108 research outputs found
The Association between Fatal Coronary Heart Disease and Ambient Particulate Air Pollution: Are Females at Greater Risk?
The purpose of this study was to assess the effect of long-term ambient particulate matter (PM) on risk of fatal coronary heart disease (CHD). A cohort of 3,239 nonsmoking, non-Hispanic white adults was followed for 22 years. Monthly concentrations of ambient air pollutants were obtained from monitoring stations [PM < 10 μm in aerodynamic diameter (PM(10)), ozone, sulfur dioxide, nitrogen dioxide] or airport visibility data [PM < 2.5 μm in aerodynamic diameter (PM(2.5))] and interpolated to ZIP code centroids of work and residence locations. All participants had completed a detailed lifestyle questionnaire at baseline (1976), and follow-up information on environmental tobacco smoke and other personal sources of air pollution were available from four subsequent questionnaires from 1977 through 2000. Persons with prevalent CHD, stroke, or diabetes at baseline (1976) were excluded, and analyses were controlled for a number of potential confounders, including lifestyle. In females, the relative risk (RR) for fatal CHD with each 10-μg/m(3) increase in PM(2.5) was 1.42 [95% confidence interval (CI), 1.06–1.90] in the single-pollutant model and 2.00 (95% CI, 1.51–2.64) in the two-pollutant model with O(3). Corresponding RRs for a 10-μg/m(3) increase in PM(10-2.5) and PM(10) were 1.62 and 1.45, respectively, in all females and 1.85 and 1.52 in postmenopausal females. No associations were found in males. A positive association with fatal CHD was found with all three PM fractions in females but not in males. The risk estimates were strengthened when adjusting for gaseous pollutants, especially O(3), and were highest for PM(2.5). These findings could have great implications for policy regulations
Case-Crossover Analysis of Air Pollution Health Effects: A Systematic Review of Methodology and Application
10 pages, 2 figures, 5 tables.-- PMID: 20356818 [PubMed].--PMCID: PMC2920078.-- Printed version published Aug 2010.BACKGROUND: Case-crossover is one of the most used designs for analyzing the health-related effects of air pollution. Nevertheless, no one has reviewed its application and methodology in this context.OBJECTIVE: We conducted a systematic review of case-crossover (CCO) designs used to study the relationship between air pollution and morbidity and mortality, from the standpoint of methodology and application.DATA SOURCES AND EXTRACTION: A search was made of the MEDLINE and EMBASE databases.Reports were classified as methodologic or applied. From the latter, the following information was extracted: author, study location, year, type of population (general or patients), dependent variable(s), independent variable(s), type of CCO design, and whether effect modification was analyzed for variables at the individual level.DATA SYNTHESIS: The review covered 105 reports that fulfilled the inclusion criteria. Of these, 24 addressed methodological aspects, and the remainder involved the design's application. In the methodological reports, the designs that yielded the best results in simulation were symmetric bidirectional CCO and time-stratified CCO. Furthermore, we observed an increase across time in the use of certain CCO designs, mainly symmetric bidirectional and time-stratified CCO. The dependent variables most frequently analyzed were those relating to hospital morbidity; the pollutants most often studied were those linked to particulate matter. Among the CCO-application reports, 13.6% studied effect modification for variables at the individual level.CONCLUSIONS: The use of CCO designs has undergone considerable growth; the most widely used designs were those that yielded better results in simulation studies: symmetric bidirectional and time-stratified CCO. However, the advantages of CCO as a method of analysis of variables at the individual level are put to little use.This study was supported by grant CIBERESP-MET-007 from the Consortium for Biomedical Research in Epidemiology and Public Health [CIBER en Epidemiología y Salud Pública (CIBERESP)], Spain. A.T. was funded by project PI080354 [Fondo de Investigaciones Sanitarias (FIS)] of the Subdirectorate-General for Research Evaluation and Development and by project 200930I008 [Consejo Superior de Investigaciones Científicas (CSIC)].This study was supported by grant CIBERESP-MET-007 from the Consortium for Biomedical Research in Epidemiology and Public Health [CIBER en Epidemiología y Salud Pública (CIBERESP)], Spain. A.T. was funded by project PI080354 [Fondo de Investigaciones Sanitarias (FIS)] of the Subdirectorate-General for Research Evaluation and Development and by project 200930I008 [Consejo Superior de Investigaciones Científicas (CSIC)].Peer reviewe
