Two-peak temporal distribution of stroke onset in Greek patients. a hospital-based study

Circadian variation in stroke onset: Differences between ischemic and hemorrhagic stroke and weekdays versus weekends

OBJECTIVES

To delineate diurnal variation onset distinguishing ischemic from hemorrhagic stroke, wake from sleep onset, and weekdays from weekends/holidays.

MATERIALS AND METHODS

We analyzed patients enrolled in the FAST-MAG trial of field-initiated neuroprotective agent in patients with hyperacute stroke within 2h of symptoms onset. Stroke onset times were analyzed in 1h, 4h, and 12h time blocks throughout the 24h day-night cycle. Patient demographic, clinical features, stroke severity, and prehospital workflow were evaluated for association with onset times.

RESULTS

Among 1615 acute cerebrovascular disease patients, final diagnoses were acute cerebral ischemia in 76.5% and Intracerebral hemorrhage in 23.5%. Considering all acute cerebrovascular disease patients, frequency of wake onset times showed a bimodal pattern, with peaks on onsets at 09:00-13:59 and 17:00-18:59 and early morning (00:00-05:59) onset in only 3.8%. Circadian rhythmicity differed among stroke subtypes: in acute cerebral ischemia, a single broad plateau of elevated incidences was seen from 10:00-21:59; in Intracerebral hemorrhage, bimodal peaks occurred at 09:00 and 19:00. The ratio of Intracerebral hemorrhage to acute cerebral ischemia occurrence was highest in early morning, 02:00-06:59. Marked weekday vs weekends pattern variation was noted for acute cerebral ischemia, with a broad plateau between 09:00 and 21:59 on weekdays but a unimodal peak at 14:00-15:59 on weekends.

CONCLUSIONS

Wake onset of acute cerebrovascular disease showed a marked circadian variation, with distinctive patterns of a broad elevated plateau among acute cerebral ischemia patients; a bimodal peak among intracerebral hemorrhage patients; and a weekend change in acute cerebral ischemia pattern to a unimodal peak.

Circadian variations in the occurrence of first-ever intracerebral hemorrhage from different sources of income: a hospital-based cross-sectional study

BACKGROUND

The onset time of intracerebral hemorrhage (ICH) may be closely related to the working style and living habits of people, which are determined by different income sources in China. Therefore, the purpose of our study was to investigate the Circadian Variations in the occurrence of ICH from different sources of income.

METHODS

This retrospective study enrolled 4,327 patients with first-ever ICH. Based on the time of day at which the patients developed symptoms, the classifiable onset time was assigned to one of eight three-hour intervals. And based on different income sources, they were categorized into three groups: Farmers, Wage-earners, and Freelancers. Demographic and risk factors of patients were then summarized, and the circadian variation of the 3 groups of patients' known time of onset and those stratified by sex and age were analyzed.

RESULTS

The frequency of ICH onset exhibited significant circadian variation among the 3 income groups, demonstrating a bimodal distribution in the daytime, with a nadir during the night (all P < 0.001). Three groups showed a significant initial peak between 06:01 and 09:00, and the same peak was observed in their subgroups of sex and age. In the 3 income source groups, there was a smaller second peak that between 15:01 and 18:00 for Farmers and Wage-earners and 18:01 and 21:00 for Freelancers. After stratification by sex and age, the second peak was between 18:01 and 21:00 for female in Farmers, female in Freelancers, under 65 years of age in Wage-earners and 65 years or older in Freelancers, while 15:01 and 18:00 for the other groups.

CONCLUSIONS

Different circadian variations of ICH onset time are found in patients with different income sources in southwest China's Chongqing Municipality cohort. Moreover, the frequency and distribution pattern of peak hours may be closely related to the working style and living habits of people with different income sources.

Association of daytime napping with incident stroke in middle-aged and older adults: a large community-based study

BACKGROUND AND PURPOSE

There are conflicting reports on the association between daytime napping and incident stroke. This study was designed to investigate the relationship between daytime napping and stroke within a community-based cohort.

METHODS

The present prospective study was based on the Sleep Heart Health Study. Napping habits were assessed with a self-reported Sleep Habits Questionnaire. Participants with napping habits of different durations and frequencies were followed up until the first stroke occurred or the final censoring date. Cox proportional hazards models were used to estimate the relationship between napping habits and stroke.

