Michael Ingre's research while affiliated with Linnaeus University and other places

Publications (77)

Article
Background According to the vulnerability model, low self-esteem makes people more depressed. Support for the vulnerability model comes almost exclusively from analyses using cross-lagged panel models, showing a negative effect of initial self-esteem on subsequent depression ratings when adjusting for initial depression. However, it is well known t...
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Background Latent change score models are often used to study change over time in observational data. However, latent change score models may be susceptible to regression to the mean. Earlier observational studies have identified a positive association between breastfeeding and child intelligence, even when adjusting for maternal intelligence. Met...
Preprint
Background: Using random-intercept cross-lagged panel models (RI-CLPM), researchers have concluded that within-individual need for cognition (WI-NFC) negatively affects subsequent within-individual anxiety and depression symptoms (WI-ADS). However, RI-CLPM may be susceptible to spurious results due to regression to the mean. We investigated the ris...
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Ability tilt refers to a within-individual difference between two abilities (X-Y), e.g. differences between tech and verbal or verbal and math abilities. Studies have found associations between ability tilts and their constituent abilities (X or Y). Here we show that such associations may be spurious due to the non-independence of the two measures....
Preprint
In a recent article, Zainal and Newman (2022) reported that need for cognition (NFC) predicted anxiety and depression symptoms (ADS) across 10 years in a large (N = 6750) sample of community-dwelling adults, and furthermore that a within-person decrease in NFC was associated with an increase in ADS. Here, we analyze the modeling approaches used in...
Preprint
Latent change score models are often used to study change over time in observational data. However, latent change score models may be susceptible to regression to the mean. In the present study, we investigate regression to the mean in the case of breastfeeding and intelligence of children. Earlier observational studies have identified a positive a...
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Objective The present simulation study aimed to assess positive predictive value (PPV) and negative predictive value (NPV) for our newly introduced Accounting for Expected Adjusted Effect test (AEAE test) and compare it to PPV and NPV for a traditional zero-order significance test. Results The AEAE test exhibited greater PPV compared to a traditio...
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Sleepy drivers have problems with keeping the vehicle within the lines, and might often need to apply a sudden or hard corrective steering wheel movement. Such movements, if they occur while driving on a slippery road, might increase the risk of ending off road due to the unforgiving nature of slippery roads. We tested this hypothesis. Twelve young...
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Cognitive functioning is known to be impaired following sleep deprivation and to fluctuate depending on the time of day. However, most methods of assessing cognitive performance remain impractical for environments outside of the lab. This study investigated whether 2-min smartphone-based versions of commonly used cognitive tests could be used to as...
Preprint
Ability tilt refers to a within-individual difference between two abilities (X-Y), e.g. differences between tech, verbal and math abilities. Studies have found associations between ability tilts and their constituent abilities (X or Y). Here we investigate whether such associations may be spurious due to the non-independence of the two measures. Us...
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Introduction Body Mass Index (BMI) is a composite variable of weight and height, often used as a predictor of health outcomes, including mortality. The main purpose of combining weight and height in one variable is to obtain a measure of obesity independent of height. It is however unclear how accurate BMI is as a predictor of mortality compared to...
Preprint
Adjusting for possible confounders is common in statistical analyses, but the degree to which confounding can be eliminated depends on the reliability of measurement of the confounding variable. We have recently proposed a new test which formally incorporates the reliability of the confounding variable: the Accounting for the Expected Adjusted Effe...
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The point that adjustment for confounders do not always guarantee protection against spurious findings and type 1-errors has been made before. The present simulation study indicates that for traditional regression methods, this risk is accentuated by a large sample size, low reliability in the measurement of the confounder, and high reliability in...
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BMI has been used as a predictor of health outcomes, including mortality, in numerous studies. However, in the present study of Swedish male conscripts with follow ups (N = 48,904, 3442 deaths), we show that there are several better ways to use measured weight and height than to calculate BMI when predicting mortality. The most accurate model indic...
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Study objectives To determine how sleepiness and sleep deprivation drive the motivation to engage in different behaviors. Methods We studied the sleepiness of 123 participants who had been randomized to sleep deprivation or normal sleep, and their willingness to engage in a range of everyday behaviors. Results Self-reported sleepiness was a stron...
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According to the intelligence-creativity threshold hypothesis, there should be a positive association between intelligence and creative potential up to a certain point, the threshold, after which a further increase in intelligence should have no association with creativity. In the present simulation study, the measured intelligence and creativity o...
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The present simulation study indicates that adjustment for confounding can leave room for spurious findings, especially if the predictor and the outcome are measured with high and the confounder with low reliability. The risk is accentuated further with a large sample size. However, this risk could, hopefully, be attenuated by calculating the expec...
Preprint
Some studies have analyzed the effect of a predictor measured at a later time point (X1), or of the X1-X0 difference, while adjusting for the predictor measured at baseline (X0), on some outcome Y of interest. The present simulation study shows that, if used to analyze the effect of a change in X on Y, there is a high risk for this analysis to prod...
