Factors associated with the sleep of carers: A survey of New Zealanders supporting a family member with cognitive impairment or dementia

Abstract

Sleep is important for healthy ageing. Data are limited concerning the sleep and health of New Zealand families affected by cognitive impairment or dementia. This postal survey asked about the sleep of 526 family carers and explored predictors of, and outcomes associated with poorer sleep. Linear and binominal logistic regression were used to identify independent predictors and outcomes of carers’ sleep status. Using the Insomnia Severity Index, 23.5% of carers scored in the moderate–severe range and 43.0% in the mild range for sleep disturbance. More than a quarter indicated that their family member had difficulties falling asleep, getting up during the night, or waking too early. Over half of care recipients were considered to sleep too much during the day. Independent predictors for carers’ reporting greater sleep disturbance included being female, caregiving at night, poorer self-rated health, and the care recipient having more disturbed sleep. Moderate–severe sleep disturbance was independently associated with poorer self-rated health and living standards, use of sleeping medications, as well as considering transitioning their family member into formal care within the year. These findings have implications for the wellbeing and trajectory of family carers as well as for health and aged care services.

Keywords

ageing caregiving dementia health sleep

Introduction

Sleep is a basic physiological need, vital for maintaining health and wellbeing. Good sleep health is multidimensional, dependent on not only achieving enough hours (duration) but also the efficiency and timing of sleep, how alert we feel during wakefulness, as well as perceived sleep satisfaction and quality (Buysse, 2014).

Life expectancy is increasing and with it the prevalence of sleep problems which can negatively impact waking function, physical and mental health, health service use and longevity (Gibson, Gander, Kepa, et al., 2017; McCurry et al., 2007; Statistics New Zealand, 2016; Wilkinson & Sainsbury, 1998). With advancing age, the prevalence of cognitive impairment and dementia also increases. This has a negative impact on the health and wellbeing of individuals and their families whilst increasing healthcare costs and adding strain on residential and hospitalised care facilities (Alzheimers New Zealand, 2017; Schofield et al., 2006; Wilkinson & Sainsbury, 1998). In 2016, an estimated 62,287 New Zealanders had dementia (1.3% of population) which was a 29% increase from 2011 and is expected to continue rising (Alzheimers New Zealand, 2017). There is a strong drive to support people with dementia to live well in place (i.e. at home). Many do so under the informal care provided by family members. This is particularly the case within Māori (the indigenous people of New Zealand (NZ), comprising 16.5% of the total population) and Pacific Island cultures (comprising 16.5% of the total population) who are increasingly represented in the older NZ community but less inclined to medicalise aging or dementia (Dyall, 2014; Statistics New Zealand, 2016, 2018).

Sleep problems are among the most disruptive behavioural symptoms of dementia and have been associated with the neurophysiological pathology of the disease, exacerbated primary sleep disorders, a reduction in exposure to time cues, changes to psychosocial context as well as the impact of comorbidities and medications. Dementia-related sleep problems have been identified as exacerbating the waking symptoms of dementia (Bliwise, 2004; McCurry & Ancoli-Israel, 2003), as well as contributing to poorer sleep, reduced vitality and quality of life among family carers (Gehrman et al., 2018; Gibson, Gander, Alpass, & Stephens, 2015; Hope et al., 1998; Maun et al., 2018; McCurry et al., 2015). In a psychosocial model, sleep disturbances have been identified as a secondary stressor to those primarily related to caregiving. Together these stressors reflect the changing relationships and life dimensions with dementia care and can affect the physical and mental health of carers as well as feelings of coping (Pearlin et al., 1990; Simpson & Carter, 2013b). A qualitative study in NZ highlights the diversity of sleep symptoms among people with dementia that impacted the sleep, health and wellbeing of their family carers. Confused awakenings in the night and daytime sleepiness were key and, along with other symptoms, were moderated by the unique context of the routines and behaviours of both care recipient and carer (Gibson, Gander, & Jones, 2014). Despite these and other research findings plus the anecdotal knowledge of regional support workers (personal communication), there is a lack of education and priority given to sleep in the training of health practitioners, including general practitioners, geriatricians and psychologists (Lee & Thomas, 2011; Meltzer et al., 2009; Scott et al., 2011). Therefore it is reasonable to assume that sleep problems are often under-diagnosed, misdiagnosed or normalised. More information is needed on the presence and consequences of sleep disturbances among carers and the implications for themselves and the people in their care, to better inform sleep-related education, healthcare services, and interventions.

