep (PB 0.01) and any of three sleep disturbances (PB 0.05), as did men who had suffered from arthritis or joint pain related to any of three sleep disturbances (P B0.05). Men who had suffered from prostatic hypertrophy were related to frequent awakening at night (PB 0.001) and any of three sleep disturbances (P B0.01). Sleep disturbances were not associated with past history of hypertension, stroke and respiratory diseases in either gender. In men, sleeping-pill users complained significantly more frequently of all sleep disturbances, but in women, only feeling not rested in the morning (PB0.01) and any of three sleep disturbances (P B0.05) with statistical significance. Sleep disturbances by physical and psychological status are shown in Table 4. Men and women with depression reported awakening at night and not feeling rested in the morning more frequently than those without depression, and men with depression also complained more frequently of any of three sleep disturbances than men without depression (P B0.05). In men, lower subjective well-being was significantly associated with all sleep disturbances (PB 0.001), whereas not at all in women. Sleep disturbances were not significantly related to limitation of IADL (physical functional limitations). To analyze the independent predictors of sleep disturbances, logistic regression analyses were performed with all variables significantly associated with any one of the sleep disturbances. In this model, sleep disturbances were significantly associated with low educational attainment, retirement from work, the use of sleeping pills and lower subjective well-being in men and with depression and the use of sleeping pills in women (Table 5). Mean demographic characteristics, lifestyle, prior medical history, and physical and psychological status compared sleep duration in h. Significantly longer sleep duration was found only in men who currently smoked (7.4 vs 7.0 h in non-smokers: P B 0.001) and those with regular bedtime (7.2 vs 6.8 h in those with irregular bedtime: P B0.05). In contrast, men who had suffered from cardiovascular diseases demonstrated significantly shorter sleep duration (6.7 vs 7.2 h in non-sufferers: P B 0.05). No significant differences in mean sleep duration were identified in women.
4. Discussion Some epidemiological surveys have previously found that women sleep longer than men (Reyner et al., 1995; Lindberg et al., 1997) and that women have more sleep disturbances than men (Mellinger et al., 1985; Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Quera-Salva et al., 1991; Lindberg et al.,
Table 3 Prevalence of sleep disturbances according to medical history in men and women aged 65 years old, N city, Japan Men N (%)
Difficulty in Frequent Not feeling Any of three N (%) falling asleep awakening at rested in the sleep distur(%) night (%) morning (%) bances (%)
Difficulty in Frequent Not feeling Any of three falling asleep awakening at rested in the sleep distur(%) night (%) morning (%) bances (%)
16.7 14.8
36.4 28.0
10.6 17.1
50.0 41.2
53 (20.0) 210 (79.8)
29.8 20.4
22.8 29.6
15.6 20.0
47.2 50.0
Cardio6ascular disease Yes 14 (5.5) 42.9* No 244 (95.7) 13.7
42.9 29.5
9.1 15.7
54.6** 43.0
4 (1.5) 259 (98.5)
25.0 22.4
0.0 28.8
33.3 18.8
50.0 49.4
Stroke Yes 14 (5.5) No 241 (94.5)
30.8 14.5
30.8 30.2
15.4 15.4
66.7 41.7
7 (2.7) 256 (97.3)
28.6 22.3
14.3 28.5
27.3 18.7
42.9 49.6
Respiratory disease Yes 46 (18.0) No 209 (82.0)
17.4 14.8
32.6 29.4
16.4 10.9
43.5 43.5
20 (7.6) 243 (92.4)
25.0 22.2
30.0 28.0
35.0 17.0
55.0 49.0
Arthritis or joint pain Yes 18 (7.1) 27.8 No 237 (92.9) 14.4
38.9 29.5
33.3 14.4
66.7** 41.7
46 (17.5) 217 (82.5)
29.6 24.1
25.9 27.1
33.3 18.3
52.2 48.9
Prostatic hypertrophy Yes 16 (6.3) 0.0 No 239 (93.7) 16.3
75.0*** 27.2
18.8 15.2
75.0* 41.4
– –
– –
– –
– –
Sleeping pill use Yes 14 (5.5) No 241 (94.5)
57.1** 28.6
50.0* 13.4
71.4** 41.8
31.9 21.7
26.3 28.3
19 (7.2) 244 (92.8)
47.4* 16.9
66.7** 48.9
93
* PB0.01. ** PB0.05. *** PB0.001.
42.9* 13.7
– –
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Hypertension Yes 66 (25.9) No 198 (74.1)
Women
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Table 4 The prevalence of sleep disturbances according to physical and pyschological status in men and women aged 65 years old, N city Japan
N (%)
Limitation of IADL 511 71 (27.8) 12 55 (21.6) 13 129 (50.6) Depression Yes 58 (22.7) No 197 (77.3)
Women Difficulty in Frequent falling asleep awakening (%) at night (%)
(scores of TMIG of competence) 18.3 30.1 14.3 16.4 27.2 22.2 13.2 31.0 13.2 17.2* 14.7
41.4* 26.9
Subjecti6e well-being a (scores of LSIK) 0–3 68 (26.6) 26.5*** 44.1*** 4–6 132 (51.8) 12.9 29.6 7–9 55 (21.6) 7.3 14.6 a
Not feeling Any of three N (%) rested in the sleep disturmorning (%) bances (%)
Difficulty in Frequent falling asleep awakening (%) at night (%)
Not feeling Any of three rested in the sleep disturmorning (%) bances (%)
48.6 44.4 40.3
55 (20.9) 45 (17.1) 163 (62.0)
27.3 20.0 21.5
30.9 31.1 26.4
21.8 28.9 15.4
56.4 53.3 46.0
28.1** 11.7
57.9** 39.3
52 (19.8) 211 (80.2)
26.9 21.3
38.5* 25.6
28.9* 16.7
55.8 47.9
26.9*** 15.2 1.9
62.7 43.2 20.4
64 (24.3) 140 (53.2) 5 (22.4)
23.8 23.6 18.6
39.7 24.3 25.4
22.6 20.7 11.9
57.1 49.3 42.4
Trend was tested by Mantel-extention test, others by chi-square test. * PB0.05. ** PB0.01. *** PB0.001.
