Optimal Questions for Sleep in Epidemiological Studies: Comparisons of Subjective and Objective Measures in Laboratory and Field Studies

Estimation bias and agreement limits between two common self-report methods of habitual sleep duration in epidemiological surveys

Accurate measurement of habitual sleep duration (HSD) is crucial for understanding the relationship between sleep and health. This study aimed to assess the bias and agreement limits between two commonly used short HSD self-report methods, considering sleep quality (SQ) and social jetlag (SJL) as potential predictors of bias. Data from 10,268 participants in the International COVID Sleep Study-II (ICOSS-II) were used. Method-Self and Method-MCTQ were compared. Method-Self involved a single question about average nightly sleep duration (HSDself), while Method-MCTQ estimated HSD from reported sleep times on workdays (HSDMCTQwork) and free days (HSDMCTQfree). Sleep quality was evaluated using a Likert scale and the Insomnia Severity Index (ISI) to explore its influence on estimation bias. HSDself was on average 42.41 ± 67.42 min lower than HSDMCTQweek, with an agreement range within ± 133 min. The bias and agreement range between methods increased with poorer SQ. HSDMCTQwork showed less bias and better agreement with HSDself compared to HSDMCTQfree. Sleep duration irregularity was - 43.35 ± 78.26 min on average. Subjective sleep quality predicted a significant proportion of variance in HSDself and estimation bias. The two methods showed very poor agreement and a significant systematic bias, both worsening with poorer SQ. Method-MCTQ considered sleep intervals without adjusting for SQ issues such as wakefulness after sleep onset but accounted for sleep irregularity and sleeping in on free days, while Method-Self reflected respondents' interpretation of their sleep, focusing on their sleep on workdays. Including an SQ-related question in surveys may help bidirectionally adjust the possible bias and enhance the accuracy of sleep-health studies.

The association of a past childbirth experience with a variety of early physical and mental symptoms in subsequent pregnancies

BACKGROUND

Some women have a perceived negative experience of childbirth due to various reasons- e.g., obstetric complications or the feeling of loss of control. We do not know enough about the effects of a perceived negative experience of a childbirth on a woman's subsequent pregnancies. The aim of this study was to investigate whether a previously perceived negative childbirth experience affects a woman's physical and mental well-being in a later pregnancy.

METHODS

A prospective cohort study in Danish general practice, based on information about women's childbirth experiences from the Pregnancy Health Record filled in by the general practitioner (GP) and data from an electronic questionnaire completed by the women.

RESULTS

A total of 1288 women were included in the analysis. Women who had given birth before were found to have a significantly higher risk of experiencing nausea, varicose veins and uterine contractions, and a lower risk of pelvic cavity pain in the current pregnancy. Women having given birth before were significantly more likely to assess their physical fitness as poor and to experience poor well-being. Women with a perceived negative experience of childbirth had more sleep problems and a higher prevalence of poor self-rated health than women with unproblematic childbirth experience.

CONCLUSION

This study showed that women with a previously perceived negative experience of childbirth are affected according to their mental health in their subsequent pregnancy.

Investigating the relationship between objective measures of sleep and self-report sleep quality in healthy adults: a review

STUDY OBJECTIVES

Sleep is one of the most common factors related to health, yet a standard definition of sleep quality has not been identified. Polysomnography provides important information about objective sleep variables. However, the relationship between objective sleep variables and perception of sleep quality remains unclear. The purpose of this review was to (1) summarize the current methods of measuring objective sleep macrostructure and microstructure, including electroencephalography arousals, spectral frequency, cyclic alternating pattern, and self-report sleep quality, and (2) investigate the relationship between objective measures of sleep physiology and self-report sleep quality in healthy adults.

METHODS

A literature search was conducted using Medline, PubMed, and PsycInfo databases and cited reference searches. Eligible studies included a comparison between self-report sleep quality and polysomnography sleep measures in healthy adults.