This study surveyed the sleep status of family carers in NZ with the aim of identifying the prevalence of sleep disturbances and the factors associated with poor sleep. This included exploring relationships between the sleep status of carers and care recipient’s sleep and dementia status, as well as the health and living standards of carers and the overall caregiving situation.

Methods

In NZ, 21 regional services (associated with Alzheimers NZ or Dementia NZ) are key charitable trusts providing dementia-specific services, advice, information and education nationwide, tailored dependent on their resources, location and clients. All these services agreed to distribute the survey to their members. Approximately 4720 study packs (including survey, information sheet and prepaid return envelope) were sent to these services, with the largest numbers going to the main urban centres (Auckland, Wellington, Waikato, Canterbury and Otago). Distribution to potential participants occurred from late 2016 to early 2017. Recipients were a convenience sample, either identified as eligible by the organisation, or on specific external mailing lists, or in some cases, packs were sent to all clients (depending on the size and conventions of each organisation). Inclusion criteria for participation were being the carer/support person of a family member with cognitive impairment or dementia with whom they lived.

The 11-page survey included sections on the carer and their situation (age, gender, ethnicity, who they support, years supporting, type of diagnosis, time of day required, respite, and permanent care considerations). Carers self-rated their standard of living using the Living Standards Capability for Elders questionnaire (LSCAPE-6; Breheny et al., 2016) which includes six items indicative of health care, social integration, contribution, enjoyment, security, and restriction, using a scale from 1 (‘not true for me at all’) to 5 (‘definitely true for me’, see Figure 2). This capabilities approach was adopted rather than measures of financial hardship because it is arguably more appropriate for older or socially-constrained individuals and has been demonstrated to be a reliable measure against the full 25-item Economic Living Standards Index as well as the Short-Form Economic Living Standards Index (Pearson’s r = 0.96 and 0.68 respectively p <0.001; Breheny et al., 2016). The amount and type of dementia-related symptoms were recorded using the Alzheimer’s Association Checklist (AAC; Alzheimer’s Association, 2009) of 10 common waking symptoms which are used for screening (see Table 2 for items).

Carers’ sleep was measured using the Insomnia Severity Index (ISI; Morin et al., 2011), which requires rating seven items associated with insomnia symptoms and impact using five-point Likert scales (see Figure 1 for items). The ISI has been validated against multiple measures of fatigue, sleep quality, mood and objective sleep efficiency and is sensitive for detecting sleep disturbance in community and clinical samples (Morin et al., 2011). Place of sleep, diagnosis of a sleep disorder, and use of sleeping medications were also recorded. The sleep of the care recipient was measured using the Sleep Disorders Inventory (SDI; Tractenberg et al., 2003), where carers rate the frequency, severity and distress associated with seven dementia-related sleep symptoms using 4-point scales (see Table 2 for items). The SDI has been validated against objective measures of sleep duration and efficiency for people with dementia and also correlates with measures of cognitive functioning and waking symptoms (Tractenberg et al., 2003). Finally, carers’ health was measured using Likert scales for general health and pain from the well-established and validated Short Form Health Survey (SF-12; Fleishman et al., 2010; Ware et al., 1996), a validated health conditions checklist (the Self-administered Comorbidity Questionnaire; Sangha et al., 2003), and a medication list. An open-ended comments section was included at the end of the survey.

Figure 1.

Sleep status of family carers using the Insomnia Severity Index to self-rate the presence and severity of sleep symptoms in the prior two weeks (^e.g. daytime fatigue, mood, ability to function at work/daily chores, concentration, memory, mood, etc.).