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Men
Table 5 Variables related to sleep disturbances in men and women aged 65 years old, N city Japan Dependant variable
Men Independent variable
Frequent awakening at night Educational attainment (less than high school) Prostatic hypertrophy Sleeping pill use Depression LSIK score 7–9 4–6 0–3 Not feeling rested in the morning Irregular bedtime Sleeping pill use Depression LSIK score 7–9 4–6 0–3
ORa,b
95% CIa
2.4 2.7 2.8
1.1–4.9 0.7–10.9 1.1–12.6
1.0 1.6 3.3
Reference 0.5–5.2 1.0–10.8
1.9 8.6 2.5 1.2
1.1–3.5 2.6–28.7 1.1–8.6 0.6–2.4
1.0 7.7 11.8 2.4 5.4 1.8 1.0 7.7 11.8
Independent variable
ORa,b 95% CIa
Depression
1.8
1.0–3.4
Sleeping pill use Depression
5.8 2.1
2.0–17.0 1.0–4.3
Reference 1.0–50.0 1.4–96.6 0.9–7.0
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Difficulty in falling asleep Not working Cardiovascular disease Sleeping pill use LSIK score 7–9 4–6 0–3
Women
Reference 1.0–50.0 1.4–96.6
95
96
Table 5 (Continued) Men Independent variable Any of three sleep disturbances BMI Lowest 1/4 2nd and 3rd Highest 1/4 Irregular bedtime Cardiovascular disease Arthritis or joint pain Prostatic hypertrophy Sleeping pill use Depression LSIK score 7–9 4–6 0–3 a b
Women ORa,b
95% CIa
1.0 1.2 0.7 2.2 1.5 1.7 3.9 2.2 1.1
Reference 0.6–2.3 0.4–1.4 0.9–5.7 0.4–5.3 0.6–5.3 1.1–13.7 0.6–7.6 0.5–2.2
1.0 2.8 5.7
Reference 1.3–6.1 2.3–14.3
OR: odd ratio; CI: confidence interval. Odds ratio adjusted for other variables listed in the table by logistic regression models.
Independent variable
ORa,b 95% CIa
Sleeping pill use
2.1
0.7–6.4
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Dependant variable
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1997; Newman et al., 1997). In our study, women aged 65 years slept 24 min shorter on average than men and complained of difficulty in falling asleep more often than men. One reasons is that the unique hormonal and psychological changes occurring in middle-age women, at the time of menopause in particular, may have a significant impact on sleep disturbances (Quera-Salva et al., 1991). Depression, which was incriminated as a risk factor for sleep disturbances (Rodin et al., 1988), is more frequent among elderly persons, particularly among women (Newman et al., 1997), though depression was not differently related to gender in our study. Habte-Gabr et al. discussed that the higher rates of sleep complaints among women may also simply be a reflection of the generally higher rates of health complaints typically seen in women (Habte-Gabr et al., 1991). Our study found that sleep disturbances were associated with lower educational status and retirement from work in men, in contrast to other studies (Ford and Kamerow, 1989; Habte-Gabr et al., 1991). Depression, which increases sleep disturbances (Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Foley et al., 1995; Newman et al., 1997), are related to life events such as retirement from work (Ohmori, 1983). Poor health was also reported to be related to sleep disturbances (Habte-Gabr et al., 1991; Hays et al., 1996; Kageyama et al., 1997; Newman et al., 1997). In our study, therefore, men with irregular bedtime and higher BMI complained significantly more often of sleep disturbances in the bivariate analyses. Those with lower educational status may have poor access to optimal medical care and have lifestyles that may result in overall poor health status, thus increasing their risk of sleep disturbances (Habte-Gabr et al., 1991). Several diseases are known to cause sleep disturbances. A low prevalence of sleep disturbances was noted with good medical and psychiatric health (Kageyama et al., 1997). Perhaps several diseases disrupt sleep by multiple mechanisms such as pain, itching, and the effects of pharmacological treatment (Kageyama et al., 1997). In our study, cardiovascular disease, arthritis or joint pain and prostatic hypertrophy were significantly linked to sleep disturbances in men. The pain produced by cardiovascular disease (angina pectoris/myocardial infarction) or anxiety associated with such pain might be clinically important as a possible cause of sleep disturbances. Our results showed that relatively few men and women aged 65 years used sleeping pills more than once per week (5.5 and 7.2%, men and women, respectively). This figures are similar to those reported for North American subjects of similar age (2.6 – 9.7%) (Mellinger et al., 1985; Hays et al., 1996). Consistent with other studies (Mellinger et al., 1985; Foley et al., 1995), we found that the use of sleeping pills was significantly associated with any of three sleep disturbances, feeling not rested in the morning in particular. Persons with poor sleep are more likely to take sleeping pills, and poor sleep may be consequently provoked by sleeping pill medication itself. Any causal inferences between sleep disturbance and medications can not be discussed because our study was a cross-sectional study. In this regard, Quera-Salva et al. (1991) demonstrated that socially isolated and unemployed elderly tended to use sleeping pills more often than others. The use of sleeping pills was correlated with an increased risk of nocturnal death as well as
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poor health (Rumble and Morgan, 1992). Long-term use of sleeping pills is associated with impaired cognition, slow psychomotor function and injury from falls, and it could also cause further insomnia (Guilleminault et al., 1984). When considered all together, it is important for clinicians to consider the appropriate prescription of sleeping pills for their elderly patients. The association between sleep disturbances and depression has been investigated by several investigators (Rodin et al., 1988; Ford and Kamerow, 1989; HabteGabr et al., 1991; Foley et al., 1995; Newman et al., 1997). Consistent with such studies, our study showed that depression was significantly associated with frequent awakening at night and not feeling rested in the morning in both genders. Early morning tiredness may be clinically considered a common manifestation of depression in the elderly (Gaylord and Zung, 1987). However, Ford and Kamerow (1989) found in their prospective study that insomnia might be an early sign or even the cause of depression. In general, sleep disturbances are associated with psychosocial and pharmacological factors, and physiological changes in sleep architecture during aging (Habte-Gabr et al., 1991; Foley et al., 1995; Hays et al., 1996; Kageyama et al., 1997; Newman et al., 1997), and also might be reflective of their quality of life. In our study, lower subjective well being was significantly associated with all three aspects of sleep disturbances in men. This finding may emphasize that good sleep was important to good quality of life in the elderly. Three limitations should be noted for our study. First, since our study was cross-sectional in design, the findings can not be regarded as providing causeeffect relationship. The findings should be confirmed by longitudinal analyses. Second, the information which was analysed represents self-reported data, and the questionnaire on sleep disturbances was structured in a manner different from that used in previous studies (Newman et al., 1997). In spite of this methodological shortcoming, however, sleep disturbances among elderly Japanese were significantly related with some social, medical and psychological health status. Third, in our study we did not include questions on nocturnal micturition and snoring. Increased nocturnal diuresis (due to low levels of anti-diuretic hormone during sleep) has been reported to be associated with sleep disturbances among elderly subjects (Asplund and Aberg, 1996). Snoring and other related breathing disorders are also known to be associated with sleep disturbances among the elderly (Habte-Gabr et al., 1991; Foley et al., 1995). In conclusion, in our study, sleep disturbances were significantly associated with low educational attainment, retirement from work, history of prostatic hypertrophy, the use of sleeping pills and lower subjective well-being in men and with depression and the use of sleeping pills in women. Since many of these related factors are more common among the elderly, there is a realistic need for clinicians to consider the impact of underlying health problems on sleep and to obtain a comprehensive sleep history with optimal treatment of sleep problems when patients complain of sleep-related symptoms.