RESULTS

Thirteen studies were identified. Measurement of self-report sleep quality varied widely across studies. Total sleep time and sleep efficiency were most consistently related to sleep quality, while other objective sleep variables, including electroencephalography spectral analysis, were not reliably predictive of self-report sleep quality in healthy adults. There is preliminary support that microstructural sleep analysis with cyclic alternating pattern may be related to self-reported sleep quality.

CONCLUSIONS

Further research is needed to define and standardize self-report measures of sleep quality and investigate the microstructure of sleep. Objective measures of sleep and experiences of "quality" sleep are not as closely related as one may expect in healthy individuals, and understanding this relationship further is necessary to improve the clinical utility of sleep physiology.

CITATION

Cudney LE, Frey BN, McCabe RE, Green SM. Investigating the relationship between objective measures of sleep and self-report sleep quality in healthy adults: a review. J Clin Sleep Med. 2022;18(3):927-936.

The impact of nocturnal road traffic noise, bedroom window orientation, and work-related stress on subjective sleep quality: results of a cross-sectional study among working women

Objective

To examine the effect of work-related stress and road noise exposure on self-rated sleep and potential additive interaction effects.

Methods

Sleep and predictor variables were surveyed within two subsamples with 2191 and 1764 working women in a cross-sectional study. Sleep was assessed using a single question on general sleep quality and four questions on specific sleep problems and subsequently dichotomized (poor sleep vs. no poor sleep). Work-related stress was operationalized by job strain and effort-reward imbalance. Nocturnal exposure to road traffic noise was assessed as (a) the orientation of the bedroom window to a quiet façade vs. a low-, medium- or high-trafficked street and (b) energy-equivalent sound pressure levels for night-time modelled at the most exposed façade (L_night). We distinguished between low (< 45 dB(A)), medium (45–50 dB(A)) and high exposure (> 50 dB(A)).

Results

Poor sleep was associated with job strain and effort-reward imbalance. The prevalence of poor sleep did not increase with increasing L_night, but bedroom window orientation showed a non-significant trend. A quiet façade had a protective effect on sleep in each L_night category. We found a non-significant trend for an additive interaction between bedroom window orientation and job strain.

Conclusion

Noise levels modelled for the most exposed façade likely overestimate the actual exposure and thus may not be a precise predictor of poor sleep. Bedroom window orientation seems more relevant. Potential additive interaction effects between bedroom window orientation and job strain should be considered when interpreting epidemiological study results on noise-induced sleep disturbances.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00420-021-01696-w.

The Sleep of Shift Workers in a Remote Mining Operation: Methodology for a Randomized Control Trial to Determine Evidence-Based Interventions

Shiftwork may adversely impact an individual’s sleep-wake patterns and result in sleep loss (<6 h. following night shift), due to the circadian misalignment and the design of rosters and shifts. Within a mining operation, this sleep loss may have significant consequences due to fatigue, including an increased risk of accidents and chronic health conditions. This study aims to (i) determine the efficacy of an intervention that comprises a sleep education program and biofeedback through a smartphone app on sleep quality, quantity, and alertness (ii) determine the prevalence of risk for a potential sleep disorder, and (iii) quantify and describe the sleep habits and behaviors of shift workers in a remote mining operation. This study consists of a randomized controlled trial whereby eighty-eight shift workers within a remote mining operation are randomized to a control group or one of three different treatment groups that are: (i) a sleep education program, (ii) biofeedback on sleep through a smartphone app, or (iii) a sleep education program and biofeedback on sleep through a smartphone app. This study utilizes wrist-activity monitors, biomathematical modeling, and a survey instrument to obtain data on sleep quantity, quality, and alertness. A variety of statistical methods will determine the prevalence of risk for a potential sleep disorder and associations with body mass index, alcohol, and caffeine consumption. A generalized linear mixed model will examine the dependent sleep variables assessed at baseline and post-intervention for the control group and intervention groups, as well as within and between groups to determine changes. The findings from this study will contribute to the current understanding of sleep and alertness behaviors, and sleep problems and disorders amongst shift workers. Importantly, the results may inform fatigue policy and practice on interventions to manage fatigue risk within the mining industry. This study protocol may have a broader application in other shiftwork industries, including oil and gas, aviation, rail, and healthcare.

