Predictive value of three thermal comfort indices in low temperatures on cardiovascular morbidity in the Iberian peninsula.

The natural environment has been considered an important determinant of cardiovascular morbidity. This work seeks to assess the impact of the winter thermal environment on hospital admissions from diseases of the circulatory system by using three biometeorological indices in five regions of the Iberian Peninsula. A theoretical index based on a thermophysiological model (Universal Thermal Climate Index [UTCI]) and two experimental biometeorological ones (Net Effective Temperature [NET] and Apparent Temperature [AT]) were estimated in two metropolitan areas of Portugal (Porto and Lisbon) and in three provinces of Spain (Madrid, Barcelona and Valencia). Subsequently, their relationship with hospital admissions, adjusted by NO2 concentration, time, and day of the week, was analyzed using a Generalized Additive Model. As the estimation method, a semi-parametric quasi-Poisson regression was used. Around 53% of the hospitalizations occurred during the cold periods. The admissions rate followed an upward trend over the 9-year period in both capitals (Madrid and Lisbon) as well as in Barcelona. An inverse and statistically significant relationship was found between thermal comfort and hospital admissions in the five regions (p < 0.001). The highest relative risk (RR) was found after a cumulative 7-day exposure in Lisbon, where there was a 1.4% increase in hospital admissions for each NET and AT degree Celsius, and 1.0% for each UTCI degree Celsius. In conclusion, low air temperatures are a significant risk factor for hospital admissions from diseases of the circulatory system in the Iberian Peninsula, regardless of the index calculated.

Association Between Suicide and Environmental Variables in the North of Spain: A 14-Year Analysis.

Suicide is a serious public health problem around the world. Since the nineteenth century, the impact of socio-environmental factors on suicide has attracted much public attention, especially in the context of global climate change. We have performed a retrospective correlation study that analyzes the demographic pattern of suicide in Cantabria, a northern coastland region of Spain. Moreover, we have created a multivariable binomial regression model to study the relationship between suicide and environmental factors (atmospheric pollutants and meteorological variables) among January 1, 2000, and December 31, 2013 in the province. During the 14-year study period, there was a suicide annual incidence of 4.9 cases per 100,000 population in Cantabria. The incidence was highest in adults aged 70-74 years old (11.8 per 100,000 population). The most common method group of suicide was hanging, strangulation and suffocation, accounting for 49.3% of all suicide deaths. When correlating suicide and meteorological variables, a statistically significant association was found with the level of cloudiness (p = 0.007). According to our results, an increase of one eighth of sky cloud-cover correlated to a 7% increase in total deaths by suicide and the association was especially strong during spring.

Fewer clouds in the Mediterranean: consistency of observations and climate simulations.

Clouds play a major role in the climate system, but large uncertainties remain about their decadal variations. Here we report a widespread decrease in cloud cover since the 1970 s over the Mediterranean region, in particular during the 1970 s-1980 s, especially in the central and eastern areas and during springtime. Confidence in these findings is high due to the good agreement between the interannual variations of cloud cover provided by surface observations and several satellite-derived and reanalysis products, although some discrepancies exist in their trends. Climate model simulations of the historical experiment from the Coupled Model Intercomparison Project Phase 5 (CMIP5) also exhibit a decrease in cloud cover over the Mediterranean since the 1970 s, in agreement with surface observations, although the rate of decrease is slightly lower. The observed northward expansion of the Hadley cell is discussed as a possible cause of detected trends.

The Influence of Nitrogen Dioxide on Arrhythmias in Spain and Its Relationship with Atmospheric Circulation.

Epidemiological studies suggest that increased ambient NO2 concentrations are associated with cardiovascular disease. However, none of them have examined the association between ambient air pollution and cardiac arrhythmias in the general population in Spain. This paper assesses the short-term association between the aforementioned air pollutant and hospital admissions for arrhythmia in nine different regions of Spain during a 6-year period (2005-2010), and the possible season-specific effects of the compound on this pathology, by performing a time-series analysis based on Poisson regression models. The results show statistically significant positive relationship increases between arrhythmia admissions and increments in NO2 concentration during the whole year, most notably in wintertime. Moreover, while trying to establish a threshold for NO2 concentration above which the incidence of arrhythmia episodes increases significantly, this study reveals that hospital admissions increased linearly in response to an increase in as we move to higher NO2 concentration levels. Finally, an analysis of NO2 concentrations and their relationship with atmospheric circulation is performed, showing higher values of NO2 under anticyclonic conditions during winter that could be used for implementing pollution level alert protocols depending on forecast circulation patterns.

Stroke: Temporal Trends and Association with Atmospheric Variables and Air Pollutants in Northern Spain.

Stroke, the second cause of death and the most frequent cause of severe disability among adults in developed countries, is related to a large variety of risk factors. This paper assesses the temporal patterns in stroke episodes in a city in Northern Spain during a 12-year period and analyzes the possible effects that atmospheric pollutants and meteorological variables may have on stroke on a daily scale. Our results show that there is an increase in stroke admissions (r = 0.818, p = 0.001) especially in patients over 85 years old. On a weekly scale, the number of hospital admissions due to stroke remains stable from Monday to Friday, whereas it abruptly decreases during the weekends, reaching its minimum values on Sunday (p < 0.005); however, mortality in patients admitted to the hospital is higher on Sundays than on other days of the week. Finally, a statistically significant positive correlation between the number of stroke hospital admissions and NO2 levels (p = 0.012) and an inverse correlation with relative humidity (p = 0.032) were found. The analysis of the relationship between ischemic strokes and atmospheric circulation shows a higher frequency of the former in Santander with enhanced negative air pressure anomalies over western Spain; the fact that under these conditions the region studied registers very low values of relative humidity is in line with the aforementioned inverse correlation, which has not been described elsewhere in the literature. This study could be a first step for implementing stroke alert protocols depending on air pollution levels and circulation patterns forecasts.

Response of vegetation to drought time-scales across global land biomes.

We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change.