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Supplements Exploring the Burden of Insomnia in Older Adults

The Epidemiology of Insomnia in Older Adults and Current Treatment Landscape

The importance of sleep health has garnered much attention in the United States. Although 65% of US adults believe that sleep affects their effectiveness the following day and 44% report having a sleep disorder, just 10% prioritize sleep.1 Although not usually life-threatening, sleep problems can negatively affect health and quality of life.2 In particular, their impact on the physical and mental health of the aging population demands careful diagnostic and treatment consideration. Older adults often present with comorbidities that further complicate the presentation and treatment of sleep difficulties, specifically insomnia, and present challenges for clinicians.

Aging Changes in Sleep Patterns

Changes in sleep patterns occur as part of the normal aging process, and many studies have highlighted the complexities of these changes, including their relationships with sleep disorders.3

In a large-scale analysis of sleep studies from 1960-2003, Ohayon et al investigated adult sleep patterns and their changes over a lifetime. In particular, they assessed sleep stages and characteristics such as total sleep time (TST), latency, efficiency, and sleep fragmentation or arousal (all of which are components of sleep macrostructure and microstructure) in different age groups. Overall, the investigators found that TST decreased with age, particularly in women, and that sleep efficiency decreased by 3% per decade in adults 40 years and older. In addition, the percentage of stage 1 sleep increased with age, and this effect was even more pronounced in women. The percentage of adults’ stage 2 sleep also was shown to increase significantly with age (P <.0001).3

Other studies have focused on sleep patterns across the day to investigate alterations in circadian and homeostatic processes that might contribute to changes in sleep among different age groups. In a 24-hour sleep study by Campbell et al, older adults, compared with younger and middle-aged adults, had a decreased sleep tendency, with peak sleep tendency occurring 2 to 3 hours earlier.4 And in another study using a “90-minute day” model, healthy older participants required more time to fall asleep (sleep initiation) and had a shorter sleep period than younger ones.5

Just as these studies have demonstrated alterations in sleep patterns during the aging process, others have shown that sleep complaints also tend to be more prevalent among older adults. For example, in the Established Populations for Epidemiological Studies of the Elderly (EPESE), a project conducted by the National Institute on Aging, investigators surveyed participants 65 years and older and found that sleep complaints increased with age, predominantly in women.2 Similarly, the number of older adults with no sleep complaints significantly decreased with age.2 In another study, the prevalence of daytime sleepiness, an attribute of insomnia, significantly increased with age (P <.0001 for age trend).6

Overall, such sleep disturbances have been shown to negatively affect the quality of life and health of affected persons. For example, the results of a large study of Medicare enrollees found that lack of sleep continuity impacted daytime function, with affected participants being significantly more likely to report both daytime sleepiness and nighttime sleep disruption (P <.0001).6 When the investigators compared findings among different age groups, they found that short evening sleep periods, or nighttime napping (ie, sleep lasting less than 4 hours), tended to occur with greater frequency in the middle-aged to older adult groups (P = .014), while longer daytime naps were more characteristic of the younger adult group.4

Investigators on the EPESE project also studied daytime sleepiness and found that when it prompted daytime napping in older adults, their 3-year mortality risk increased (odds ratio [OR], 1.17; 95% CI, 1.03-1.33).2

These symptoms of increased daytime sleepiness with impacted night sleep in older adults can indicate cognitive impairment (affecting memory, concentration, and physical function).7

Insomnia in Older Adults

Insomnia is associated with the biologic and neurologic changes of aging, including altered circadian rhythm and arousal. The results of a sleep study comparing circadian patterns among different age groups indicated that older participants, when compared with younger adults, had less circadian rhythm variation during sleep and reduced sleep efficiency, but more circadian rhythm variation during waking periods.5 And in another study, patients with insomnia had more evidence of decreased metabolism in the brain arousal system during the transition from waking to non-REM sleep, compared with healthy study participants.8 This hypometabolism was evident, in particular, in the bilateral frontal cortex, as well as in the left hemisphere superior temporal, parietal, and occipital brain structures during the awake state in patients with insomnia.8

Other forms of cognitive and psychological disease have also been associated with insomnia. For example, the risk of developing Alzheimer disease (AD) has been significantly associated with sleep fragmentation (hazard ratio [HR], 1.22; 95% CI, 1.03-1.44; P = .02).9 Depression has been shown to be associated with waking too early and daytime sleepiness.6 For example, the results of the National Sleep Foundation’s 2003 Sleep in America poll found that reports of sleep difficulties were associated with depression and memory difficulty.10

