Weather patterns and occurrence of epileptic seizures.

BACKGROUND: The results of various studies that have so far evaluated the influence of meteorological conditions on seizures are often divergent. No studies have been performed so far that evaluate the possible correlation between the occurrence of seizure-related events, surface and upper level atmospheric conditions and biometeorological forecasts. The aim of this study is to investigate those interactions. METHODS: Records of "Sveti Duh" University hospital, Zagreb, Croatia between January 2016 and May 2020 were analysed in order to determine number of patients per day who were assessed through Emergency room because of a recent epileptic seizure. The dates were assessed for surface and upper level atmospheric conditions and biometeorological forecasts. Analyses of these factors were performed for two consecutive days preceding that day, the day of seizure, as well as for the following day. Data was analysed using chi-squared test, Mann-Whitney U-test or Kruskal-Wallis test (with Conover's test for post-hoc analyses), depending on variable type. Additionaly, logistic regression was used to study effects of variables on seizure occurrence. Statistical significance was set to p < 0.05. RESULTS: Results showed significant difference between the numbers of patients with seizure depending on upper level type on the following day. We also observed fewer daily patients with seizures when the synoptic situation on the following day was high pressure field then when it was low pressure or non-gradient pressure field (observed just during the colder part of the year), which was supported in our regression analyses. A greater frequency of seizures was observed if the biometerological prognosis was deemed unfavourable on the following day. Furthermore, our results showed significantly larger proportion of days with seizure patients in warmer, than in colder days of the year. CONCLUSIONS: All of the analyzed weather-related parameters seem to be associated with daily numbers of seizures on the previous day. The reason behind this phenomenon is uncertain; however, the results indicate that weather patterns have a certain influence on patients with epilepsy, but are not yet fully understood or adequately appreciated.

IS THERE A RELATIONSHIP BETWEEN COMPLICATIONS OF EARLY PREGNANCY AND BIOMETEOROLOGICAL FORECAST?

The aim of our study was to connect the possible complications of early pregnancy (miscarriage and symptomatic ectopic pregnancy) up to the 12th week of gestation with biometeorological conditions while assuming a greater number of incidents with an unfavorable biometeorological forecast. We performed a retrospective observational study using medical data of a single medical center of Department of Gynecology and Obstetrics, Sveti Duh University Hospital and meteorological data from the Croatian Meteorological and Hydrometeorological Service in Zagreb. We tracked the number of visits to the gynecology and obstetrics emergency unit on a daily basis during 2017. Days with five or more visits were selected and underwent further analysis, during which the number of miscarriages and symptomatic ectopic pregnancies was noted. The information from the biometeorological forecast was then extracted and added to the database. Our results did not show a statistically significant difference between the groups determined by biometeorological forecast in the number of spontaneous abortions or ectopic pregnancy. Also, statistically significant results did not follow the expected trend of the increasing number of complications related to worse biometeorological forecast, or vice versa, a decreased number of complications with better forecast. Our single-center retrospective analysis of emergency unit visits related to weather conditions did not show a connection between the complications of early pregnancy and biometeorological conditions. However, different results could emerge in future studies. Considering the large and high-quality database collected for this study, efforts in researching the connection between other gynecologic pathologies and weather conditions will be feasible.

Atmospheric conditions during high ragweed pollen concentrations in Zagreb, Croatia.

We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (> 600 grains/m(3)) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m(3). Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

Diurnal variation in airborne pollen concentrations of the selected taxa in Zagreb, Croatia.

The number of individuals allergic to plant pollen has recently been on a constant increase. The knowledge of diurnal distribution and abundance of allergenic pollen types, their patterns and response to source position and weather is useful to correlate hay fever symptoms with the presence of allergenic pollen in the atmosphere. The aim of this study was to determine diurnal distribution of total airborne pollen, pollen of particular allergenic taxa, possible variation in diurnal pollen distribution at measuring sites placed at different heights, and effect of some meteorological parameters on airborne pollen concentrations. A 7-day Hirst-type volumetric pollen trap was used for pollen sampling. Qualitative and quantitative pollen analysis was performed under a light microscope (magnification x400). Total pollen of all plant taxa (Ambrosia sp., Betula sp., Cupressaceae, Urticaceae, Poaceae, Quercus sp., Fraxinus sp., Alnus sp., Corylus sp., Populus sp., Pinus sp., Picea sp.) observed showed a regular diurnal distribution at both sampling sites in both study years, with a rise in the pollen concentration recorded after 4.00 a.m. and 6.00 a.m., respectively. The peak pollen concentration occurred between 12.00 a.m. and 4.00 p.m., and the lowest diurnal pollen concentrations were recorded overnight. About 50% of the 24-h pollen concentration were released to the atmosphere between 10.00 a.m. and 4.00 p.m. The timing and size of diurnal peaks were closely related to high temperature, low humidity and south-west maximum wind direction.

