 |
|
Mortality Associated With Sleep Duration and Insomnia
Daniel F. Kripke, MD;
Lawrence Garfinkel, MA;
Deborah L. Wingard, PhD;
Melville R. Klauber, PhD;
Matthew R. Marler, PhD
Arch Gen Psychiatry. 2002;59:131-136.
ABSTRACT
| |
Background Patients often complain about insufficient sleep or chronic insomnia
in the belief that they need 8 hours of sleep. Treatment strategies may be
guided by what sleep durations predict optimal survival and whether insomnia
might signal mortality risks.
Methods In 1982, the Cancer Prevention Study II of the American Cancer Society
asked participants about their sleep duration and frequency of insomnia. Cox
proportional hazards survival models were computed to determine whether sleep
duration or frequency of insomnia was associated with excess mortality up
to 1988, controlling simultaneously for demographics, habits, health factors,
and use of various medications.
Results Participants were more than 1.1 million men and women from 30 to 102
years of age. The best survival was found among those who slept 7 hours per
night. Participants who reported sleeping 8 hours or more experienced significantly
increased mortality hazard, as did those who slept 6 hours or less. The increased
risk exceeded 15% for those reporting more than 8.5 hours sleep or less than
3.5 or 4.5 hours. In contrast, reports of "insomnia" were not associated with
excess mortality hazard. As previously described, prescription sleeping pill
use was associated with significantly increased mortality after control for
reported sleep durations and insomnia.
Conclusions Patients can be reassured that short sleep and insomnia seem associated
with little risk distinct from comorbidities. Slight risks associated with
8 or more hours of sleep and sleeping pill use need further study. Causality
is unproven.
INTRODUCTION
MANY PATIENTS complain to physicians about insufficient sleep and chronic
insomnia. Often they request medications for sleep year after year. There
has been little evidence-based guidance for the physician indicating when
treatment to increase sleep is advisable.1
A patient who sleeps 6 to 7 hours may be concerned that she or he is
not sleeping long enough, not realizing that 6 to 7 hours is currently the
population average.2-3 Many people
believe that 8 hours of sleep is required for health, but there is little
medical basis to recommend sleeping 8 hours or more. For example, a classic
study found that long sleepers reported less energy and had more psychopathology
than did short sleepers.4
Insomnia is not synonymous with short sleep. Patients commonly complain
of insomnia when their sleep durations are well within the range of those
people without sleep symptoms.5-6
A patient may be concerned by a 20-minute latency to fall asleep, or by awakenings
during the night, or by early awakening, when many people with the same sleep
latencies and awakenings consider their sleep perfectly satisfactory. Sometimes,
such complaints arise from misinformation about what sleep pattern is normal
for a person's age. At other times, sleep complaints may reflect a negative
self-view and the somatic concerns arising from depression. Insomnia complaints
are common symptoms of depression and a large variety of other emotional and
medical comorbidities that may not entail particularly short sleep.1, 7-11
Indeed, in the presence of sleep complaints, physicians make a diagnosis of
depression more often than a diagnosis of insomnia.12
Epidemiology can inform us what sleep patterns are associated with the
lowest mortality risk. In 1959 to 1960, the Cancer Prevention Study I (CPSI)
gave health questionnaires to more than 1 million adult Americans who were
followed up prospectively for 6 years. The lowest mortality was experienced
by women and men who reported sleeping 7 hours.6, 13
More excess mortality was associated with sleep durations of 8 hours or more
than with sleep of less than 7 hours. Excess mortality associated with long
sleep has also been observed in smaller prospective studies.14-23
The CPSI results indicated little if any association of "insomnia" with mortality.
In contrast, reported "sleeping pill" use "often" was associated with statistically
robust increased mortality risk after control for insomnia.6
A more recent study, the Cancer Prevention Study II (CPSII) of the American
Cancer Society, offered an opportunity to consider whether sleep durations,
insomnia, or sleeping pill use predicts mortality after more extensive control
for various sources of comorbidity.
SUBJECTS AND METHODS
PARTICIPANTS AND PROCEDURES
Data collection methods of CPSII have been described previously by the
American Cancer Society,24 and many results
of CPSII have been published.25-29
The current analyses were approved by the institutional review board of the
University of California, San Diego. Briefly, data were examined from more
than 1.1 million participants, mainly friends and relatives of American Cancer
Society volunteers, who were a diverse selection of American adults ranging
from 30 to 102 years of age. Participants completed health questionnaires
in the fall of 1982. The survival or date of death (from death certificates)
was ascertained 6 years later for more than 98% of the sample. Because recruitment
avoided the institutionalized as well as the most mobile individuals, sample
mortality was about 20% lower than for the US population of the same age,
but major causes of death resembled the distribution for the population. Data
tapes were kindly lent by the American Cancer Society.
Responses to the question, "On the average, how many hours do you sleep
each night?" were coded in categories from 2 to 9 hours. Fractional-hour responses
were coded as rounded integers, ie, 8 hours represented responses from 7.5
to 8.4 hours. All responses from 9.5 to 16.5 hours were combined in a final
category. There were too few responses of 2 hours for analysis. Reports of
sleeping less than 2 hours or more than 16 hours each night were considered
invalid (<0.1% of responses and coded missing). Responses were missing
or invalid for 1.4% of men and 1.7% of women. Responses to the question, "On
the average, how many times a month do you have insomnia?" were compressed
into categories of 0, 1, 2, 3, 4 to 9, and 10 or more times per month. Participants
reported past-month use of "prescription sleeping pills,"30
which probably included a mixture of different classes of medications.
