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Results for “epidemiology”

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bioRxiv2017

Is a large eye size a risk factor for myopia? A Mendelian randomization study

Myopia (nearsightedness) is an increasingly common cause of irreversible visual impairment. The ocular structures with greatest impact on refractive error are corneal curvature and axial length. Emmetropic eyes range in size within and across species, yet possess a balance between corneal curvature and axial length that is under genetic control. This scaling goes awry in myopia: 1 mm axial elongation is associated with ~3 Dioptres (D) myopia. Evidence that eye size prior to onset is a risk factor for myopia is conflicting. We applied Mendelian randomisation to test for a causal effect of eye size on refractive error. Genetic variants associated with corneal curvature identified in emmetropic eyes (22,180 individuals) were used as instrumental variables and tested for association with refractive error (139,697 individuals). A genetic risk score for the variants was tested for association with corneal curvature and axial length in an independent sample (315 emmetropes). The genetic risk score explained 2.3% (P=0.007) and 2.7% (P=0.002) of the variance in corneal curvature and axial length, respectively, in the independent sample, confirming these variants are predictive of eye size in emmetropes. The estimated causal effect of eye size on refractive error was + 1.41 D (95% CI. 0.65 to 2.16) less myopic refractive error per mm flatter cornea (P<0.001), corresponding to +0.48 D (95% CI. 0.22 to 0.73) more hypermetropic refractive error for an eye with a 1mm longer axial length. These results do not support the hypothesis that a larger eye size is a risk factor for myopia. We conclude the genetic determinants of normal eye size are not shared with those influencing susceptibility to myopia.

epidemiology↗

bioRxiv2018

Using paired serology and surveillance data to quantify dengue transmission and control during a large outbreak in Fiji

Dengue is a major health burden, but it can be challenging to examine transmission dynamics and evaluate control measures because outbreaks depend on multiple factors, including human population structure, prior immunity and climate. We combined population-representative paired sera collected before and after the major 2013/14 dengue-3 outbreak in Fiji with surveillance data to determine how such factors influence dengue virus transmission and control in island settings. Our results suggested the 10-19 year-old age group had the highest risk of acquiring infection, but we did not find strong evidence that other demographic or environmental risk factors were linked to seroconversion. Mathematical modelling showed that temperature-driven variation in transmission and herd immunity could not fully explain observed dynamics. However, there was evidence of an additional reduction in transmission coinciding with a vector clean-up campaign, which may have contributed to the decline in cases and prevented transmission continuing into the following season.

epidemiology↗

bioRxiv2018

Cigarette smoking and personality: Investigating causality using Mendelian randomization

BackgroundDespite the well-documented association between smoking and personality traits such as neuroticism and extraversion, little is known about the potential causal nature of these findings. If it were possible to unpick the association between personality and smoking, it may be possible to develop more targeted smoking cessation programmes that could lead to both improved uptake and efficacy.\n\nMethodsRecent genome-wide association studies (GWAS) have identified variants robustly associated with both smoking phenotypes and personality traits. Here we use publicly available GWAS summary statistics in addition to data from UK Biobank to investigate the link between smoking and personality. We first estimated genetic overlap between traits using LD score regression and then applied both one- and two-sample Mendelian randomization methods to unpick the nature of this relationship.\n\nResultsWe found clear evidence of a modest genetic correlation between smoking behaviours and both neuroticism and extraversion, suggesting shared genetic aetiology. We found some evidence to suggest an association between neuroticism and increased smoking initiation. We also found some evidence that personality traits appear to be causally linked to certain smoking phenotypes: higher neuroticism and heavier cigarette consumption, and higher extraversion and increased odds of smoking initiation. The latter finding could lead to more targeted smoking prevention programmes.\n\nConclusionThe association between neuroticism and cigarette consumption lends support to the self-medication hypothesis, while the association between extraversion and smoking initiation could lead to more targeted smoking prevention programmes.

epidemiology↗

bioRxiv2018

Vascular risk factors for male and female urgency urinary incontinence at age 68 from a British birth cohort study

