Environmental effects and gene-environment interactions: air pollution and temperature effects on cardiovascular risk factors.

Epidemiological studies have shown that elevated air pollution levels and day-to-day variations in air temperature are associated with increases in cardiovascular events such as arrhythmias, myocardial infarctions, and sudden cardiac death. Precursors of these events might be acute changes in heart rate, a reduced heart rate variability (HRV), and changes in the repolarization of the heart, such as QTc-prolongation as well as changes in T-wave amplitude. Furthermore, elevated levels of blood markers of inflammation and coagulation might also lead to the observed adverse cardiac health outcomes. There is already a large body of literature with regard to air pollution effects on HRV parameters and blood markers but the exact biological pathways are still unclear. Little is known about the association between temperature and HRV as well as blood markers. Moreover, potential mechanisms how air pollutants and temperature affect repolarization have received less attention. Researchers have reported that individuals with genetic predispositions or underlying diseases such as diabetes mellitus type 2 might be more susceptible to air pollution exposure. Therefore, more comprehensive investigations in these groups of individuals are necessary in order to gain a better insight in the biological mechanisms. In the first publication of this thesis, I examined the effects of air temperature on markers of inflammation and coagulation in men with coronary or pulmonary disease. A temperature decrease was associated with changes in several blood biomarkers such as platelet counts, factor VII, fibrinogen, and C-reactive protein. However, the direction and timing of the relationship differed between patients with coronary and pulmonary disease. In a second publication, I observed a prolongation of the QT-interval in association with elevated levels of particulate matter (PM) in myocardial infarction survivors. This association was more pronounced in participants with at least one minor allele of the NFE2L2 single nucleotide polymorphism (SNP) rs2364725 which is believed to be involved in the defense against oxidative stress. Furthermore, I detected immediate T-wave flattening and delayed increases in T-wave amplitude associated with elevated air pollution levels. The association between temperature and the T-wave amplitude was inversely U-shaped with highest values at 5C. In a third study among participants with diabetes or impaired glucose tolerance (IGT), I detected reduced HRV, predominantly the standard deviation of normal-to-normal intervals, in association with increases in PM and ultrafine particles. These effects were more pronounced in participants with IGT. I also observed air pollution effect modifications by SNPs supposed to influence cardiac rhythm. In conclusion, this thesis confirms and extends published results on short-term air pollution effects on intermediate markers of cardiovascular system. Furthermore, it is among the first to examine air temperature effects on blood and ECG parameters. Certain medical conditions as well as certain genetic profiles seem to make some subpopulations more susceptible to environmental stressors. The observed changes in HRV and blood markers might partly explain the reported associations between environmental conditions and cardiovascular events

Air temperature and inflammatory and coagulation responses in men with coronary or pulmonary disease during the winter season

Background and Objective Air temperature changes are associated with increased cardiovascular and respiratory risk, but the roles of inflammatory and coagulation markers are not well understood. We investigated the associations between temperature and several blood markers in patients with coronary heart disease (CHD) and pulmonary disease (PD). Methods Two studies were conducted in Erfurt, Germany, over two successive winters. 578 and 381 repeated blood measurements were collected from 57 CHD and 38 PD patients, respectively. Data on patient characteristics and disease history were gathered at baseline. Meteorological data were collected from existing networks. Associations were analysed using additive mixed models with random patient effects. Effect modification by diabetes status was investigated only in CHD patients, as only two PD patients had diabetes. Results Mean daily air temperature varied between -13 degrees C and 16 degrees C in both study periods. A 10 degrees C decrease in the 5-day temperature average before blood withdrawal led to an increase in platelet counts (% change from the mean: 3.0%, 95% CI 0.6% to 5.5%) and fibrinogen (5.5%, 1.3% to 9.7%), no change in C-reactive protein in PD patients, and a decrease in C-reactive protein in CHD patients. A 2-day delayed increase in factor VII associated with temperature decrease was seen in CHD patients (4.9%; 0.7% to 9.2%), while PD patients showed no effect. `Effects in CHD patients without diabetes' into `Effects on factor VII in CHD patients without diabetes'. Conclusions This study suggests that temperature decrease is associated with change in several blood parameters. The complex interplay of blood markers at low temperature may contribute to the observed association between cold and cardiovascular mortality and morbidity