Medical cannabis and insomnia in older adults with chronic pain: a cross-sectional study

OBJECTIVES

Medical cannabis (MC) is increasingly being used for treatment of chronic pain symptoms. Among patients there is also a growing preference for the use of MC to manage sleep problems. The aim of the current study was to examine the associations between use of whole plant cannabis and sleep problems among chronic pain patients.

METHODS

A total of 128 individuals with chronic pain over the age of 50 years were recruited from the Rambam Institute for Pain Medicine in Haifa, Israel. Of them, 66 were MC users and 62 were non-users. Regression models tested the differences in sleep problems between the two groups. Furthermore, Pearson correlations between MC use measures (dose, length and frequency of use, number of strains used, tetrahydrocannabinol/cannabidiol levels) and sleep problems were assessed among MC users.

RESULTS

After adjustment for age, sex, pain level and use of sleep and anti-depressant medications, MC use was associated with less problems with waking up at night compared with non-MC use. No group differences were found for problems with falling asleep or waking up early without managing to fall back asleep. Frequent MC use was associated with more problems waking up at night and falling asleep.

CONCLUSIONS

MC use may have an overall positive effect on maintaining sleep throughout the night in chronic pain patients. At the same time, tolerance towards potential sleep-inducing properties of MC may occur with frequent use. More research based on randomised control trials and other longitudinal designs is warranted.

A laboratory study on the effects of wind turbine noise on sleep: results of the polysomnographic WiTNES study

STUDY OBJECTIVES

Assess the physiologic and self-reported effects of wind turbine noise (WTN) on sleep.

METHODS

Laboratory sleep study (n = 50 participants: n = 24 living close to wind turbines and n = 26 as a reference group) using polysomnography, electrocardiography, salivary cortisol, and questionnaire endpoints. Three consecutive nights (23:00-07:00): one habituation followed by a randomized quiet Control and an intervention night with synthesized 32 dB LAEq WTN. Noise in WTN nights simulated closed and ajar windows and low and high amplitude modulation depth.

RESULTS

There was a longer rapid eye movement (REM) sleep latency (+16.8 min) and lower amount of REM sleep (-11.1 min, -2.2%) in WTN nights. Other measures of objective sleep did not differ significantly between nights, including key indicators of sleep disturbance (sleep efficiency: Control 86.6%, WTN 84.2%; wakefulness after sleep onset: Control 45.2 min, WTN 52.3 min; awakenings: Control n = 11.4, WTN n = 11.5) or the cortisol awakening response. Self-reported sleep was consistently rated as worse following WTN nights, and individuals living close to wind turbines had worse self-reported sleep in both the Control and WTN nights than the reference group.

CONCLUSIONS

Amplitude-modulated continuous WTN may impact on self-assessed and some aspects of physiologic sleep. Future studies are needed to generalize these findings outside of the laboratory and should include more exposure nights and further examine possible habituation or sensitization.

Changes in effort-reward imbalance at work and risk of onset of sleep disturbances in a population-based cohort of workers in Denmark

Objective/background

Associations between exposure to effort-reward imbalance at work (eg, high time pressure/low appreciation) and risk of sleep disturbances have been reported, but the direction of the effect is unclear. The present study investigated changes in effort-reward imbalance and risk of concomitant and subsequent onset of sleep disturbances.