STATISTICAL ANALYSES
To explore whether sleep durations predicted mortality, Cox proportional
hazards survival models31-32 (Cox
models) were computed for 636 095 women and 480 841 men, considering
the sexes as separate replicates. A total of 32 covariates were entered simultaneously
into the models, including sleep duration, insomnia frequency, and variables
reflecting demographic risk factors, habits, health, and medication use, selected
by preliminary identification of variables substantially predictive of mortality
risk (Table 1). The Cox models
estimated hazard ratios for each covariate, which indicated the extent to
which a covariate was associated with increased mortality as compared with
a reference. Hazard ratios for each reported sleep duration were referenced
to a hazard ratio of 1.0, which was assigned to the duration of 7 hours. This
arbitrary reference duration had been selected on the basis of CPSI results
and pilot analyses of CPSII data, suggesting that it would be the minimum.
For example, a hazard ratio of 1.12 for a group sleeping 8 hours would indicate
that those sleeping 8 hours were 12% more likely to die within the 6-year
follow-up than those sleeping 7 hours, other factors being equal. Similarly,
hazard ratios for each reported frequency of insomnia were compared with a
hazard ratio of 1.0 arbitrarily assigned to the reference of never having
insomnia. The 95% confidence intervals for the hazard ratios associated with
each reported sleep duration and each reported frequency of insomnia were
then estimated from the multivariate model. As a P<.05
significance criterion was selected, hazard ratios were considered significant
when a ratio of 1.0 was not included within these 95% confidence intervals.
Unlike the analyses of prescription sleeping pill hazards reported previously,30 all ages were considered together in these models.
Orthogonal linear, quadratic, and cubic terms were included for age and also
for estimated dietary fat and fiber. Categorical variables were entered as
several distinct levels. Model selection by backward elimination was used
to exclude from the models covariates with P>.10,
but almost all variables were retained. Inspection of cumulative hazard functions
based on Kaplan-Meier survival curves indicated that the proportional hazards
assumptions were acceptable.
|
|
|
|
Covariate-Adjusted* Mortality Hazard Ratios From the Cancer Prevention
Study II (1982-1988)
|
|
|
Similar Cox models were computed for 9 specific causes of death and
for all other causes. In addition, to examine interactions among sleep variables,
simplified Cox models were computed with SPSS10.0 (SPSS Inc, Chicago, Ill),
first including sleep duration, insomnia, sleeping pill use, and age in the
models, and then recomputing the models, removing either sleep duration, insomnia,
or sleeping pill use, one at a time.
RESULTS
The mean (SD) age for women was 57 (11) years, and for men, 58 (10)
years at the time when initial questionnaires were completed. Of the more
than 98% for whom follow-up was available, 9.4% of the men and 5.1% of the
women had died within the 6 years of follow-up. For women and men, respectively,
the causes of death were ischemic heart disease in 24% and 33%, other heart
disease in 9% and 9%, cerebrovascular accidents in 10% and 7%, breast cancer
in 10% and 0%, colon cancer in 4% and 3%, other cancers in 22% and 26%, accidents
in 2% and 2%, suicide in 1% and 1%, homicide in 0.2% and 0.2%, and other causes
in 18% and 18%.
The modal reported sleep duration was 8 hours among both women and men.
Almost half the sample reported a sleep duration of 7.5 hours or more. Almost
half of the women and more than 70% of men reported that they never had insomnia
(Table 1). Only 4.3% of women
and 2.6% of men reported insomnia 10 or more times per month. As might be
expected, more frequent insomnia and more frequent sleeping pill use were
reported among those sleeping less than 7 hours, but there was also a slightly
greater frequency of reported insomnia and sleeping pill use among those reporting
more than 8 hours sleep (Figure 1
and Figure 2). Partly because of
this U-shaped distribution, the product-moment correlations of reported hours
of sleep and frequency of insomnia were only -0.22 (P<.001) for women and -0.18 (P<.001)
for men, reflecting that reported insomnia had little linear association with
short reported sleep durations. Among women, the body mass index likewise
had a U-shaped relationship to sleep duration (Figure 1), but among men, there was a virtually monotonic trend
toward lower body mass indexes among those with longer sleep durations (Figure 2). Note that the mean body mass index
for men reporting 3 hours sleep had sufficiently wide confidence intervals
to be consistent with this trend.
|
|
|
|
Figure 1. For 636 095 women, the average
reported frequency of insomnia, the average number of sleeping pills used
per month, and the mean body mass index (BMI) according to reported hours
of sleep. The 95% confidence intervals of the BMI are shown. Also shown are
the hazard ratios from the 32-covariate Cox models and the percentage of women
reporting each sleep duration. The reference duration of 7 hours is represented
by the lighter bars.
|
|
|
|
|
|
|
Figure 2. For 480 841 men, data comparable
to those shown in Figure 1. BMI indicates body mass index.
|
|
|
The hazard ratios for various sleep durations adjusted for 32 covariates
are given in Table 1. Figure 1 and Figure 2 illustrate that, among both women and men, the best survival
was experienced by those reporting a usual sleep duration of 7 hours, which
was 1 hour less than the modal sleep duration. Participants who reported sleeping
8 hours or more had distinctly and significantly increased mortality hazard:
the longer the reported sleep, the higher the mortality hazard. When reported
sleep exceeded 8.5 hours (as occurred among 7.5% of women and 7.7% of men),
the added risk associated with long sleep exceeded 15%. Reported sleep had
to be less than 3.5 hours among women (as occurred among only 0.1%) or less
than 4.5 hours among men (0.7% of men) for the added risk associated with
short sleep to exceed 15%.