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Acknowledgements The authors thank the public health nurses of the N city, Japan for their help in conducting this study. Also we thank the staffs of the Department of Preventive Medicine, Nagoya University School of Medicine for their great assistance for data collection.
References Asplund, R., Aberg, H., 1996. Nocturnal micturition, sleep and well being in women of ages 40 – 64 years. Maturitas 24, 73–81. Brink, L.T., 1982. Screening test for geriatric depression. Clin. Gerontol. 1, 37 – 43. Burke, W.J., Roccaforte, W.H., Wengel, S.P., 1991. The short form of the geriatric depression scale: a comparison with the 30-item form. J.Geriatr. Psychiatr. Neurol. 4, 173 – 178. Foley, D.J., Monjan, A.A., Brown, S.L., Simonsick, E.M., Wallace, R.B., Blazer, D.G., 1995. Sleep complaints among elderly persons: an epidemiologic study of three communities. Sleep 18, 425 – 432. Ford, D.E., Kamerow, D.B., 1989. Epidemiologic study of sleep disturbances and psychiatric disorders: an opportunity for prevention? J. Am. Med. Assoc. 262, 1479 – 1484. Gaylord, S.A., Zung, W.W.K., 1987. Affective disorders among the aging. In: Handbook of Clinical Gerontology. Pergamon Press, New York, pp. 76 – 95. Guilleminault, C., Silvestri, R., Mondini, S., Coburn, S., 1984. Aging and sleep apnea: action of benzodiazepine, acetazolamide, alcohol, and sleep deprivation in a healthy elderly group. J. Gerontol. 39, 655–661. Habte-Gabr, E., Wallace, R.B., Colsher, P.L., Hulbert, J.R., White, L.R., Smith, I.M., 1991. Sleep patterns in rural elders: demographic, health, and psychobehavioral correlates. J. Clin. Epidemiol. 44, 5–13. Hays, J.C., Blazer, D.G., Foley, D.J., 1996. Risk of napping: excessive daytime sleepiness and mortality in an older community population. J. Am. Geriatr. Soc. 44, 693 – 698. Kageyama, T., Kabuto, M., Nitta, H., Kurokawa, Y., Taira, K., Suzuki, S., Takemoto, T.A., 1997. Population study on risk factors for insomnia among adult Japanese women: a possible effect of road traffic volume. Sleep 20, 963–971. Koyano, W., Shibata, H., 1991. Measurement of competence: reliability and validity of the TMIG index of competence. Arch. Gerontol. Geriatr. 13, 103 – 116. Koyano, W., Shibata, H., 1994. Development of a measure of subjective well being in Japan: construct validity and reliability of the life satisfaction index K. Facts Res. Gerontol. 181 – 187. Lindberg, E., Janson, C., Gislason, T., Bjornsson, E., Hetta, J., Boman, G., 1997. Sleep disturbances in a young adult population: can gender differences be explained by differences in psychological status? Sleep 20, 381–387. Mantel, N., 1963. Chi-square tests with one degree of freedom; extensions of the Mantel – Haenszel procedure. J. Am. Statist. Assoc. 58, 690 – 700. Mellinger, G.D., Balter, M.B., Uhlenhuth, E.H., 1985. Insomnia and its treatment: prevalence and correlates. Arch. Gen. Psychiatr. 42, 225 – 232. Newman, A.B., Enright, P.L., Manolio, T.A., Haponik, E.F., Wahl, P.W., 1997. Sleep disturbance, psychosocial correlates, and cardiovascular disease in 5201 older adults: the cardiovascular health study. J. Am. Geriatr. Soc. 45, 1–7. Niino, N., 1991. A Japanese translation of the geriatric depression scale. Clin. Gerontol. 10, 85 – 87. Ohmori, K., 1983. Clinical and psychopathological study of the onset situation of depression in the presenium and senium. Psychiat. Neurol. Jap. 85, 156 – 178. Quera-Salva, M.A., Orluc, A., Goldenberg, F., Guilleminault, C., 1991. Insomnia and use of hypnotics: study of a French population. Sleep 14, 386 – 391.
