Cold: A risk factor for stroke?

Abstract

A retrospective study was performed to investigate seasonal variation in stroke incidence and to evaluate the hypothesis that cold might be a risk factor. Data were obtained from the central registry of the Hospital de S. João, Porto, Portugal, concerning 4048 patients consecutively admitted for cerebrovascular disease during a period of 33 months. Monthly admissions for stroke and its subtypes were related to mean values of ambient temperature using linear correlation. There was a strong inverse correlation between average temperature and total admissions for cerebrovascular disease (r = -0.72, P < 0.00005), intracerebral haemorrhage (r = -0.66, P < 0.00005), ischaemic stroke (r = -0.46, P = 0.007) and transient ischaemic attack (r = -0.41, P = 0.017). These correlations were independent of any seasonal variation in the number of hospital admissions due to all causes. No relation was found between temperature and subarachnoid haemorrhage. The rhythmometric analysis showed the presence of a statistically significant rhythm with an acrophase in the coldest months. These results support the hypothesis of stroke being a chronorisk disease to which cold might represent a triggering factor.

Urbanization and Stroke Prevalence in Taiwan: Analysis of a Nationwide Survey

“…Other prior studies have also reported that higher air pollution levels and greater levels of depression can lead to a correspondingly higher prevalence of strokes. [31][32][33][34][35][36][37] Furthermore, it is also possible that those study subjects in the upper income group would be more likely to reside in the less urbanized areas and more likely to receive regular health check-ups, possibly from private health care facilities which tend to be better equipped; thus, they would be at a lower risk of suffering a stroke attack. In contrast, the study subjects in the lower income group may well work and live in the inner city areas, and for various reasons, may be exposed to a higher risk of disease and a corresponding increase in the risk of a stroke attack.…”

“…Given that some of the prior literature has consistently demonstrated that fluctuations in climate have a significant impact on the occurrence of strokes, [31][32][33][34] it is possible that the majority of the communities at urbanization level 2 would be located in the central and southern regions of Taiwan, which are renowned for having a very stable climate, and this could potentially affect this result.…”

Involvement of Meteorological Factors and Sex in the Occurrence of Subarachnoid Hemorrhage in Japan

“…[4][5][6]15,20,24,26,32,33) No statistically significant seasonal variations were also observed in some studies. 2,12,14,17,22,27,[29][30][31] The highest occurrences of SAH were found in spring in women and in late fall in men, 4) in spring and fall in men, and in winter in women, 24) and in winter in women and no peak in men. 32) Our data resembled the results of 10 years of the Canadian Collaborative Study Group although the lowest occurrence in their male group was in summer whereas that of in the present study was in winter.…”

“…2,4,6,11,12,14,15,17,18,20,22,24,26,27,[29][30][31][32][33] Hospital-based and populationbased studies that demonstrated significant seasonal variation found that the peak period for SAH differed widely. [4][5][6]15,20,24,26,32,33) No statistically significant seasonal variations were also observed in some studies.…”

“…8,13) However, investigation of the seasonal incidence of SAH has identified environmental and sociomedical factors correlated with aneurysm rupture. 2,4,6,11,12,14,15,17,18,20,22,24,26,27,[29][30][31][32][33] The present study investigated the relationship between sex and seasonal occurrence of SAH.…”