Methods

Participants with sleep disturbances at baseline were excluded. We included participants from a population-based cohort in Denmark (n = 8,464, 53.6% women, mean age = 46.6 years), with three repeated measurements (2012 (T₀); 2014 (T₁); 2016 (T₂)). Changes in effort-reward imbalance (T₀-T₁) were categorized into 'increase', 'decrease' and 'no change'. Self-reported sleep disturbances (difficulties initiating or maintaining sleep, non-restorative sleep, daytime tiredness) were dichotomized (presence versus absence). We regressed concomitant (T₁) and subsequent (T₂) sleep disturbances on changes in effort-reward imbalance (T₀-T₁) and calculated odds ratios (OR) and 95% confidence intervals, adjusted for sex, age, education and cohabitation.

Results

At follow-up, 8.4% (T₁) and 12.5% (T₂) reported onset of sleep disturbances. Increased effort-reward imbalance was associated with concomitant sleep disturbances (T₁) (OR = 3.16, 2.56-3.81), whereas decreased effort-reward imbalance was not (OR = 1.22, 0.91-1.63). There was no association between increased effort-reward imbalance and subsequent sleep disturbances (T₂) (OR = 1.00, 0.74-1.37). Results were similar for men and women.

Conclusions

Increased effort-reward imbalance was associated with a three-fold higher risk of concomitant onset of sleep disturbances at two-year follow-up, but not subsequent onset of sleep disturbances at four-year follow-up, indicating that changes in effort-reward imbalance have immediate rather than delayed effects on sleep impairment. It is possible that the results from the two-year follow-up were to some extent affected by reverse causality.

On the feasibility of measuring physiologic and self-reported sleep disturbance by aircraft noise on a national scale: A pilot study around Atlanta airport

Aircraft noise can disturb sleep and impair recuperation. Research is needed to develop exposure-response relationships that are representative of noise-exposed communities and can be used to inform noise mitigation policy in the United States. For a national field study on physiologic response to aircraft noise during sleep to be feasible, an inexpensive yet sound study methodology is needed. In the pilot study presented here, the methodology of using electrocardiography and actigraphy to monitor sleep was implemented around Atlanta Hartsfield-Jackson International Airport (ATL). The primary objective was to evaluate the quality and quantity of data that could be obtained with the following study approaches: recruiting participants by postal questionnaire, shipping them the physiologic and noise measurement equipment, and the unattended setup of the equipment and recording of data by the participants themselves. The secondary objective was to compare objective and subjective measures of sleep and health between groups exposed to different levels of nocturnal aircraft noise. We mailed 4080 questionnaires containing items on sleep, health and noise disturbance to residences around ATL that were exposed to at least 35 dB L_night aircraft noise. From 407 questionnaire respondents, 34 participants completed five nights of unattended sleep measurements. Data of sufficient quality and quantity to investigate the effects of aircraft noise on sleep were obtained. Self-reported awakenings increased as a function of the highest maximum aircraft noise level occurring during the sleep period. Event-related physiologic awakenings increased as a function of the maximum noise level of individual aircraft noise events, although this effect was of only borderline statistical significance (p = 0.057) likely due to the low sample size of this pilot study. The approach used in the presented pilot study has been demonstrated to be feasible for the purpose of the larger-scale study among a representative population around multiple airports in the future.

Sleep complaints in early pregnancy. A cross-sectional study among women attending prenatal care in general practice

BACKGROUND

Sleep problems in late pregnancy are common, but sleep in early pregnancy is less well described. The aim of this study was to describe the occurrence and severity of sleep complaints in early pregnancy. We asked the women about worries due to sleep problems. Furthermore, we investigated the associations between sleep complaints and pregnancy-related symptoms. This association was studied taking into account physical and mental health, sociodemographic characteristics, and reproductive history of the women.

METHODS

Cross-sectional study in Danish general practice based on an electronic questionnaire completed by pregnant women and a Pregnancy Health Record filled in by the general practitioner (GP). The questionnaire measured three sleep complaints and 11 common physical pregnancy-related symptoms. The sleep complaints were measured as mild, moderate or severe, and it was recorded how much they worried the women. The associations between the physical pregnancy-related symptoms and sleep complaints were assessed by odds ratios from multivariable logistic regression models.

