Age and Meteorological Factors in the Occurrence of Spontaneous Intracerebral Hemorrhage in a Metropolitan City

OBJECTIVE: The aim of this study was to investigate the correlation between meteorological factors and occurrence of spontaneous intracerebral hemorrhage (ICH) according to age. MATERIALS AND METHODS: We retrospectively analyzed the records of 735 ICH patients in a metropolitan hospital-based population. Observed and expected numbers of ICH patients were obtained at 5℃ intervals of ambient temperature and a ratio of observed to expected frequency was then calculated. Changes in ambient temperature from the day before ICH onset day were observed. The Wilcoxon-Mann-Whitney test was used to test differences in meteorological variables between the onset and non-onset days. The Kruskal-Wallis test was used for comparison of meteorological variables across gender and age. RESULTS: ICH was observed more frequently (observed/expected ratio ≥ 1) at lower mean, minimum, and maximum ambient temperature (p = 0.0002, 0.0003, and 0.0002, respectively). Significantly lower mean, minimum, and maximum ambient temperature, dew point temperature, wind speed, and atmospheric pressure (p = 0.0003, 0.0005, 0.0001, 0.0013, 0.0431, and 0.0453, respectively) was observed for days on which spontaneous ICH occurred. In the subgroup analysis, the ICH onset day showed significantly lower mean, minimum, and maximum ambient temperature, dew point temperature, relative humidity, and higher atmospheric pressure in the older (≥ 65 years) female group (p = 0.0093, 0.0077, 0.0165, 0.0028, 0.0055, and 0.0205, respectively). CONCLUSION: Occurrence of spontaneous ICH is closely associated with meteorological factors and older females are more susceptible to lower ambient temperature.