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Reyner, L.A., Horne, J.A., Reyner, A., 1995. Gender- and age-related differences in sleep determined by home-recorded sleep logs and actimetry from 400 adults. Sleep 18, 127 – 134. Rodin, J., McAvay, G., Timko, C., 1988. A longitudinal study of depressed mood and sleep disturbances in elderly adults. J. Gerontol. 43, 45– 53. Rumble, R., Morgan, K., 1992. Hypnotics, sleep, and mortality in elderly people. J. Am. Geriatr. Soc. 40, 787–791. SAS Institute, 1990. SAS Procedures Guide Version 6, third ed. SAS Institute, Cary, NC. Sheikh, J.I., Yesavage, J.A., 1986. GDS; resent evidence and development of a shorter version. Clin. Gerontol. 56, 509–513. Wingard, D.L., Berkman, L.F., 1983. Mortality risk associated with sleeping patterns among adults. Sleep 6, 102–107. Yesavage, J.A., Brink, T.L., Rose, T.L., Lum, O., 1982. Development and validation of a geriatric depression screening scale: a preliminary report. J. Psychiatr. Res. 17, 37 – 49.
.
Sleep disturbance and its correlates among elderly Japanese Yuko Ito a,*, Akiko Tamakoshi b, Kenichi Yamaki a, Kenji Wakai b, Takashi Kawamura b, Kenzo Takagi c, Tetsuo Hayakawa a, Yoshiyuki Ohno b a
Second Department of Internal Medicine, Nagoya Uni6ersity School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 -8550, Japan b Dpartment of Pre6enti6e Medicine, Nagoya Uni6ersity School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466 -8550, Japan c Department of Medical Technology, Nagoya Uni6ersity School of Health Sciences, 65 Tsurumai-cho, Showa-ku, Nagoya 466 -8550, Japan Received 4 October 1999; received in revised form 7 December 1999; accepted 8 December 1999
Abstract Although sleep disturbance is a major public health problem in the elderly, few studies have examined the association between sleep disturbance and other related factors in Japan. We examined correlates of sleep disturbance among Japanese elderly. Participants in this cross-sectional study (255 men and 263 women) were those enrolled in a population-based health examination for 65 year-old residents in N City, Japan in 1996 and 1997. Epidemiological data were collected by a self-administered questionnaire. Sleep disturbances were assessed by three common symptoms: difficulty in falling asleep, frequent awakening at night and not feeling rested in the morning. The mean sleep duration was longer in men than in women (7.2 vs 6.8 h, PB0.01), and women reported difficulty in falling asleep more frequently than men (22.4 vs 15.3%, PB 0.05). Sleep disturbances were associated with low educational attainment, retirement from work, higher body mass index (BMI), irregular bedtime, history of cardiovascular disease, arthritis or joint pain and prostatic hypertrophy, and lower subjective well-being in men, and the use of sleeping pills and depression in both genders, but not with marital status, residential status, smoking habits, exercise, limited instrumental activity of daily living, and past episode of such chronic diseases as hyperten -
* Corresponding author. Tel.: +81-52-7442167; fax: + 81-52-7442175. E-mail address: [email protected] (Y. Ito) 0167-4943/00/$ - see front matter © 2000 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0 1 6 7 - 4 9 4 3 ( 9 9 ) 0 0 0 5 4 - 0
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sion and stroke. Our study suggests a close association of sleep disturbances among elderly Japanese with several medical/psychiatric health problems that are usually more prevalent in such an age group. Our findings emphasize the realistic need for clinicians to take underlying health problems into consideration when their patients complain of sleep-related symptoms. © 2000 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Sleep disturbances; Health habits; Medical and psychiatric health problems; Japanese elderly
1. Introduction Sleep disturbances are common and clinically important in elderly people. Several epidemiological and clinical studies have demonstrated that the prevalence rate of insomnia among the elderly varies from 17 to 45% (Habte-Gabr et al., 1991; Hays et al., 1996; Lindberg et al., 1997; Newman et al., 1997), with a higher rate in women (Mellinger et al., 1985; Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Quera-Salva et al., 1991; Lindberg et al., 1997; Newman et al., 1997). Sleep disturbances increase with advancing age (Mellinger et al., 1985; Habte-Gabr et al., 1991; Hays et al., 1996; Newman et al., 1997). Previous studies have also suggested that sleep disturbances are usually associated with the presence of cardiovascular diseases (Newman et al., 1997), respiratory diseases (Habte-Gabr et al., 1991; Foley et al., 1995), stroke or arthritis (Newman et al., 1997), lower socioeconomic status (Habte-Gabr et al., 1991), limited physical functions (HabteGabr et al., 1991; Foley et al., 1995; Newman et al., 1997), depression (Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Foley et al., 1995; Newman et al., 1997), anxiety (Mellinger et al., 1985; Quera-Salva et al., 1991; Newman et al., 1997) and sleeping-pill use (Habte-Gabr et al., 1991; Foley et al., 1995). In addition, sleep duration is linked to an increased total mortality risk (Wingard and Berkman, 1983), and the use of sleeping pills is known to be associated with an increased risk of nocturnal death and poor health (Rumble and Morgan, 1992). It is, therefore, important to understand the relationship between sleep disturbances and their correlates. In Japan, however, neither gender-specific prevalence of sleep disturbances nor epidemiological factors related to sleep disturbances have been examined in detail among elderly populations. In this study, we examined the prevalence rate of self-reported sleep disturbances and their associations with demographic characteristics, lifestyle, medical history, and physical and psychological status. The population sample studied consisted of 518 inhabitants aged 65 years (255 men and 263 women), who participated in a health check-up program in N City, Japan.