ObjectiveTo investigate the prevalence of UUI at age 68 and the contribution of vascular risk factors to male and female UUI pathogenesis in addition to the associations with raised BMI\n\nSubjects and methods1762 participants were from the MRC National Survey for Health and Development (NSHD) birth cohort, who answered the International Consultation on Incontinence Questionnaire short form (ICIQ-SF) at age 68. Logistic regression was used to estimate associations between UUI and earlier life vascular risk factors including: lipid status, diabetes, hypertension, body mass index (BMI), previous stroke or transient ischaemic attack (TIA) diagnosis; adjusting for smoking status, physical activity, co-presentation of SUI symptoms, educational attainment and in women only, type of menopause, age at period cessation and use of hormone replacement therapy.\n\nResultsUUI was reported by 12% of men and 19% of women at 68. Female sex, previous stroke or TIA diagnosis, increased BMI and hypertension (in men only) at age 60-64 were independent risk factors for UUI. Female sex, increased BMI and a previous diagnosis of stroke/ TIA increased the relative risk of more severe UUI symptoms. Type and timing of menopause and HRT use did not alter the estimated associations between UUI and vascular risk factors in women.\n\nConclusionMultifactorial mechanisms lead to UUI and vascular risk factors may contribute to pathogenesis of bladder overactivity in addition to higher BMI. Severe UUI appears to be a distinct presentation with more specific contributory mechanisms than milder UUI.

epidemiology↗

bioRxiv2018

The 2017 plague outbreak in Madagascar: data descriptions and epidemic modelling

From August to November 2017, Madagascar endured an outbreak of plague. A total of 2417 cases of plague were confirmed, causing a death toll of 209. Public health intervention efforts were introduced and successfully stopped the epidemic at the end of November. The plague, however, is endemic in the region and occurs annually, posing the risk of future outbreaks. To understand on the plague transmission, we collected real-time data from official reports, described the outbreaks characteristics, and estimated transmission parameters using statistical and mathematical models. The pneumonic plague epidemic curve exhibited multiple peaks, coinciding with sporadic introductions of new bubonic cases. Optimal climate conditions for rat flea to flourish were observed during the epidemic. Estimate of the plague basic reproduction number during the large wave of the epidemic was high, ranging from 5-7 depending on model assumptions. The incubation and infection period for bubonic and pneumonic plague were 4.3 and 3.4 days and 3.8 and 2.9, respectively. Parameter estimation suggested that even with a small fraction of the population exposed to infected rat fleas (1/10000) and a small probability of transition from a bubonic case to a secondary pneumonic case (3%), the high human-to-human transmission rate can still generate a large outbreak. Controlling rodent and fleas can prevent new index cases, but managing human-to-human transmission is key to prevent large-scale outbreaks.

epidemiology↗

bioRxiv2018

Estimating the distance to an epidemic threshold

The epidemic threshold of the susceptible-infected-recovered (SIR) model is a boundary separating parameters that can permit epidemics from those that cannot. This threshold corresponds to points where the stability of the systems equilibrium reaches zero. Consequently, we use the average rate at which deviations from the equilibrium shrink to define a distance to this threshold. However, the vital dynamics of the host population may occur slowly even when transmission is far from threshold levels. Here we show analytically how such slow dynamics can prevent estimation of the distance to the threshold for some individual variables of the model. Although these results are exact only in the limit of long-term observation of a large system, we find that they still provide useful insight into the behaviour of estimates from simulations with a range of population sizes, environmental noise, and observation schemes. Having established some guidelines about when estimates are accurate, we then illustrate how multiple distance estimates can be used to estimate the rate of approach to the threshold. The estimation approach is general and may be applicable to zoonotic pathogens such as MERS-CoV as well as vaccine-preventable diseases such as measles.

epidemiology↗

bioRxiv2018

Micro-hotspots of Risk in Urban Cholera Epidemics

Targeted interventions have been delivered to neighbors of cholera cases in epidemic responses in Haiti and Africa despite little evidence supporting impact. Using data from urban epidemics in Chad and D.R. Congo we estimate the size and extent of spatiotemporal zones of increased cholera risk around cases. In both cities, we found zones of increased risk of at least 200-meters during the 5-days immediately following case presentation to a clinic. Risk was highest for those living closest to cases and diminished in time and space similarly across settings. These results provide a rational basis for targeting interventions, if delivered rapidly.

epidemiology↗

bioRxiv2018

The Delirium and Population Health Informatics Cohort study protocol: ascertaining the determinants and outcomes from delirium in a whole population.