Consent was implied by completion and return of the survey. All data were anonymous except in cases where participants chose to share their contact details for inclusion on a mailing list for future research or to receive an educational booklet about sleep (as thanks for taking part). Ethical approval was obtained from the Health and Disability Ethics Committee (16/CEN/101).

Data analysis

The primary variable examined was the sleep of carers. The ISI score (Morin et al., 2011) was used as a continuous variable based on the sum of seven 5-point items (0, no problem – 28, severe), as well as using the standard stratification of ‘mild’ (8–14), ‘moderate’ (15–21) and ‘severe’ (22–28) sleep disturbance.

Care recipients’ sleep status was one of the factors tested for associations with carers ISI scores classified by the number of SDI sleep symptoms identified by carers as occurring at least once per week (Tractenberg et al., 2003). The severity and distress (moderate–severe versus not present-mild) associated with sleep symptoms were also calculated, however the global SDI score (frequency X severity) was not used due to skewed data.

Univariate analyses (Mann–Whitney U tests, Kruskal–Wallis, and/or Spearman’s correlations) were used to identify factors associated with carers’ sleep. Due to small numbers of participants in some categories, ethnicity, and relationship status variables were not explored for univariate associations with ISI scores. All variables with significant univariate associations (p < 0.05, Table 1) were included in further multivariate models.

Table 1.

Factors associated with carers’ Insomnia Severity Index scores.

		Descriptive statistics		Carers sleep (ISI scores)
Variable	Sub groups	Mean/median or percentage	(SD or range)	Median	Range	Rs	P
Age (years)^a		72.2	(10.2)			−0.11	0.011
							0.000
Gender^b
Female		66%		11.0	0.0–28.0
Male		34%		8.7	0.0–23.0
LSCAPE-6^a^		19.0	(5.5)			−0.29	0.000
Diagnosed health conditions count^a		2	(0–12)			0.18	0.000
Medication count^a		3	(0–10)			0.08	0.088
Use sleeping medications^b							0.000
Yes		27%		13.0	0.0–28.0
No		73%		9.3	0.0–25.2
General health^c							0.000
Fair-poor		24%		13.5	10.0–18.7		0.000
Good		41%		10.5	0.0–25.2		0.000
Very good – excellent		35%		7.0	0.0–20.0		0.000
Pain interfering with daily life^c							0.000
Quite a bit – extreme		20%		13.0	0.0–28.0		0.001
Moderate – a little		45%		10.5	0.0–25.2		0.000
Not at all		35%		8.0	0.0–24.5		0.001
Care recipient demographic and care situation
Diagnosis^c							0.570
Diagnosed dementia known type		64%		10.0	0.0–28.0
Diagnosed dementia unspecified type		18%		11.0	0.0–22.2
MCI or undiagnosed dementia		16%		10.0	0.0–25.2
Waking symptom count^a		8	(1–11)			0.28	0.000
Years requiring dementia-related care^a		4.5	(8.1)			0.13	0.003
Time of day care assistance required^c							0.000
24 hours or over night		39%		11.1	0.0–28.0		0.000
All day		21%		9.0	0.0–22.0		0.272
A few hours a day		35%		8.4	0.0–23.0		1.000
Place of sleep^b							0.424
Share a bed/room		61%		11.0	0.0–25.2
Sleep in another room		35%		9.9	0.0–28.0
Use of respite services^b							0.082
Yes		68%		11.0	0.0–28.0
No		27%		10.0	0.0–25.2
Considering residential care facilities^c							0.000
Awaiting placement or possibly within year		24%		12.0	0.0–25.2		0.000
Possibly within five years		52%		10.0	0.0–28.0		0.027
Not at all		24%		8.2	0.0–25.0		0.012

ISI: Insomnia Severity Index; LSCAPE-6: Living Standards Capability for Elders 6 item questionnaire (^see Figure 2 for itemised results); p: significance; Rs: Spearman’s Rho; SD: standard deviation.

^aSpearman’s correlations.

^bMann–Whitney U tests.

^cKruskal–Wallis tests.