Women reporting insomnia 1, 2, 3, 4 to 9, or 10 or more times per month
had covariate-adjusted hazard ratios between 0.81 and 0.87, all of which were
significantly less than the reference hazard of those reporting no insomnia
(Table 1). Men reporting insomnia
1, 2, 3, 4 to 9, or 10 or more times per month had hazard ratios of 0.87 to
0.94, all of which were likewise significantly less than the reference. Women
and men whose answer was missing also had ratios significantly less than the
reference, which would be expected if some with missing responses had insomnia.
As previously reported,30 participants
who reported prescription sleeping pill use had significantly elevated mortality
hazards, with control for sleep duration, insomnia, and other covariates (Table 1). The sleeping pill x insomnia
interaction terms, when tested, were not significant additions to the models.
In the simplified models without full covariate control for comorbidities,
hazard ratios (95% confidence interval) associated with 3 hours and 10 hours
of sleep reached 2.05 (1.68-2.50) and 2.14 (2.04-2.28) for women and 2.49
(2.05-3.01) and 2.19 (2.09-2.29) for men, respectively. However, removing
insomnia or sleeping pill use from these simplified Cox models had only negligible
effects (well within the confidence intervals) on the hazards ratios associated
with sleep duration. When sleeping pill use was removed from the simplified
models (ie, not controlled), the hazard ratio associated with insomnia increased
slightly; eg, for insomnia 10 or more times per month, the ratio increased
from 0.99 (0.94-1.05) to 1.05 (0.99-1.10) for women and from 1.15 (1.09-1.21)
to 1.24 (1.17-1.30) for men. Removal of sleep duration had even smaller effects
on insomnia hazard ratios. Moreover, there were only negligible effects on
the hazard ratios associated with sleeping pill use when insomnia or sleep
duration were removed from the simplified models.
For 8, 9, and 10 or more hours of sleep, the hazard ratios for cerebrovascular
deaths were elevated over the hazard ratios for death from all causes among
both women and men (P<.05 in 3 of 6 comparisons
in data not shown). Hazard ratios for deaths from accidents, cancers, heart
disease, suicide, and homicide were not consistently higher than the all-cause
hazard ratios associated with short and long sleep.
COMMENT
A physician can reassure a patient that it is no longer average to sleep
8 hours. The lowest mortality hazard was experienced by participants reporting
usual sleep of 7 hours (6.5-7.4 hours) per night. Sleep durations as short
as 4.5 hours were associated with mortality hazards lower than that of almost
half the sample. Comparison of the 32-covariate models with the simplified
CPSII models and the less-controlled CPSI tabulations6
showed that most mortality risk associated with short sleep could be explained
by comorbidities. Also, a recent population sampling found that short sleep
durations were not related to impaired health-related quality of well-being.33
Insomnia was not well defined in CPSII. There was only a weak correlation
of reported insomnia with short sleep and little interaction. Reported insomnia
was associated with no excess mortality hazard whatsoever, once sleeping pill
use and other comorbidities were controlled. The absence of significant insomnia
hazard noted in CPSI and CPSII has likewise been observed in smaller epidemiologic
studies that controlled for comorbidities.9-10,19, 23, 34-38
There is evidence that sleep complaints of various forms (not necessarily
insomnia) predict coronary heart disease, but the odds ratios may be reduced
with control for medications.39 Moreover, some
studies indicate that primary insomnia causes no substantial impairment of
function.1, 11 For example, patients
with insomnia may have no demonstrable loss of daytime alertness.1, 40 Less than 25% of patients referred
for insomnia have primary insomnia as a first diagnosis.41
Although there may be risks in depression, anxiety, heart disease, cancer,
lack of exercise, sleep apnea, and other conditions in which insomnia is often
present, patients with insomnia without underlying comorbidities can be reassured
that there appears to be no survival risk, as long as the patients refrain
from long-term use of sleeping pills. In one study, awakening during the night
predicted decreased mortality,8 similar to
the hazard ratios less than 1.0 shown in Table 1. However, we are not persuaded that insomnia is beneficial,
because we found no dose-response relationship of insomnia frequency to decreasing
hazard ratio, and a protective effect of insomnia was not suggested by the
simplified models before 32-covariate adjustment. By comparison, mortality
increased progressively in both men and women from 7 to 10 hours of sleep
and with increasing sleeping pill use, and these associations were even stronger
before adjustment for 32 covariates.
It is likely that control for additional risk factors or qualitatively
improved control would further reduce apparent sleep-associated risks. However,
there is a possibility that controlling statistically for comorbidities underestimates
the mortality risk associated with short or long sleep. For example, if short
or long sleep causes heart disease,42 then
correcting for a history of heart disease might obscure an underlying effect
of sleep duration.
Above 7.5 hours, the longer participants reported sleeping, the greater
their mortality hazard. Slightly elevated mortality hazard was noted even
among those with the modal sleep duration (8 hours), suggesting that sleep
duration is not merely a proxy for nonspecific hazardous deviations from modal
health. This result was highly consistent between replications for women and
men. It was also entirely consistent among age groups (unpublished observations
from Cox models described previously, examining 4 age ranges from age 30-50
to >70 years).30 Moreover, CPSII results were
consistent with those of smaller studies14-23
and with the previous results of CPSI.6
Currently, we do not know why sleep exceeding 7.5 hours was associated
with excess mortality. Sleep duration in itself may not be a causal factor.
