UTCI as a bio-meteorological tool in the assessment of cold-induced stress as a risk factor for hypertension.

BACKGROUND: Hypertension (HT) affects >1/3 of adult populations in developed countries. Several studies reported periodic changes in blood pressure (BP) values depending on atmospheric conditions, and analyzed the impact of outdoor temperature, atmospheric pressure, relative humidity and other meteorological parameters. The Universal Thermal Climate Index (UTCI) is a bio-meteorological index derived from an analysis of human thermal balance that comprehensively describes the impact of meteorological factors, including both cold stress and heat stress and their physiological consequences. AIM: Our aim was to assess the relationship between UTCI values and the number of consultations for HT within the framework of the healthcare system. METHODS: This work presents a retrospective epidemiological study of data collected in Olsztyn (Poland), characterized by cold climate type. The analytical material comprised 5578 consultations in emergency departments (EDs) due to HT. RESULTS: Seasonal differences in the numbers of HT consultations with a significant increase in winter months were noticed, especially as regards women. Under cold stress conditions, the relative risk (RR) related to consultations for HT was 2-fold higher for women as compared to thermoneutral conditions (p < 0.001). For men these differences were also statistically significant, though at a much smaller level (p = 0.03). The increased RR of HT due to cold stress was found among younger and older women contrary to the women at the perimenopausal age. CONCLUSIONS: Cold stress should be considered as a significant risk factor among patients, particularly women, diagnosed with cardiovascular diseases. The UTCI is an adequate bio-meteorological tool for the assessment of relationships between atmospheric conditions and occurrence of cardiac symptoms.

Are the Levels of Lipid Parameters Associated with Biometeorological Conditions?

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.

Applicability of the universal thermal climate index for predicting the outbreaks of respiratory tract infections: a mathematical modeling approach.

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.