BackgroundDelirium affects 25% of older inpatients and is associated with long-term cognitive impairment and future dementia. However, no population studies have systematically ascertained cognitive function before, cognitive deficits during, and cognitive impairment after delirium. Therefore, there is a need to address the following question: does delirium, and its features (including severity, duration, and presumed aetiologies), predict long-term cognitive impairment, independent of cognitive impairment at baseline?\n\nMethodsThe Delirium and Population Health Informatics Cohort (DELPHIC) study is an observational population-based cohort study based in the London Borough of Camden. It is recruiting 2000 individuals aged [≥]70 years and prospectively following them for two years, including daily ascertainment of all inpatient episodes for delirium. Daily inpatient assessments include the Memorial Delirium Assessment Scale, the Observational Scale for Level of Arousal, and the Hierarchical Assessment of Balance and Mobility. Data on delirium aetiology is also collected. The primary outcome is the change in the modified Telephone Interview for Cognitive Status at two years.\n\nDiscussionDELPHIC is the first population sample to assess older persons before, during and after hospitalisation. The cumulative incidence of delirium in the general population aged [≥]70 will be described. DELPHIC offers the opportunity to quantify the impact of delirium on cognitive and functional outcomes. Overall, DELPHIC will provide a real-time public health observatory whereby information from primary, secondary, intermediate and social care can be integrated to understand how acute illness is linked to health and social care outcomes.

epidemiology↗

bioRxiv2018

The PrEP Care Continuum and Racial Disparities in HIV Incidence among Men Who Have Sex with Men

The potential for HIV preexposure prophylaxis (PrEP) to reduce the racial disparities in HIV incidence in the United States may be limited by racial gaps in PrEP care. We used a network-based mathematical model of HIV transmission for younger black and white men who have sex with men (B/WMSM) in the Atlanta area to evaluate how race-stratified transitions through the PrEP care continuum from initiation to adherence and retention could impact HIV incidence overall and disparities in incidence between races, using current empirical estimates of BMSM continuum parameters. Relative to a no-PrEP scenario, implementing PrEP according to observed BMSM parameters was projected to yield a 23% decline in HIV incidence (HR = 0.77) among BMSM at year 10. The racial disparity in incidence in this observed scenario was 4.95 per 100 person-years at risk (PYAR), a 19% decline from the 6.08 per 100 PYAR disparity in the no-PrEP scenario. If BMSM parameters were increased to WMSM values, incidence would decline by 47% (HR = 0.53), with an associated disparity of 3.30 per 100 PYAR (a 46% decline in the disparity). PrEP could simultaneously lower HIV incidence overall and reduce racial disparities despite current gaps in PrEP care. Interventions addressing these gaps will be needed to substantially decrease disparities.

epidemiology↗

bioRxiv2018

The effect of education on adult mortality, health, and income: triangulating across genetic and policy reforms

1On average, educated people are healthier, wealthier and have higher life expectancy than those with less education. Numerous studies have attempted to determine whether these differences are caused by education, or are merely correlated with it and are ultimately caused by another factor. Previous studies have used a range of natural experiments to provide causal evidence. Here we exploit two natural experiments, perturbation of germline genetic variation associated with education which occurs at conception, known as Mendelian randomization, and a policy reform, the raising of the school leaving age in the UK in 1972. Previous studies have suggested that the differences in outcomes associated with education may be due to confounding. However, the two independent sources of variation we exploit largely imply consistent causal effects of education on outcomes much later in life.

epidemiology↗

bioRxiv2018

Key components of the delirium syndrome and mortality: greater impact of acute change and disorganised thinking in a prospective cohort study

