D. Chyatte et al., SEASONAL FLUCTUATION IN THE INCIDENCE OF INTRACRANIAL ANEURYSM RUPTURE AND ITS RELATIONSHIP TO CHANGING CLIMATIC CONDITIONS, Journal of neurosurgery, 81(4), 1994, pp. 525-530
Seasonal and climatic variations have been linked to the occurrence of
some types of cerebrovascular disease; however, the conditions that l
ead to intracranial aneurysm rupture are not known. The purpose of the
present study was to determine whether seasonal and climatic conditio
ns are related to intracranial aneurysm rupture. Data provided by the
Connecticut Health Information Management and Exchange were analyzed f
or all patients with a primary diagnosis of aneurysmal subarachnoid he
morrhage (SAH) for the fiscal years 1981, 1983, 1985, 1987, 1988, and
1989. Patient records were correlated with climatic conditions for the
years 1981 to 1989 obtained from the National Climatic Data Center, N
ational Oceanic and Atmospheric Administration, National Environmental
Satellite Data, and Information Service. During the time periods stud
ied, 1487 patients with a primary diagnosis of aneurysmal SAH were tre
ated by reporting hospitals. Seasonal variation in the incidence of an
eurysmal SAH and admission clustering were observed but differed signi
ficantly between men and women. Men showed a single large peak in late
fall(Roger's r = 11.5, p < 0.005), whereas women had an annual peak o
ccurring in late spring (Roger's r = 10.3, p < 0.01). Substantial clim
atic change occurred during the 72 hours prior to 10 of the 14 cluster
s of men who were admitted (p < 0.01, Yates' corrected chi-square 7.33
, df = 1). In contrast, clusters of women admitted were not related to
preceding climatic change (p > 0.25, Yates' corrected chi-square 0.06
, df = 1). Hospital admissions for aneurysmal SAH display seasonal flu
ctuation, with women showing a different seasonal pattern from men. Ch
anging climatic conditions precede aneurysm rupture in men but not in
women, which suggests that weather is causally related to aneurysm rup
ture in men, and that factors that lead to aneurysm rupture in women m
ay be different from those in men. These data do not explain why weath
er fronts or gradients are associated with aneurysm rupture in men.