Our group has suggested that sleep apnea might be a crucial underlying abnormality.43 The elevated hazard for cerebrovascular deaths might
be consistent with an apnea effect. Nevertheless, in a population study, we
more recently found no significant relationship of long sleep to sleep disordered
breathing.44 Furthermore, since obesity is
a key cause of sleep apnea, if sleep apnea were the major explanation, we
would have expected more association of high body mass indexes with long sleep
than is shown in Figure 2. Also,
the hazard ratios were controlled for body mass index. Depression was not
measured effectively in CPSII questionnaires, although depression might be
associated with short and long sleep. However, because most insomnia complaints
are accompanied by depression, we would have expected insomnia to predict
excess mortality if depression explained the mortality hazard associated with
short and long sleep. In addition, suicide deaths were not associated with
short or long sleep out of proportion. Lacking understanding of causality,
we cannot answer the crucial question of whether patients who sleep long could
extend their survival by curtailing their sleep.
Long sleepers composed more than 90% of those whose sleep duration was
associated with 15% or greater excess risk, although even for those sleeping
10 hours or more, the excess risk was modest. We may estimate that the sample
excess fraction of deaths related to sleep duration was 6.3% for women and
5.3% for men.45 If we allow the unproven assumption
that long and short sleep cause the excess hazards with which they are associated,
these would be the attributable risk fractions. In women, 83% of the excess
and 78% of the excess in men were associated with sleep of 8 hours or more.
Although polling and other data suggest a reduction in US population sleep
durations in the latter part of the 20th century since CPSI and CPSII questionnaires
were collected,2, 46-48
the health of the population has been improving. These data do not support
any speculation that the population is sleeping too little on average.
As previously observed30 and reiterated
in Table 1, the CPSII risk associated
with sleeping pill use was greater than any risk associated with insomnia.
Important limitations are that CPSII did not associate this mild mortality
risk with particular hypnotic compounds or prove causality. The most popular
hypnotics at the time CPSII data were collected, temazepam, triazolam, and
flurazepam hydrochloride, have been largely supplanted by new benzodiazepine
agonists with greater receptor specificity. It is unknown whether contemporary
hypnotics are associated with comparable risks.30
A multitude of factors are associated with insomnia, short sleep, and
the use of sleeping pills. No epidemiologic approach could leave us completely
confident that statistical control for comorbidities would be sufficient but
not excessive. To define causality, following the example of large randomizing
trials examining diet, exercise, and critical medications, it might be possible
to ascertain experimentally whether voluntary curtailment of sleep can prolong
life or influence comorbid conditions. Likewise, it should be possible to
determine experimentally whether any long-term treatment of chronic insomnia
is safe and efficacious.
AUTHOR INFORMATION
Accepted for publication June 26, 2001.
The American Cancer Society, New York, NY, supported collection of these
data. Analyses were supported by grants HL55983, HL61280, AG15763, and AG12364
from the National Institutes of Health, Bethesda, Md (Dr Kripke).
Presented in part at the Third International Congress of the World Federation
of Sleep Research Societies, Dresden, Germany, October 7, 1999, and the 14th
Annual Meeting of the Associated Professional Sleep Societies, Las Vegas,
Nev, June 20, 2000.
Corresponding author and reprints: Daniel F. Kripke, MD, Department
of Psychiatry 0667, University of California, San Diego, 9500 Gilman Dr, La
Jolla, CA 92093-0667 (e-mail: DKripke{at}UCSD.edu).
From the Departments of Psychiatry (Drs Kripke and Marler) and Family
and Preventive Medicine (Drs Wingard and Klauber), University of California,
San Diego; and The American Cancer Society, New York, NY (Mr Garfinkel).
REFERENCES
| |
1. Sateia MJ, Doghramji K, Hauri PJ, Morin CM. Evaluation of chronic insomnia. Sleep. 2000;23:243-308.
WEB OF SCIENCE
| PUBMED
2. Johnson EO. Sleep in America: 1999. Washington, DC: National Sleep Foundation; 1999.
3. Jean-Louis G, Kripke DF, Ancoli-Israel S, Klauber MR, Sepulveda RS. Sleep duration, illumination, and activity patterns in a population
sample: effects of gender and ethnicity. Biol Psychiatry. 2000;47:921-927.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
4. Hartmann E, Baekeland F, Zwilling GR. Psychological differences between long and short sleepers. Arch Gen Psychiatry. 1972;26:463-468.
FREE FULL TEXT
5. Carskadon MA, Dement WC, Mitler MM, Guilleminault C, Zarcone VP, Spiegel R. Self-reports versus sleep laboratory findings in 122 drug-free subjects
with complaints of chronic insomnia. Am J Psychiatry. 1976;133:1382-1388.
FREE FULL TEXT
6. Kripke DF, Simons RN, Garfinkel L, Hammond EC. Short and long sleep and sleeping pills: is increased mortality associated? Arch Gen Psychiatry. 1979;36:103-116.
FREE FULL TEXT
7. Foley DJ, Monjan A, Simonsick EM, Wallace RB, Blazer DG. Incidence and remission of insomnia among elderly adults: an epidemiologic
study of 6,800 persons over three years. Sleep. 1999;22(suppl 2):S366-S372.
8. Foley DJ, Monjan AA, Brown SL, Simonsick EM, Wallace RB, Blazer DG. Sleep complaints among elderly persons: an epidemiologic study of three
communities. Sleep. 1995;18:425-432.