Linear multiple regression models were used to explore the factors independently associated with carers’ ISI scores (Table 3). The first model included carers’ demographic variables, the second added care recipients’ waking and sleeping symptoms, and the full model also included variables associated with carers’ health. Models included between 82% and 83% of participants due to missing data for some variables.

Logistic multiple regression models were used to explore whether having a moderate–severe sleep problem (ISI scores 15–28) was an independent predictor for other health issues, standard of living, and plans for the care situation compared to those with a mild or no sleep problem versus mild–no sleep problem (ISI scores <15, Table 4). All analyses were undertaken in SPSS software version 23.0 (SPSS Inc. Chicago, IL, USA).

Results

A total of 526 carers returned completed surveys (11% response rate). The majority (87%) supported their spouse/partner (11% supported a parent and 2% another family member) and 92% identified as being of NZ European ethnicity (only 7% identified as Māori). Details on the remaining demographics and caregiving situation can be found in Table 1, as well as the univariate relationships between these variables and carers sleep (ISI scores). The age distribution was broad (23–96 years), however most were ≥65 years (80%) and 20% were ≥80 years. The care recipients were significantly older (mean = 78 years, SD = 7.5, t = 235.7, p = 0.000), and the majority were male (68%). Half of those with a dementia diagnosis had Alzheimer’s disease (the remainder had various other diagnoses, e.g. frontal temporal, vascular, or Lewy body dementia, or a mixed diagnosis). Over a third required support from their family carer overnight or on a 24 hour basis.

Carers’ mean ISI score was 10.2 (SD 5.9), 43% were categorised as having mild–no sleep problem, and 24% moderate–severe. Common symptoms were dissatisfaction with their current sleep pattern, difficulty staying asleep, and waking too early (see Figure 1). Carers’ sleep scores did not differ between those who shared a room with the care recipient and those who did not. Sleeping medications were being used by more than a quarter of carers (ranging from less than once a week to three or more times a week). Use was more likely among women than men (33% vs. 12%, Chi square = 23.2, p < 0.001), and those with a moderate–severe sleep problem compared to those with a mild or no sleep problem (42% vs. 22%, Chi square = 18.8, p < 0.001). A small number of carers (8%) had a formally diagnosed sleep disorder (e.g. insomnia or sleep apnoea).

Table 2 shows the prevalence of waking and sleeping symptoms of the care recipients. Carers rated their family member’s memory loss and difficulty completing familiar tasks as the waking symptoms which were most disruptive to daily life (35% and 12%, respectively). The number of waking symptoms differed by diagnosis of the care recipient (Kruskal–Wallis = 28.7 p = 0.00). Those with Alzheimer’s disease had more symptoms (median = 8.5, range = 1–11) than those other diagnosed types of dementia (median = 8.0, range = 2–11), or with a mild cognitive impairment (MCI, median 7.0, range = 1–11). Mann–Whitney U tests showed that the number of symptoms was also higher among those requiring care at night (U = 39,430 p = 0.000), using respite services (U = 34,757 p = 0.001), or considering formal care within the year (U = 31,235 p = 0.000).

Table 2.

Waking and sleeping symptoms of care recipients.

Waking symptoms (AAC)	Frequency %
Memory loss	87.8
Problem solving	88.8
Completing familiar tasks	77.8
Confusion with time or place	85.0
Visual or spatial trouble	50.2
Language problems	59.3
Misplacing things	79.3
Decreased or poor judgement	71.1
Withdrawal from work or social life	67.5
Changed mood or personality	66.7
Other symptoms	24.0
	Frequency %	Severity %	Distress %
Sleep symptom (SDI)	Occurring ≥ once per week	Moderate-marked	Moderate–extreme
Difficulty falling asleep	28.2	19.9	18.0
Getting up in the night^	30.7	27.4	22.8
Wandering, pacing or getting involved in inappropriate activities in the night	16.5	19.6	18.7
Awakening others during the night	16.3	17.0	14.7
Awakening at night, dressing and planning to go out, thinking that it is morning and time to start the day	8.3	12.4	10.0
Awakening too early in the morning (earlier than is habit)	26.2	20.8	18.0
Sleeping excessively (too much) during the day	59.5	21.5	20.5
Other night-time behaviours that are bothersome	24.7	27.3	24.4

AAC: Alzheimer’s Association Checklist; SDI: Sleep Disorders Inventory (^do not count if subject gets up once or twice per night to go to the bathroom and quickly falls back to sleep).