2. Materials and methods
2.1. Population sample A population-based health examination of 65 year-old residents commenced in 1996. All inhabitants aged 65 years (530 in 1996 and 614 in 1997) were eligible for
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health examination and encouraged to participate by postcard and a notice in local newspapers. A total of 253 inhabitants (47.7%) participated in the examination in 1996 and 266 (43.3%) in 1997. A postal questionnaire was mailed to those who participated. Approval of this study was obtained from the institutional review board, and informed consent from each subject. Excluded from this study was only one individual who did not give informed consent for the study. A total of 518 respondents (255 men and 263 women) completed the questionnaire, i.e. an overall response rate of 45.3%. At entry, information on the study subjects was collected by a self-administered questionnaire, which inquired about demographic characteristics, lifestyle, prior medical history, socio-psychological status, and others. Clinical and physical examinations were given to all subjects at entry. Educational status was dichotomized by the highest educational attainment: completion of junior high school or less, and some higher education beyond junior high school. Marital status included never married, married, widowed, divorced or separated. Smoking status was categorized as current smokers or others. Body weight and height were reported, and BMI (body mass index) was calculated as body weight in kg/(height in meter)2. Prior and present illnesses such as hypertension, cardiovascular diseases (angina pectoris/myocardial infarction), stroke, respiratory diseases, arthritis or joint pain and prostatic hypertrophy were reported. Instrumental activities of daily living (IADL) was measured by a multidimensional 13-item index of functional capacity according to the Tokyo metropolitan institute of gerontology (TMIG) index of competence (Koyano and Shibata, 1991). Limitation of IADL was defined as a score of 12 or less. Depression was assessed using the short form of the geriatric depression scale (GDS) (Brink, 1982; Yesavage et al., 1982; Sheikh and Yesavage, 1986; Niino, 1991). Depression was defined as a score of six or more (Burke et al., 1991). Subjective well being was evaluated using life satisfaction index K (LSIK) (Koyano and Shibata, 1994). This scale is composed of a nine-item index including satisfaction with life as a whole, psychological stability, and evaluation of own aging (Koyano and Shibata, 1994). The range of score is zero to nine points, and a high score indicates high subjective well being.
2.2. Sleep questionnaire Sleep disturbances were assessed by a self-administered questionnaire that included the following questions and answers: 1. How many h do you sleep at night on an average?; 2. How long does it take from going to bed to falling asleep? (answer: B 10 min, 10 – 30 min, 30 – 60 min, or \60 min); 3. How many times do you usually wake up at night? (answer: never, once , twice, or three times or more); and 4. How do you feel when you wake up in the morning? (answer: good or bad). Three major types of sleep disturbance (difficulty in falling asleep, frequent awakening at night and feeling not rested in the morning) were defined as follows.
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Falling asleep was judged as difficult when the difference between bedtime and time of falling asleep exceeded 30 min. Frequent awakening at night was defined when the reported number of awakenings was more than twice, and feeling not rested in the morning when felt bad in the morning. The questionnaire also inquired about the use of sleeping pills with frequency of usage per week.
2.3. Statistical analysis All statistical analyses were performed using statistical analysis system (SAS) (SAS Institute, 1990). Chi-square test was used to evaluate differences in categorical variables, and t-test was applied when examining continuous variables. Trends were examined by the Mantel-extension test for categorical variables with adjustment for year of examination (Mantel, 1963). Associations of sleep disturbances with demographic characteristics, lifestyle, medical history, and physical and psychological status were assessed. All variables significantly associated with any one of the sleep disturbances in the bivariate analyses were considered for inclusion in a logistic regression model. All analyses were conducted separately for men and women. P values of B0.05 was considered statistically significant.
3. Results Table 1 shows the demographic characteristics, lifestyle, medical history, and physical and psychological status among elderly men and women aged 65 years. At age 65 years, more women were widowed, divorced or separated than men (PB 0.01), and had a past history of arthritis or joint pain (P B 0.01). More men were still working (P B0.01) and smoking (PB 0.01) than women, and had such past history as respiratory diseases (PB 0.01) and limitation of IADL (PB 0.05) than women. Educational status, residential status, BMI, physical exercise, some medical histories, depression and subjective well being were not different by gender. Fourteen men (5.5%) and 19 women (7.2%) were using sleeping pills. The prevalence of sleep disturbances in our population sample was computed. Women reported difficulty in falling asleep more frequently than men (22.4 vs 15.3%, PB 0.05). Frequent awakening at night (30.2% in men and 28.1% in women), feeling not rested in the morning (15.4% in men and 19.1% in women), and any of three sleep disturbances (43.5% in men and 49.4% in women) did not significantly differ by gender. Mean sleep duration was significantly longer in men (7.2 h) than in women (6.8 h, P B 0.01). Table 2 details the prevalence of sleep disturbances by demographic characteristic and lifestyle. Men with less than high school education reported more frequent awakening at night than those with a higher education (PB 0.05). Not-working men complained more frequently of difficulty in falling asleep than working men (PB0.01). Higher BMI was significantly associated with any of three sleep disturbances (P B 0.05). Men with irregular bedtime complained significantly more
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Table 1 Demographic characteristics, lifestyle, prior medical history, physical and phychological status in men and women aged 65 years old, N city, Japan Men
Women
N (%)
N (%)
N
255
263
Educational attainment Less than high school High school or more
82 (32.5) 172 (67.5)
89 (33.8) 174 (66.2)
NS
Marital status Married Othersa
243 (95.3) 12 (4.7)
207 (78.7) 56 (21.3)
B0.01
Work–retirement status Working Not working
149 (58.4) 106 (41.6)
81 (30.8) 182 (69.2)
B0.01
Residential status With others Alone
236 (92.5) 19 (7.5)
217 (82.5) 46 (17.5)
NS
BMI Lowest 1/4 Second and third 1/4 Highest 1/4 Current smoker
64 (25.1) 126(49.4) 65 (25.5) 95 (37.3)
68 131 64 8
Physical exercise More than once a week One time or more a week
138 (54.1) 117 (45.9)
138 (52.5) 125 (47.5)
Prior medical history Irregular bedtime Hypertension Cardiovascular disease Stroke Respiratory diseases Arthritis or joint pain Prostatic hypertrophy Sleeping pill use
26 66 11 14 46 18 16 14
(10.2) (25.9) (4.3) (5.5) (18.0) (7.1) (6.3) (5.5)
Limitation of IADL (scores of Tmig of competence) 11 71 (27.8) 12 55 (21.6) 13 129 (50.6) Depression (GDS ` 6) Subjecti6e wll being (scores of LSIK) 0–3 4–6 7–9 a b
27 53 4 7 20 46 – 19
(25.9) (49.8) (24.3) (3.0)
(10.3) (20.2) (1.5) (2.7) (7.6) (17.5) (7.2)
55 (20.9) 45 (17.1) 163 (62.0)
P values
B0.01
NS NS NS NS NS B0.01 B0.01 – NS B0.05b
58 (22.7)
52 (19.8)
NS
68 (26.6) 132 (51.8) 55 (21.6)
64 (24.3) 140 (53.2) 59 (22.4)
NS
Others include those never married, widowed, divorced or seperated. Test for trend by Mantel-extention test, others by chi-squared test.
