Diurnal and Seasonal Variations in the Onset of Spontaneous Intracerebral Hemorrhage

Shin, M H; Park, H K; Joo, W I; Lee, K J; Rha, H K

Abstract

OBJECTIVE
The purpose of this hospital-based study is first to estimate the diurnal and seasonal variations in the onset of spontaneous intracerebral hemorrhage (ICH) and second to investigate whether or not there are differences between young and old age groups.
METHODS
During 2004 through 2006, 140 consecutive patients with primary spontaneous ICH were treated in our hospital. Diurnal and seasonal variations in the onset of ICH among the entire population were evaluated. Differences of periodicities between young (65 years of age or younger) and old (66 years of age or older) age groups were also determined.
RESULTS
In the analysis of diurnal variation among the entire population, the onset of ICH exhibited a bimodal distribution, with an initial higher peak between 10:00 and 12:00 a.m. (15%) and a second lower peak between 4:00 and 6:00 p.m. (13.5%). In young age group (65 years of age or younger), the diurnal variation showed a very similar bimodal distribution with a higher peak between 10:00 and 12:00 a.m. (19.4%) and a lower peak between 4:00 and 6:00 p.m. (14.9%). In old age group (66 years of age or older), the onset of ICH exhibited a different variation with a unimodal peak between 12:00 a.m. and 2:00 p.m. (13.6%). In the analysis of seasonal variation, there was an increase of occurrence during the winter months (December to February) and a decrease during the summer months (June to August) among the whole population. No difference of seasonal distribution was observed between the two age groups.
CONCLUSIONS
The occurrence of spontaneous ICH is increased in the late morning and in the early afternoon. The occurrence of ICH is increased during the winter months. At the treatment for HTN, the choice of medication and the schedule of prescription should be made considering an occurring pattern of ICH.