Over a quarter of care recipients were reported to have frequent difficulties with falling asleep, getting up during the night, or waking too early. Furthermore, 60% were considered to be sleeping too much in the daytime (Table 2). The average number of symptoms to be endorsed (occurring at least once per week) was low (median = 1) but variable (range = 0–7) and almost 20% had three or more symptoms. Carers typically rated the severity and distress associated with their care recipient’s sleep symptoms as mild, however this was also variable. Carers ISI scores were significantly associated with their ratings of the frequency, severity and distress of their care recipient’s sleep symptoms, with a medium effect size (Table 2).

Table 3 shows the results from the multiple linear regression models. After controlling for other factors identified as significant at the univariate level, greater sleep disturbance was more likely among female carers, those providing care overnight or across 24 hours compared to just during the day, and those who rated their health as fair-poor or good as opposed to very good-excellent. Sleep of carers was also highly related with that of their care recipient. Each additional sleep symptom endorsed for their care recipient accounted for an equivalent 1-point increase in the carer’s ISI score (range = 0.7–1.2). The number of waking symptoms of the care recipient was also associated. However, the effect size was much smaller (0.2) and, after controlling for carers health status, was no longer significant. Carers’ sleep scores were negatively correlated with all of the self-rated living standards items at the univariate level (LSCAPE-6; Breheny et al., 2016; Figure 2). The carers’ global LSCAPE-6 score remained independently associated with their sleep in models 1 and 2; however, the effect size was small and no longer significant after factoring in carer health status.

Table 3.

Multiple Linear regression models exploring the independent predictors of carers’ Insomnia Severity Index scores (n = 439; Unstandardised beta coefficients and 95% CI).

	Model 1 Carer situation			Model 2 + Care recipient			Model 3 + Carer health
Predictors (df)	Beta	95% CI	P	Beta	95% CI	P	Beta	95% CI	p
Age (1)	−0.01	−0.06–0.04	0.685	0.01	−0.04–0.06	0.622	−0.00	−0.05–0.05	0.885
Female gender (1)	1.20	0.09–2.31	0.034	1.15	0.10–2.19	0.032	1.43	0.42–2.44	0.006
Living standards^a (1)	−0.26	−0.35 −0.16	0.000	−0.19	−0.28− −0.10	0.000	−0.08	−0.18–0.01	0.075
Years spent caring (1)	0.12	−0.02–0.25	0.095	0.06	−0.07–0.19	0.371	0.02	−0.01–0.15	0.727
Providing night care (1)	2.46	1.42–3.51	0.000	1.43	0.41–2.45	0.006	1.43	0.46–2.41	0.004
Care recipient waking symptoms^b (1)				0.23	0.01–0.46	0.043	0.21	−0.01–0.42	0.062
Care recipient SDI symptoms^c (1)				1.02	0.73–1.31	0.000	0.96	0.68–1.24	0.000
Carer health rating^d (2)							−2.00	−2.76 to −1.23	0.000
Carer pain rating^d (2)							−0.46	−1.26–0.35	0.269
Carer comorbidity count^e (1)							−0.03	−0.33–0.27	0.848

Model summary	F	(df), R²	p	F	(df), R²	p	F	(df), R²	p

	14.17	(434), 0.14	0.000	19.87	(432), 0.24	0.000	19.74	(429), 0.31	0.000

Variables/items from the ^aLiving Standards Capabilities for Elders 6 item measure, ^bAlzheimer’s Association 10 signs, ^cnumber of sleep symptoms endorsed (occurring ≥once per week) Sleep Disorders Inventory for Alzheimer’s Disease, ^dSF-12® Health survey, and ^eSelf-Administered Comorbidity Questionnaire.

Figure 2.

Correlation between the six items of living standards and sleep status of family carers. The figure indicates increased sleep disturbances with poorer self-rated living standards (dashed lines represent items associated with hardship, solid lines social engagement).