BackgroundDelirium increases the risk of mortality during an acute hospital admission. Full syndromal delirium (FSD) is associated with greatest risk and subsyndromal delirium (SSD) is associated with intermediate risk, compared to patients with no delirium - suggesting a dose-response relationship. It is not clear how individual diagnostic symptoms of delirium influence the association with mortality. Our objectives were to measure the prevalence of FSD and SSD, and assess the effect that FSD, SSD and individual symptoms of delirium (from the Confusion Assessment Method-short version (s-CAM)) have on mortality rates.\n\nMethodsExploratory analysis of a prospective cohort (aged [≥] 70 years) with acute (unplanned) medical admission (4/6/2007-4/11/2007). The outcome was mortality (data censored 6/10/2011). The principal exposures were FSD and SSD compared to no delirium (as measured by the CAM), along with individual delirium symptoms on the CAM. Cox regression was used to estimate the impact FSD and SSD and individual CAM items had on mortality.\n\nResultsThe cohort (n=610) mean age was 83 (SD 7); 59% were female. On admission, 11% had FSD and 33% had SSD. Of the key diagnostic symptoms for delirium, 17% acute onset, 19% inattention, 17% disorganised thinking and 17% altered level of consciousness. Unadjusted analysis found FSD had an increased hazard ratio (HR) of 2.31 (95%CI 1.71, 3.12), for SSD the HR was 1.26 (1.00, 1.59). Adjusted analysis remained significant for FSD (1.55 95%CI 1.10, 2.18) but nonsignificant for SSD (HR=0.92 95% CI 0.70, 1.19). Two CAM items were significantly associated with mortality following adjustment: acute onset and disorganised thinking.\n\nConclusionWe observed a dose-response relationship between mortality and delirium, FSD had the greatest risk and SSD having intermediate risk. The CAM items \"acute onset\" and \"disorganised thinking\" drove the associations observed. Clinically, this highlights the necessity of identifying individual symptoms of delirium.

epidemiology↗

bioRxiv2018

Modelling longitudinal binary outcomes with outcome-dependent observation times: an application to a malaria cohort study

Inspite of the global reduction of 21% in malaria incidence between 2010 and 2015, the disease still threatens many lives of children and pregnant mothers in African countries. A correct assessment and evaluation of the impact of malaria control strategies still remains quintessential in order to eliminate the disease and its burden. Malaria follow-up studies typically involve routine visits at pre-scheduled time points and/or clinical visits whenever individuals experience malaria-like symptoms. In the latter case, infection triggers outcome assessment, thereby leading to outcome-dependent sampling (ODS). Ordinary methods used to analyse such longitudinal data ignore ODS and potentially lead to biased estimates of malaria-specific transmission parameters, hence, inducing an incorrect assessment and evaluation of malaria control strategies. In this paper, we propose novel methodology to handle ODS using a joint model for the longitudinal binary outcome measured at routine visits and the clinical event times. The methodology is applied to malaria parasitaemia data from a cohort of n = 988 Ugandan children aged 0.5-10 years from 3 regions (Walukuba - 300 children, Kihihi - 355 children and Nagongera - 333 children) with varying transmission intensities (entomological inoculation rate equal to 2.8, 32 and 310 infectious bites per unit year, respectively) collected between 2011-2014. The results indicate that malaria parasite prevalence and force of infection (FOI) increase with age in the region of high malaria intensities with FOI highest in age group 5-10 years. For the region of medium intensity, the prevalence slightly increases with age and the FOI for the routine process is highest in age group 5-10 years yet for the clinically observed infections, the FOI gradually decreases with increasing age. For the region with low intensity, both the prevalence and FOI peak at the age of one year after which the former remains constant with age yet the latter suddenly decreases with age for the clinically observed infections. In all study sites, both the prevalence and FOI are highest among previously asymptomatic children and lowest among their symptomatic counterparts. Using a simulation study inspired by the malaria data at hand, the proposed methodology shows to have the smallest bias, especially when consecutive positive malaria parasitaemia presence results within a time period of 35 days were considered to be due to the same infection.

epidemiology↗

bioRxiv2018

Transmission of and susceptibility to seasonal influenza in Switzerland from 2003-2015

Understanding the seasonal patterns of influenza transmission is critical to help plan public health measures for the management and control of epidemics. Mathematical models of infectious disease transmission have been widely used to quantify the transmissibility of and susceptibility to past influenza seasons in many countries. The objective of this study was to obtain a detailed picture of the transmission dynamics of seasonal influenza in Switzerland from 2003-2015. To this end, we developed a compartmental influenza transmission model taking into account social mixing between different age groups and seasonal forcing. We applied a Bayesian approach using Markov chain Monte Carlo (MCMC) methods to fit the model to the reported incidence of influenza-like-illness (ILI) and virological data from Sentinella, the Swiss Sentinel Surveillance Network. The maximal basic reproduction number, R0, ranged from 1.46 to 1.81 (median). Median estimates of susceptibility to influenza ranged from 29% to 98% for different age groups, and typically decreased with age. We also found a decline in ascertainability of influenza cases with age. Our study illustrates how influenza surveillance data from Switzerland can be integrated into a Bayesian modeling framework in order to assess age-specific transmission of and susceptibility to influenza.