RESULTS

A total of 4757 participants (2219 men, mean age 63.6 ± 11.1 years) were enrolled in this study. Compared with those taking no naps, multivariate proportional hazards models analysis indicated that individuals taking naps with a duration of >60 min [hazard ratio (HR), 2.460; 95% confidence interval (CI), 1.538-3.934] had a higher risk of stroke. There was also an increased risk of stroke among participants taking naps daily (HR, 1.563; 95% CI, 1.059-2.307) or five to six times/week (HR, 1.548; 95% CI, 1.026-2.335). After combining napping durations and frequencies, regular long naps (HR, 1.903; 95% CI, 1.182-3.065) and regular short naps (HR, 1.451; 95% CI, 1.010-2.084) were independent risk factors for incident stroke.

CONCLUSION

Daytime napping with a long duration (>30 min) or a high frequency (≥5 times/week) may increase the risk of stroke.

Daily Variation in the Occurrence of Different Subtypes of Stroke

Three thousand two hundred and ninety-eight patients admitted to our Stroke Unit with hemorrhagic, large artery atherosclerosis, cardioembolic, small-vessel occlusion, and undetermined etiology-cryptogenic strokes were included in the study. The circadian variability in onset in each stroke subgroup and the associations with various risk factors were analyzed. In each subgroup, a significant minority of patients suffered from stroke during sleep. In the ischemic group, hypercholesterolemia, paroxysmal atrial fibrillation, and previous myocardial infarction facilitated the onset during waking. During waking, stroke onset was significantly higher in the morning compared to the afternoon both in the hemorrhagic and in the ischemic type. In hemorrhagic stroke, a previous stroke was associated with a lower early morning occurrence. In large artery atherosclerosis stroke, males were at higher risk of early morning occurrence (p < 0.01). In small-vessel occlusion stroke, hypertension is significantly more present in the morning compared to the afternoon onset (p < 0.005). Circadian patterns of stroke onset were observed both in hemorrhagic and in ischemic stroke, irrespective of the ischemic subgroup. In all groups, stroke was more likely to occur during waking than during sleep and, in the diurnal period, during morning than during afternoon. Moreover, sex and some clinical factors influence the diurnal pattern.

Circadian Variation of Stroke Onset: A Hospital-Based Study

Aims and background.

The circadian pattern of stroke occurrence variation has been recognized with certain differences between authors and stroke types. The underlying reason may be related to exogenous factors (cyclic physical activity, including sleep–awake cycles and assuming the up-right posture) and endogenous factors, with their diurnal variation (blood pressure, hemostatic balance, autonomic system activity). The aims of the present study are to investigate the existence of a circadian variation of stroke and the possible differences between stroke subtypes in the Cluj Napoca area.

Materials and method.

The stroke event data were acquired from the Patient Records of a consecutive series of 1083 patients admitted through the Emergency Room at Neurology Departments I and II of the District Hospital of Cluj Napoca, between 1 January 2012 and 31 December 2012. The classifiable onset time was assigned to one of four six-hour intervals: 00.01–06.00 (night), 06.01–12.00 (morning), 12.01–18.00 (afternoon) and 18.01–24.00 (evening). Demographic data and vascular risk factors were recorded.

Results.

All three stroke types (ischemic stroke, hemorrhagic stroke and subarachnoid hemorrhage) have shown a circadian variation regarding their occurrence, with the peak of incidence in the morning and the nadir during nighttime. This circadian pattern is independent by demographic factors and vascular risk factors.

Conclusion.

Our study confirmed the circadian variation of onset occurrence for all stroke subtypes. Some triggering factors promote ischemic stroke and prevent hemorrhagic stroke. The diurnal pattern of variation with the higher incidence in the morning and the lower in the night may lead to chrono-therapeutic and preventive approach (chrono-therapy of the risk factors), which targets the period of the highest vulnerability after awaking.