Table 4 shows the results from the logistic multiple regression models exploring carers’ sleep status as an independent predictor of outcomes related to their health and living standards. Carers with a moderate–severe sleep problem were more likely to also rate their health as fair–poor (44%) compared to those without or a mild sleep problem (18%). They were also more than twice as likely to be using sleeping medications and to be in the lowest quartile of self-rated living standards. Furthermore, problem sleepers had a 74% increased odds of being amongst those considering transitioning their family member into formal care imminently or within the year.

Table 4.

Multiple logistic regression models exploring whether having a sleep problem is an independent predictor of other health issues, standard of living, and care situation plans.

Dependent variable (model n)
	Fair-poor health^a (473)	Quite a bit-severe pain^a (440)	≥3 comorbid symptoms^b (423)	Use sleeping meds (422)	Low (25%) living standards^c (423)	Considering formal care (405)
Sleepproblem OR(95% CI) p	3.77(2.04–6.96) 0.000	1.2(0.61–2.35) 0.59	0.83(0.46–1.50) 0.54	2.15(1.29–3.57) 0.003	2.1(1.26–3.52) 0.01	1.74(1.01–2.98) 0.04
Covariates^	Female*, age, living standards, dementia symptoms, care recipient sleep, pain rating**, comorbidities, medications	Female, age, living standards, years caring, night care, care recipient sleep, health rating*, comorbidities, medications	Female, age, living standards, dementia symptoms, health and pain ratings, medications*	Female***, age, living standards, health and pain ratings, comorbidities, medications	Female, Age*, dementia symptoms, health* and pain ratings, comorbidities	Female, age, living standards, years caring, night care, dementia symptoms**

^Covariates included variables which were significantly related to the dependent variable at the univariate level, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

Variables/items from the ^aSF-12® Health survey, ^bSelf-Administered Comorbidity Questionnaire, and ^cthe Living Standards Capabilities for Elders 6 item measure.

Discussion

This cross-sectional study provides the first data on self-rated sleep and wellbeing within a large convenience sample (N = 526) of NZ carers supporting a family member with a cognitive impairment or dementia. Participants were all clients of regional dementia-related services, however only 64% of care recipients had a formal diagnosis. This is indicative of the state of the health services as well as a common reticence in seeking formal diagnosis and care for dementia-related diseases (Ministry of Health, 2013). In this context, the Alzheimer’s Association Checklist (Alzheimer’s Association, 2009) was considered a useful measure of the waking symptoms and disease severity of care recipients as it correlated well with other variables.

The focus of the analyses was on the factors associated with carers sleep. Almost a quarter (24%) were defined as having a moderate–severe sleep problem and 43% were mild (Morin et al., 2011). Notably, only 30% rated themselves as satisfied or very satisfied with their sleep. The prevalence of sleep disturbances was higher than in the general adult population (Paine et al., 2004; Sadeghniiat-Haghighi et al., 2014) and comparable to other studies including older people or carers (Gibson et al., 2015; Gibson, Gander, Paine, et al., 2016; Maun et al., 2018; Peng & Chang, 2013). Dementia-related carers have been identified as particularly vulnerable to sleep disturbances due to the heightened responsibilities associated with supporting their family member across day and night (e.g. assisting with personal care, monitoring for their safety, and comforting them to sleep), the mental impact of the carer role (e.g. anxiety or grief related to the changing of roles and prognosis of their family member), as well as disturbances due to the dementia-related sleep symptoms of the care recipient (e.g. if their sleep timing has become unstable or advanced, or from confused awakenings, behaviours and hallucinations) (Gibson et al., 2014; McCurry et al., 2015; Peng & Chang, 2013; Simpson & Carter, 2013a).

Among the demographic variables tested, women had significantly higher ISI scores than men (beta 1.4 point more, 95% CI: 0.4–2.5). They were also more likely to be using sleeping medications. This is consistent with the higher prevalence of insomnia symptoms among women reported elsewhere. Possible contributing factors include less healthy sleep habits triggered by hormonal disruptions, as well as stress and unbalanced roles and responsibilities associated with work, family and social life (Bos & Macedo, 2019).

