BackgroundThe homeless constitute a subpopulation particularly exposed to atmospheric conditions, which, in the temperate climate zone, can result in both cold and heat stress leading to the increased mortality hazard. Environmental conditions have become a significant independent risk factor for mortality from specific causes, including circulatory or respiratory diseases. It is known that this group is particularly prone to some addictions, has a shorter life span, its members often die of different causes than those of the general population and may be especially vulnerable to the influence of weather conditions.Materials and methodsThe retrospective analysis is based on data concerning 615 homeless people, out of which 176 died in the analyzed period (2010–2016). Data for the study was collected in the city of Olsztyn, located in north-east Poland, temperate climatic zone of transitional type. To characterize weather conditions, meteorological data including daily minimum and maximum temperatures and the Universal Thermal Climate Index (UTCI) were used.ResultsThe average life span of a homeless person was shorter by about 17.5 years than that recorded for the general population. The average age at death of a homeless male was 56.27 years old (SD 10.38), and 52.00 years old (SD 9.85) of a homeless female. The most frequent causes of death were circulatory system diseases (33.80%). A large number of deaths were attributable to smoking (47.18%), whereas a small number was caused by infectious diseases, while a relatively large proportion of deaths were due to tuberculosis (2.15%). Most deaths occurred in the conditions of cold stress (of different intensity). Deaths caused by hypothermia were thirteen-fold more frequently recorded among the homeless than for the general population. A relative risk of death for a homeless person even in moderate cold stress conditions is higher (RR = 1.84) than in thermoneutral conditions.ConclusionsOur results indicate excessive mortality among the homeless as well as the weak and rather typical influence of atmospheric conditions on mortality rates in this subpopulation, except for a greater risk of cold related deaths than in the general population. UTCI may serve as a useful tool to predict death risk in this group of people.

Respiratory tract infections (RTI) are one of the most frequent reasons for medical consultations. As air temperature decreases, but also in connection with other meteorological parameters, evident seasonal fluctuations in the number of consultations for RTI can be observed. The Universal Thermal Climate Index (UTCI) is a complex meteorological index derived from an analysis of human thermal balance that depends on air temperature, air humidity, and wind speed. Our aims were to check if this index, although never used before for that purpose, is an adequate tool for forecasting seasonal increases in RTI prevalence. This study is a retrospective analysis of patients' consultations with general practitioners in the period of 2012-2015 (453,674 records) recorded in the city of Olsztyn (Poland), which is characterized by a cold climate type (Dfb). The values of air temperature, atmospheric pressure, relative air humidity, wind speed, and UTCI were used for a statistical analysis and a mathematical analysis of curve fitting in order to determine correlations between analyzed meteorological parameters and a number of medical consultations for RTI. Analysis of the number of medical consultations for RTI revealed an evident seasonal pattern in a 4-year observation period, with a strong inverse correlation between the number of patients with RTI and the UTCI. A statistically significant increase in the number of patients with RTI appeared when the UTCI decreased, especially when it reached the classes of strong cold stress and very strong cold stress. In conclusion, the UTCI is a valuable predictive parameter for forecasting seasonal increases in RTI cases. Its decrease may initiate a seasonal increased prevalence. This effect is strongest about the 10th day following a change in the thermal climate conditions and is not continuous. A larger number of consultations for RTI after weekends and holidays (the Monday effect) may blur the results of statistical analyses.

The incidence of asthma exacerbation depends on atmospheric conditions, including such meteorological factors as the ambient temperature, relative air humidity or concentration of atmospheric aerosols. An assessment of relations between the frequency of asthma exacerbation and environmental conditions was made according to the meteorological components, the biometeorological index UTCI (Universal Thermal Climate Index), as well as selected air quality parameters, including concentrations of PM 10 and PM 2.5. the study was conducted on the basis of a retrospective analysis of medical data collected at the Independent Public Hospital of Tuberculosis and Pulmonary Diseases in Olsztyn (Poland). Our analysis of patient data (from 1 January 2013 until 31 December 2017) showed a significant correlation between the number of asthma exacerbation and the UTCI value. More frequent asthma exacerbations are observed in patients aged over 65 years when air humidity increases. the UTCI values contained within class 5, describing thermoneutral conditions, correspond to an average frequency of asthma exacerbation. A decline in the UTCI value leads to a reduced number of asthma exacerbation, while a rise makes the cases of asthma exacerbations increase.

This study analysed the effects of weather conditions on the growth and yield of five cultivars of Actinidia arguta, also called hardy kiwifruit, kiwiberry cultivated during 2005-2014 in the Experimental Garden of the University of Warmia and Mazury in Olsztyn, north-eastern Poland. The following cultivars were studied: 'Figurnaja', 'Kijevskaja Gibrydnaja', 'Kijevskaja Krupnoplodnaja', 'Purpurovaja Sadovaja' and 'Sientiabrskaja'. For each cultivar, the following were determined: yielding and the beginning dates of the following phenophases: budswelling, flowering, fruit setting, fruit maturity and the plant growth stages. For the phenophases, the following values were calculated: mean daily temperature (°C), sum of effective temperatures (>5°C and >10°C) and sum of precipitation (mm). Individual phenophases of the analysed cultivars of hardy kiwifruit started in a given year almost on the same dates and demonstrated high year-on-year variety. The largest differences (in four weeks) between the extreme dates were recorded for the fruit maturity of the Actinidia arguta. The differences between the extreme dates of other phases averaged two weeks. Simulated data satisfying the assumptions of the assumed climate change scenarios (GISS model E) were used in order to obtain information about future climatic conditions in which kiwiberry could be cultivated in the region of north-eastern Poland. Using the weather generator WGENK, 300 probable variants of weather sequences were generated in annual periods, which made it possible to examine the probable diversity of future weather conditions. Comparative characteristics of climatic indicators determined on the basis of the data from the 2005-2014 years and the generated data demonstrated that the climatic conditions of the area of north-eastern Poland could be subject to significant change, particularly in thermal resources. Spring frosts, which in the future could be more intense and could emerge much later than now, continue to pose an element of risk related to Actinidia arguta cultivation.

Lipid disorders, especially hypercholesterolemia, are one of the most thoroughly investigated cardiovascular risk factors. Their correlation with biometeorological conditions has been reported, with authors stressing seasonal increases of total cholesterol (TC) levels, mostly occurring in winter. This study aims at determining the correlation between the level of lipid parameters (LP) and meteorological conditions, analyzing seasonal variations in LP levels, and attempting to answer the following questions: do changes in LP levels result from the organism’s response to cold or heat stress, or are they secondary to seasonal dietary variations? An observational study comprised ambulatory patients from the city of Olsztyn (Poland), for whom laboratory test were performed in 2016–2018, with 106,325 records of TC, high-density lipoprotein (HDL), and triglycerides (TG). LP levels were matched with atmospheric conditions on the day when the test was conducted and expressed by the universal thermal climate index (UTCI). We demonstrated seasonal increases of TC in cold stress (in wintertime) and of TG in heat stress (summer). The analysis of LP levels in specific periods revealed the increase of TC levels after holidays (i.e., Christmas and Easter) in men by 4.56%, and the increase of TG levels in women by 13.46% in the same period. Our results suggest the secondary, diet-dependent underlying cause of the observed changes. This work contributes to the discussion concerning the impact of biometeorological factors on LP levels and may be of significance when planning population-dedicated preventive activities.