Abrupt shift of the pattern of diurnal variation in stroke onset with daylight saving time transitions

Daylight Saving Time transitions and Cardiovascular Disease in Andalusia: Time Series Modeling and Analysis Using Visibility Graphs

The present study aimed to determine whether transitions both to and from daylight saving time (DST) led to an increase in the incidence of hospital admissions for major acute cardiovascular events (MACE). To support the analysis, natural visibility graphs (NVGs) were used with data from Andalusian public hospitals between 2009 and 2019. We calculated the incidence rates of hospital admissions for MACE, and specifically acute myocardial infarction and ischemic stroke during the 2 weeks leading up to, and 2 weeks after, the DST transition. NVG were applied to identify dynamic patterns. The study included 157 221 patients diagnosed with MACE, 71 992 with AMI (42 975 ST-elevation myocardial infarction (STEMI) and 26 752 non-ST-elevation myocardial infarction (NSTEMI)), and 51 420 with ischemic stroke. Observed/expected ratios shown an increased risk of AMI (1.06; 95% CI (1.00-1.11); P = .044), NSTEMI (1.12; 95% CI (1.02-1.22); P = .013), and acute coronary syndrome (1.05; 95% CI (1.00-1.10); P = .04) around the autumn DST. The NVG showed slight variations in the daily pattern of pre-DST and post-DST hospitalization admissions for all pathologies, but indicated that the increase in the incidence of hospital admissions after the DST is not sufficient to change the normal pattern significantly.

Daylight saving time affects European mortality patterns

Daylight saving time (DST) consists in a one-hour advancement of legal time in spring offset by a backward transition of the same magnitude in fall. It creates a minimal circadian misalignment that could disrupt sleep and homoeostasis in susceptible individuals and lead to an increased incidence of pathologies and accidents during the weeks immediately following both transitions. How this shift affects mortality dynamics on a large population scale remains, however, unknown. This study examines the impact of DST on all-cause mortality in 16 European countries for the period 1998-2012. It shows that mortality decreases in spring and increases in fall during the first two weeks following each DST transition. Moreover, the alignment of time data around DST transition dates revealed a septadian mortality pattern (lowest on Sundays, highest on Mondays) that persists all-year round, irrespective of seasonal variations, in men and women aged above 40.

Taking to "heart" the proposed legislation for permanent daylight saving time

In March 2022, the US Senate passed the Sunshine Protection Act that would abolish the biannual change in clocks each fall and spring and permanently adopt daylight saving time that aligns with the "spring forward" time change each March. A number of scientific and medical societies have endorsed the abolishment of the biannual clock change, but oppose the permanent adoption of daylight saving time. Instead, leading organizations such as the American Academy of Sleep Medicine (AASM) and the Society for Research on Biological Rhythms (SRBR) position statements highlight peer-reviewed evidence in favor of a permanent shift to standard time. The present perspectives will summarize some of the key AASM and SRBR recommendations, with a particular focus on the potential cardiovascular implications of a legislative change that would result in a permanent switch to either standard time or daylight saving time. Collectively, although there is building scientific consensus that abolishing the biannual time change has several sleep and circadian health benefits, the preponderance of evidence is opposite to the current legislation and instead suggests a permanent switch to standard time may offer the maximum health and safety benefits. This scientific evidence should be considered as the United States House of Representatives considers the Sunshine Protection Act.

Duplex ultrasonography as prognostic tool of acute ischemic stroke patients

Background

Cerebral stroke is a major source of mortality and morbidity. Duplex ultrasonography is used to evaluate carotid and cerebral arteries. The objectives of this work are to study the correlation between carotid duplex parameters with risk factors of ischemic stroke and evaluate duplex parameter as prognostic tool of ischemic stroke.

Methods

The study was conducted on 100 patients presented by acute ischemic stroke submitted to history taking, medical, and neurological examination. Neurological deficit was assessed by National Institute of Health Stroke Scale (NIHSS); the functional state of the patients was assessed by modified Rankin scale (mRS). Brain CT and/or MRI, routine laboratory investigations, extracranial, and transcranial duplex (TCD) were done.

Results

The end diastolic velocities (EDVs) and peak systolic velocities (PSVs) of common carotid arteries (CCA) were significantly decreased in smokers and hypertensive (P<0.05). Smoking and hypertension were positively correlated with resistive index (RI). In 80 patients, PSV in the symptomatic middle cerebral artery (MCA) did not exceed 70 cm/s within averaged 50.7 ± 4.6 cm/s. EDV was 12.0 ± 3.0 cm/s, RI was 0.78 ± 0.05, and pulsativity index (PI) was 1.61 ± 0.09. There was significant difference in all hemodynamic parameters in comparison with the asymptomatic side.