A novel finding was the significant association between having a sleep problem and poorer carer-rated living standards. The LSCAPE-6 focuses on capabilities rather than hardship and is considered more valid for older people for whom employment and income measures are less meaningful. The distribution of the itemised scores was comparable to those of the general population of older NZrs (Breheny et al., 2016), apart from the item rating ability to ‘do all of the things I love’ which was lower (mean = 2.8, SD = 1.3 versus mean = 3.7, SD = 1.2). These findings indicate a bidirectional relationship between sleep and not only health but also social integration, enjoyment, contribution, and hardship. This is important as these factors can, in turn, influence the ability to manage the role of family carer (Horrell et al., 2015). Future studies could consider including more explicit measures of quality of life and coping, as well as qualitative inquiry to better explore the relationships between carers sleep and quality of life.

Sleep of the care recipients was a strong independent predictor of the sleep of carers (Table 3). Almost a third of care recipients were reportedly getting up during the night and 60% were sleeping excessively during the day. These symptoms are indicators of disturbed sleep at night, circadian misalignment and/or social disengagement and can negatively affect the sleep and wellbeing of family carers by constraining their own routine (McCurry et al., 2007). Carers seldom rated their family member’s sleep symptoms as very severe or distressing compared to more homogeneous samples of people with dementia (Tractenberg et al., 2003). However the findings here are consistent with those reported among smaller samples and may be associated with a broader range of dementia severity among in the present survey, as well as the tendency to normalise sleep-related disturbances with ageing and dementia (Gibson et al., 2014; McCurry et al., 2011).

A bidirectional relationship between poor sleep and health is indicated here (Tables 3 and 4) and has been reported elsewhere (Foley et al., 2004; Reid et al., 2006). This is of importance as subjective health status has been identified as a reliable predictor of morbidity and mortality (Idler & Benyamini, 1997). Pain and mental illnesses such as depression and anxiety have been identified as key factors for predisposing as well as exacerbating insomnia-related sleep disturbances (Alvaro et al., 2013; McCurry et al., 2015). This survey collected limited data on health status. Reports of self-rated pain and health status, as well as diagnosed health conditions and use of medications were similar to previous studies (Adams et al., 2017; Gibson, Gander, Paine, et al., 2016; Reid et al., 2006). All these items were significantly related to ISI scores at the univariate level, but only self-reported health status remained independently associated with sleep status in the multiple linear and logistic regression models (Tables 3 and 4). These findings provide support for the theory of sleep as a secondary stressor resulting from the caregiving role (Maun et al., 2018; Simpson & Carter, 2013b) and the tendency of carers to relegate their own health issues to the background, given the often encompassing nature of the caregiving role (Cheng, 2017; Pearlin et al., 1990). However, the present survey did not include detailed scales evaluating carers’ mood and stress in relation to carer burden, which might be of value for future studies.

Sleep disturbances have previously been associated with more severe disease status and the movement of people with dementia into formal care (Hope et al., 1998; Pollak & Perlick, 1991). The present analyses demonstrates that when the sleep of carers is affected, they are more likely to be considering formal care for their family member imminently or within the year. This has important implications not only for the wellbeing of families affected by dementia but also for health service requirements. Aged residential care facilities in NZ are already oversubscribed and costly to the economy, strategies to enable ageing well in place are necessary (Alzheimers New Zealand, 2017; Ministry of Health, 2013).

This study adds to the evidence that sleep plays an important role in family carers’ health and ability to live well and care for their family member with dementia at home. Findings highlight that optimising the sleep health of both the care recipient and their carer should be an integral feature of future support services. Pilot trials of non-pharmacological sleep interventions have been shown to be feasible and to have positive effects for some people with dementia and/and their family carers (Gibson, Gander, Jones, & Dowell, 2016; McCurry et al., 2011). These findings support the value of evaluating the effectiveness of these interventions in larger trials. This may be facilitated by future action research, for example by providing a transformative service change whilst simultaneously conducting community-based research in a reflective and appropriate manner to include unique populations underrepresented here (O’Sullivan et al., 2014).

