Saturday, August 19, 2006
Published: Thursday, 17-Aug-2006
All forms of tobacco exposure - smoking, chewing or inhaling second hand smoke - increase the risk of heart attack up to three times, according to an Article in this week's issue of The Lancet.
Previous studies have shown that tobacco smoking increases the risk of heart disease. However, to date most of these studies have been in developed countries and few large studies have been done to examine the effects of tobacco in other geographical regions.
In the INTERHEART study, Salim Yusuf and Koon Teo (McMaster University, Ontario, Canada) and colleagues calculated the risk of heart attack for various forms of active tobacco use (both smoking and non-smoking) and second hand smoking (SHS) in all areas of the world. The study included data from over 27 000 people in 52 countries. The investigators adjusted their calculations to exclude the effect of other lifestyle factors that could affect heart attack risk, such as diet and age.
They found that tobacco use in any form, including sheesha smoking popular in the Middle East and beedie smoking common in South Asia, was harmful. Compared to people who had never smoked, smokers had a three-fold increased risk of a heart attack. Even those with relatively low levels of exposure (8-10 cigarettes a day) doubled their risk of heart attack. However, the researchers did find that the risk of heart attack decreased with time after stopping smoking; among light smokers (<10 cigarettes a day) there was no excess risk 3-5 years after quitting. By contrast, moderate and heavy (20> cigarettes a day) smokers still had an excess risk of around 22%, 20 years after quitting. The team also found that exposure to second hand smoke increased the risk of heart attack in both former and non-smokers. The findings suggest that individuals with the highest levels of exposure to SHS (22 hours or more per week) may increase their risk of heart attack by around 45%.
"Chewing tobacco also increased the risk of a heart attack two fold, indicating that all forms of tobacco use or exposure are harmful," added Dr Koon Teo.
Professor Yusuf concludes: "Since the risks of heart attack associated with smoking dissipate substantially after smoking cessation, public-health efforts to prevent people from starting the habit, and promote quitting in current smokers, will have a large impact in prevention of heart attack worldwide."
Wednesday, August 02, 2006
By Karen Schrock, Scientific American
People who have been exposed to pesticides are 70 percent more likely to develop Parkinson's disease than those who haven't, according to a new study. The results suggest that any pesticide exposure, whether occupationally related or not, will increase a person's risk of the disease. This means that using pesticides in the home or garden may have similarly harmful effects as working with the chemicals on a farm or as a pest controller.
The research, published in the July issue of Annals of Neurology, provides the strongest evidence to date of the link between pesticide exposure and Parkinson's. The study included over 143,000 men and women who completed extensive lifestyle questionnaires beginning in 1982, and follow-up surveys through 2001. All subjects were symptom-free at the beginning of the project, when they were asked about their occupation and exposure to potentially hazardous materials. Since then, 413 of them have developed confirmed cases of Parkinson's, with a greater incidence of the disease in those who spent time around pesticides. "Low- dose pesticide exposure was associated with a significant increase in risk for Parkinson's disease," says lead author Alberto Ascherio of the Harvard School for Public Health. "I think this is one reason to be careful about using pesticides in general."
Although the causes of Parkinson's are not well understood, it has long been suspected that environmental factors play a large role. Animal studies have shown that chemical compounds commonly used as pesticides can cause a degeneration of dopamine-producing neurons. In Parkinson's, a shortage of dopamine causes the disease's characteristic motor abnormalities, including muscle tremors and muscle rigidity. Previous small-scale human studies had suggested a link between pesticides and Parkinson's, but this new study is the first to establish a clear correlation in a large patient population.
The researchers also looked for links between Parkinson's and other environmental contaminants, including asbestos, coal dust, exhaust, formaldehyde and radioactive material. They found no correlation between the disease and any of the materials besides pesticides, however. Because of the design of the questionnaires, the study was not able to determine how the frequency, duration, or intensity of pesticide exposure affected the incidence of Parkinson's. The next step, according to Ascherio, is to figure out which class of chemicals is actually causing the disease, so that people can reduce their exposure.
It is well known within the air purification industry that purification devices that produce ozone are actually harmful, not helpful. Though it is well known that ozone itself carries negative health effects, a recent study also points to other dangers of ozone. Ozone (O3) "neutralizes" chemicals in the air by attaching a oxygen atom to the chemical. However, this new chemical that is produced may carry its own dangers.
United Press International
BERKELEY, Calif., July 17 (UPI) -- Ground-level ozone pollution, aproblem in summer in many U.S. cities, may contribute to a previously unrecognized form of indoor air pollution.
Ozone seeps indoors from outdoor air and it also forms indoors from operation of certain increasingly popular electronic "air purifiers," as well as printers, faxes and other office equipment, according to William Nazaroff.
Nazaroff, Hugo Destaillats and colleagues at the Lawrence Berkeley National Laboratory report that ozone can interact with ingredients in household cleaning products and air fresheners to produce a group of secondary air pollutants. The researchers' tests included a pine-oil cleaner, an orange-based household cleaner and a plug-in air freshener.
Ozone interacted with the products to form secondary air pollutants that included formaldehyde, a known human carcinogen and mucus membrane irritant, according to the study published in the journal Environmental Science & Technology.
The full study can be found here (pdf) - http://pubs.acs.org/cgi-bin/sample.cgi/esthag/2006/40/i14/pdf/es052198z