WEB OF SCIENCE
| PUBMED
9. Brabbins CJ, Dewey ME, Copeland RM, Davidson IA, McWilliam C, Saunders P, Sharma VK, Sullivan C. Insomnia in the elderly: prevalence, gender differences and relationships
with morbidity and mortality. Int J Geriatr Psychiatry. 1993;8:473-480.
10. Jensen E, Dehlin O, Hagberg B, Samuelsson G, Svensson T. Insomnia in an 80-year-old population: relationship to medical, psychological
and social factors. J Sleep Res. 1998;7:183-189.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
11. Simon GE, VonKorff M. Prevalence, burden, and treatment of insomnia in primary care. Am J Psychiatry. 1997;154:1417-1423.
ABSTRACT
12. Skaer TL, Robison LM, Sclar DA, Galin RS. Psychiatric comorbidity and pharmacological treatment patterns among
patients presenting with insomnia: an assessment of office-based encounters
in the USA in 1995 and 1996. Clin Drug Invest. 1999;18:161-167.
FULL TEXT
13. Hammond EC. Some preliminary findings on physical complaints from a prospective
study of 1,064,004 men and women. Am J Public Health. 1964;54:11-24.
14. Branch LG, Jette AM. Personal health practices and mortality among the elderly. Am J Public Health. 1984;74:1126-1129.
FREE FULL TEXT
15. Breslow L, Enstrom JE. Persistence of health habits and their relationship to mortality. Prev Med. 1980;9:469-483.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
16. Wingard DL, Berkman LF. Mortality risk associated with sleeping patterns among adults. Sleep. 1983;6:102-107.
WEB OF SCIENCE
| PUBMED
17. Wingard DL, Berkman LF, Brand RJ. A multivariate analysis of health-related practices. Am J Epidemiol. 1982;116:765-775.
FREE FULL TEXT
18. Kaplan GA, Seeman TE, Cohen RD, Knudsen LP, Guralnik J. Mortality among the elderly in the Alameda County Study: behavioral
and demographic risk factors. Am J Public Health. 1987;77:307-312.
FREE FULL TEXT
19. Huppert FA, Whittington JE. Symptoms of psychological distress predict 7-year mortality. Psychol Med. 1995;25:1073-1086.
WEB OF SCIENCE
| PUBMED
20. Qureshi AI, Giles WH, Croft JB, Bliwise DL. Habitual sleep patterns and risk for stroke and coronary heart disease:
a 10-year follow-up from NHANES I. Neurology. 1997;48:904-911.
FREE FULL TEXT
21. Chen D, Foley D. Prevalence of sleep disturbance and mortality in the U.S. population
[abstract]. Sleep Res. 1994;23:116.
22. Kripke DF, Ancoli-Israel S, Fell RL, Mason WJ, Klauber MR, Kaplan O. Health risk of insomnia. In: Peter JH, Penzel T, Podszus T, von Wichert P, eds. Sleep and Health Risk. Berlin, Germany: Springer-Verlag; 1991:547-554.
23. Kojima M, Wakai K, Kawamura T, Tamakoshi A, Aoki R, Lin Y, Nakayama T, Horibe H, Aoki N, Ohno Y. Sleep patterns and total mortality: a 12-year follow-up study in Japan. J Epidemiol. 2000;10:87-93.
PUBMED
24. Garfinkel L. Selection, follow-up, and analysis in the American Cancer Society prospective
studies. Natl Cancer Inst Monogr. 1985;67:49-52.
25. Garfinkel L, Stellman SD. Mortality by relative weight and exercise. Cancer. 1988;62:1844-1850.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
26. Thun MJ, Namboodiri MM, Heath CW Jr. Aspirin use and reduced risk of fatal colon cancer. N Engl J Med. 1991;325:1593-1596.
ABSTRACT
27. Willis DB, Calle EE, Miracle-McMahill HL, Heath CW Jr. Estrogen replacement therapy and risk of fatal breast cancer in a prospective
cohort of postmenopausal women in the United States. Cancer Causes Control. 1996;7:449-457.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
28. Changes in Cigarette-Related Disease Risks and Their Implication
for Prevention and Control. Rockville, Md: National Cancer Institute; 1997. Monograph 8.
29. Garfinkel L, Stellman SD. Smoking and lung cancer in women: finding in a prospective study. Cancer Res. 1988;48:6951-6955.
FREE FULL TEXT
30. Kripke DF, Klauber MR, Wingard DL, Fell RL, Assmus JD, Garfinkel L. Mortality hazard associated with prescription hypnotics. Biol Psychiatry. 1998;43:687-693.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
31. SAS Institute. SAS/STAT Software: Changes and Enhancements Through
Release 6.12. Cary, NC: SAS Institute Inc; 1997.
32. Klein J, Moeschberger M. Survival Analysis Techniques for Censored and Truncated
Data. New York, NY: Springer; 1997.
33. Jean-Louis G, Kripke DF, Ancoli-Israel S. Sleep and quality of well-being. Sleep. 2000;23:1115-1121.
WEB OF SCIENCE
| PUBMED
34. Ganguli M, Reynolds CF, Gilby JE. Prevalence and persistence of sleep complaints in a rural older community
sample: the MoVIES project. J Am Geriatr Soc. 1996;44:778-784.
WEB OF SCIENCE
| PUBMED
35. Althuis MD, Fredman L, Langenberg PW, Magaziner J. The relationship between insomnia and mortality among community-dwelling
older women. J Am Geriatr Soc. 1998;46:1270-1273.