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Pain is subjective and largely shaped by context, yet, little is known about the boundaries for such influences, in particular in relation to conscious awareness. Here, we investigated processing of noxious stimuli during sleep. Four experiments were performed where participants (n = 114) were exposed to repetitions of noxious heat, either when awa...
Preprint
According to the intelligence-creativity threshold hypothesis, there should be a positive association between intelligence and creative potential up to a certain point, the threshold, after which a further increase in intelligence should have no association with creativity. In the present simulation study, the measured intelligence and creativity o...
Preprint
To estimate a combined effect of two different exposures, the standard method is to include both exposures as independent variables in a statistical model, together with an interaction term. Journals such as Epidemiology recommend this method as best practice in their instructions for authors. However, in occupational stress research it is common t...
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There is strong experimental support that infections increase the drive for sleep in animals, and it is widely believed that more sleep is part of an adaptive immune response. While respiratory infections (RI) are very prevalent in humans, there is a striking lack of systematic knowledge on how it affects sleep. We recruited 100 people, among whom...
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The present simulation study indicates that a method where the regression effect of a predictor (X) on an outcome at follow-up (Y1) is calculated while adjusting for the outcome at baseline (Y0) can give spurious findings, especially when there is a strong correlation between X and Y0 and when the test–retest correlation between Y0 and Y1 is relati...
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In this paper, we show how Bayes' theorem can be used to better understand the implications of the 36% reproducibility rate of published psychological findings reported by the Open Science Collaboration. We demonstrate a method to assess publication bias and show that the observed reproducibility rate was not consistent with an unbiased literature....
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In response to recommendations to redefine statistical significance to P ≤ 0.005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.
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In response to recommendations to redefine statistical significance to P ≤ 0.005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.
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The pleiotropic cytokine interleukin-6 (IL-6) has been proposed to participate in the regulation of sleepiness. Early studies reported that IL-6 increases in the blood at night, but estimates of its diurnal phase are conflicting. In a meta-analysis of diurnal variation, including 1100 participants from 56 datasets, we confirmed that IL-6 varied acr...
Preprint
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In response to recommendations to redefine statistical significance to p ≤ .005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.
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The pleiotropic cytokine interleukin-6 (IL-6) has been proposed to contribute to circadian regulation of sleepiness by increasing in the blood at night. Earlier studies have reported diurnal variation of IL-6, but phase estimates are conflicting. We have therefore performed a meta-analysis on the diurnal variation of circulating IL-6. Studies were...
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The Open Science Collaboration recently reported that 36% of published findings from psychological studies were reproducible by their independent team of researchers. We can use this information to estimate the statistical power needed to produce these findings under various assumptions of prior probabilities and type-1 errors to calculate the expe...
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Sleepiness and fatigue are important risk factors in the transport sector and bio-mathematical sleepiness, sleep and fatigue modeling is increasingly becoming a valuable tool for assessing safety of work schedules and rosters in Fatigue Risk Management Systems (FRMS). The present study sought to validate the inner workings of one such model, Three...
Data
Demand control support questionnaire (in English and Swedish). (DOCX)
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To examine the factor structure and to evaluate the longitudinal measurement invariance of the demand-control-support questionnaire (DCSQ), using the Swedish Longitudinal Occupational Survey of Health (SLOSH). A confirmatory factor analysis (CFA) and multi-group confirmatory factor analysis (MGCFA) models within the framework of structural equation...
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Sleep and subjective health are both prospectively related to objective indices of health and health care use. Here, we tested whether five days with restricted sleep and subsequent recovery days affect subjective health and is related to increased levels of circulating IL-6 and TNF-α and fatigue. Nine healthy men (23-28 years) went through a 6-wee...
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The aim of this study is to describe the relationship between objective measures of sleep, physical activity and BMI in Swedish pre-adolescents. The day-to-day association between physical activity and sleep quality as well as week-day and weekend pattern of sleep is also described. We conducted a cross sectional study consisted of a cohort of 1.23...
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It is sometimes argued that small studies provide better evidence for reported effects because they are less likely to report findings with small and trivial effect sizes (Friston, 2012). But larger studies are actually better at protecting against inferences from trivial effect sizes, if researchers just make use of effect sizes and confidence int...
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The main objective of the present study was to investigate relative personal fit as the association between rated needs and preferences for work hours, on the one hand, and actual work hours, on the other hand, in three groups (hospital, call-center, and police) working with periodic self-rostering. We also examined the association between personal...
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This study investigated the effects of two very commonly used countermeasures against driver sleepiness, opening the window and listening to music, on subjective and physiological sleepiness measures during real road driving. In total, 24 individuals participated in the study. Sixteen participants received intermittent 10-min intervals of: (i) open...