Conclusion

Patients who have risk factors of stroke should be evaluated with duplex ultrasonography. Duplex parameters can give informative data about prognosis and outcome.

Daylight Saving Time: Pros and Cons

The original rationale for the adoption of daylight saving time (DST) was to conserve energy; however, the effects of DST on energy consumption are questionable or negligible. Conversely, there is substantial evidence that DST transitions have the cumulative effect on sleep deprivation with its adverse health effects. In light of current evidence, the European Commission in 2018 decided that biannual clock change in Europe would be abolished. Current indirect evidence supports the adoption of perennial standard time, which aligns best with the human circadian system and has the potential to produce benefits for public health and safety.

Ramadan fasting and liver diseases: A review with practice advices and recommendations

Ramadan fasting is obligatory for Muslim healthy adults. However, there are many exemptions from fasting; including patients, whose diseases will be aggravated by fasting. Muslim patients with different liver diseases are frequently seen in the clinics discussing their intent to fast this month with their treating physicians. To answer our patients' inquiries about the expected benefits and/or risks of fasting and delivering them the best care, we carried out this review and we draw advices and recommendations based on the available evidence. A web-based search, combining multiple keywords representing different liver diseases with Ramadan fasting had been carried out. To answer the research question: Do adult Muslim patients with different liver diseases who fast the month of Ramadan have had a deleterious effect on their health in comparison to those who did not fast? Relevant publications were retrieved. No randomized controlled trials were focusing on Ramadan fasting and liver diseases in the filtered databases, eg Cochrane library. Consequently, non-filtered databases, eg PubMed, Google Scholar and Egyptian Knowledge Bank searched and full-text high-quality research articles were carefully analysed to draw recommendations. Other relevant publications with low quality of evidence like case studies and short communications were also reviewed to address practice advices. Although Ramadan fasting was found beneficial for patients with NAFLD, it was found deleterious to patients with Child B and C cirrhosis and patients with peptic ulcer. Patients with chronic hepatitis, Child A cirrhosis and those with non-complicated liver transplant can fast with prefasting assessment and strict follow up.

Experimental observations of synchronization between two bidirectionally coupled physically dissimilar oscillators

We experimentally study the complex dynamics of two mutually coupled physically dissimilar oscillators with two different kinds of coupling mechanisms. Specifically, an optoelectronic oscillator is coupled to a Colpitts oscillator via optical power and the Colpitts oscillator is coupled back to the optoelectronic oscillator via electric voltage. We investigate and characterize phase synchronization and generalized chaos synchronization in this coupled system. Phase synchronization is observed when both oscillators are preset to oscillate periodically prior to coupling while generalized chaos synchronization is observed when both oscillators are preset to oscillate chaotically prior to coupling. In the periodical oscillation regime, we observe a linear relationship between the strengths of the two unidirectional coupling factors at which the system transitions to a synchronized state. In the chaotic regime, we observe a transition from hyperchaos to chaos associated with the onset of generalized synchronization.

Changes in atrial fibrillation admissions following daylight saving time transitions

BACKGROUND

Daylight saving time (DST) imposes a twice-yearly hour shift. The transitions to and from DST are associated with decreases in sleep quality and environmental hazards. Detrimental health effects include increased incidence of acute myocardial infarction (MI) following the springtime transition and increased ischemic stroke following both DST transitions. Conditions effecting sleep are known to provoke atrial fibrillation (AF), however the effect of DST transitions on AF are unknown.

METHODS

Admitted patients aged 18-100 with primary ICD9 code of AF between 2009 and 2016 were included. The number of admissions was compiled and means were compared for the Monday to Thursday period and the entire seven day interval following each DST transition and the entire year for the entire cohort and separated by gender. Significance was determined with Wilcoxon nonparametric tests.

RESULTS

Admission data for 6089 patients were included, with mean age of 68 years and 53% female. A significant increase was found in mean AF admissions over the Monday to Thursday period (3.09 vs 2.47 admissions/day [adm/d], P = 0.017) and entire week (2.48 vs 2.09 adm/d, P = 0.025) following the DST spring transition compared to the yearly mean. When separated by gender, women exhibited an increase in AF admissions following the DST spring transition (1.78 vs 1.28 adm/d for Monday to Thursday period, P = 0.036 and 1.38 vs 1.11 adm/d for entire week, P = 0.050) while a non-significant increase was seen in men. No significant differences were found following the autumn transition for the entire cohort or when separated by gender.