THE PRESENT STATUS OF THE GERM-CELL PROBLEM IN VERTEBRATES
(i) Morphological studies relating to the origin and differentiation of the definitive germ cells in vertebrates have, as indicated, resulted in conflicting views. In many instances two or more competent investigators who have studied the same form have reached different conclusions. (2) Some contend that the germ cells are set aside from the soma during the early stages of embryonic development, and that these alone serve as the progenitors of the functional sex cells. (3) Others recognize an early differentiation of sex cells but hold that these are supplemented by others produced from the somatic epithelium of the gonad in late embryonic or post-embryonic stages. (4) Another group recognizes the early differentiated cells as germ cells but contend that these all degenerate and that the definitive ones are formed from the germinal epithelium. These degenerating germ cells are believed by certain authors to be a phylogenetic recapitulation of the condition in lower forms. (5) Finally, yet another group contends that the so-called primordial germ cells are not germ cells at all but are enlarged cells in some stage of mitosis or in some specific metabolic phase. This group believes that all germ cells are derived from the somatic cells of the germinal epithelium. (6) Experimental work supports the view that the primordial germ cells, which are recognized early, are the progenitors of the definitive sex cells. When these primordial germ cells are prevented from reaching the site of the developing gonad the individual fails to develop sex cells, although a sterile gonad and its associated structures may develop. (7) I suggest that the observed proliferation of germ cells from the germinal epithelium, reported by numerous investigators, can be interpreted in another way by a thorough study of the enlarged germ cells in relation to the epithelium. It seems probable that the cells of the epithelium, which form functional sex elements, are not and never were a part of the mesothelial covering, but are cells which were segregated early, and are merely stored in the epithelium.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74677/1/j.1469-185X.1945.tb00313.x.pd
Internações e óbitos e sua relação com a poluição atmosférica em São Paulo, 1993 a 1997
OBJETIVO: Investigar efeitos de curto prazo da poluição atmosférica na morbidade respiratória de menores de 15 anos e na mortalidade de idosos. MÉTODOS: O estudo foi realizado na cidade de São Paulo, Brasil. Foram analisadas as contagens diárias de admissões hospitalares, de menores de 15 anos e de mortes de idosos (>64 anos) no período de 1993 a 1997, em relação às variações diárias de poluentes atmosféricos (PM10, CO, O3). Foi utilizada para análise a regressão de Poisson em modelos aditivos generalizados. Os modelos foram ajustados para efeitos da tendência temporal, sazonalidade, dias da semana, fatores meteorológicos e autocorrelação. RESULTADOS: Variações do 10° ao 90° percentil dos poluentes foi significativamente associada com o aumento de admissões por doenças respiratórias em menores de 15 anos para PM10 (%RR=10,0), CO (%RR=6,1) e O3 (%RR=2,5). Associação similar foi encontrada para mortalidade em idosos e PM10 (%RR=8,1) e CO (%RR=7,9). CONCLUSÕES: Os resultados encontrados são coerentes com os estudos que apontam associação entre variações de curto prazo dos poluentes atmosféricos e incremento na morbidade e mortalidade nos grandes centros urbanos
Physicians and the Danger of Nuclear War
International Physicians for the Prevention of Nuclear War (IPPNW), the 1985 Nobel Peace Prize winners, are active in some sixty different countries. Their action is based on the outlook that any nuclear war would cause not only millions of deaths, but also millions of severely injured or burnt victims for whom the medical profession, decimated as well, would be most helpless. They strive to obtain that governments, in agreement with treaties that almost all countries have signed, ascertain that nuclear weapons, which are internationally illegal, be globally abolished. The impact on political authorities would undoubtedly be reinforced if the number of physicians supporting the action of IPPNW was increased
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