RESULTS

The questionnaire was completed by 1338 out of 1508 eligible women before the end of gestation week 16. The gestational age ranged from 5 to 16 weeks (median 11 weeks) among the included women. On average, more than one third of the women reported to have at least one of the three sleep complaints in the questionnaire. Problems "taking a long time to fall asleep" was reported by 312 women (23%), "waking up too early" was reported by 629 (47%), and 183 (14%) had been "lying awake most of the night". One sleep complaint was reported by 38%, two by 16, and 4% had all three symptoms. The majority were not at all or only mildly worried because of their sleep disturbances, but moderate or severe worries were found among 46% of those" taking a long time to fall asleep" and among 40% of those "lying awake most of the night". "Moderate or severe complaints" were reported by 277 (21%) women "Moderate or severe complaints" were associated with pregnancy-related physical symptoms, such as back pain, pelvic girdle pain and pelvic cavity pain, but only the association with pelvic cavity pain stayed significant after adjustment for depression.

CONCLUSION

This study showed that sleep complaints in early pregnancy are common, and sleep complaints showed association with physical as well as mental symptoms. It may be important for pregnant patients that clinicians address depression, and mood in relation to sleep problems during pregnancy.

Wind Turbine Noise and Sleep: Pilot Studies on the Influence of Noise Characteristics

The number of onshore wind turbines in Europe has greatly increased over recent years, a trend which can be expected to continue. However, the effects of wind turbine noise on long-term health outcomes for residents living near wind farms is largely unknown, although sleep disturbance may be a cause for particular concern. Presented here are two pilot studies with the aim of examining the acoustical properties of wind turbine noise that might be of special relevance regarding effects on sleep. In both pilots, six participants spent five consecutive nights in a sound environment laboratory. During three of the nights, participants were exposed to wind turbine noise with variations in sound pressure level, amplitude modulation strength and frequency, spectral content, turbine rotational frequency and beating behaviour. The impact of noise on sleep was measured using polysomnography and questionnaires. During nights with wind turbine noise there was more frequent awakening, less deep sleep, less continuous N2 sleep and increased subjective disturbance compared to control nights. The findings indicated that amplitude modulation strength, spectral frequency and the presence of strong beats might be of particular importance for adverse sleep effects. The findings will be used in the development of experimental exposures for use in future, larger studies.

Assessing sleep health in a European population: Results of the Catalan Health Survey 2015

Objective

To describe the overall sleep health of the Catalan population using data from the 2015 Catalan Health Survey and to compare the performance of two sleep health indicators: sleep duration and a 5-dimension sleep scale (SATED).

Methods

Multistage probability sampling representative of the non-institutionalized population aged 15 or more years, stratified by age, gender and municipality size, was used, excluding nightshift-workers. A total of 4385 surveys were included in the analyses. Associations between sleep health and the number of reported chronic diseases were assessed using non-parametric smoothed splines. Differences in the predictive ability of age-adjusted logistic regression models of self-rated health status were assessed. Multinomial logistic regression models were used to assess SATED determinants.

Results

Overall mean (SD) sleep duration was 7.18 (1.16) hours; and SATED score 7.91 (2.17) (range 0–10), lower (worse) scores were associated with increasing age and female sex. Alertness and efficiency were the most frequently impaired dimensions across age groups. SATED performed better than sleep duration when assessing self-rated health status (area under the curve = 0.856 vs. 0.798; p-value <0.001), and had a linear relationship with the number of reported chronic diseases, while the sleep duration relationship was u-shaped.

Conclusions

Sleep health in Catalonia is associated with age and gender. SATED has some advantaged compared to sleep duration assessment, as it relates linearly to health indicators, has a stronger association with self-rated health status, and provides a more comprehensive assessment of sleep health. Therefore, the inclusion of multi-dimensional sleep health assessment tools in national surveys should be considered.