WEB OF SCIENCE
| PUBMED
36. Rumble R, Morgan K. Hypnotics, sleep, and mortality in elderly people. J Am Geriatr Soc. 1992;40:787-791.
WEB OF SCIENCE
| PUBMED
37. Foley DJ, Monjan AA, Izmirlian G, Hays JC, Blazer DG. Incidence and remission of insomnia among elderly adults in a biracial
cohort. Sleep. 1999;22(suppl 2):S373-S378.
38. Mallon L, Broman J-E, Hetta J. Relationship between insomnia, depression, and mortality: a 12-year
follow-up of older adults in the community. Int Psychogeriatr. 2000;12:295-306.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
39. Schwartz S, Anderson WM, Cole SR, Cornoni-Huntley J, Hays JC, Blazer D. Insomnia and heart disease: a review of epidemiologic studies. J Psychosom Res. 1999;47:313-333.
FULL TEXT
|
WEB OF SCIENCE
| PUBMED
40. Stepanski E, Zorick F, Roehrs T, Young D, Roth T. Daytime alertness in patients with chronic insomnia compared with asymptomatic
control subjects. Sleep. 1988;11:54-60.
WEB OF SCIENCE
| PUBMED
41. Buysse DJ, Reynolds CF, Hauri PJ, Roth T, Stepanski EJ, Thorpy MJ, Bixler EO, Kales A, Manfredi RL, Vgontzas AN, Stapf DM, Houck PR, Kupfer DJ. Diagnostic concordance for DSM-IV sleep disorder:
a report from the APA/NIMH DSM-IV field trial. Am J Psychiatry. 1994;151:1351-1360.
FREE FULL TEXT
42. Partinen M, Putkonen PTS, Kaprio J, Koskenvuo M, Hilakiui I. Sleep disorders in relation to coronary heart disease. Acta Med Scand Suppl. 1982;660:69-83.
PUBMED
43. Kripke DF, Ancoli-Israel S, Mason WJ, Kaplan O. Sleep apnea: association with deviant sleep durations and increased
mortality. In: Guilleminault C, Partinen M, eds. Obstructive
Sleep Apnea Syndrome: Clinical Research and Treatment. New York, NY:
Raven Press Ltd; 1990:9-14.
44. Kripke DF, Ancoli-Israel S, Klauber MR, Wingard DL, Mason WJ, Mullaney DJ. Prevalence of sleep disordered breathing in ages 40-64 years: a population-based
survey. Sleep. 1997;20:65-76.
WEB OF SCIENCE
| PUBMED
45. Szklo M, Nieto FJ. Attributable risk. In: Epidemiology. Gaithersburg, Md: Aspen;
2000:98-105.
46. Gallup Organization. The Gallup Study of Sleeping Habits. Princeton, NJ: Gallup Organization; 1979.
47. National Commission on Sleep Disorders Research. Wake Up America: A National Sleep Alert: Volume One:
Executive Summary and Executive Report. Bethesda, Md: National Institutes of Health; 1993.
48. Bliwise DL. Historical change in the report of daytime fatigue. Sleep. 1996;19:462-464.
WEB OF SCIENCE
| PUBMED
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati  Twitter
What's this?
RELATED ARTICLE
Can Sleep Be Bad For You? Can Insomnia Be Good?
Daniel J. Buysse and Mary Ganguli
Arch Gen Psychiatry. 2002;59(2):137-138.
EXTRACT
| FULL TEXT
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
|
Sleep disorders and secondhand smoke exposure in the U.S. population
Davila et al.
Nicotine Tob Res 2010;0:ntp193v1-ntp193.
ABSTRACT
| FULL TEXT
Gender-Specific Association Between Self-reported Sleep Duration and Falls in High-Functioning Older Adults
Kuo et al.
J Gerontol A Biol Sci Med Sci 2010;65A:190-196.
ABSTRACT
| FULL TEXT
Self-Reported Sleep Duration and Sleep Disturbance Are Independently Associated with Cortisol Secretion in the Whitehall II Study
Kumari et al.
J. Clin. Endocrinol. Metab. 2009;94:4801-4809.
ABSTRACT
| FULL TEXT
Association of Sleep Adequacy With More Healthful Food Choices and Positive Workplace Experiences Among Motor Freight Workers
Buxton et al.
AJPH 2009;99:S636-S643.
ABSTRACT
| FULL TEXT
Sleep Deprivation, Physician Performance, and Patient Safety
Olson et al.
Chest 2009;136:1389-1396.
ABSTRACT
| FULL TEXT
Night shift work and the cardiovascular health of medical staff
Steptoe
Eur Heart J 2009;30:2560-2561.
FULL TEXT
Sleep Duration, Lifestyle Intervention, and Incidence of Type 2 Diabetes in Impaired Glucose Tolerance: The Finnish Diabetes Prevention Study
Tuomilehto et al.
Diabetes Care 2009;32:1965-1971.
ABSTRACT
| FULL TEXT
Evaluation and Management of Insomnia in the Psychiatric Setting
Doghramji et al.
Focus 2009;7:441-454.
ABSTRACT
| FULL TEXT
Exposure to Recurrent Sleep Restriction in the Setting of High Caloric Intake and Physical Inactivity Results in Increased Insulin Resistance and Reduced Glucose Tolerance
Nedeltcheva et al.
J. Clin. Endocrinol. Metab. 2009;94:3242-3250.
ABSTRACT
| FULL TEXT
Health Behavior Risk Factors Across Age as Predictors of Cardiovascular Disease Diagnosis
Cardi et al.
J Aging Health 2009;21:759-775.