CONCLUSION

An increase in AF hospital admissions was found following the DST springtime transition. When separated by gender, this finding persisted only among women. This finding adds to evidence of negative health effects associated with DST transitions and factors that contribute to AF episodes.

Cerebral Small Vessel Diseases and Sleep Related Strokes

BACKGROUND AND PURPOSE

Sleep related Stroke (SRS) is common and has been associated with cerebral small vessel diseases (SVD) in ischemic strokes (ISs). We tested the hypothesis that SRS is associated with SVD in both ischemic and hemorrhagic stroke.

METHODS

Prospectively collected data from patients consecutively enrolled after intracerebral hemorrhage (ICH) related to SVD or after IS were analyzed. Symptom onset was recorded as SRS versus awake. Each ICH was grouped according to lobar and deep locations. The IS cohort was etiologically characterized based on the Causative Classification of Stroke system. Frequencies of SRS within and between ICH and IS cohorts as well as its associations (etiology, risk factors) were analyzed.

RESULTS

We analyzed 1812 IS (mean age 67.9 years ± 15.9 years, 46.4% female) and 1038 ICH patients (mean age 72.5 years ± 13.0 years, 45.4% female). SRS was significantly more common among SVD-related ICH patients (n = 276, 26.6%) when compared to all IS (n = 363, 20.0%, P < .001) and in both, small artery occlusion (SAO) related IS and lobar ICH within the respective IS and ICH cohorts (16.3% SRS versus 9.1% awake for SAO within all IS, P < .001; and 57.1% SRS versus 47.7% awake for lobar bleeds within all ICH, P = .008). These associations remained significant after controlling for age, sex and risk factors.

CONCLUSIONS

SRS was associated with SVD. The SAO etiology and cerebral amyloid angiopathy related lobar ICH suggest that the presence of SVD can interact with sleep or arousal related hemodynamic changes to cause ischemic and hemorrhagic stroke.

Sex-Dependent Effects of Bmal1-Deficiency on Mouse Cerebral Cortex Infarction in Response to Photothrombotic Stroke

Stroke is a leading cause of disability and death worldwide. There is increasing evidence that occurrence of ischemic stroke is affected by circadian system and sex. However, little is known about the effect of these factors on structural recovery after ischemic stroke. Therefore, we studied infarction in cerebral neocortex of male and female mice with deletion of the clock gene Bmal1 (Bmal1-/-) after focal ischemia induced by photothrombosis (PT). The infarct core size was significantly smaller 14 days (d) as compared to seven days after PT, consistent with structural recovery during the sub-acute phase. However, when sexes were analyzed separately 14 days after PT, infarct core was significantly larger in wild-type (Bmal1+/+) female as compared to male Bmal1+/+ mice, and in female Bmal1+/+, as compared to female Bmal1-/- mice. Volumes of reactive astrogliosis and densely packed microglia closely mirrored the size of infarct core in respective groups. Estradiol levels were significantly higher in female Bmal1-/- as compared to Bmal1+/+ mice. Our data suggests a sex-dependent effect and an interaction between sex and genotype on infarct size, the recruitment of astrocytes and microglia, and a relationship of these cells with structural recovery probably due to positive effects of estradiol during the subacute phase.

Impact of daylight savings time on spontaneous pregnancy loss in in vitro fertilization patients

Transition into daylight savings time (DST) has studied negative impacts on health, but little is known regarding impact on fertility. This retrospective cohort study evaluates DST impact on pregnancy and pregnancy loss rates in 1,654 autologous in vitro fertilization cycles (2009 to 2012). Study groups were identified based on the relationship of DST to embryo transfer. Pregnancy rates were similar in Spring and Fall (41.4%, 42.2%). Pregnancy loss rates were also comparable between Spring and Fall (15.5%, 17.1%), but rates of loss were significantly higher in Spring when DST occurred after embryo transfer (24.3%). Loss was marked in patients with a history of prior spontaneous pregnancy loss (60.5%).

Changes in ischemic stroke occurrence following daylight saving time transitions

BACKGROUND

Circadian rhythm disruption has been associated with increased risk of ischemic stroke (IS). Daylight saving time (DST) transitions disrupt circadian rhythms and shifts the pattern of diurnal variation in stroke onset, but effects on the incidence of IS are unknown.

METHODS

Effects of 2004-2013 DST transitions on IS hospitalizations and in-hospital mortality were studied nationwide in Finland. Hospitalizations during the week following DST transition (study group, n = 3033) were compared to expected hospitalizations (control group, n = 11,801), calculated as the mean occurrence during two weeks prior to and two weeks after the index week.

