The lipophilic character of quercetin suggests that it can cross enterocyte membranes via simple diffusion. Therefore, it should be more bioavailable than its glucosides, which require preliminary hydrolysis or active transport for absorption. However, the published human studies show that quercetin is less bioavailable than its glucosides. Assuming that low bioavailability of quercetin aglycone provided to humans as a pure substance is the result of its low solubility in the digestive tract, we studied its bioavailability from dietary sources in which quercetin was dispersed in the food matrix. In a randomized crossover study, 9 volunteers took a single dose of either shallot flesh (99.2% quercetin glucosides and 0.8% quercetin aglycone) or dry shallot skin (83.3% quercetin aglycone and 16.7% quercetin glucosides), providing 1.4 mg quercetin per kg of body weight. Blood samples were collected before and after consumption of shallot preparations. Plasma quercetin was measured on HPLC with electrochemical detection after plasma enzymatic treatment. The maximum plasma quercetin concentration of 1.02 ± 0.13 μmol/L was reached at 2.33 ± 0.50 h after shallot flesh consumption compared with 3.95 ± 0.62 μmol/L at 2.78 ± 0.15 h after dry skin consumption. The area under the concentration-time curve after dry skin consumption was 47.23 ± 7.53 μmol·h⁻¹·L⁻¹ and was significantly higher than that after shallot flesh intake (22.23 ± 2.32 μmol·h⁻¹·L⁻¹). When provided along with dietary sources, quercetin aglycone is more bioavailable than its glucosides in humans. Results point to the food matrix as a key factor.

The 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. The 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. The 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. Our 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.

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 indexUTCI(Universal Thermal Climate Index), as well as selected air quality parameters, including concentrations of PM₁₀and 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 theUTCIvalue. More frequent asthma exacerbations are observed in patients aged over 65 years when air humidity increases. TheUTCIvalues contained within class 5, describing thermoneutral conditions, correspond to an average frequency of asthma exacerbation. A decline in theUTCIvalue leads to a reduced number of asthma exacerbation, while a rise makes the cases of asthma exacerbations increase.

The ways in which homeless individuals cope with stress may differ from those relied upon by the members of the general population and these differences may either be the result or the cause of their living conditions. The aim of the study was to determine the preferred coping style among the homeless and its relationship with alcohol dependence. The study included 78 homeless individuals and involved the collection of demographic, sociological, psychological and medical data from each participant. Coping styles relied upon when dealing with stressful situations were assessed using a Polish adaptation of the Coping Inventory for Stressful Situations. Alcohol dependence was assessed using the Michigan Alcoholism Screening Test (MAST) and a quantitative analysis of alcohol consumption. Men accounted for 91.93% of the study population. Nearly 75% of the subjects met the alcohol dependence criterion. Significant relationships were observed between the individual's age, preferred coping style and alcohol consumption level. As an individual’s age increased, the use of emotion-oriented coping styles decreased, while an increase in alcohol consumption was associated with a more frequent use of emotion- and avoidance-oriented strategies. The findings of this study, similarly to those of many other studies of homeless individuals but investigating other areas (e.g. epidemiology of tuberculosis and traumatic injuries), are an exaggerated representation of associations observed in the general population. The results describe a group of people living on the margins of the society, often suffering from extremely advanced alcoholism, with clear evident psychodegradation. The presence of specific ways of coping with stress related to excessive alcohol consumption in this group of individuals may interfere with active participation in support programmes provided for the homeless and may further exacerbate their problems.