Men Variables
N (%)
89 (33.8)
22.5
32.6
13.5
50.6
40.0
174 (66.2)
22.4
25.9
22.0
48.9
14.5 25.0
43.2 33.3
207 (78.7) 50.0
23.2 56 (21.3)
27.5 20.0
19.4 29.1
48.3 18.2
31.5 28.3
17.6 12.4
43.2 43.8
81 (30.8) 182 (69.2)
20.1 23.1
25.9 29.1
17.5 19.8
46.9 50.6
15.7 (7.5) 10.5
30.9 21.1
15.8 10.5
44.0 36.8
217 (82.5) 46 (17.5)
22.1 23.9
30.0 19.6
18.1 23.9
50.0 49.3
64 (25.1) 126 (49.4)
6.3 22.4
21.9 32.8
9.4 19.4
29.7* 49.2
68 (25.9) 131 (49.8)
17.7 22.9
29.7 46.0
16.2 23.1
47.1 51.9
65 (25.5)
10.6
33.3
13.9
46.2
64 (24.3)
26.6
24.3
14.1
46.9
Work-retirement status Working 149 (58.4) Not work- 106 (41.6) ing Residential status With others 236 (92.5) Alone 19
Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Any of three sleep disturbances
20.7
40.2*
13.4
51.2
12.8
25.6
16.5
14.8 (4.7)
30.5 25.0
10.1** 22.6
N (%)
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Any of three sleep disturbances (%)
Marital status Married 243 Others 12
BMI a Lowest 1/4 Second and third 1/4 Highest 1/4
Women Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Demographic 6ariables Educational attainment Less than 83 high school High school 172 or more
90
Table 2 Prevalence of sleep disturbances according to demographic characteristics and lifestyles in men and women aged 65 years old, N city, Japan
Table 2 (Continued)
Variables
N (%)
Lifestyles 6ariables Current smorker Smoking 95 (37.3) Not smoking 160 (62.7) Physical exercise Less than 138 (54.1) once/week Once or 117 (45.9) more/week Irregular bedtime Yes 26 (10.2) No 229 (89.8)
Women Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Any of three sleep disturbances
N (%)
Difficulty in Frequent Not feeling falling awakening rested in asleep (%) at night (%) the morning (%)
Any of three sleep disturbances (%)
16.8 14.5
23.2 34.6
18.1 13.9
39.4 45.9
8 (3.0) 255 (97.0)
12.5 22.8
12.5 28.7
0.0 14.8
12.5 50.6
17.5
27.7
18.4
43.4
138 (52.5)
26.8
26.8
21.9
52.9
12.7
23.1
12.0
43.6
125 (47.5)
17.6
29.6
16.0
45.6
17.4 15.3
34.8 29.7
30.4** 13.7
60.9* 41.4
27 (10.3) 236 (89.7)
12.0 23.7
8.0 28.0
16.7 19.5
44.0 50.0
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Men
a
Trend was testedby Mandel-extension test, others by chi-square test. * PB0.05. ** PB0.01.
91
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frequently of not feeling rested in the morning (PB 0.01) and any of three sleep disturbances (P B 0.05), compared to men with regular bedtime. No significant associations were identified at all in women. In men, sleep disturbances were also found to be unrelated to marital status, residential status, smoking habits and physical exercise. Table 3 shows the relationships between sleep disturbances and past medical history. Men who had suffered from cardiovascular diseases complained more frequently of difficulty in falling asleep (PB 0.01) and any of three sleep disturbances (PB 0.05), as did men who had suffered from arthritis or joint pain related to any of three sleep disturbances (P B0.05). Men who had suffered from prostatic hypertrophy were related to frequent awakening at night (PB 0.001) and any of three sleep disturbances (P B0.01). Sleep disturbances were not associated with past history of hypertension, stroke and respiratory diseases in either gender. In men, sleeping-pill users complained significantly more frequently of all sleep disturbances, but in women, only feeling not rested in the morning (PB0.01) and any of three sleep disturbances (P B0.05) with statistical significance. Sleep disturbances by physical and psychological status are shown in Table 4. Men and women with depression reported awakening at night and not feeling rested in the morning more frequently than those without depression, and men with depression also complained more frequently of any of three sleep disturbances than men without depression (P B0.05). In men, lower subjective well-being was significantly associated with all sleep disturbances (PB 0.001), whereas not at all in women. Sleep disturbances were not significantly related to limitation of IADL (physical functional limitations). To analyze the independent predictors of sleep disturbances, logistic regression analyses were performed with all variables significantly associated with any one of the sleep disturbances. In this model, sleep disturbances were significantly associated with low educational attainment, retirement from work, the use of sleeping pills and lower subjective well-being in men and with depression and the use of sleeping pills in women (Table 5). Mean demographic characteristics, lifestyle, prior medical history, and physical and psychological status compared sleep duration in h. Significantly longer sleep duration was found only in men who currently smoked (7.4 vs 7.0 h in non-smokers: P B 0.001) and those with regular bedtime (7.2 vs 6.8 h in those with irregular bedtime: P B0.05). In contrast, men who had suffered from cardiovascular diseases demonstrated significantly shorter sleep duration (6.7 vs 7.2 h in non-sufferers: P B 0.05). No significant differences in mean sleep duration were identified in women.