ABSTRACT
Sleep Disturbances and Their Relationship to Cardiovascular Disease
Quan
AMERICAN JOURNAL OF LIFESTYLE MEDICINE 2009;3:55S-59S.
ABSTRACT
Adolescents Living the 24/7 Lifestyle: Effects of Caffeine and Technology on Sleep Duration and Daytime Functioning
Calamaro et al.
Pediatrics 2009;123:e1005-e1010.
ABSTRACT
| FULL TEXT
Generalized Anxiety Disorder, Major Depressive Disorder, and Their Comorbidity as Predictors of All-Cause and Cardiovascular Mortality: The Vietnam Experience Study
Phillips et al.
Psychosom. Med. 2009;71:395-403.
ABSTRACT
| FULL TEXT
Sleep Duration in the United States: A Cross-sectional Population-based Study
Krueger and Friedman
Am J Epidemiol 2009;169:1052-1063.
ABSTRACT
| FULL TEXT
Pretreatment Health Behaviors Predict Survival Among Patients With Head and Neck Squamous Cell Carcinoma
Duffy et al.
JCO 2009;27:1969-1975.
ABSTRACT
| FULL TEXT
Sleep, Sleep Disorders, and Cognition
Gay
ACCP Sleep Med Brd Rev 2009;4:313-324.
FULL TEXT
Sleep in Older People
Phillips
ACCP Sleep Med Brd Rev 2009;4:325-338.
FULL TEXT
Correlates of Short and Long Sleep Duration: A Cross-Cultural Comparison Between the United Kingdom and the United States: The Whitehall II Study and the Western New York Health Study
Stranges et al.
Am J Epidemiol 2008;168:1353-1364.
ABSTRACT
| FULL TEXT
Sleep Duration and Coronary Heart Disease Mortality Among Chinese Adults in Singapore: A Population-based Cohort Study
Shankar et al.
Am J Epidemiol 2008;168:1367-1373.
ABSTRACT
| FULL TEXT
Sleep Duration and Risk of Ischemic Stroke in Postmenopausal Women * Supplemental Appendix
Chen et al.
Stroke 2008;39:3185-3192.
ABSTRACT
| FULL TEXT
Short Sleep Duration as an Independent Predictor of Cardiovascular Events in Japanese Patients With Hypertension
Eguchi et al.
Arch Intern Med 2008;168:2225-2231.
ABSTRACT
| FULL TEXT
Childhood Sleep Time and Long-Term Risk for Obesity: A 32-Year Prospective Birth Cohort Study
Landhuis et al.
Pediatrics 2008;122:955-960.
ABSTRACT
| FULL TEXT
Long Sleep Duration is Associated With Serum Cholesterol in the Elderly: The Rotterdam Study
van den Berg et al.
Psychosom. Med. 2008;70:1005-1011.
ABSTRACT
| FULL TEXT
Sleep Problems and Associated Daytime Fatigue in Community-Dwelling Older Individuals
Goldman et al.
J Gerontol A Biol Sci Med Sci 2008;63:1069-1075.
ABSTRACT
| FULL TEXT
Sleep/Wake Patterns of Individuals With Advanced Cancer Measured by Ambulatory Polysomnography
Parker et al.
JCO 2008;26:2464-2472.
ABSTRACT
| FULL TEXT
Quantitative Genetic Analysis of Sleep in Drosophila melanogaster
Harbison and Sehgal
Genetics 2008;178:2341-2360.
ABSTRACT
| FULL TEXT
How is Your Sleep: A Neglected Topic for Health Care Screening
Sorscher
J Am Board Fam Med 2008;21:141-148.
ABSTRACT
| FULL TEXT
Sleep duration, general and abdominal obesity, and weight change among the older adult population of Spain
Lopez-Garcia et al.
Am. J. Clin. Nutr. 2008;87:310-316.
ABSTRACT
| FULL TEXT
Cross-sectional versus Prospective Associations of Sleep Duration with Changes in Relative Weight and Body Fat Distribution: The Whitehall II Study
Stranges et al.
Am J Epidemiol 2008;167:321-329.
ABSTRACT
| FULL TEXT
Association of Fewer Hours of Sleep at 6 Months Postpartum with Substantial Weight Retention at 1 Year Postpartum
Gunderson et al.
Am J Epidemiol 2008;167:178-187.
ABSTRACT
| FULL TEXT
Is Siesta More Beneficial Than Nocturnal Sleep?
Patel
Arch Intern Med 2007;167:2143-2144.
FULL TEXT
Socioeconomic Status Predicts Objective and Subjective Sleep Quality in Aging Women
Friedman et al.
Psychosom. Med. 2007;69:682-691.
ABSTRACT
| FULL TEXT
Why Is Nondipping in Ambulatory Blood Pressure Monitoring Not Prognostic in Poor Sleepers?
Martinez and Fuchs
Hypertension 2007;50:e20-e20.
FULL TEXT
Response to Why Is Nondipping in Ambulatory Blood Pressure Monitoring Not Prognostic in Poor Sleepers?
Verdecchia et al.
Hypertension 2007;50:e21-e21.
FULL TEXT
RE: "OBJECTIVELY MEASURED SLEEP CHARACTERISTICS AMONG EARLY-MIDDLE-AGED ADULTS: THE CARDIA STUDY"
Hale and Do
Am J Epidemiol 2007;165:231-232.
FULL TEXT
The link between short sleep duration and obesity: we should recommend more sleep to prevent obesity
Taheri
Arch. Dis. Child. 2006;91:881-884.