RESULTS

Hospitalizations for IS increased during the first two days (Relative Risk 1.08; CI 1.01-1.15, P = 0.020) after transition, but difference was diluted when observing the whole week (RR 1.03; 0.99-1.06; P = 0.069). Weekday-specific increase was observed on the second day (Monday; RR 1.09; CI 1.00-1.90; P = 0.023) and fifth day (Thursday; RR 1.11; CI 1.01-1.21; P = 0.016) after transition. Women were more susceptible than men to temporal changes during the week after DST transitions. Advanced age (>65 years) (RR 1.20; CI 1.04-1.38; P = 0.020) was associated with increased risk during the first two days, and malignancy (RR 1.25; CI 1.00-1.56; P = 0.047) during the week after DST transition.

CONCLUSIONS

DST transitions appear to be associated with an increase in IS hospitalizations during the first two days after transitions but not during the entire following week. Susceptibility to effects of DST transitions on occurrence of ischemic stroke may be modulated by gender, age and malignant comorbidities.

Circadian misalignment and health

Circadian rhythms are near 24-h patterns of physiology and behaviour that are present independent of external cues including hormones, body temperature, mood, and sleep propensity. The term 'circadian misalignment' describes a variety of circumstances, such as inappropriately timed sleep and wake, misalignment of sleep/wake with feeding rhythms, or misaligned central and peripheral rhythms. The predominance of early research focused on misalignment of sleep to the biological night. However, discovery of clock genes and the presence of peripheral circadian oscillators have expanded the definitions of misalignment. Experimental studies conducted in animal models and humans have provided evidence of potential mechanisms that link misalignment to negative outcomes. These include dysregulation of feeding behaviours, changes in appetite stimulating hormones, glucose metabolism and mood. This review has two foci: (1) to describe how circadian misalignment has been defined and evaluated in laboratory and field experiments, and (2) to describe evidence linking different types of circadian misalignment to increased risk for physical (cardiovascular disease, diabetes, obesity, cancer) and psychiatric (depression, bipolar, schizophrenia, attention deficit) disorders. This review will describe the role of circadian misalignment as a risk factor for disease in the general population and in clinical populations, including circadian rhythm sleep disorders and psychiatric disorders.

The impact of daylight saving time on sleep and related behaviours

Daylight saving time is currently adopted in over 70 countries and imposes a twice yearly 1 h change in local clock time. Relative ease in adjustment of sleep patterns is assumed by the general population but this review suggests that the scientific data challenge a popular understanding of the clock change periods. The start of daylight saving time in the spring is thought to lead to the relatively inconsequential loss of 1 h of sleep on the night of the transition, but data suggests that increased sleep fragmentation and sleep latency present a cumulative effect of sleep loss, at least across the following week, perhaps longer. The autumn transition is often popularised as a gain of 1 h of sleep but there is little evidence of extra sleep on that night. The cumulative effect of five consecutive days of earlier rise times following the autumn change again suggests a net loss of sleep across the week. Indirect evidence of an increase in traffic accident rates, and change in health and regulatory behaviours which may be related to sleep disruption suggest that adjustment to daylight saving time is neither immediate nor without consequence.

Ambient temperature and spontaneous intracerebral haemorrhage: a cross-sectional analysis in Tainan, Taiwan

OBJECTIVES

Ambient temperature has been reported to play a role in the occurrence of spontaneous intracerebral haemorrhage (ICH). This study aimed to investigate the relation between ambient temperature of onset time and ICH and the effect of hourly temperature within 72 h before ICH.

DESIGN

This is a cross-sectional case-only study and a retrospective analysis of a prospective database.

SETTING

Two medical centres in Southern Taiwan participating a prospective stroke registry.

PARTICIPANTS

A total of 933 patients with ICH registered from August 2006 to July 2008.

PRIMARY AND SECONDARY OUTCOME MEASURES

The hourly temperature was collected, and patients were grouped according to the deciles of hourly temperature at onset. Primary outcome was the association between the number of ICH cases and mean temperature (or temperature variation). Secondary outcome was the difference of onset temperature and hourly temperature before onset in patients with known onset time.

RESULTS

Winter (n=282) had significant higher ICH cases than other seasons (n=651; p=0.002). Of those patients with an exact time of onset, the results showed 13% patients occurred at the lowest decile temperature group (<17.4°C) and 8% patients occurred at the highest decile temperature group (>30.8°C). It showed a significant temperature change before onset for these patients (p<0.005).

