Stroke in the Lehigh Valley: seasonal variation in incidence rates.

Abstract

We investigated the seasonal pattern of stroke using the Lehigh Valley Stroke Register. This register includes all patients hospitalized with stroke or transient ischemk attack (TIA) from among the 600,000 Lehigh Valley residents. Meterological data were obtained from the National Oceanic and Atmospheric Administration. The study, which uses 18 months of data, included 1,944 cases. Using single harmonic regression analysis, the seasonal pattern of TIA and infarction, but not hemorrhage, fit a sine-cosine wavefunction with a 12-month period (R 2 = 41% and 36%, respectively). For infarction, the strongest seasonal pattern was exhibited for women of all ages and for both sexes in the age groups 65-74 and 75-84, but only the sine component was significant. The peak months for TIA were June-August, while the peak months for infarcts were February-April. Correlations between ambient temperature and each type of stroke were computed. A significant positive correlation for TIA was found (r = 0.57, p = 0.01). After adjusting for a 2-month lag between the low for infarction and the peak for temperature, a significant negative correlation was found (r = -0.64, p = 0.01). No significant correlation was found for hemorrhage. Possible reasons for the opposite relations of TLA and infarct are discussed. (Stroke 1987; 18:38-42)

Effect of Seasonal and Monthly Variation in Weather and Air Pollution Factors on Stroke Incidence in Seoul, Korea

“…An earlier study from Japan reported that diurnal temperature change may affect daily blood pressure or autonomic nervous system balance, and, if a considerable diurnal temperature change induces considerable hemodynamic change, it may trigger cerebral stroke. 31 In addition, some studies reported stronger seasonality in stroke in older age groups than in younger ones, 10,11,32,33 as seen in our study. We found a September preponderance in the monthly incidence of AS and IS.…”

“…Predictor variables included in these models were mean temperature, diurnal temperature range, humidity, PM 10 , and NO 2 . We scaled RR for temperature at increments of 1°C, for humidity at increments of 5%, and for pollutants at increments of 10 mg/m 3 .…”

“…Most studies have demonstrated that the incidence of stroke increases in the winter and spring and decreases in the summer and autumn. [3][4][5][6][7][8][9][10][11] However, some studies have reported increases in the incidence of stroke in response to dramatic temperature changes in the spring and autumn, [12][13][14] whereas in other studies, no seasonal variation has been demonstrated. [15][16][17] Because most previous studies have addressed large regions with varying climate, studies on smaller regions with similar weather and environments could provide important information on this topic.…”

Temperature variation in the 24 hours before the initial symptoms of stroke

“…Palavras-chave: acidente vascular cerebral, temperatura, risco cardiovascular, sazonal. The correlation between strokes and seasonal variations have been studied in various places [1][2][3][4][5][6][7][8] . Some studies around the world have reported an increase of incidence, mortality, and stroke hospitalization during the coldest months of winter.…”

Probability of stroke in the couples of stroke patients; using framingham stroke risk profile

“…For example; although some studies mentioned that the incidence and/or mortality of stroke were highest in winter through colder months (17,18), several reported that ischemic stroke incidence peaks in winter -spring months (19). Some authors also reported that improvement of in home heating might cause decline in stroke incidence (20).…”