FULL TEXT
Effects of sleep deprivation on the development of autoimmune disease in an experimental model of systemic lupus erythematosus
Palma et al.
Am. J. Physiol. Regul. Integr. Comp. Physiol. 2006;291:R1527-R1532.
ABSTRACT
| FULL TEXT
Sleep disruption, oxidative stress, and aging: New insights from fruit flies
Cirelli
Proc. Natl. Acad. Sci. USA 2006;103:13901-13902.
FULL TEXT
Sleep duration and health in young adults.
Steptoe et al.
Arch Intern Med 2006;166:1689-1692.
ABSTRACT
| FULL TEXT
Sleep duration and body mass index in a rural population.
Kohatsu et al.
Arch Intern Med 2006;166:1701-1705.
ABSTRACT
| FULL TEXT
Sleep deprivation and activation of morning levels of cellular and genomic markers of inflammation.
Irwin et al.
Arch Intern Med 2006;166:1756-1762.
ABSTRACT
| FULL TEXT
Impaired Performance in Commercial Drivers: Role of Sleep Apnea and Short Sleep Duration
Pack et al.
Am. J. Respir. Crit. Care Med. 2006;174:446-454.
ABSTRACT
| FULL TEXT
Objectively Measured Sleep Characteristics among Early-Middle-Aged Adults: The CARDIA Study
Lauderdale et al.
Am J Epidemiol 2006;164:5-16.
ABSTRACT
| FULL TEXT
Invited Commentary: How Much Do We Really Sleep?
Quan
Am J Epidemiol 2006;164:17-18.
FULL TEXT
Sleep Quality and Its Correlates in the First Year of Dialysis
Unruh et al.
CJASN 2006;1:802-810.
ABSTRACT
| FULL TEXT
Socioeconomic position and sleep quantity in UK adults.
Adams
J. Epidemiol. Community Health 2006;60:267-269.
ABSTRACT
| FULL TEXT
Explaining social inequalities in health by sleep: the Japanese civil servants study
Sekine et al.
J Public Health (Oxf) 2006;28:63-70.
ABSTRACT
| FULL TEXT
Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes
Spiegel et al.
J. Appl. Physiol. 2005;99:2008-2019.
ABSTRACT
| FULL TEXT
Timing and Consolidation of Human Sleep, Wakefulness, and Performance by a Symphony of Oscillators
Dijk and von Schantz
J Biol Rhythms 2005;20:279-290.
ABSTRACT
In Reply
Benca
Psychiatr. Serv. 2005;56:752-753.
FULL TEXT
Association of Sleep Time With Diabetes Mellitus and Impaired Glucose Tolerance
Gottlieb et al.
Arch Intern Med 2005;165:863-867.
ABSTRACT
| FULL TEXT
Brief Communication: Sleep Curtailment in Healthy Young Men Is Associated with Decreased Leptin Levels, Elevated Ghrelin Levels, and Increased Hunger and Appetite
Spiegel et al.
ANN INTERN MED 2004;141:846-850.
ABSTRACT
| FULL TEXT
Leptin Levels Are Dependent on Sleep Duration: Relationships with Sympathovagal Balance, Carbohydrate Regulation, Cortisol, and Thyrotropin
Spiegel et al.
J. Clin. Endocrinol. Metab. 2004;89:5762-5771.
ABSTRACT
| FULL TEXT
Microarousals During Sleep Are Associated With Increased Levels of Lipids, Cortisol, and Blood Pressure
Ekstedt et al.
Psychosom. Med. 2004;66:925-931.
ABSTRACT
| FULL TEXT
Incidence of Diabetes in Middle-Aged Men Is Related to Sleep Disturbances
Nilsson et al.
Diabetes Care 2004;27:2464-2469.
ABSTRACT
| FULL TEXT
Naps and Circadian Rhythms in Postmenopausal Women
Yoon et al.
J Gerontol A Biol Sci Med Sci 2004;59:M844-M848.
ABSTRACT
| FULL TEXT
Reductions in circulating anabolic hormones induced by sustained sleep deprivation in rats
Everson and Crowley
Am. J. Physiol. Endocrinol. Metab. 2004;286:E1060-E1070.
ABSTRACT
| FULL TEXT
Self-reported Sleep Complaints With Long and Short Sleep: A Nationally Representative Sample
Grandner and Kripke
Psychosom. Med. 2004;66:239-241.
ABSTRACT
| FULL TEXT
Effect of sleep loss on C-Reactive protein, an inflammatory marker of cardiovascular risk
Meier-Ewert et al.
J Am Coll Cardiol 2004;43:678-683.
ABSTRACT
| FULL TEXT
A Prospective Study of Self-Reported Sleep Duration and Incident Diabetes in Women
Ayas et al.
Diabetes Care 2003;26:380-384.
ABSTRACT
| FULL TEXT
A Longer Biological Night in Long Sleepers Than in Short Sleepers
Aeschbach et al.
J. Clin. Endocrinol. Metab. 2003;88:26-30.
ABSTRACT
| FULL TEXT
OTHER ARTICLES NOTED (Nov 01 to 18 Oct 02)
Evid. Based Nurs. 2003;6:e1-1.
FULL TEXT
Other articles noted
Evid. Based Ment. Health 2002;5:104-104.
FULL TEXT
To Sleep, Perchance to Live
JWatch Psychiatry 2002;2002:3-3.
FULL TEXT
Can Sleep Be Bad For You? Can Insomnia Be Good?
Buysse and Ganguli
Arch Gen Psychiatry 2002;59:137-138.
FULL TEXT
|