Immediate ozone effects on heart rate and repolarisation parameters in potentially susceptible individuals

Elevated ozone levels have been associated with cardiovascular morbidity and mortality. We investigated the effects of ozone on heart rate (HR) and repolarisation parameters in potentially susceptible populations

Changes in deceleration capacity of heart rate and heart rate variability induced by ambient air pollution in individuals with coronary artery disease

<p>Abstract</p> <p>Background and Objective</p> <p>Exposure to ambient particles has been shown to be responsible for cardiovascular effects, especially in elderly with cardiovascular disease. The study assessed the association between deceleration capacity (DC) as well as heart rate variability (HRV) and ambient particulate matter (PM) in patients with coronary artery disease (CAD).</p> <p>Methods</p> <p>A prospective study with up to 12 repeated measurements was conducted in Erfurt, Germany, between October 2000 and April 2001 in 56 patients with physician-diagnosed ischemic heart disease, stable angina pectoris or prior myocardial infarction at an age of at least 50 years. Twenty-minute ECG recordings were obtained every two weeks and 24-hour ECG recordings every four weeks. Exposure to PM (size range from 10 nm to 2.5 μm), and elemental (EC) and organic (OC) carbon was measured. Additive mixed models were used to analyze the association between PM and ECG recordings.</p> <p>Results</p> <p>The short-term recordings showed decrements in the high-frequency component of HRV as well as in RMSSD (root-mean-square of successive differences of NN intervals) in association with increments in EC and OC 0-23 hours prior to the recordings. The long-term recordings revealed decreased RMSSD and pNN50 (% of adjacent NN intervals that differed more than 50 ms) in association with EC and OC 24-47 hours prior to the recordings. In addition, highly significant effects were found for DC which decreased in association with PM_2.5, EC and OC concurrent with the ECG recordings as well as with a lag of up to 47 hours.</p> <p>Conclusions</p> <p>The analysis showed significant effects of ambient particulate air pollution on DC and HRV parameters reflecting parasympathetic modulation of the heart in patients with CAD. An air pollution-related decrease in parasympathetic tone as well as impaired heart rate deceleration capacity may contribute to an increased risk for cardiac morbidity and sudden cardiac death in vulnerable populations.</p

Altered Cardiac Repolarization in Association with Air Pollution and Air Temperature among Myocardial Infarction Survivors

Background: Epidemiological studies have shown that ambient particulate matter (PM) and changes in air temperature are associated with increased cardiopulmonary events. Objective: We hypothesized that patients with previous myocardial infarction (MI) experience changes in heart rate (HR) and repolarization parameters, such as Bazett-corrected QT interval (QTc), and T-wave amplitude (Tamp), in association with increases in air pollution and temperature changes. Methods: Between May 2003 and February 2004, 67 MI survivors from the Augsburg KORA-MI registry repeatedly sent 16 sec electrocardiograms (ECGs) with a personal transmitter (Viapac) via telephone to the Philips Monitoring Center, where ECG parameters were immediately analyzed. Meteorological data and air pollutants were acquired from fixed monitoring sites on an hourly basis. Additive mixed models were used for analysis. Effect modification by patient characteristics was investigated. Results: The analysis of the 1,745 ECGs revealed an increased HR associated with interquartile range (IQR) increases in PM levels among participants not using beta-adrenergic receptor blockers and among those with body mass index ≥ 30 kg/m2. We observed a 24- to 47-hr lagged QTc prolongation [0.5% change (95% confidence interval, 0.0–1.0%)] in association with IQR increases in levels of PM ≤ 2.5 µm in aerodynamic diameter, especially in patients with one [0.6% (0.1–1.0%)] or two [1.2% (0.4–2.1%)] minor alleles of the nuclear factor (erythroid-derived 2)-like 2 (NFE2L2) single-nucleotide polymorphism rs2364725. Positive immediate (0–23 hr) and inverse delayed (48–71 hr up to 96–119 hr) associations were evident between PM and Tamp. We detected an inverse U-shaped association between temperature and Tamp, with a maximum Tamp at 5°C. Conclusions: Increased air pollution levels and temperature changes may lead to changes in HR and repolarization parameters that may be precursors of cardiac problems.The AIRGENE study was funded as part of the European Union’s 5th Framework Programme, key action 4: “Environment and Health,” contract QLRT-2002-02236. This research has been funded wholly or in part by the U.S. Environmental Protection Agency through Science to Achieve Results grants RD827354 and RD832415 to the University of Rocheste