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Several studies show increases in activity for certain frequency bands (10-14 Hz) and visually scored parameters during sleep after exposure to radiofrequency electromagnetic fields. A shortened REM latency has also been reported. We investigated the effects of a double-blind radiofrequency exposure (884 MHz, GSM signaling standard including non-DT...
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To investigate whether sleep deprived people are perceived as less healthy, less attractive, and more tired than after a normal night's sleep. Experimental study. Sleep laboratory in Stockholm, Sweden. 23 healthy, sleep deprived adults (age 18-31) who were photographed and 65 untrained observers (age 18-61) who rated the photographs. Participants w...
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Previous studies indicate that the effect of a given shift schedule may depend on individual factors. The aim of the present study was to investigate whether a misfit between individual preferences and actual working hours affected the association between working hours and self-reported indicators of health and well-being. The study population cons...
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Studies of driving and sleepiness indicators have mainly focused on prior sleep reduction. The present study sought to identify sleepiness indicators responsive to several potential regulators of sleepiness: sleep loss, time of day (TOD) and time on task (TOT) during simulator driving. Thirteen subjects drove a high-fidelity moving base simulator i...
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Sleep reduction normally causes a homeostatic response during subsequent recovery sleep, but this does not seem to be true for repeated partial sleep loss. The aim of the present study was to test the response to repeated partial sleep loss through detailed focus on spectral data and parts of sleep. The experiment involved 4 h of sleep across 5 day...
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Study Objectives Sleep reduction normally causes a homeostatic response during subsequent recovery sleep, but this does not seem to be true for repeated partial sleep loss. The aim of the present study was to test the response to repeated partial sleep loss through detailed focus on spectral data and parts of sleep. Design The experiment involved...
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There is an ongoing debate of how best to measure the effects of sleep loss in a reliable and feasible way, partly because well controlled laboratory studies and field studies have come to different conclusions. The aims of the present study were to investigate both sleepiness and performance in response to long-term sleep restriction and recovery...
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Forty-six male train drivers (mean age = 46.5, SD = 5.1) were recruited to participate in a diary study for 14 consecutive days with questions about their sleep and working hours. A polynomial mixed-effect regression model showed a curvilinear relation ( p < .001) between shift-start time and sleep duration for shifts starting at 03:00-12:00 hand w...
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Mathematical models designed to predict alertness or performance have been developed primarily as tools for evaluating work and/or sleep-wake schedules that deviate from the traditional daytime orientation. In general, these models cope well with the acute changes resulting from an abnormal sleep but have difficulties handling sleep restriction acr...
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Very little is known about differences in sleep between day and shift workers in representative samples of the population. This study compared a national representative sample (N=3400) of shift (with night shifts) and day workers regarding the different types of sleep disturbances and also the level of sleep symptoms with that of insomnia patients....
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The present study of sleepiness and accident risk in a HI-FI car simulator aimed to provide subject-level relative risks (RR) with 95% confidence intervals (CI) for different levels of subjective sleepiness measured with the Karolinska Sleepiness Scale (KSS), 1 = very alert, 9 = very sleepy, fighting sleep, an effort to staying awake. Five male and...
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The present study aimed to provide subject-specific estimates of the relation between subjective sleepiness measured with the Karolinska Sleepiness Scale (KSS) and blink duration (BLINKD) and lane drifting calculated as the standard deviation of the lateral position (SDLAT) in a high-fidelity moving base driving simulator. Five male and five female...
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It is not yet clear whether the diurnal variation in testosterone is regulated by circadian or homeostatic (sleep) influences. The present study tested whether testosterone is driven by a circadian-independent sleep effect by shifting sleep acutely to daytime in a 24-h sampling regiment. In the sleep laboratory, seven healthy young men (age, 22-32...
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The present study sought to investigate the effects of lifetime accumulated night work on subjective health and sleep in monozygotic twins discordant on the exposure to night work. A total of 169 twin pairs (83 males, 86 females) over 65 years of age were analyzed on variables that describe the presence or absence of complaints regarding subjective...
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The present study aimed to experimentally evaluate the effect of early morning shifts on sleep and sleepiness of train drivers during normal working conditions. A total of 17 experienced train drivers were studied during a 4.5 h drive in two directions with a 2.5 h break in between on three different shifts: an early shift that started at 05:49 h (...
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The purpose of the TRAIN project was to describe and analyse the train drivers information environment, working hours, work situation and work environment and their effect on drivers' behaviour and the train driver system safety as well as to propose safety enhancing measures. The results indicate several problems of significance to the train drive...
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The study examined the relation between daily workhours and the occurrence of neck-shoulder or back pain in physically demanding care work. Unpublished data were obtained from three intervention projects in care institutions. The projects had been conducted independently in Oslo (46 participants, 175 referents before and 158 referents after the int...
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The effect of the total amount of work hours and the benefits of a shortening is frequently debated, but very little data is available. The present study compared a group (N = 41) that obtained a 9 h reduction of the working week (to a 6 h day) with a comparison group (N = 22) that retained normal work hours. Both groups were constituted of mainly...