Exposure to ambient air pollutants and the onset of dementia in Québec, Canada.

BACKGROUND: Effects of air pollutants are related to oxidative stress which is also linked to the pathogenesis of dementia including Alzheimer's and related diseases. OBJECTIVE: We assessed associations between exposure to air pollutants and the onset of dementia; the association with the distance between residence and major roads was also assessed for the island of Montreal. METHODS: We created an open cohort of adults aged 65 years and older starting in 2000 and ending in 2012 in the province of Québec, Canada using linked medico-administrative databases. New cases of dementia were defined based on a validated algorithm. Annual residential levels of nitrogen dioxide (NO2) and fine particles (PM2.5) at residential levels were estimated for each year of follow up using estimates based on satellite images and ground air monitoring data. Hazard ratios (HRs) were assessed with Extended (time dependent exposure) Cox models with age as the time axis and stratified for sex, for the annual exposure level at each residential address. Models were adjusted for the calendar year, area-wide social and material deprivation indexes and for NO2 or PM2.5; they were also indirectly adjusted for smoking. RESULTS: 1,807,133 persons (13,242,270 person-years) were followed and 199,826 developed dementia. From models (adjusted for calendar year, social and material deprivation indexes), HRs for an interquartile range (IQR) increase in time-varying exposure to NO2 (IQR 13.26 ppb), PM2.5 (IQR 3.90 µg/m³), and distance to major roads (IQR 150 m, in Montreal only), were 1.005 (CI 95% 0.994-1.017), 1.016 (CI 95% 1.003-1.028) and 0.969 (CI 95% 0.958-0.980), respectively. CONCLUSIONS: Results suggest that the onset of dementia may be related to residential exposure to PM2.5, NO2, and distance to major roads.

Influenza A (H1N1) 2009 pandemia. The experience of a tertiary care center in Beirut.

INTRODUCTION: In March 2009, a new influenza virus strain emerged, currently known as the 2009 pandemic H1N1 virus. The virus first appeared in Mexico and rapidly spread globally to reach a pandemic level in June of the same year. We describe here the experience of one major referral center in Beirut, Lebanon. MATERIALS AND METHODS: The laboratory department at St. George Hospital University Medical Center received respiratory specimens from hospital wards, the emergency department, in addition to a considerable proportion collected directly from "outpatients" in the lab. We used the real time RT-PCR as our main diagnostic test. We collected data about the patients from the laboratory information system and from the hospital medical records department. RESULTS: From mid-August 2009 till the end of January 2010, a total of 1771 specimens were analyzed, with 948 (53.5%) returning positive for influenza A (H1N1) by RT-PCR. Only 79 patients with H1N1 infection required hospitalization. Most of H1N1 confirmed patients were children and adolescents aged 5 to 17 years and young adults between 25 and 44 years. The most common symptoms at presentation were: fever, cough, shortness of breath, chills, rhinorrhea or nasal congestion, as well as gastrointestinal symptoms. Twenty-three patients required ICU care and eight patients died. The vast majority had an uncomplicated course of illness and was managed in an outpatient setting. CONCLUSION: The percentage of positive tests during the pandemia was significantly elevated, although few patients experienced drastic clinical outcomes.

Outbreak of Burkholderia cepacia bacteremia traced to contaminated hospital water used for dilution of an alcohol skin antiseptic.

OBJECTIVE: To identify the source of an epidemic of Burkholderia cepacia bloodstream infections during 7 years (411 episodes in 361 patients). DESIGN: Outbreak investigation. SETTING: A 250-bed university hospital in Beirut, Lebanon. METHODS: Matched case-control and retrospective cohort studies, and microbiological surveillance and polymerase chain reaction-restriction fragment length ascertainment were employed. Special media and filtration techniques were used to isolate organisms from water and diluted alcohol solutions. RESULTS: In a group of 50 randomly selected case-matched patients from 1999, the positive blood cultures were concomitant with fever in 98%, intravenous phlebitis in 44%, and recurrent bacteremia in 20%. Fever disappeared approximately 6 hours after intravenous catheter removal. Polymerase chain reaction-restriction fragment length polymorphism revealed strain homogeneity in patient, water, and alcohol isolates. Contaminated tap water had been used to dilute alcohol for skin antisepsis and for decontamination of the caps of heparin vials. Only sporadic cases directly attributable to breach of protocol were reported after single-use alcohol swabs were substituted. CONCLUSION: This is potentially the largest single-source nosocomial bloodstream infection outbreak ever reported, and the first report of an alcohol skin antiseptic contaminated by tap water as a source for nosocomial bacteremia.