epidemiology↗

bioRxiv2018

Socioeconomic status associated with carpal tunnel syndrome: A retrospective nationwide 11-year population-based cohort study in South Korea

ImportanceThere have only been a few large-scale studies that have included a risk factor analysis for CTS. No prior study has investigated the relationship between the occurrence of CTS and stratified socioeconomic status, which is closely related to a persons type of job.\n\nObjectiveTo confirm the known risk factors for CTS and also to determine the correlation between stratified socioeconomic status and the occurrence of CTS.\n\nDesignWe conducted this study using a retrospective cohort model based on the combined databases of the Korean National Health Insurance System from 2003-2013, a database compiled using information from a national periodic health-screening program that is used for reimbursement claims.\n\nSettingThe setting was a population-based retrospective cohort study.\n\nParticipantsFirst, we randomly sampled 514,795 patients who represented 10% of the 5,147,950 people who took part in periodic health screenings from 2002-2003. Existing CTS patients were excluded from this group. Therefore, this study finally included 512,942 participants and followed their medical records from 2003-2013.\n\nMain Outcomes and MeasuresDesired outcomes were the incidence rate of CTS and the hazard ratios according to stratified socioeconomic status.\n\nResultsA correlation analysis showed that CTS was more likely to occur in patients from a lower socioeconomic status.\n\nConclusions and RelevanceCTS was associated with people of a lower socioeconomic status who work in simple but repetitive manual labor jobs. We believe that the results of our study will be helpful to determine the pathophysiology of CTS and to set up a new industrial health policy for this condition.\n\nKey PointsO_ST_ABSQuestionC_ST_ABSWhat is the relationship between stratified socioeconomic status and the incidence of carpal tunnel syndrome (CTS)?\n\nFindingsIn this retrospective population-based cohort study that included 512,942 participants sampled from the Korean National Health Insurance System(KNHIS) database, the incidence rate and hazard ratios for CTS tended to increase with lower socioeconomic status.\n\nImplicationsLow socioeconomic status was identified as a risk factor for the incidence of CTS.

epidemiology↗

bioRxiv2018

Validation of known risk factors associated with carpal tunnel syndrome: A retrospective nationwide 11-year population-based cohort study in South Korea

Key PointsO_ST_ABSQuestionC_ST_ABSWhat is the relationship between the previously known risk factors and occurrence of carpal tunnel syndrome (CTS)?\n\nFindingsIn this retrospective population-based cohort study that included 512,942 participants sampled from the Korean National Health Insurance System database, we determined the following known risk factors were related to the occurrence of CTS: the age of 40s, female, being overweight, diabetes, rheumatoid arthritis, gout, and Raynauds syndrome. However, ESRD, hypothyroidism and smoking were not correlated with CTS occurrence.\n\nImplicationsWe identified the age of 40s, female, overweight, diabetes, rheumatoid arthritis, gout, and Raynauds syndrome as risk factors for the occurrence of CTS.\n\nAbstractO_ST_ABSImportanceC_ST_ABSThere have been few large-scale studies that have included a risk factor analysis for CTS. No prior study has investigated and validated the relationship between the occurrence of CTS and known risk factors using nationwide health care database.\n\nObjectiveTo confirm the actual risk factors for CTS out of various known risk factors\n\nDesignWe conducted this study using a retrospective cohort model based on the combined two databases of the Korean National Health Insurance System; the national periodic health screening program database from 2002-2003 and health insurance database of reimbursement claims from 2003 through 2013.\n\nSettingA population-based retrospective cohort study.\n\nParticipantsFirst, we randomly sampled 514,795 patients who represented 10% of the 5,147,950 people who took part in periodic health screenings in 2002-2003. Existing CTS patients were excluded from this group. Therefore, this study finally included 512,942 participants and followed up their medical records from 2003-2013.\n\nMain Outcomes and MeasuresDesired outcomes were the incidence rate of CTS in patients with various risk factors and the hazard ratios of risk factors affecting the diseases occurrence.\n\nResultsThe incidence of CTS was highest in patients in the age of 40s, in the moderate obesity group, in females, and in patients with diabetes mellitus (DM). The hazard ratio analysis revealed that the following risk factors were strongly related to the occurrence of CTS: age of 40s, female, obesity, DM, rheumatoid arthritis, gout, and Raynauds syndrome. However, ESRD, hypothyroidism and smoking were not correlated with CTS occurrence.\n\nConclusions and RelevanceIn our large-scale cohort study, risk factors such as being in ones 40s, obesity, being female, suffering from DM, and rheumatoid arthritis were reaffirmed as those of CTS occurrence.