CONCLUSIONS

This study showed that lower ambient temperature and variation of temperatures precipitated ICH in southern Taiwan. Better protecting vulnerable people from cold temperatures may prevent the occurrences of ICH.

Timing pattern of onset in hypertensive intracerebral hemorrhage patients

The temporal pattern of onset of hypertensive intracerebral hemorrhage (ICH) has been evaluated in previous reports, but there are few published data on this pattern in Chongqing, China. The purpose of this study is to explore the temporal pattern of diurnal, weekly and monthly variations in the onset of hypertensive ICH from a hospital-based population. The study retrospectively reviewed 230 residents who suffered from hypertensive ICH between January 2008 and August 2009 in our hospital. The temporal pattern was investigated by hours, days and months. Chi-square test for goodness of fit was used for statistical analysis. Significant differences of the onset time of hypertensive ICH patients could be seen in diurnal variation (p=0.000) and in monthly variation (p=0.000), but could not be found in weekly variation (p=0.466). There was a bimodal distribution in diurnal variation, and monthly variation showed that the occurrence of hypertensive ICH mainly focuses on the period from December to May. Our study demonstrated the existence of diurnal and monthly variations and no significant weekly variation can be found in the time of onset of hypertensive ICH.

Circadian rhythm of stroke onset during the month of Ramadan

BACKGROUND AND PURPOSE

The onset of acute stroke exhibits a circadian pattern occurring more frequently in late morning hours. The objective of this study was to investigate the diurnal pattern of stroke during the month of Ramadan.

PATIENTS AND METHODS

We studied consecutive stroke patients 1 month before Ramadan (BR) and during Ramadan (DR) over two successive years 2007 and 2008. The age, gender, risk factor profiles were analyzed. The National Institute of Health and Stroke Scale Score (NIHSS) was used for clinical assessment at admission. The exact time of stroke onset in both groups was obtained.

RESULTS

A total of 507 patients were studied: 245 patients in the DR group and 262 patients in the BR group. The age distribution of patients was not significantly different between the two groups. There was no statistically significant difference in the sex ratio, risk factors, and NIHSS score between the two groups (P > 0.05). The higher frequency of stroke onset time in the BR group was in the time between 6:00 a.m. and noon; whereas the frequency was higher between noon and 6:00 p.m. in the DR group.

CONCLUSION

A significant shift of the circadian pattern of stroke onset time from the period between 6:00 a.m. and noon to that between noon and 6:00 pm has been found during the month of Ramadan.

[Billing based on a case-based lump sum for stroke. Did this lead to discharge of patients in a worse clinical condition?]

BACKGROUND

It has been supposed that the introduction of a new inpatient reimbursement system starting in 2004 in Germany using the German diagnosis-related groups (G-DRG) may lead to false incentives with encouragement of premature hospital discharge of patients. Exploring a large database on stroke patients, we addressed the question whether length of stay (LOS) and discharge in more severe condition were associated with the introduction of the G-DRG. We further examined other factors with probable effect on LOS such as variations of patient characteristics and treatment during the observation period.

PATIENTS AND METHODS

All stroke patients treated in 2003-2006 in the German state of Hesse (6,100,000 inhabitants) were assessed with respect to stroke severity, symptoms on admission and discharge, LOS and stroke-related deficits on discharge. We compared LOS and outcome in 2003 (before introduction of the G-DRG) with 2004 when the G-DRG had recently been introduced and with 2006 when the G-DRG was already well established in the clinical routine. The effects of LOS and treatment year on outcome were assessed using a logistic regression model.

RESULTS

During the observation period, we evaluated 37,396 stroke patients. The length of stay was reduced significantly from 12.2 to 10.4 days (p<0.001). Both severity of stroke on admission and outcome on discharge decreased during the observation period. A multivariate analysis revealed a minor but significant association [odds ratio (OR): 1.020 per day of hospital treatment; 95% confidence interval (CI): 1.016-1.024] of LOS on outcome. Treatment in 2006 compared to 2003 led to good outcome with an OR of 1.378 (95% CI: 1.279-1.485). Subgroup analysis limited to patients with severe stroke revealed that LOS was significantly lower in 2006 compared to 2003 also in this patient subgroup; moreover, the proportion of patients discharged with severe outcome was lower in 2006 compared to 2003.

CONCLUSIONS

This study reveals a significant reduction of LOS during the years after introduction of the G-DRG. However, reduction of LOS was not associated with more severe outcome on discharge, possibly due to changes in stroke treatment implemented during the observational period. Our results do not support the conjecture that changes in the reimbursement system were associated with compromised patient care.