Differential Effects of Activity and Climate on Onset of Subarachnoid Hemorrhage.

Abstract

Conflicting findings of the effect of climate on onset of subarachnoid hemorrhage (SAH) may result from the influence of strenuous activities which can trigger aneurysmal rupture independent of climatological factors. The effect of climate and patient activities on onset of SAH were analyzed. The clinical records of 786 consecutive patients with aneurysmal SAH admitted to our hospital for 10 years were reviewed. Activities at onset were categorized according to the intensity of strain at onset. Seasonal variation, circannual cyclic trend, and association with 90 meteorological factors were examined in each category and the results were compared between categories. Bimonthly occurrence in the light strain group showed a significant seasonal variation and cyclic trend with two peaks in early spring and fall, whereas no significant trend was detected in the overall patients and in the heavy strain group. The significant meteorological factors were global solar radiation, sunshine hours, changes in mean and minimum temperature and mean vapor pressure from the previous day, and minimum pressure in the previous 7 days. Lower global solar radiation in the light strain group was associated with onset with the lowest p value (p ＝ 0.0046). No factors were significant in the heavy strain group. There is some evidence of the possible influence of climatological factors on onset of SAH without strenuous activity. Strenuous activity seems to affect onset more strongly, which masks any effect of climate.

Monthly variations in aneurysmal subarachnoid hemorrhage incidence and mortality: Correlation with weather and pollution

“…Several studies have reported a possible correlation between SAH occurrence and atmospheric pressure, humidity, or insolation. [ 7 – 10 , 13 , 38 , 39 ] In the present study, we observed strong correlation between the incidence of SAH and temperature, atmospheric pressure, and precipitation ( S5 Table ). According to Gay-Lussac's Law (k = pressure/temperature; k = constant), atmospheric pressure is dependent on air temperature.…”

Geographical Analysis of Aneurysmal Subarachnoid Hemorrhage in Japan Utilizing Publically-Accessible DPC Database

“…Among the six highly-ranked prefectures continuously for 3 years with aSAH incidence, four prefectures (Aomori, Iwate, Akita and Yamagata) are in the northern territory, and two (Kochi and Kumamoto) in the south. Although climactic factors are expected to affect aneurysmal rupture [ 18 , 19 ], the climate does not completely explain the regional differences, since in several other northern territories, such as Hokkaido or Miyagi, aSAH is not so frequent, and the climate in Kochi or Kumamoto, where high aSAH incidence is observed, is very different from that in the northern territory. Other possible factors resulting in the regional difference are genetic factors [ 20 ], dietary habits in the region [ 21 ], or other unknown environmental factors.…”

Preventing Rupture: Clipping of Unruptured Intracranial Aneurysms

“…Aneurysmal rupture can also occur during stressful or strenuous activities such as sexual intercourse, labor, defecation, physical exertion, or sports [55]. However, these external factors may in fact conceal the climate impact, as numerous studies indicate a higher incidence of aneurysm rupture during the winter season, as well as during daytime [56][57][58][59].…”