Airborne ragweed (Ambrosia artemisiifolia L.) pollen content in the city of Zagreb and implications on pollen allergy.

The increasing problem of sensitization to Ambrosia pollen in Europe has stimulated studies on Ambrosia pollen occurrence and pollinosis in Croatia. The aim of this study was to analyze the ragweed pollen pattern in Zagreb and to determine the incidence of sensitization to this pollen types in patients with seasonal respiratory allergy. The study was performed in the city of Zagreb during the 2002-2005 seasons. Skin prick test were performed on a total of 750 patients aged 18-80 in Zagreb between 2 January - 31 December 2004. The mean 4-year rate of ragweed pollen in the Zagreb atmosphere was 14.8% of all plant pollen. The highest rate of airborne ragweed pollen was recorded in August and September. 365 patients were allergic to ragweed pollen; 20.3% of them monosensitized; 10.9% allergic to Ambrosia and Artemisia pollen. Almost all study patients suffered the most severe symptoms in August and September. The highest proportion of allergic patients were recorded in the 31-50 age group and the lowest proportion in the >50 age group. Forecasting of allergenic pollen season in an area is a crucial pursuit for all developed countries, in order to minimize clinical symptoms in patients suffering from respiratory allergy. This can be achieved through public announcements by mass media (radio, television, internet, etc.) aiming to protect allergic individuals.

Variation in ragweed (Ambrosia artemisiifolia L.) pollen concentration in central Croatia, 2002-2003.

The aim of the study was to determine the onset, duration and termination of the ragweed pollen season; intradiurnal, daily and monthly pollen variation, and possible differences in the occurrence and concentration of ragweed pollen according to sampling sites between 2002 and 2003. The study was conducted at three sampling sites in central Croatia over two pollen seasons (2002 and 2003) using the volumetric method of sampling (Hirst type sampler). In 2003, the ragweed pollen season was by 43 % longer and the percentage proportion of ragweed pollen by 3.4 % greater in comparison with 2002. The total ragweed pollen count and number of days with ragweed pollen concentration greater than 30 pollen grains per m (3) air showed a declining tendency from East to West in both seasons. The intradiurnal peak concentration occurred between 10.00-14.00. The air concentration of ragweed pollen decreased with temperature decline and precipitation. Results of the study provided useful information to individuals allergic to ragweed pollen thereby allowing them to adjust their outdoor activities to avoid contact with the allergen.

Atmospheric pollen season in Zagreb (Croatia) and its relationship with temperature and precipitation.

The number of individuals allergic to plant pollen has recently been on a constant increase, especially in large cities and industrial areas. Therefore, monitoring of airborne pollen types and concentrations during the pollen season is of the utmost medical importance. The research reported in this paper aims to determine the beginning, course and end of the pollen season for the plants in the City of Zagreb, to identify allergenic plants, and to assess the variation in airborne pollen concentration as a function of temperature and precipitation changes for the year 2002. A volumetric Hirst sampler was used for airborne pollen sampling. Qualitative and quantitative pollen analysis was performed under a light microscope (magnification x400). In the Zagreb area, 12 groups of highly allergenic plants (alder, hazel, cypress, birch, ash, hornbeam, grasses, elder, nettles, sweet chestnut, artemisia and ambrosia) were identified. Birch pollen predominated in spring, the highest concentrations being recorded in February and March. Grass pollen prevailed in May and June, and pollen of herbaceous plants of the genus Urtica (nettle) and of ambrosia in July, August and September. Air temperature was mostly higher or considerably higher than the annual average in those months, which resulted in a many days with high and very high airborne pollen concentrations. The exception was April, when these concentrations were lower because of high levels of precipitation. This also held for the first half of August and the second half of September. Pollen-sensitive individuals were at high risk from February till October because of the high airborne pollen concentrations, which only showed a transient decrease when the temperature fell or there was precipitation.