4. Discussion Some epidemiological surveys have previously found that women sleep longer than men (Reyner et al., 1995; Lindberg et al., 1997) and that women have more sleep disturbances than men (Mellinger et al., 1985; Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Quera-Salva et al., 1991; Lindberg et al.,
Table 3 Prevalence of sleep disturbances according to medical history in men and women aged 65 years old, N city, Japan Men N (%)
Difficulty in Frequent Not feeling Any of three N (%) falling asleep awakening at rested in the sleep distur(%) night (%) morning (%) bances (%)
Difficulty in Frequent Not feeling Any of three falling asleep awakening at rested in the sleep distur(%) night (%) morning (%) bances (%)
16.7 14.8
36.4 28.0
10.6 17.1
50.0 41.2
53 (20.0) 210 (79.8)
29.8 20.4
22.8 29.6
15.6 20.0
47.2 50.0
Cardio6ascular disease Yes 14 (5.5) 42.9* No 244 (95.7) 13.7
42.9 29.5
9.1 15.7
54.6** 43.0
4 (1.5) 259 (98.5)
25.0 22.4
0.0 28.8
33.3 18.8
50.0 49.4
Stroke Yes 14 (5.5) No 241 (94.5)
30.8 14.5
30.8 30.2
15.4 15.4
66.7 41.7
7 (2.7) 256 (97.3)
28.6 22.3
14.3 28.5
27.3 18.7
42.9 49.6
Respiratory disease Yes 46 (18.0) No 209 (82.0)
17.4 14.8
32.6 29.4
16.4 10.9
43.5 43.5
20 (7.6) 243 (92.4)
25.0 22.2
30.0 28.0
35.0 17.0
55.0 49.0
Arthritis or joint pain Yes 18 (7.1) 27.8 No 237 (92.9) 14.4
38.9 29.5
33.3 14.4
66.7** 41.7
46 (17.5) 217 (82.5)
29.6 24.1
25.9 27.1
33.3 18.3
52.2 48.9
Prostatic hypertrophy Yes 16 (6.3) 0.0 No 239 (93.7) 16.3
75.0*** 27.2
18.8 15.2
75.0* 41.4
– –
– –
– –
– –
Sleeping pill use Yes 14 (5.5) No 241 (94.5)
57.1** 28.6
50.0* 13.4
71.4** 41.8
31.9 21.7
26.3 28.3
19 (7.2) 244 (92.8)
47.4* 16.9
66.7** 48.9
93
* PB0.01. ** PB0.05. *** PB0.001.
42.9* 13.7
– –
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Hypertension Yes 66 (25.9) No 198 (74.1)
Women
94
Table 4 The prevalence of sleep disturbances according to physical and pyschological status in men and women aged 65 years old, N city Japan
N (%)
Limitation of IADL 511 71 (27.8) 12 55 (21.6) 13 129 (50.6) Depression Yes 58 (22.7) No 197 (77.3)
Women Difficulty in Frequent falling asleep awakening (%) at night (%)
(scores of TMIG of competence) 18.3 30.1 14.3 16.4 27.2 22.2 13.2 31.0 13.2 17.2* 14.7
41.4* 26.9
Subjecti6e well-being a (scores of LSIK) 0–3 68 (26.6) 26.5*** 44.1*** 4–6 132 (51.8) 12.9 29.6 7–9 55 (21.6) 7.3 14.6 a
Not feeling Any of three N (%) rested in the sleep disturmorning (%) bances (%)
Difficulty in Frequent falling asleep awakening (%) at night (%)
Not feeling Any of three rested in the sleep disturmorning (%) bances (%)
48.6 44.4 40.3
55 (20.9) 45 (17.1) 163 (62.0)
27.3 20.0 21.5
30.9 31.1 26.4
21.8 28.9 15.4
56.4 53.3 46.0
28.1** 11.7
57.9** 39.3
52 (19.8) 211 (80.2)
26.9 21.3
38.5* 25.6
28.9* 16.7
55.8 47.9
26.9*** 15.2 1.9
62.7 43.2 20.4
64 (24.3) 140 (53.2) 5 (22.4)
23.8 23.6 18.6
39.7 24.3 25.4
22.6 20.7 11.9
57.1 49.3 42.4
Trend was tested by Mantel-extention test, others by chi-square test. * PB0.05. ** PB0.01. *** PB0.001.
Y. Ito et al. / Arch. Gerontol. Geriatr. 30 (2000) 85–100
Men
Table 5 Variables related to sleep disturbances in men and women aged 65 years old, N city Japan Dependant variable
Men Independent variable
Frequent awakening at night Educational attainment (less than high school) Prostatic hypertrophy Sleeping pill use Depression LSIK score 7–9 4–6 0–3 Not feeling rested in the morning Irregular bedtime Sleeping pill use Depression LSIK score 7–9 4–6 0–3
ORa,b
95% CIa
2.4 2.7 2.8
1.1–4.9 0.7–10.9 1.1–12.6
1.0 1.6 3.3
Reference 0.5–5.2 1.0–10.8
1.9 8.6 2.5 1.2
1.1–3.5 2.6–28.7 1.1–8.6 0.6–2.4
1.0 7.7 11.8 2.4 5.4 1.8 1.0 7.7 11.8
Independent variable
ORa,b 95% CIa
Depression
1.8
1.0–3.4
Sleeping pill use Depression
5.8 2.1
2.0–17.0 1.0–4.3
Reference 1.0–50.0 1.4–96.6 0.9–7.0
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Difficulty in falling asleep Not working Cardiovascular disease Sleeping pill use LSIK score 7–9 4–6 0–3
Women
Reference 1.0–50.0 1.4–96.6
95
96
Table 5 (Continued) Men Independent variable Any of three sleep disturbances BMI Lowest 1/4 2nd and 3rd Highest 1/4 Irregular bedtime Cardiovascular disease Arthritis or joint pain Prostatic hypertrophy Sleeping pill use Depression LSIK score 7–9 4–6 0–3 a b
Women ORa,b
95% CIa
1.0 1.2 0.7 2.2 1.5 1.7 3.9 2.2 1.1
Reference 0.6–2.3 0.4–1.4 0.9–5.7 0.4–5.3 0.6–5.3 1.1–13.7 0.6–7.6 0.5–2.2
1.0 2.8 5.7
Reference 1.3–6.1 2.3–14.3
OR: odd ratio; CI: confidence interval. Odds ratio adjusted for other variables listed in the table by logistic regression models.