RELAÇÕES MORFOMÉTRICAS PARA Araucaria angustifolia (Bertol.) Kuntze EM SANTA CATARINA

Conhecer a morfometria de uma espécie e descrever suas relações auxilia no planejamento e uso sustentável da floresta. O trabalho objetivou analisar relações morfométricas, a fim de ajustar modelos que representem 121 árvores de Araucaria angustifolia amostradas em dois sítios em São José do Cerrito, Planalto Catarinense. Foram mensurados: diâmetro à altura do peito (Dap), altura (h), altura de inserção de copa (hic), raio de copa (rc), comprimento de copa (cc), diâmetro de copa (dc), índice de abrangência (IA), índice de saliência (IS), grau de esbeltez (GE), formal de copa (FC), proporção de copa (Pc%) e a posição sociológica (PS) de cada indivíduo. Foi usada correlação de Person para avaliar as relações entre variáveis morfométricas. Empregou-se a análise de covariância para verificar diferença de nível e inclinação nos ajustes dos modelos para os sítios. O ajuste dos modelos foi realizado pelos modelos lineares generalizados (MLG) nos campos de distribuição gama e normal, função de ligação identidade e logarítmica para correlações maiores ou iguais a 0,7. A análise de covariância demonstrou diferenças nas relações para cada sítio, indicando o ajuste de equações distintas. As equações demonstraram variações nas relações morfométricas pela mudança forma-dimensão de cada árvore. Os resultados mostram a modificação na forma da copa, a partir da posição social de cada árvore, além da influência diamétrica e do espaço ocupado por cada árvore na floresta, competição e condições do sítio. As relações morfométricas estabelecidas foram importantes para explicar a dinâmica de crescimento da espécie e a aplicação de intervenções silviculturais.Palavras-chave: morfometria, modelagem, manejo florestal. AbstractMorphometric relations for Araucaria angustifolia (Bertol.) Kuntze in Santa Catarina, Brazil. Knowing the morphometry of a species and describing its relations help us in the planning and in the sustainable use of the forest. The objective of this study was to analyze morphometric relationships in order to fit models representing 121 Araucaria angustifolia trees sampled at two sites in São José do Cerrito, Planalto Catarinense. The measures were: diameter at breast height (Dap), height (h), crown insertion height (hic), crown radius (rc), crown length (cc), crown diameter (dc), slenderness index (IS), degree of slenderness (GE), formal cup (HR), crown ratio (Pc%) and sociological position (PS) of each individual. Person correlation was used to evaluate the relationships between morphometric variables. The covariance analysis was used to verify difference of level and slope in the adjustments of the models for the sites. The fit of the models was done by generalized linear models (MLG) in the gamma and normal distribution fields, identity and logarithmic link function for correlations greater than or equal to 0.7. The covariance analysis showed differences in the relations for each site, indicating the adjustment of different equations. The equations showed variations in morphometric relationships due to the shape-dimension change of each tree. The results show the modification in the shape of the canopy, from the social position of each tree, besides the diametrical influence and the space occupied by each tree in the forest, competition and site conditions. The established morphometric relationships were important to explain the growth dynamics of the species and the application of silvicultural interventions.Keywords: morphometry, modeling, forest management