epidemiology↗

bioRxiv2018

Risk factors associated with Parkinson’s disease: An 11-year population-based South Korean study

ObjectiveTo validate various known risk factors of Parkinsonism and to establish basic information to formulate public health policy by using a 10-year follow-up cohort model.\n\nMethodsThis population based nation-wide study was performed using the National Health Insurance Database of reimbursement claims of the Health Insurance Review and Assessment Service of South Korea data on regular health check-ups in 2003 and 2004, with 10 years follow-up.\n\nResultsWe identified 7,746 patients with Parkinsonism. Old age, hypertension, diabetes, depression, anxiety, taking statin medication, high body mass index, non-smoking, non-alcohol drinking, and low socioeconomic status were each associated with an increase in the risk of Parkinsonism (fully adjusted Cox proportional hazards model: hazard ratio (HR) 1.259, 95% confidence interval (CI) 1.194-1.328 for hypertension, HR 1.255, 95% CI 1.186-1.329 for diabetes, HR 1.554, 95% CI 1.664-1.965 for depression, HR 1.808, 95% CI 1.462-1.652 for anxiety, and HR 1.157, 95% CI 1.072-1.250 for taking statin medication).\n\nConclusionsIn our study, old age, depression, anxiety, and a non-smoker status were found to be risk factors of Parkinsonism, in agreement with previous studies. However, sex, hypertension, diabetes, taking statin medication, non-drinking of Alcohol, and lower socioeconomic status have not been described as risk factors in previous studies and need further verification in future studies.

epidemiology↗

bioRxiv2018

Data mining and classification of polycystic ovaries in pelvic ultrasound reports

ObjectivesTo develop and evaluate the performance of a rules-based classifier and a gradient boosted tree model for automatic feature extraction and classification of polycystic ovary morphology (PCOM) in pelvic ultrasounds\n\nMethodsPelvic ultrasound reports from patients at Boston Medical Center between October 1, 2003 and December 12, 2016 were included for analysis, which resulted in 39,093 ultrasound reports from 25,535 unique women. Following the 2003 Rotterdam Consensus Criteria for polycystic ovary syndrome, 2000 randomly selected ultrasounds were manually labeled for PCOM status as present, absent, or unidentifiable. Half of the labeled data was used as a training set, and the other half was used as a test set.\n\nResultsOn the test set of 1000 random US reports, the accuracy of rules-based classifier (RBC) was 97.6% (95% CI: 96.5%, 98.5%) and 96.1% (94.7%, 97.2%) for the gradient boosted tree model (GBT). Both models were more adept at identifying non-PCOM ultrasounds than either unidentifiable or PCOM ultrasounds. The two classifiers estimated prevalence of PCOM within our populations ultrasounds to be about 44%, unidentifiable 32%, and PCOM 24%.\n\nConclusionsAlthough accuracy measured on the test set and inter-rater agreement between the two classifiers (Cohens Kappa = 0.988) was high, a major limitation of our approach is that it uses the ultrasound report text as a proxy and does not directly count follicles from the ultrasound images themselves.

epidemiology↗

bioRxiv2018

Estimating sleep parameters using an accelerometer without sleep diary

Wrist worn raw-data accelerometers are used increasingly in large scale population research. We examined whether sleep parameters can be estimated from these data in the absence of sleep diaries. Our heuristic algorithm uses the variance in estimated z-axis angle and makes basic assumptions about sleep interruptions. Detected sleep period time window (SPT-window), was compared against sleep diary in 3752 participants (range=60-82years) and polysomnography in sleep clinic patients (N=28) and in healthy good sleepers (N=22). The SPT-window derived from the algorithm was 10.9 and 2.9 minutes longer compared with sleep diary in men and women, respectively. Mean C-statistic to detect the SPT-window compared to polysomnography was 0.86 and 0.83 in clinic-based and healthy sleepers, respectively. We demonstrated the accuracy of our algorithm to detect the SPT-window. The value of this algorithm lies in studies such as UK Biobank where a sleep diary was not used.

epidemiology↗