Independent variable
ORa,b 95% CIa
Sleeping pill use
2.1
0.7–6.4
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Dependant variable
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1997; Newman et al., 1997). In our study, women aged 65 years slept 24 min shorter on average than men and complained of difficulty in falling asleep more often than men. One reasons is that the unique hormonal and psychological changes occurring in middle-age women, at the time of menopause in particular, may have a significant impact on sleep disturbances (Quera-Salva et al., 1991). Depression, which was incriminated as a risk factor for sleep disturbances (Rodin et al., 1988), is more frequent among elderly persons, particularly among women (Newman et al., 1997), though depression was not differently related to gender in our study. Habte-Gabr et al. discussed that the higher rates of sleep complaints among women may also simply be a reflection of the generally higher rates of health complaints typically seen in women (Habte-Gabr et al., 1991). Our study found that sleep disturbances were associated with lower educational status and retirement from work in men, in contrast to other studies (Ford and Kamerow, 1989; Habte-Gabr et al., 1991). Depression, which increases sleep disturbances (Rodin et al., 1988; Ford and Kamerow, 1989; Habte-Gabr et al., 1991; Foley et al., 1995; Newman et al., 1997), are related to life events such as retirement from work (Ohmori, 1983). Poor health was also reported to be related to sleep disturbances (Habte-Gabr et al., 1991; Hays et al., 1996; Kageyama et al., 1997; Newman et al., 1997). In our study, therefore, men with irregular bedtime and higher BMI complained significantly more often of sleep disturbances in the bivariate analyses. Those with lower educational status may have poor access to optimal medical care and have lifestyles that may result in overall poor health status, thus increasing their risk of sleep disturbances (Habte-Gabr et al., 1991). Several diseases are known to cause sleep disturbances. A low prevalence of sleep disturbances was noted with good medical and psychiatric health (Kageyama et al., 1997). Perhaps several diseases disrupt sleep by multiple mechanisms such as pain, itching, and the effects of pharmacological treatment (Kageyama et al., 1997). In our study, cardiovascular disease, arthritis or joint pain and prostatic hypertrophy were significantly linked to sleep disturbances in men. The pain produced by cardiovascular disease (angina pectoris/myocardial infarction) or anxiety associated with such pain might be clinically important as a possible cause of sleep disturbances. Our results showed that relatively few men and women aged 65 years used sleeping pills more than once per week (5.5 and 7.2%, men and women, respectively). This figures are similar to those reported for North American subjects of similar age (2.6 – 9.7%) (Mellinger et al., 1985; Hays et al., 1996). Consistent with other studies (Mellinger et al., 1985; Foley et al., 1995), we found that the use of sleeping pills was significantly associated with any of three sleep disturbances, feeling not rested in the morning in particular. Persons with poor sleep are more likely to take sleeping pills, and poor sleep may be consequently provoked by sleeping pill medication itself. Any causal inferences between sleep disturbance and medications can not be discussed because our study was a cross-sectional study. In this regard, Quera-Salva et al. (1991) demonstrated that socially isolated and unemployed elderly tended to use sleeping pills more often than others. The use of sleeping pills was correlated with an increased risk of nocturnal death as well as
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poor health (Rumble and Morgan, 1992). Long-term use of sleeping pills is associated with impaired cognition, slow psychomotor function and injury from falls, and it could also cause further insomnia (Guilleminault et al., 1984). When considered all together, it is important for clinicians to consider the appropriate prescription of sleeping pills for their elderly patients. The association between sleep disturbances and depression has been investigated by several investigators (Rodin et al., 1988; Ford and Kamerow, 1989; HabteGabr et al., 1991; Foley et al., 1995; Newman et al., 1997). Consistent with such studies, our study showed that depression was significantly associated with frequent awakening at night and not feeling rested in the morning in both genders. Early morning tiredness may be clinically considered a common manifestation of depression in the elderly (Gaylord and Zung, 1987). However, Ford and Kamerow (1989) found in their prospective study that insomnia might be an early sign or even the cause of depression. In general, sleep disturbances are associated with psychosocial and pharmacological factors, and physiological changes in sleep architecture during aging (Habte-Gabr et al., 1991; Foley et al., 1995; Hays et al., 1996; Kageyama et al., 1997; Newman et al., 1997), and also might be reflective of their quality of life. In our study, lower subjective well being was significantly associated with all three aspects of sleep disturbances in men. This finding may emphasize that good sleep was important to good quality of life in the elderly. Three limitations should be noted for our study. First, since our study was cross-sectional in design, the findings can not be regarded as providing causeeffect relationship. The findings should be confirmed by longitudinal analyses. Second, the information which was analysed represents self-reported data, and the questionnaire on sleep disturbances was structured in a manner different from that used in previous studies (Newman et al., 1997). In spite of this methodological shortcoming, however, sleep disturbances among elderly Japanese were significantly related with some social, medical and psychological health status. Third, in our study we did not include questions on nocturnal micturition and snoring. Increased nocturnal diuresis (due to low levels of anti-diuretic hormone during sleep) has been reported to be associated with sleep disturbances among elderly subjects (Asplund and Aberg, 1996). Snoring and other related breathing disorders are also known to be associated with sleep disturbances among the elderly (Habte-Gabr et al., 1991; Foley et al., 1995). In conclusion, in our study, sleep disturbances were significantly associated with low educational attainment, retirement from work, history of prostatic hypertrophy, the use of sleeping pills and lower subjective well-being in men and with depression and the use of sleeping pills in women. Since many of these related factors are more common among the elderly, there is a realistic need for clinicians to consider the impact of underlying health problems on sleep and to obtain a comprehensive sleep history with optimal treatment of sleep problems when patients complain of sleep-related symptoms.
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Acknowledgements The authors thank the public health nurses of the N city, Japan for their help in conducting this study. Also we thank the staffs of the Department of Preventive Medicine, Nagoya University School of Medicine for their great assistance for data collection.
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