Browsing by Subject "CASE-CROSSOVER"

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  • Rivas, Ioar; Vicens, Laia; Basagana, Xavier; Tobias, Aurelio; Katsouyanni, Klea; Walton, Heather; Hüglin, Christoph; Alastuey, Andres; Kulmala, Markku; Harrison, Roy M.; Pekkanen, Juha; Querol, Xavier; Sunyer, Jordi; Kelly, Frank J. (2021)
    Background: The evidence on the association between ultrafine (UFP) particles and mortality is still inconsistent. Moreover, health effects of specific UFP sources have not been explored. We assessed the impact of UFP sources on daily mortality in Barcelona, Helsinki, London, and Zurich. Methods: UFP sources were previously identified and quantified for the four cities: daily contributions of photonucleation, two traffic sources (fresh traffic and urban, with size mode around 30 nm and 70 nm, respectively), and secondary aerosols were obtained from data from an urban background station. Different periods were investigated in each city: Barcelona 2013-2016, Helsinki 2009-2016, London 2010-2016, and Zurich 2011-2014. The associations between total particle number concentrations (PNC) and UFP sources and daily (natural, cardiovascular [CVD], and respiratory) mortality were investigated using city-specific generalized linear models (GLM) with quasi-Poisson regression. Results: We found inconsistent results across cities, sources, and lags for associations with natural, CVD, and respiratory mortality. Increased risk was observed for total PNC and natural mortality in Helsinki (lag 2; 1.3% [0.07%, 2.5%]), CVD mortality in Barcelona (lag 1; 3.7% [0.17%, 7.4%]) and Zurich (lag 0; 3.8% [0.31%, 7.4%]), and respiratory mortality in London (lag 3; 2.6% [0.84%, 4.45%]) and Zurich (lag 1; 9.4% [1.0%, 17.9%]). A similar pattern of associations between health outcomes and total PNC was followed by the fresh traffic source, for which we also found the same associations and lags as for total PNC. The urban source (mostly aged traffic) was associated with respiratory mortality in Zurich (lag 1; 12.5% [1.7%, 24.2%]) and London (lag 3; 2.4% [0.90%, 4.0%]) while the secondary source was associated with respiratory mortality in Zurich (lag 1: 12.0% [0.63%, 24.5%]) and Helsinki (4.7% [0.11%, 9.5%]). Reduced risk for the photonucleation source was observed for respiratory mortality in Barcelona (lag 2,-8.6% [-14.5%,-2.4%]) and for CVD mortality in Helsinki, as this source is present only in clean atmospheres (lag 1,-1.48 [-2.75,-0.21]). Conclusions: We found inconsistent results across cities, sources and lags for associations with natural, CVD, and respiratory mortality.
  • Kollanus, Virpi; Tiittanen, Pekka; Niemi, Jarkko V.; Lanki, Timo (2016)
    Introduction: Fine particulate matter (PM2.5) emissions from vegetation fires can be transported over long distances and may cause significant air pollution episodes far from the fires. However, epidemiological evidence on health effects of vegetation-fire originated air pollution is limited, particularly for mortality and cardiovascular outcomes. Objective: We examined association between short-term exposure to long-range transported PM2.5 from vegetation fires and daily mortality due to non-accidental, cardiovascular, and respiratory causes and daily hospital admissions due to cardiovascular and respiratory causes in the Helsinki metropolitan area, Finland. Methods: Days significantly affected by smoke from vegetation fires between 2001 and 2010 were identified using air quality measurements at an urban background and a regional background monitoring station, and modelled data on surface concentrations of vegetation-fire smoke. Associations between daily PM2.5 concentration and health outcomes on i) smoke-affected days and ii) all other days (i.e. non smoke days) were analysed using Poisson time series regression. All statistical models were adjusted for daily temperature and relative humidity, influenza, pollen, and public holidays. Results: On smoke-affected days, 10 mu g/m(3) increase in PM2.5 was associated with a borderline statistically significant increase in cardiovascular mortality among total population at a lag of three days (12.4%, 95% CI -0.2% to 26.5%), and among the elderly (>= 65 years) following same-day exposure (13.8%, 95% CI -0.6% to 30.4%) and at a lag of three days (11.8%, 95% CI -2.2% to 27.7%). Smoke day PM2.5 was not associated with non-accidental mortality or hospital admissions due to cardiovascular causes. However, there was an indication of a positive association with hospital admissions due to respiratory causes among the elderly, and admissions due to chronic obstructive pulmonary disease or asthma among the total population. In contrast, on non-smoke days PM2.5 was generally not associated with the health outcomes, apart from suggestive small positive effects on non-accidental mortality at a lag of one day among the elderly and hospital admissions due to all respiratory causes following same-day exposure among the total population. Conclusions: Our research provides suggestive evidence for an association of exposure to long-range transported PM2.5 from vegetation fires with increased cardiovascular mortality, and to a lesser extent with increased hospital admissions due to respiratory causes. Hence, vegetation-fire originated air pollution may have adverse effects on public health over a distance of hundreds to thousands of kilometres from the fires. (C) 2016 The Authors. Published by Elsevier Inc.
  • Zheng, Danni; Arima, Hisatomi; Sato, Shoichiro; Gasparrini, Antonio; Heeley, Emma; Delcourt, Candice; Lo, Serigne; Huang, Yining; Wang, Jiguang; Stapf, Christian; Robinson, Thompson; Lavados, Pablo; Chalmers, John; Anderson, Craig S.; INTERACT2 Investigators; Scheperjans, Filip; Kaste, Markku (2016)
    Background Rates of acute intracerebral hemorrhage (ICH) increase in winter months but the magnitude of risk is unknown. We aimed to quantify the association of ambient temperature with the risk of ICH in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2) participants on an hourly timescale. Methods INTERACT2 was an international, open, blinded endpoint, randomized controlled trial of patients with spontaneous ICH ( Results were presented as overall cumulative odds ratios (ORs) and 95% CI. Results Low ambient temperature ( Conclusions Exposure to low ambient temperature within several hours increases the risk of ICH.
  • Sallinen, Hanne; Putaala, Jukka; Strbian, Daniel (2020)
    Background: In ischemic stroke and subarachnoid hemorrhage, there are known preceding triggering events that predispose to the stroke by, for example, abruptly raising blood pressure. We explored, whether triggering events can be identified in non-traumatic intracerebral hemorrhage (ICH). Methods: We used structured questionnaires to interview consented patients with ICH treated in a tertiary teaching hospital, between 2014 and 2016. We asked of possible trigger factors, including Valsalva-inducing activity, heavy physical exertion, sexual activity, abrupt change in position, a heavy meal, a sudden change in temperature, exposure to traffic jam, and the combination of the first three (any physical trigger) during the hazard period of 0-2 h prior to ICH. The ratio of the reported trigger during the hazard period was compared to the same 2-h period the previous day (control period) to calculate the relative risks for each factor (case-crossover design). Results: Of our 216 consented ICH patients, 97 (35.0%) could be interviewed for trigger questions. Reasons for not able to provide consistent and reliable responses included lowered level of consciousness, delirium, impaired memory, and aphasia. None of the studied possible triggers alone were more frequent during the hazard period compared to the control period. However, when all physical triggers were combined, we found an association with the triggering event and onset of ICH (risk ratio 1.32, 95% confidence interval 1.01-1.73). Conclusions: Obtaining reliable information on the preceding events before ICH onset was challenging. However, we found that physical triggers as a group were associated with the onset of ICH.