Together, the present findings confirm associations between carers’ perceived sleep status and waking health and care outcomes. They also provide examples of predisposing (risk factors) and precipitating factors (life events) associated with disturbed sleep. Caregiving at night and being disturbed by the sleep problems of the care recipient will inevitably impact on a family carer’s sleep. Psychosocial factors such as a carer’s perceptions of symptoms, situation, stress, environmental and social support are increasingly being highlighted as important mediators for carers’ sleep, including the development of persistent symptoms of insomnia even after the caregiving role ceases (Altena et al., 2010; Brummett et al., 2006; Peng & Chang, 2013). The personal sleep experience and the mediating effect of the care recipient’s sleep cannot be assumed via brief questionnaire items alone but do arise in written comments provided by 79% of participants which will be presented elsewhere.

A limitation of this study was the low response rate. However this was still considered reasonable given the challenges of recruiting from a population who, due to the nature of dementia care, are anticipated to be time constrained, stressed, and older (Beattie et al., 2018). Furthermore, the response rate is likely underestimated as it is anticipated that not all of the surveys distributed would have been forwarded on by organisations (due to overestimations and their own time constraints) and that many of those on mailing lists would have been ineligible for the study. People with limited access to diagnostic services (for geographical or financial reasons), of Māori or Pacific Island ethnicity, those with poorer physical and mental health, and/or who do not identify with the ‘dementia’ and ‘carer’ terminology are less likely to be represented due to reduced engagement of these groups with dementia-related organisations and services, as well as their being less likely to respond to postal surveys (Beattie et al., 2018; Coughlan et al., 2009; Dyall, 2014; Minister of Health, 2016). These groups have also been identified as being at greater risk of having sleep problems (Bos & Macedo, 2019; Foley et al., 2004; Paine et al., 2004). Thus, the present findings cannot be generalised to all dementia-related carers and are likely to underestimate the severity of sleep problems and poor health status among NZ carers and care recipients. Specific engagement is required to understand the experience of these under-represented groups when developing future intervention strategies.

Conclusions

This study found that problematic sleep is a common and important issue for those supporting a family member with cognitive impairment or dementia. Being female and having poorer health status were significant predictors of increased sleep disturbance (ISI scores). Providing care at night and the sleep disturbances of the care recipient were also highly associated with carer sleep. Those categorised as having a moderate–severe sleep problem had poorer self-rated health and living standards, were more likely to be using sleeping medications and to be considering formal care placement for the person in their care within the year.

Sleep is essential for carers’ health and wellbeing. Understanding and supporting good sleep has important implications for managing the overall caregiving situation and for people with dementia or MCI to live well with dementia in place. Findings support the need for an increased focus on sleep health in general practice as well as aged and dementia-related services.

Footnotes

Acknowledgements

We gratefully acknowledge the participants for their time and consideration in completing the questionnaire. We are also very grateful to the regional teams associated with Alzheimers NZ and Dementia NZ who distributed the survey to their clients, particularly staff of Dementia Wellington who supported the development and piloting of the survey and have provided continuing advice and support. Thanks also to Kathryn Teal and Tracey Alexander for their assistance with data management and entry.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Funders include the Massey University Research fund and the Alzheimers NZ Charitable Trust (2016).

ORCID iD

Rosemary Gibson

Rosemary Gibson is a research officer at the Sleep/Wake Research Centre, Massey University, NZ. She has established the only NZ-based research programme regarding sleep in healthy aging, dementia and caregiving. She has experience in measuring and interpreting objective and subjective sleep data within older and vulnerable adults, as well as trialling low-risk, community-based interventions for improving sleeping and waking health.

Philippa Gander is the founder and director of the Sleep/Wake Research Centre, Massey University and is internationally renowned for her basic and applied research concerning sleep and the circadian timing system. She was recently made an Officer of the New Zealand Order of Merit recognising her services to the field and has a particular interest in changes in the circadian timing system and sleep regulation with aging.

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