Twenty-four-hour patterns in occurrence and pathophysiology of acute cardiovascular events and ischemic heart disease

The scientific literature clearly establishes the occurrence of cardiovascular (CV) accidents and myocardial ischemic episodes is unevenly distributed during the 24 h. Such temporal patterns result from corresponding temporal variation in pathophysiologic mechanisms and cyclic environmental triggers that elicit the onset of clinical events. Moreover, both the pharmacokinetics and pharmacodynamics of many, though not all, CV medications have been shown to be influenced by the circadian time of their administration, even though further studies are necessary to better clarify the mechanisms of such influence on different drug classes, drug molecules, and pharmaceutical preparations. Twenty-four-hour rhythmic organization of CV functions is such that defense mechanisms against acute events are incapable of providing the same degree of protection during the day and night. Instead, temporal gates of excessive susceptibility exist, particularly in the morning and to a lesser extent evening (in diurnally active persons), to aggressive mechanisms through which overt clinical manifestations may be triggered. When peak levels of critical physiologic variables, such as blood pressure (BP), heart rate (HR), rate pressure product (systolic BP × HR, surrogate measure of myocardial oxygen demand), sympathetic activation, and plasma levels of endogenous vasoconstricting substances, are aligned together at the same circadian time, the risk of acute events becomes significantly elevated such that even relatively minor and usually harmless physical and mental stress and environmental phenomena can precipitate dramatic life-threatening clinical manifestations. Hence, the delivery of CV medications needs to be synchronized in time, i.e., circadian time, in proportion to need as determined by established temporal patterns in risk of CV events, and in a manner that averts or minimizes undesired side effects.

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.

Acute changes in cardiovascular function during the onset period of daytime sleep: comparison to lying awake and standing

The siesta habit is associated with a 37% reduction in coronary mortality, possibly because of reduced cardiovascular stress associated with daytime sleep. Whether the most important behavior is the daytime nap itself, a supine posture, or the expectancy of a nap is unknown. We present the first detailed description on healthy individuals of the acute changes in cardiovascular function during defined phases of the daytime sleep-onset period. These responses were compared with lying awake and standing. Following a night of restricted (4 h) sleep, nine healthy participants (aged 34 ± 5 yr) were allowed to sleep at 1400 for up to 1 h. Polysomnography was used to calculate three phases of daytime sleep onset: phase 1, a baseline period of relaxed wakefulness before lights out; phase 2, the period between lights out and onset of stage 1 sleep; and phase 3, the period between onsets of stages 1 and 2 sleep. Differences (means ± SD) in blood pressure, heart rate, and forearm cutaneous vascular conductance (CVC) between phases were analyzed. During the 9.7 ± 13.8 min of phase 2, systolic and diastolic blood pressure was 4.7 ± 4.5 and 3.6 ± 2.8 mmHg lower than baseline, whereas CVC was 9.5 ± 4.3% higher than baseline ( P < 0.05). Subsequent changes in cardiovascular function during the sleep itself were trivial ( P > 0.05). The above changes were not observed when subjects stood or laid supine in relaxed wakefulness for 1 h ( P > 0.05). Our findings suggest that the period between lights out and sleep onset is associated with the largest acute reduction in blood pressure during one afternoon siesta.

Usefulness of nocturia as a mortality risk factor for coronary heart disease among persons born in 1920 or 1921

Cardiovascular events are clustered in the morning hours, after increases in blood pressure and heart rate that accompany awakening and arising. Similar hemodynamic changes occur during the night after nocturnal awakening and getting up. Such changes are common among older patients who have nocturia frequently and rise to urinate. We tested the hypothesis that nocturia may be associated with increased mortality in a population sample of 456 subjects born from 1920 to 1921, examined in 1990, and followed for total mortality until 2002. At baseline, they were questioned about nocturia (> or =2 times at night) as part of a detailed questionnaire and examination. Twelve-year survival was significantly lower (61% vs 72%, p = 0.0206) among subjects reporting nocturia (n = 160, 64% men) compared with those without nocturia (n = 296, 50% men). After accounting for numerous confounders, a proportional hazard model determined the mortality hazard ratio (HR) for nocturia alone to be 0.89 (95% confidence interval [CI] 0.55 to 1.43). The interaction between nocturia and previous coronary heart disease (CHD) was highly significant (p <0.0001), with an interaction variable HR of 2.16 (95% CI 1.01 to 4.61). Survival of patients who had CHD with nocturia (n = 54) versus those without nocturia (n = 65) was 44% versus 66% (p = 0.0201). Among patients with CHD, the mortality HR for nocturia was 2.11 (95% CI 1.16 to 4.00). In conclusion, nocturia is a significant independent predictor of mortality among 70-year-old patients with known CHD and thus warrants special attention.