Insomnia in older adults also has been associated with substance abuse. This was highlighted by analyzing data on binge drinking and insomnia from the 2004 Health and Retirement Study, which involved people 50 years and older.11 The investigators defined binge drinking as having 4 or more alcoholic drinks on 1 occasion. Of the 6027 participants included in the analysis, 32.5% reported occasional (1-2 days per week) binge drinking, and 3.6% reported frequent (more than 2 days per week) binge drinking. Overall, men were more likely than women to be binge drinkers, comprising 74.4% of all occasional binge drinkers and 86.9% of all frequent binge drinkers.11 Insomnia was reported by 37.6% of the study population as a whole, by 48.1% of the frequent binge drinkers, and by 39.2% of the occasional binge drinkers. Compared with non–binge drinkers, the frequent binge drinkers were 64% more likely (adjusted odds ratio [aOR], 1.64; 95% CI, 1.09-2.47; P = .007), and the occasional binge drinkers 35% more likely (aOR, 1.35; 95% CI, 1.15-1.59; P = .001), to report having insomnia.11

The investigators hypothesized that cigarette smoking may also partly drive the link between binge drinking and insomnia: 37.9% of the occasional binge drinkers and 51.6% of the frequent binge drinkers also reported being current smokers. When the investigators accounted for smoking behavior in the regression analysis, the link between binge drinking and insomnia dropped to below significance level.11

The Impact of Comorbid Conditions on Sleep in Older Adults

Studies have shown that comorbid psychiatric or medical conditions can substantially impact sleep in adults.

Comorbid psychiatric conditions

Investigations of comorbid psychiatric conditions have found associations between depression and insomnia symptoms. For example, the results of the EPESE survey showed that depression in older individuals correlated with increased odds of insomnia and patient reports of decreased restful sleep.2 In another study that surveyed Medicare enrollees, depression was associated with difficulty falling asleep and frequent awakenings.6 Psychosocial factors were also investigated as possible contributors to insomnia in older individuals. Poor social support was linked with increased difficulty falling asleep and greater nighttime waking frequency among older women and men.6

To further complicate the relationship between insomnia and depression, taking prescription medications for depression has also been associated with insomnia. In the EPESE survey, for example, the odds for insomnia increased for older adults using anxiolytics or barbiturates.2 For older adults, difficulty falling asleep was linked to use of psychotropic medication and benzodiazepines in the survey of Medicare enrollees.6 Psychotropic drug use among older adults was also associated with early awakening.6

Comorbid medical conditions

Several studies also have demonstrated additional insomnia comorbidity trends in the older adult population, associated with a wide range of medical conditions. The results of the 2003 Sleep in America poll, for example, indicated that 4 in 5 older participants reported a medical comorbidity such as diabetes, cancer, or hypertension. Of those reporting a comorbidity, 40% indicated having fair to poor sleep quality, whereas only 10% of those without a comorbidity indicated poor sleep quality.10

Comorbid respiratory disturbances also negatively impact sleep, as shown in the EPESE survey, in which respiratory symptoms increased sleep disturbance in older adults by 40%.2 Data from a sleep study involving older adults also demonstrated that those who snored had a greater index score for respiratory disturbances. The findings also highlighted a negative correlation between sleep apnea and both TST and alcohol consumption within 2 hours before bedtime.12

The results of another large study published in 2019, indicated that among professional adult women who participated in the Women’s Health Stress Study, a lack of weekday sleep was significantly associated with a likelihood of poor (OR, 1.61; 95% CI, 1.23-2.10) to intermediate (OR, 1.28; 95% CI, 1.04-1.59) cardiovascular health.13 The study involving Medicare enrollees also found that difficulty falling asleep and more frequent awakenings were associated with angina, arthritis, and myocardial infarction.6 And, a cohort study found a significant interaction between sleep difficulty and sleep duration on hypertension risk (OR, 4.1; 95% CI, 1.15-14.5; P = .029 for chronic insomnia; and OR, 3.36; 95% CI, 1.42-7.94; P = .006 for poor sleep). Hypertension risk was significantly higher in patients with chronic insomnia (OR, 3.75; 95% CI, 1.58-8.95; P = .012).14

The results of a study involving patients with chronic illnesses showed that a larger percentage of those who developed osteoarthritis, hip impairment, or peptic ulcers indicated either a recent onset of insomnia or worsening of chronic insomnia.15 Findings from another study indicated that compared with adults without insomnia, those with insomnia were more likely to report having medical problems such as cancer, urinary disease, neurologic disease, and gastrointestinal difficulties.16 And a recent study in older women found that menopausal symptoms may exacerbate insomnia, with nocturnal awakening demonstrated in association with hot flashes.17

 
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